Very good video. This is a quantum difference. You did an excellent job of defining the reason and results of the busbar system vs daisy chain. This is foundational battery info. Thanks David.
@11:00 - If more parents would get their kids involved with their own projects/work we'd have a much better society to live in. Great job! I remember working with my Dad in his shop as a 5 y/o. Those are the years when you instill in your kid the work ethics they will need for the rest of their lives. Thumbs up sir!
Hi David, thanks for making this video. Daisy chaining is one of the reasons I dislike server rack batteries. Thanks for showing people why this is a poor practice. Of course the other reason is that the batteries get used asymmetrically when there is greater resistance in the circuit from one battery to the other. That means that your C. rate will be higher than it needs to be on one or two of the batteries early on and it will shift to the others later in the discharge. Thanks again sir. I have learned a lot from your channel when I was getting started in this DIY journey. I like your style as well.
It’s great seeing you teach her mechanical and other skills. The irrational fear many have of electricity creates opportunities for me as electrician but ignorance is not an asset for anyone.
Thanks for the video David. Great presentation and explanation of the benefits of busbar configured battery storage. I realize most will know the tidbit of heat adds resistance, which creates more heat (nice to see the lower temps here). Also great to see the kids involved as well!! Keep up the great work ☺️👍!
You are definitely an engineer (and not merely a DIYer). I am overwhelmed just looking at your configuration, and intimidated at the prospect of trying to build a system (that hopefully won't be as complex, but also will be therefore less functional/ efficient).
Perfect workflow and presentation. The apprentices are learning quickly! It shows clearly they have a wise and patient instructor :-) Another way to quantify efficiency gains is to measure the change in voltage drop across the load-carrying conductors as they heat up, though how you've done it with a temperature reading does quickly get the point across in the video. Thanks (as always) for sharing with us all.
Excellent presentation highlighting the benefits of using bus bars instead of daisy chaining. This is why I think Signature Solar's rack mount enclosure with the bus bars is superior to the other rack mount options that I've seen on the market.
David, you were the very first YT person I followed for batteries and solar. I love how thoroughly you go through everything and I always learn from your content. I will be building out my system next spring using 6 of the EG4-LL batteries and the Sol-Ark 15k. Yes, I know your thoughts on the Sol-Ark but I need something fully UL certified for codes and will be using it for a whole home backup and to save on time of use charges until I get my solar arrays in place. I have also spent the last year analyzing my loads using the Emporia Smart Home Monitoring solution so I hope to avoid the unbalanced load issues you were seeing. Waiting on Solar until I can win the HOA battle, Oklahoma doesn’t have a law luke CAN and other states do that prevents HOAs from banning Solar. Keep up the great work and thank you for inspiring me!!
Hi EB, thanks for the comment. I wish you luck against the HOA. I wish HOA's were more willing to accept solar. When you choose to buy some EG4's, please use my affiliate link as it makes a huge difference for me. These videos take an enormous amount of time.
@@DavidPozEnergy You can count on me using your affiliate link. I plan on going down to visit Signature Solar on 9/9 & 9/10 and will make sure to share your impact on the community while I am there. Not going to buy yet, just visiting while I am “in the neighborhood”. Send me a DM if there is anything I can get for you while I am there. I cover shipping up to $300 for you. I’ll also you your link for Sol-Ark and panels so I’ll reach out in March when I will be ready to buy.
I just bought two of these batteries and will be getting two more in a few months. I will make my own cables or of oversized welding cable. Possibly 25-35mm2. I'll also make my own bus bars out of thick copper flat bar with stand offs or the plastic sheet stock. Lots of options. I think diy is better, more flexible and more cost effective than pre made commercial product. Never skimp on good fuses either
Busbars are the way to go for sure. I have the EG4-LL batteries and the 6 battery enclosed cabinet with built in busbars. Those are most similar to your setup here because each battery has a jumper to the busbar so nothing in front of the battery is blocked or putting stress on the terminals. Cheers
This may have already been said, but during this entire video I was thinking, "why not run a solid copper buss bar from the inner posts"?!?! But after watching 22:53 in to the video, I found that you covered that! Good job! Thank you, and great video!
Our old standard for copper buss was 1 sq in per thousand amps - 6" x 1/4" gave us 1600 amp buss. But then we were running continuous heavy loads in hot environments. Also guard those fuses against becoming shrapnel. Heaviest I ran was an 8 stack of 1x8" for salt tanks.
@@DavidPozEnergy I think what Bill Burton is trying to say is that your bent bar, based on his rule of thumb, being 1/8" x 1" or .125in square is capable of 125A. I didn't know that rule of thumb so I just look it up in tables, and I've found that a 1/8" x 1" bar can handle 270A with a 30 degree C temp rise. It won't ever get that hot because the fuse block and junction block will act as heat sinks. For comparison your bar is 0.125 , 2/O cable is 0.1045 and 3/O is 0.1318 square inches cross sectional area. What you have is fine, but if you had to make it again I'd use a thicker or wider copper bar.
Great job on demonstrating a DIY the right way. I'm not crazy about the plastic the bus bar is mounted to, I would prefer something like fiberglass, but if used within its rating, it's fine.
Using ohm's law the power loss on each cable, link between the terminals on a battery pack, etc, in the daisy chain can be calculated. V x I. Amps is what the clamp meter reads, V is the voltage drop across the thing being observed, ie a cable, a link, etc. At full tilt, 400A, through the top cable 30mV of drop would equate to 12 watts. That's more than enough to heat up the cable, but in the overall picture considering the load (400A!) that's not a lot of power. I'm guessing at full tilt daisy chain loss would total maybe 100 watts. Sure it's more than nothing, but again considering the power draw to get there, 20kW, it really is nothing to worry about so long as the temperature rise stays within the rating of the insulation in its installation environment. That said, there's nothing wrong with a cool running system and it would be 100 watts less to remove from the room the equipment is in. 30mV drop was fictive, actual drop may be higher so measurements would obviously need to be done.
I run a combination of daisy chained with a 1000A buss bar. The reasoning for this is that I have 20 batteries, so both daisy chaining and buss bars alone would not be appropriate. I have 4 banks of 5 batteries. Each bank is daisy chained, then combined on a 1000A blue sea systems buss bar, where the inverters also can be tied in. With the size of the battery pack, even at full output with 3 inverters I’ll never pull more than 30% of the max battery output anyways, so the daisy chaining isn’t a big deal as far as balancing the load in each battery goes.
Great demonstration of the effects of cable resistance. You are effectively reducing the current through the cables by a factor of 4, thus greatly reducing the effects of cable resistance. Since you have two terminals on each battery module, you could double up the cable connections to the bus bar to decrease the resistance by an additional factor of 2. I don't know if this is cost effective, or the gains would be worth it, but you could probably reduce cable temperature rise to single digits. Probably approaching the point of diminishing returns...
I usually fuse the negative side and use switches or breakers for the positive side. Blue Sea Systems make a great 1000amp busbar, and great class-T fuse holders.
For overkill I suppose you could use the second terminal to provide an alternative route for battery to battery balancing current and just use the side buss bar for input and output. Unreasonable overkill but could be fun.
Definitely makes sense. Instead of the load passing via basically a 4 gauge cable with each battery adding more load to it at each daisy chain point, you now have each battery using it's on dedicated 4 gauge cable to the busbars with the busbar passing the load to the heavy cables tied to your inverters. Not that it should make much of a difference with the short jumpers you have but ideally the cables to the busbars should all be the same length as well, this minimizes the voltage difference and will spread the load as evenly as possible.
You could improve efficiency by making all your wires the same distance from the bus bar. Also 4 gauge wire will heat up if you draw large amps out of each battery. 00, 000, or 0000 would give you more max output from each battery. But keeping the wire distance the same from the bus bar to the battery terminals will give less resistance and less overall energy loss.
The max output for each battery is 100amps and 4 gauge welding wire will handle that easily, though during his load test at 95% he didn't go much above 55 amps on any of those batteries. So he's still got a lot of headroom left, plus his fuse will limit it to 75 amps per battery since it'll blow at 300 amps which would be almost 17 kilowatts of draw. If he had fewer batteries then it might make more sense to upgrade to heavier cables.
Great work David. Cute helper too. My she has grown so fast. Thanks for posting this test, as I am about to connect 7 batteries together. I will try my best to use same wire length. I dont have a server rack like you, but bought a home depot husky rack to hold the batteries. Its rated at 5000lbs. (We will see).
If you increase the wire gauge a few gauges (which is always a good idea anyway) you don't have to be so concerned about making sure the lengths are the same. They just need to be close but the larger the gauge, the less voltage drop, since internal resistance is lower so it will make less of a difference under heavy load with larger wires. Your crimps and connections will be more important than a small variation in wire length if you use a larger gauge.
You could also secure 3ft bus bars to the rack with stand-offs and run cables from the batteries. That'd let you use shorter cables and keep them out of the way.
BUILD A RAKE SHAPED COPPER BUS BAR for the right terminal to * not cover or hide anything * solve the tension issue You take a long copper bus bar, drill 4 holes in it with the distance of the terminals and then cut 4 short copper busbars of 10 cm as connectors from the terminal to the vertical bus bar on the left connected with screws and nuts. This way the tensions from low 20°C to maybe 30°C will be divided onto the 4 terminal screws and the 4 bus bar connection screws you then will have to check from time to time which you will also feel quite easily if you do check the displays. That right main busbar might also be rerouted on the right once you have removed the handles there. At the end always a compromise one way or the other, but a least possible and quite usefull I guess in the case you have a close rack behind glas or acryl without having such bus bar outside of the rack. Adds a bit of safety for all.
Both issues can be solved by bending the bar into M shape as it rise from the terminals. So it’s bending at thinest part. Do not use oval or slot hole. It doesn’t really allowed to slide because you have to torque it down. At the same time, you lose contact surface area. May I also suggest using some bulb grease at the contacts and plasti-dip the rest.
First, I think the long hair and beard on you looks terrific! Once I got over the shock and realized that it was really you. Great job and video series, David. I'm curious about how you incorporated your entire wiring system in your home to the breaker panel in your garage that your solar system's AC power from your inverters is connected to. Additionally, how much voltage and amperage is the breaker switch between the inverters and AC panel rated for? Lastly, do you know any way a poor old man can get a rack and 4 48V server rack batteries given to him without making hundreds of UA-cam videos? Great job, as always, my man!
If you arc the bus bars between the batteries you gain the flexibility so you can tighten the nuts without having to slot the holes, and you won't block the screens or ports. You would use more heatshrink.
@@DavidPozEnergy I've seen arcs used in other fields to allow a controlled flex between 2 ridged points. I've seen it done in plumbing when there are wide temperature swings in the fluid or gas. As you can imagine metal pipes also change length with temperature. There are charts and formulas that will tell you how much copper bars will change length for a given temperature change. If you make a curve in the bar it will curve more when it gets hot and straighten out when it cools down.
Nice work on the busbars. One thing I don’t understand is why the fuse is rated at 300a when the max your inverters can draw is 200a DC. I’d down the size of the fuse to protet the inverters from a potential surge.
Another point about busbars that directly connect all the batteries together. With busbars you can't easily or very safely disconnect a single battery if you need to. It can also be more difficult to insulate the busbar between terminals though it can be done with judicious shrink tube efforts however the little plastic cable caps don't work then for the terminals.
You can only daisy chain 2 batteries without unbalancing the loads on the batteries too. Main pos and main neg to different batteries. But no matter how you set up your daisy chain with more than 2 batteries the ones with the mains will see more amps pass through and fewer amps as you move away I work on RVs. And see lots of what are basically small house inverter systems. A lot of the newer ones have lithium ion batteries similar to what you have. And they have charge controllers to balance voltage. They use an extra wire to the negative to vary the ground side potential I believe. But the older big class A’s with big inverter’s with lots of flooded batteries always had better performance from 6 volt batteries for same watt hours of batteries vs 12 volt partially because now I can run 4 batteries from 1 main neg and pos with a balanced load since will be wired as a pair in series and parallel but making 2 12 volt batteries instead of 4 in the same space. Putting more than 2 battery packs in a daisy chain will always make an unbalanced load and more stress on your end batteries. The charge controller can balance batteries on the charge cycle but not the discharge cycle. If you need more then 2 batteries you should not daisy chain or use appropriate voltage in series to make a 2 battery pack system. So off the shelf batteries much more practical to have your bus bars and only daisy chain 2 battery systems of relatively equal potential
Btw, the US really needs to start using NH fuses, they are so cheap here in germany, a 300A NH2 fuse (rated up to 440Vdc, smaller fuses are rated for 250Vdc) with 25kA DC interrupting capacity, with base will cost me roughle 15€ used or 35€ new.
You could put a longer bolt and put 2 lugs on the first battery(in and to 2nd battery) with a 1/0 wire, then next battery with a 1 awg wire, and last with 4awg wire. Could also use a double wire lug. But the advantage of having a central buss bar the way you did is that you can remove a battery from service without effecting the others.
I'm not sure if anyone has commented but u have a thick 400AMP busbar connected to the fuse with 3MM copper plate on a rough observation it is about 20 x 3 MM which calculates to 84AMP rating
Good job. That looks soo much better!! Though you did forget to stagger the main positive and negative. You have the main positive and main negative on the tops of both bussbars. Sure it shouldnt make much difference since the bussbar has a nice low resistance, but it still has resistance. So just move the main negative cable to the bottom and shift the cables up one. Though as long as it doesnt trigger your OCD I dont mind either 😉 Cheers keep up the awesome battery/inverter creations!
I appreciate the time you took to write a comment. I disagree with you about the need to stagger the +/-. I actually address this exact question, and then demonstrate it in the video.
@@DavidPozEnergy yea, I saw, The bussbar has such low resistance it doesnt make a noticeable difference. Though I think the main imbalance is from doubling up on the studs, then the ESR of the packs.
Dave If you ever need more 48v 100a server batteries. I buy a lot of Jakiper for over sea in Ukraine.I can sell you customs server rack or wall mounts for $1,400 each or $1,350 for 5 with free server rack. plus shipping straight from wear house. Love your UA-cam channel.
Another alternative test that would be very interesting. Using fully charged batteries show the difference in time with a specific load(1000watts). Run both ways to reach 50% point. So I would see how much difference exactly this improvement makes.
It would be nice to see the wiring diagram, just to make sure I am understanding the way you use the bus bar. But basically, three batteries to the bus bar, and the 12v bus bar connection for the fourth "pin" ? Been googling how to wire batteries together (in parallel). The manufacturer of my canper has wired it daisy chain. Now I rarely use more than 50A, so maybe it does not matter as much..?
You can buy bus bars with 4, 6, 8, or more studs for your situation. If you have 3x 12V batteries wired in parallel, and you buy a bus bar with 4 studs, then yes. The 4th stud can be for your inverter out.
I think anyway the connection order on both busbars has a matter, that's maybe why you did have a small unbalance in those batteries. Did you try to connect shunt and fuse at the opposite sides of the busbars? Thanks for the video!
you started talking about 20 ft lb didn't think about getting a 6 year old girl to do it lol that can be useful knowledge I don't have a torque wrench lol 👍
Thank you so much. I did the exact same setup after watching your video. I have same 2 x batteries and 1 x same inverter with the busbar. I am using 2AWG 35mm cables with 250A Class T Fuse. Should I have bigger cable between Busbar to Fuse and to inverter due to total potential being 200A?
A larger wire will have many benefits. Less Voltage drop, not get as hot, help the inverter not trip under hard situations. I would prefer using a thicker wire with a 200A fuse than 2AWG. I tend to use thicker wire whenever I have a choice.
Could u just replace the 4 awg cables with 00 cable or something bigger than 4 awg thus reducing heat as well yet also enabling the display to be seen? Great intel!
That would certainly help, but not alleviate all the concern. The power would still flow through the small brass jumpers inside each battery box. (it sits just behind the terminals).
@@DavidPozEnergy thanks for the reply I wonder why they are making these terminals small like this when they are selling these into rack systems and marketing them to be used with six or even more units together which would be 600 A? I guess I feel kind of fortunate I haven’t pulled the trigger yet still saving up maybe by the time I get started buying my system in the fall things will be improved
I thought busbars are those bars you hold onto when entering or exiting a bus (public transportation), in case you trip going up or down the steps. But seriously, maybe manufacturers don't use busbars cuz they are concerned about safety. Thick insulated wires seem to be fairly safe.
Great video, David. Good explanation of the neat/energy loss and the need to compensate with the A/C which loses even more energy. In your explanation about the solid busbar - I agree it would cover things best left exposed. However, what about running a solid copper busbar up both sides where you put your small busbars then using solid copper bars to run horizontally from the battery terminals to the vertical busbar. That way the copper jumpers could be connected to both terminals on each pole of each battery instead of only one terminal and without covering anything. BWT - I have four daughters. I included them like you do with your kids. As a result, they are not afraid to "get their hands dirty" doing things. They also know how to do a variety of maintenance tasks. Oh ... I liked you better clean shaven.
Your plan with long busbars would work too. If it were me, I'd still use a flexible jumper wire to the battery terminal. Glad to know your kids are not afraid to get their hands dirty.
HOWdy D-P, Thanks I wish that the SOLAR Industry would STANDARDIZE on one single LUG / BOLT Size I noticed that BLUE-Sea "T"-Class FUSE-HOLDERS utilize 3/8" Studs While PIKE BUS-BARS utilize 5/16" Studs While EG4-LL Batteries utilize 1/4" Bolts Even if they ALL decided on an OVERLY Large STUD / BOLT ( ie: 3/8" ) it would simplify installation tremendously COOP
Hi! Good job David, and firstly i have to say; this beard fit you very nice! 🧔 But why don`t you use a thicker cables between those batteries? They`ll probably not cost too much.. 🤔👍
Ok, I'll bet your wife is rolling her eyes at a few of your (expensive) projects, but your kids adore you! That's your #1 job as dad, well done Dave!
I am a long time subscriber. Love seeing your friends and family members participate in your project throughout the years.
Thanks. My kids love helping me.
@@DavidPozEnergy I can’t believe how big your kids are getting. Enjoy them while you have them at home. Time flies.
Very good video. This is a quantum difference. You did an excellent job of defining the reason and results of the busbar system vs daisy chain.
This is foundational battery info.
Thanks David.
Thanks for your comment. I hope the information helps the DIY community.
@11:00 - If more parents would get their kids involved with their own projects/work we'd have a much better society to live in. Great job! I remember working with my Dad in his shop as a 5 y/o. Those are the years when you instill in your kid the work ethics they will need for the rest of their lives. Thumbs up sir!
Hi David, thanks for making this video. Daisy chaining is one of the reasons I dislike server rack batteries. Thanks for showing people why this is a poor practice. Of course the other reason is that the batteries get used asymmetrically when there is greater resistance in the circuit from one battery to the other. That means that your C. rate will be higher than it needs to be on one or two of the batteries early on and it will shift to the others later in the discharge. Thanks again sir. I have learned a lot from your channel when I was getting started in this DIY journey. I like your style as well.
It’s great seeing you teach her mechanical and other skills. The irrational fear many have of electricity creates opportunities for me as electrician but ignorance is not an asset for anyone.
Except for the one sitting in the oval office... ignorance is his bread and butter. 🤣
So I guessed right using a busbar arrangement. Your work is quite valuable to us DIYers. (I now have one of those big ass fuses.)
Thanks for the video David. Great presentation and explanation of the benefits of busbar configured battery storage. I realize most will know the tidbit of heat adds resistance, which creates more heat (nice to see the lower temps here). Also great to see the kids involved as well!! Keep up the great work ☺️👍!
Thank you for your nice comment.
Heat is the result of resistance.
@@DavidPozEnergy In your code book there should be a generic torque table for different stud sizes types, If any part may lack that info
As always brother, you are fantastic. Great dad too!
Nice to see Elenor as she grows. 🙂 I agree with the busbar approach.
You are definitely an engineer (and not merely a DIYer). I am overwhelmed just looking at your configuration, and intimidated at the prospect of trying to build a system (that hopefully won't be as complex, but also will be therefore less functional/ efficient).
nice, also great points about the solid bus bar and expansion issues..
Thank you.
I was surprised by the difference. Thanks!
Hopefully surprised in a good way?
Perfect workflow and presentation. The apprentices are learning quickly! It shows clearly they have a wise and patient instructor :-) Another way to quantify efficiency gains is to measure the change in voltage drop across the load-carrying conductors as they heat up, though how you've done it with a temperature reading does quickly get the point across in the video. Thanks (as always) for sharing with us all.
So cool that you get your kids involved in your projects.
Excellent presentation highlighting the benefits of using bus bars instead of daisy chaining. This is why I think Signature Solar's rack mount enclosure with the bus bars is superior to the other rack mount options that I've seen on the market.
Thanks for the video David. Great presentation
David, you were the very first YT person I followed for batteries and solar. I love how thoroughly you go through everything and I always learn from your content. I will be building out my system next spring using 6 of the EG4-LL batteries and the Sol-Ark 15k. Yes, I know your thoughts on the Sol-Ark but I need something fully UL certified for codes and will be using it for a whole home backup and to save on time of use charges until I get my solar arrays in place. I have also spent the last year analyzing my loads using the Emporia Smart Home Monitoring solution so I hope to avoid the unbalanced load issues you were seeing. Waiting on Solar until I can win the HOA battle, Oklahoma doesn’t have a law luke CAN and other states do that prevents HOAs from banning Solar. Keep up the great work and thank you for inspiring me!!
Hi EB, thanks for the comment. I wish you luck against the HOA. I wish HOA's were more willing to accept solar. When you choose to buy some EG4's, please use my affiliate link as it makes a huge difference for me. These videos take an enormous amount of time.
@@DavidPozEnergy You can count on me using your affiliate link. I plan on going down to visit Signature Solar on 9/9 & 9/10 and will make sure to share your impact on the community while I am there. Not going to buy yet, just visiting while I am “in the neighborhood”. Send me a DM if there is anything I can get for you while I am there. I cover shipping up to $300 for you. I’ll also you your link for Sol-Ark and panels so I’ll reach out in March when I will be ready to buy.
That's generous of you, thanks.
I just bought two of these batteries and will be getting two more in a few months. I will make my own cables or of oversized welding cable. Possibly 25-35mm2.
I'll also make my own bus bars out of thick copper flat bar with stand offs or the plastic sheet stock. Lots of options. I think diy is better, more flexible and more cost effective than pre made commercial product.
Never skimp on good fuses either
Always good info. Thank you. Kids are a joy. God bless you. Thanks for sharing
Great video David -- Was hilarious seeing your kids running around with the terminal caps on their fingers!
Good to see you training up the next generation of engineers 👍
very helpful
Great video Dave. Perhaps up sizing the conductors to the next size would also reduce power losses to heat.
Busbars are the way to go for sure. I have the EG4-LL batteries and the 6 battery enclosed cabinet with built in busbars. Those are most similar to your setup here because each battery has a jumper to the busbar so nothing in front of the battery is blocked or putting stress on the terminals. Cheers
This may have already been said, but during this entire video I was thinking, "why not run a solid copper buss bar from the inner posts"?!?! But after watching 22:53 in to the video, I found that you covered that! Good job! Thank you, and great video!
Thanks for watching to the end.
One of your best videos to date. thanks
Great to hear, thank you.
Our old standard for copper buss was 1 sq in per thousand amps - 6" x 1/4" gave us 1600 amp buss. But then we were running continuous heavy loads in hot environments. Also guard those fuses against becoming shrapnel. Heaviest I ran was an 8 stack of 1x8" for salt tanks.
Thank you, that rule of thumb is very helpful.
@@DavidPozEnergy I think what Bill Burton is trying to say is that your bent bar, based on his rule of thumb, being 1/8" x 1" or .125in square is capable of 125A. I didn't know that rule of thumb so I just look it up in tables, and I've found that a 1/8" x 1" bar can handle 270A with a 30 degree C temp rise. It won't ever get that hot because the fuse block and junction block will act as heat sinks. For comparison your bar is 0.125 , 2/O cable is 0.1045 and 3/O is 0.1318 square inches cross sectional area. What you have is fine, but if you had to make it again I'd use a thicker or wider copper bar.
I would recommend a thermal imager for looking at the temperatures of various components and wiring. The FLIR One connects to most smartphones.
EG4 are set up like that on their racks. My system runs cool to the tough all the time. Excellent video!
Great job ... awesome video. The difference is amazing.
Great Job David...the system is much better now!!
Regards..
Dude that beard.. I can’t get used to it
LOL. It's fun.
Hadn't seen a video in a while and oh yeah it's a shocking change lol.
Teenwolf!
Same here!!
I was wondering if your wife traded you in or something 😂
Thanks David and helpers 😀
Very nice video David.that way we can balance discharge and charge currently of battery pack.
Great video David!!!
Good to know, thanks very much for sharing.
Priceless information. Thanks for sharing.
Awesome video, very very useful test !! Thanks for sharing !!
Your welcome, and thank you for watching.
Great job on demonstrating a DIY the right way. I'm not crazy about the plastic the bus bar is mounted to, I would prefer something like fiberglass, but if used within its rating, it's fine.
Using ohm's law the power loss on each cable, link between the terminals on a battery pack, etc, in the daisy chain can be calculated. V x I. Amps is what the clamp meter reads, V is the voltage drop across the thing being observed, ie a cable, a link, etc. At full tilt, 400A, through the top cable 30mV of drop would equate to 12 watts. That's more than enough to heat up the cable, but in the overall picture considering the load (400A!) that's not a lot of power. I'm guessing at full tilt daisy chain loss would total maybe 100 watts. Sure it's more than nothing, but again considering the power draw to get there, 20kW, it really is nothing to worry about so long as the temperature rise stays within the rating of the insulation in its installation environment. That said, there's nothing wrong with a cool running system and it would be 100 watts less to remove from the room the equipment is in. 30mV drop was fictive, actual drop may be higher so measurements would obviously need to be done.
Thanks David, I love your work, congratulacion from México City
I use 1/2"copper tubing works very well.
Perfect way to hookup batteries. This way will extend the life of the batteries. Heat is the enemy.
Thanks for watching.
I run a combination of daisy chained with a 1000A buss bar. The reasoning for this is that I have 20 batteries, so both daisy chaining and buss bars alone would not be appropriate. I have 4 banks of 5 batteries. Each bank is daisy chained, then combined on a 1000A blue sea systems buss bar, where the inverters also can be tied in. With the size of the battery pack, even at full output with 3 inverters I’ll never pull more than 30% of the max battery output anyways, so the daisy chaining isn’t a big deal as far as balancing the load in each battery goes.
Great demonstration of the effects of cable resistance. You are effectively reducing the current through the cables by a factor of 4, thus greatly reducing the effects of cable resistance. Since you have two terminals on each battery module, you could double up the cable connections to the bus bar to decrease the resistance by an additional factor of 2. I don't know if this is cost effective, or the gains would be worth it, but you could probably reduce cable temperature rise to single digits. Probably approaching the point of diminishing returns...
Love the new beard! Hopefully you like it enough to keep it, even in the summer! Woof! As always, love your content!
Great Stuff.. Watching from Kenya!. Love the kids too in the mix😊
Thank you, David for this most valuable information. Stay Safe!
I usually fuse the negative side and use switches or breakers for the positive side. Blue Sea Systems make a great 1000amp busbar, and great class-T fuse holders.
For overkill I suppose you could use the second terminal to provide an alternative route for battery to battery balancing current and just use the side buss bar for input and output.
Unreasonable overkill but could be fun.
Definitely makes sense. Instead of the load passing via basically a 4 gauge cable with each battery adding more load to it at each daisy chain point, you now have each battery using it's on dedicated 4 gauge cable to the busbars with the busbar passing the load to the heavy cables tied to your inverters. Not that it should make much of a difference with the short jumpers you have but ideally the cables to the busbars should all be the same length as well, this minimizes the voltage difference and will spread the load as evenly as possible.
I agree. All the 4 gauge wires I have are the same length.
You could improve efficiency by making all your wires the same distance from the bus bar. Also 4 gauge wire will heat up if you draw large amps out of each battery. 00, 000, or 0000 would give you more max output from each battery. But keeping the wire distance the same from the bus bar to the battery terminals will give less resistance and less overall energy loss.
All the 4 gauge wires are exactly the same length.
The max output for each battery is 100amps and 4 gauge welding wire will handle that easily, though during his load test at 95% he didn't go much above 55 amps on any of those batteries. So he's still got a lot of headroom left, plus his fuse will limit it to 75 amps per battery since it'll blow at 300 amps which would be almost 17 kilowatts of draw. If he had fewer batteries then it might make more sense to upgrade to heavier cables.
Great work David. Cute helper too. My she has grown so fast.
Thanks for posting this test, as I am about to connect 7 batteries together. I will try my best to use same wire length. I dont have a server rack like you, but bought a home depot husky rack to hold the batteries. Its rated at 5000lbs. (We will see).
I'm sure that shelving unit will work great for you. Are you going to have any videos on it?
you're a SAN dude ;)
i'm sure you can find a second hand san rack on ebay somewhere on ebay
If you increase the wire gauge a few gauges (which is always a good idea anyway) you don't have to be so concerned about making sure the lengths are the same. They just need to be close but the larger the gauge, the less voltage drop, since internal resistance is lower so it will make less of a difference under heavy load with larger wires. Your crimps and connections will be more important than a small variation in wire length if you use a larger gauge.
Great Job! I hope they appreciate it.
Great video. Thanks for the great videos.
Huge difference.
You could also secure 3ft bus bars to the rack with stand-offs and run cables from the batteries. That'd let you use shorter cables and keep them out of the way.
Absolutely. That's how my Gyll batteries are built: ua-cam.com/video/r0vuSo5eIOY/v-deo.html
Al Borland lol. you gotta rock the plaid shirt !
Holy Lumberjack! Dude you look 😍 amazing!
Damn I think it’s time I retired my vice. That thing is CLEAN! 😂
Awesome video David . Thks
Any heat increases resistance. Increase gauge til cool. Love your video’s.
BUILD A RAKE SHAPED COPPER BUS BAR for the right terminal to
* not cover or hide anything
* solve the tension issue
You take a long copper bus bar, drill 4 holes in it with the distance of the terminals and then cut 4 short copper busbars of 10 cm as connectors from the terminal to the vertical bus bar on the left connected with screws and nuts.
This way the tensions from low 20°C to maybe 30°C will be divided onto the 4 terminal screws and the 4 bus bar connection screws you then will have to check from time to time which you will also feel quite easily if you do check the displays.
That right main busbar might also be rerouted on the right once you have removed the handles there.
At the end always a compromise one way or the other, but a least possible and quite usefull I guess in the case you have a close rack behind glas or acryl without having such bus bar outside of the rack. Adds a bit of safety for all.
Good idea.
Rake is interesting, but the cost might be a lot higher than current solution.
Both issues can be solved by bending the bar into M shape as it rise from the terminals. So it’s bending at thinest part.
Do not use oval or slot hole. It doesn’t really allowed to slide because you have to torque it down. At the same time, you lose contact surface area.
May I also suggest using some bulb grease at the contacts and plasti-dip the rest.
First, I think the long hair and beard on you looks terrific! Once I got over the shock and realized that it was really you. Great job and video series, David. I'm curious about how you incorporated your entire wiring system in your home to the breaker panel in your garage that your solar system's AC power from your inverters is connected to. Additionally, how much voltage and amperage is the breaker switch between the inverters and AC panel rated for? Lastly, do you know any way a poor old man can get a rack and 4 48V server rack batteries given to him without making hundreds of UA-cam videos? Great job, as always, my man!
If you arc the bus bars between the batteries you gain the flexibility so you can tighten the nuts without having to slot the holes, and you won't block the screens or ports. You would use more heatshrink.
That would be interesting. Have you seen anyone do that across 3 feet of copper bar?
@@DavidPozEnergy I've seen arcs used in other fields to allow a controlled flex between 2 ridged points. I've seen it done in plumbing when there are wide temperature swings in the fluid or gas. As you can imagine metal pipes also change length with temperature.
There are charts and formulas that will tell you how much copper bars will change length for a given temperature change. If you make a curve in the bar it will curve more when it gets hot and straighten out when it cools down.
Good video as usual. Busbars are absolutely better than daisy chaining.. I use aluminum power distribution blocks for my busbars.
Sick video bro
Nice work on the busbars. One thing I don’t understand is why the fuse is rated at 300a when the max your inverters can draw is 200a DC. I’d down the size of the fuse to protet the inverters from a potential surge.
I used a 300A fuse to protect the 4/0 wire.
Thanks that was very interesting. Best of luck to you all. M
Another point about busbars that directly connect all the batteries together. With busbars you can't easily or very safely disconnect a single battery if you need to. It can also be more difficult to insulate the busbar between terminals though it can be done with judicious shrink tube efforts however the little plastic cable caps don't work then for the terminals.
If installed in a cold basement, I would want to downsize the wires and busbars so they heat up MORE, to help take the chill out of the air.
LOL.
You can only daisy chain 2 batteries without unbalancing the loads on the batteries too. Main pos and main neg to different batteries. But no matter how you set up your daisy chain with more than 2 batteries the ones with the mains will see more amps pass through and fewer amps as you move away
I work on RVs. And see lots of what are basically small house inverter systems. A lot of the newer ones have lithium ion batteries similar to what you have. And they have charge controllers to balance voltage. They use an extra wire to the negative to vary the ground side potential I believe. But the older big class A’s with big inverter’s with lots of flooded batteries always had better performance from 6 volt batteries for same watt hours of batteries vs 12 volt partially because now I can run 4 batteries from 1 main neg and pos with a balanced load since will be wired as a pair in series and parallel but making 2 12 volt batteries instead of 4 in the same space. Putting more than 2 battery packs in a daisy chain will always make an unbalanced load and more stress on your end batteries.
The charge controller can balance batteries on the charge cycle but not the discharge cycle.
If you need more then 2 batteries you should not daisy chain or use appropriate voltage in series to make a 2 battery pack system. So off the shelf batteries much more practical to have your bus bars and only daisy chain 2 battery systems of relatively equal potential
Man you really threw daisy chaining under the bus!
Btw, the US really needs to start using NH fuses, they are so cheap here in germany, a 300A NH2 fuse (rated up to 440Vdc, smaller fuses are rated for 250Vdc) with 25kA DC interrupting capacity, with base will cost me roughle 15€ used or 35€ new.
You could put a longer bolt and put 2 lugs on the first battery(in and to 2nd battery) with a 1/0 wire, then next battery with a 1 awg wire, and last with 4awg wire. Could also use a double wire lug. But the advantage of having a central buss bar the way you did is that you can remove a battery from service without effecting the others.
I'm not sure if anyone has commented but u have a thick 400AMP busbar connected to the fuse with 3MM copper plate on a rough observation it is about 20 x 3 MM which calculates to 84AMP rating
Good job. That looks soo much better!! Though you did forget to stagger the main positive and negative. You have the main positive and main negative on the tops of both bussbars. Sure it shouldnt make much difference since the bussbar has a nice low resistance, but it still has resistance. So just move the main negative cable to the bottom and shift the cables up one.
Though as long as it doesnt trigger your OCD I dont mind either 😉
Cheers keep up the awesome battery/inverter creations!
hmm also stacking the terminals isnt great either. you need 5 terminal bussbars
I appreciate the time you took to write a comment. I disagree with you about the need to stagger the +/-. I actually address this exact question, and then demonstrate it in the video.
@@DavidPozEnergy yea, I saw, The bussbar has such low resistance it doesnt make a noticeable difference. Though I think the main imbalance is from doubling up on the studs, then the ESR of the packs.
This is why the signature solar rack for 6 EG4 batters is a better way to as it does use bus bars in it's design.
Great video
since both connections coming off the batteries are from a single busbar you could just use 2x 4awg cables will handle 200Amps easily.
Dave If you ever need more 48v 100a server batteries. I buy a lot of Jakiper for over sea in Ukraine.I can sell you customs server rack or wall mounts for $1,400 each or $1,350 for 5 with free server rack. plus shipping straight from wear house.
Love your UA-cam channel.
My favourite caveDave! ;-)
Another alternative test that would be very interesting. Using fully charged batteries show the difference in time with a specific load(1000watts). Run both ways to reach 50% point. So I would see how much difference exactly this improvement makes.
Balance on the batteries us important.
It would be nice to see the wiring diagram, just to make sure I am understanding the way you use the bus bar. But basically, three batteries to the bus bar, and the 12v bus bar connection for the fourth "pin" ? Been googling how to wire batteries together (in parallel). The manufacturer of my canper has wired it daisy chain. Now I rarely use more than 50A, so maybe it does not matter as much..?
You can buy bus bars with 4, 6, 8, or more studs for your situation. If you have 3x 12V batteries wired in parallel, and you buy a bus bar with 4 studs, then yes. The 4th stud can be for your inverter out.
@@DavidPozEnergy Thanks for that. But also to my 12v general distribution bus, right ? One to the inverter, one to the distribution ?
I think anyway the connection order on both busbars has a matter, that's maybe why you did have a small unbalance in those batteries.
Did you try to connect shunt and fuse at the opposite sides of the busbars?
Thanks for the video!
Not for nothing, but get a railroader to show you the DC electrical cabinet. It will maybe give you some good ideas for videos and best practices
DC cabinet in a locomotive
That would be cool.
There is an online calculator for current capacity of bus bar... its pretty cheap to buy the stock bars .... "Busbar Current Calculator Online"
Those Jakiper cables are they pure copper? Difficult to tell with them all sealed up .. if they’re cheap Chinese aluminum they’re not heavy enough
you started talking about 20 ft lb didn't think about getting a 6 year old girl to do it lol that can be useful knowledge I don't have a torque wrench lol 👍
Thank you so much. I did the exact same setup after watching your video. I have same 2 x batteries and 1 x same inverter with the busbar. I am using 2AWG 35mm cables with 250A Class T Fuse. Should I have bigger cable between Busbar to Fuse and to inverter due to total potential being 200A?
A larger wire will have many benefits. Less Voltage drop, not get as hot, help the inverter not trip under hard situations. I would prefer using a thicker wire with a 200A fuse than 2AWG. I tend to use thicker wire whenever I have a choice.
Could u just replace the 4 awg cables with 00 cable or something bigger than 4 awg thus reducing heat as well yet also enabling the display to be seen? Great intel!
That would certainly help, but not alleviate all the concern. The power would still flow through the small brass jumpers inside each battery box. (it sits just behind the terminals).
@@DavidPozEnergy thanks for the reply I wonder why they are making these terminals small like this when they are selling these into rack systems and marketing them to be used with six or even more units together which would be 600 A? I guess I feel kind of fortunate I haven’t pulled the trigger yet still saving up maybe by the time I get started buying my system in the fall things will be improved
I thought busbars are those bars you hold onto when entering or exiting a bus (public transportation), in case you trip going up or down the steps. But seriously, maybe manufacturers don't use busbars cuz they are concerned about safety. Thick insulated wires seem to be fairly safe.
Yes....efficiency! >=]
Would there be any advantage putting busbars across the two pos posts and negative posts eg doubling up, and of course some kind of insulation?
Are the short cables from each battery to the busbar exactly the same length?
All the 4 gauge wires are exactly the same length. They were pre-made and sold by Orient Power. I have a link to them in the description.
One solid copper bar would also make it hard to remove a battery if you had to.
Great video, David. Good explanation of the neat/energy loss and the need to compensate with the A/C which loses even more energy.
In your explanation about the solid busbar - I agree it would cover things best left exposed. However, what about running a solid copper busbar up both sides where you put your small busbars then using solid copper bars to run horizontally from the battery terminals to the vertical busbar. That way the copper jumpers could be connected to both terminals on each pole of each battery instead of only one terminal and without covering anything.
BWT - I have four daughters. I included them like you do with your kids. As a result, they are not afraid to "get their hands dirty" doing things. They also know how to do a variety of maintenance tasks. Oh ... I liked you better clean shaven.
Your plan with long busbars would work too. If it were me, I'd still use a flexible jumper wire to the battery terminal. Glad to know your kids are not afraid to get their hands dirty.
HOWdy D-P,
Thanks
I wish that the SOLAR Industry would STANDARDIZE on one single LUG / BOLT Size
I noticed that BLUE-Sea "T"-Class FUSE-HOLDERS utilize 3/8" Studs
While PIKE BUS-BARS utilize 5/16" Studs
While EG4-LL Batteries utilize 1/4" Bolts
Even if they ALL decided on an OVERLY Large STUD / BOLT ( ie: 3/8" ) it would simplify installation tremendously
COOP
Hi! Good job David, and firstly i have to say; this beard fit you very nice! 🧔 But why don`t you use a thicker cables between those batteries? They`ll probably not cost too much.. 🤔👍