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Top 10 Questions Answered about DIY Battery
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- Опубліковано 16 сер 2024
- Answering the top ten questions, comments, and concerns from my previous video about building my DIY Battery. Things like: Is there cold temperature protection in the BMS?
Original Video: • Save $500/day when you...
Insulated Battery Box Video: • Bills Off Grid Battery...
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But, if you want more fun and the satisfaction of making things yourself, then you are like me. I want to DIY my own battery. Luckily, Battery Hookup recently started selling their own branded cells. These things are LiFePO4 cells, nominal 3.2 volts. They are 32700 (32650) cell size.
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SPOT WELDER:
18650'ed Heat Shrink and Cell Holders
I have no affiliate with Keith, from 18650'ed. He sells accessories for builds. I purchased my K-weld spot welder from him, along with the Kapton tape, and nickel strip.
Case, Empty. I purchased mine through Aliexpress. However, you may be able to find it locally. Keith, from 18650'ed, sometimes has some empty cases in stock. I suggest checking with him first.
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10 AWG Wire, Silicon: amzn.to/3nzbCtI
8 AWG Ring Terminals: amzn.to/30RNmcB
Bolts, Flange Head: amzn.to/2GKP7Sb
Circuit Breaker, DC: amzn.to/36QPDbJ
Barley Paper (not exact to video): amzn.to/3ls7qKD
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Disclaimer:
My videos are in no way intended to be instructional "how-to" lessons. I am simply documenting my project for informational purposes. Property damage, personal injury, or death may result, even when following manufacturer's instructions. I cannot be held liable for such damage or injury. It is YOUR OBLIGATION to ensure that you are complying with any local and federal laws as well as code and permit requirements.
Regarding Q5: locktite on the bolts shouldn't make much of a difference, however "less steps and less resistance" is wrong.
You can look at those two paths as two (very low value) resistors in parallel, together they form a combined path with a smaller resistance than any of them individually.
Increase any individual path's resistance, e.g. by adding locktite between metal interfaces, and you increase the combined resistance.
Since the combined resistance is never more than the lower resistor value, and brass is a very good conductor, this should have no practical impact.
Thank you for the clear visual explanation. Makes a lot more sense now.
And any difference in resistance between two paths, will result in an imbalance, since more current will be drawn through cells with lower internal resistance V/R=I V is fixed so increasing R results in less I (current) . Power = V^2R that additional resistance is wasting Power as heat!
Also, when you crank down on the bolt, the threads are GOING to be metal on metal. The liquid lock-tite GTFOs from where the pressure is, and just fills the voids where there would normally be just air. If that's enough to cause any trouble, the system is simply insufficient to begin with.
also the capillar effect sucks locktite between the contact surfaces
@@DavidPozEnergy While i do agree with the premiss, thread locker works in fairly small quantities and you have quite a lot of it there. If it spills to the brass mating surface then it will very much so affect the conductivity in a bad way. The cross section of the brass is quite large and there should be no problems with carrying the proposed 50 amps.
For low temp cutoff, I think many are looking for batteries for rv, or van conversions where heating or conditioned spaces aren’t always possible - or even if it is possible there may be a time when you are out of the rig hiking or tourisming where the heating is not turned on and dips low suddenly or something
The current will chose the least resistance path which will be from the ring terminal to the brass contact. nothing wrong with using locktite as long as it's not all over in between the ring terminal and the brass terminal.
When i disassembled my nissan leaf battery pack for the cells, each bolt was threadlocked with blue locktite just as you are using.
And thread locker will go in the spaces between metals part, not where metal contact metal to let the current flow... Thanks for the update David :)
Lets be specific - Current follows ALL paths simultaneously. The amount of current will be proportional to the path resistance.
Any additional path available to the current will lower the overall resistance of the joint
@@TrackGeekslol! I say this exact phrase. Its correct though
Path of lease resistance. Locktite is just fine plus where the threads interlock the glue will be squeezed out by the intense clamping force thus creating a long spiral of little resistance. Hi amp builds may want to solder on the ring terminals in addition to crimping. Great build!!
Great follow-up! I don't see a problem with the loctite on bolts. I agree that electricity is going to take the path of least resistance, which is brass to ring terminal, not through the bolt. I'm not sure why so many are concerned about that? Unless I'm missing something. That being said, I do think the flange bolt would have been enough on its own as it's got those grooves cut in to help avoid backing out.
Yes, most of the current will take the path of least resistance, but any additional available path will have non-zero current and lower the overall resistance of the joint. Example: One path is 1 milliohms and one path is 2 milliohms. 2/3 of the current will go the first path and 1/3 the second path and the overall resistance will be 2/3 milliohms.
There will allways be some locktite on the ring metal too, trough to capillar effect
Loktite the terminals after they are tightened. It will still work by creeping into any gaps between the bolt, the terminal & the crimp, but will not reduce any contact surface area.
In the electrochemical lab I work in at the technical university of Denmark the contact with pure Nickel is avoided with the use of gloves. The content of Nickel is regulated in consumer products for a reason as Nickel can give you allergies and cause skin rashes. I don't see it as a major safety hazard, but just wanted to let you know regardless 😊
Thanks! Didn’t know this.
@6:40 David. I wold use a lock washer instead of the locktite. There are various locking solutions for your project such as a wavy washer or a nylock nut. But I feel the locking washer should be sufficient provided you torque the nut properly.
Great video.
Couple of things I'd suggest for future ones:
1.) When discussing the threadlocker / no threadlocker, it would have been nice to pop a multimeter across the connection without threadlocker to measure the resistance and then put the threadlocker on and see if you get a higher resistance with the threadlocker on. I'd guess that it makes almost no difference but would be cool to see.
2.) When doing the "nickel test", splitting the salt water solution between two pots and having a nail or similar in one will be a good control and make it clear that rust would have developed in a given time period if there were any iron in the nickel strip.
I've subbed and going through all your other content - the UA-cam algorithm did a good job suggesting your channel to me!
David, electricity will follow the shortest path. From the photo you are correct, the juice will flow from the collar to the ring, since that’s where the shortest transfer distance is located. Also, you have more than sufficient contact thickness for the current to easily flow through that ring/collar contact, this would prevent arcing of any sort resulting from insufficient conductivity.
On a battery you are supposed to put the high-current leads on the terminal and lower current leads by the bolt.
It isn't that the current "wants to flow" but the current will divide proportionally according to the resistance of the paths.
This is what I thought too, electricity will take all paths but at different currents. I believe it's equivalent to a circuit with two resisters. Current will flow through both resisters but at different rates. For example ohms law says I = V/R so if one path has say a 1k ohm resister and we have a voltage of 12v then that path will have 0.012 amps and let's say the other path has a resistance of 10k ohms then that path will have 0.0012 amps. Weather or not the loctite is safe I would think would depend on how much resistance it had the load on the battery and at what temperature it would start to fail. Just my .02 but I think it backs up your statement.
Great answers and as an TV, Radio engineer and a past electrician I would not worry about the Loctite. I agree that a loose connection is far more of a possible issue. Thank you
Loctite is a polymer. You are reducing the surface area in contact by 2*2^-2 x H pi D and only using the area of the bolt head - the area of the thread part. I suggest you all do the maths!
There are probably a lot of viewers that live in cold weather climate or like me have a motorhome that I use in the winter for snowmobiling and had questions about your low temp cutoff. That's probably the biggest issue that I have about switching to Lithium. Our workshop is an unheated building at 4400 ft elevation. It's cold in the winter with some days never getting above zero. I don't have to worry about our lead-acid batteries unless they discharge to where they would freeze. I have 800 watts of solar and when it's really cold and below zero, the chances are that it is super clear out and solar charging won't be a problem. Thanks for your time to make these videos!
You never mentioned what you are going to use it on. When I built relays that went into space we used conductive silver epoxy on threaded connections. I would put some dessicant inside and a usb adapter port too. A led light on the side would work too.
You are correct. The current will ALWAYS take the path of least resistance.
Loctite on the threads is not an issue. Threads only engage by around 60 - 70% anyway. Once the bolt is torqued all the Loctite will be squashed out of the part of the treads that actually make contact. Also the terminal is squashed down hard onto the top of the battery post. If the Loctite is a problem, the terminals will get hot during a heavy discharge, and they don't.
I like your explanation of the current flow through the bolts/terminal and the use of locktite David. That does make sense to me. One could measure this - use two identical terminals with a thin insulator between them, bolt the assembly down using locktite and measure the current in each leg - it doesn't need to be a high current - so a 10A multimeter on each terminal would give you a comparative value of resistance of the top terminal where the current flows through the bolt, threads and locktite and the bottom terminal where the current flows from the terminal block into the terminal face directly. Heck, I can try it here with my 10 amp power supply.
Wow... that was an EXCELLENT IDEA!
I LOVE YOUR CONCERN FOR SAFETY BY USING THE LOCTITE. I'M PRETTY SURE JUST TIGHTEN THE BOLT WITHOUT THE LOCTITE WOULD HAVE BEEN SUFFICIENT. BUT U CAN NEVER BE TO SAFE WITH ELECTRICITY OF FIRE. I TOO WOULD DO THE LOCTITE FOR ADDED SAFETY GREAT VIDEO. I WONDER WHERE THE VIDEOS R OF THE CRITICS IN THIS VIDEO IS I WOULD LOVE TO SEE THEIR BATTERY BUILDS.
It sounds so simple to have your battery in a heated environment. Those of us who have remote cabins in cold weather areas and don't live in the structure, that is not so easy or should I say.........impossible. This is presently being addressed by the leading commercial battery manufacturers and I expect within a year this will become practically a non-issue. However, this issue kept me from going LiFePO when I bought new batteries for the cabin 15 months ago. The advancement of the technology surrounding this chemistry evolves so rapidly it is amazing.
Mr David the only problem that I see is no problem you are a champion love your work keep it up on Joy all of your show's thank you very
I commented on your last video about using foam spacers between the battery and the box. That would be a better thermal insulator than a cutting board.
You might want to check out "film heater" elements available on-line to put between the foam and the cells. They should be able to keep the cells above 50F in most cold weather.
Dont see an issue on a little locktite on the THREAD of the bolt, just as you did. That is where its needed anyway.
Another way to check for pure nickel is to put it on a grinder (benchgrinder, anglegrinder, linisher....) nickel plated steel will spark as soon as you go through the nickel plating. Pure Nickel won't spark.
Keep up the good work.
Good catch! Excellent idea!
The threads will pull up, squeezing and loctite out of the way and making good metal to metal contact.
This will be a current path parallel to the 'crimp-brass' junction. It's insignificant you'll have more resistance in the 'wire-crimp' junction.
I'd be more concerned about galvanic corrosion between the dissimilar metals. I once had a lead-acid battery with just 20 amps flowing and there was a 100mV drop across the 'post-terminal' junction. The slightest of movement cleared this, but it's something I keep a close eye on now.
That BMS low temperature protection test was pretty nice, thanks for sharing
I’m happy to see that everything is working well with your battery. I am sure that you are right about the loctite question.The steel bolt is of lower conductivity than the brass and copper. The area of contact of the copper connector to the terminal looks to me to be at least equivalent to the cross section of the wire bundle, and probably greater. So the current will take the path of least resistance, through the terminal and the connector on the wire. In any case, as another commenter points out, when you tighten the steel bolt, the small amount of loctite will be squeezed so that metal to metal contact will occur between the bolt and terminal threads, since the surfaces of the threads will be microscopically rough. The feedback you got was helpful to prevent possible short circuiting by rubbing and wear between the nickel and the battery cases. Your improvement will ensure that this doesn’t occur. I’m happy that your trusted supplier of nickel sheet was shown to be correct by the lack of corrosion. Someone suggested using a magnet, but nickel is ferromagnetic so that wouldn’t distinguish between iron (Fe) and Nickel (Ni). Resistivity measurements would determine if the Ni was plated onto Fe because of the lower conductivity of Fe. However that would have taken a little more effort to measure than your salt water test. By the way you could have added a lot less salt to the water and it would still have rusted overnight if Fe was at the centre. Good luck with your new battery and thanks for sharing your ideas and methods.
The metal surfaces will make metallic contact where they are tightened. The locktite will glue the gaps on the opposite site where there is no metallic contact. So don’t worry about the application of locktite.
As far as loctite - it's going to fill gaps in the threads, the bolt isn't going to just be floating in a sea of loctite. When you torque it down the threads of the bolt will pull against the "nut" and create plenty of connections.
That said - loctite is really not necessary in a non moving part like this, especially if you toss a locking type washer on it.
Dave, just use your multimeter to test the resistance from the lead to the top of the terminal on the other side with and without the Loctite(or before you install the Loctite). That way you know for sure. I bet it won't even register a difference.
Most cheap multimeters won't measure that small value of a resistance. You will have more resistance in the meter connections and leads.
Maybe with some expensive 4 wire meter measurement to measure those values.
I don't know the equipment that you have available but most hobby folks don't invest that sort of money. I have one of those cheap meters used in this video and its good value for money, but forget trying to measure those sort of micro ohm values.
I've invested in a variety of test equipment for my lab and your talking big bucks. That meter is a throw away chinese meter for just general use not accurate measurement and certainly not to measure the low ohm readings to see what's really going on there.
@@KB1UIF For sure. Need a mho's meter lol!!! Easiest way is put insulator under head of bolt. DC volts lowest scale (millivolts or uv) - test from top of bolt to terminal.
Hello,for all the non electrical people who view your channel, can you kindly tell us what this build will be used for,what are the possible applications, it's totally weight when build is finished,how long this will last before it goes dead? This build can power what? And for how long? Examples of what it can power up and estimated duration? Thanks! Awesome video of the complete build!
Thanks for clarifying what others found as possible issues. Even if their concerns are not found to be an worry, you really did a great job explaining why some solutions or ideas may or may not be necessary.
I agree the threads only purpose is to hold the screw in place. The brass is doing the work.
My goodness, most of all these were in the video, i can only imagine the comments you deal with. Great video
Think you need a "control piece" in the "corrosion bath". I agree that a "magnet test" might also yield some valuable data...
A bolt getting lose can produce more heat at connection then worrying about if lock tight not getting enough contact between post and cable end
I believe the way to determine whether the loctite on the threads is significant would be to determine the surface area of the lug-to-ring connection. If that cross section is greater than the wire's cross section then the connection should not be a bottleneck.
The threads have nil to do with your connection. It is all about lug to brass connection.
PS the lugs you are using are primarily designed for a solder joint not compression. That's why they have no hole in the bottom of the wire sleeve part. Although you can use them for compression. Pleased to see you using a good compression tool.
Any junction will conduct, the spade on the end of that cable will conduct current from the brass contact and the bolt.
The only thing I might consider doing is adding a couple of silica gel packets into the case of the battery if you should ever require exposure to cold. Dropping the battery into the freezer causes the air/humidity in the box to pass through the condensation point. Having standing moisture on the contacts/components is something I'd be worried about. Once the battery warms up all those little frozen droplets will flow before they evaporate so you could get an electrical short.
Great detail between the two videos! And thanks for actually testing the low temperature cutoff -- a lot of BMS's have that as a listed feature, but don't seem to work. (I can only imagine how the discussion went to clear the freezer like that! 🤣👍)
The best thing for you contacts would be Humiseal. Don't use Locktide, torque the contacts correct and then apply a thin layer of Humiseal. Thats protect you contacts for corrosion and loosing. Its always used in the Aircraft Industry for the electrical connectors with thermal lugs. A added spring washer will help you to lock the screw.
Thanks for the follow up! And for the humble responses. I think your attitude is the best of anyone on YT.
My question is, what charger would you recommend for charging this from mains AC power? I have a particular application that requires I let the battery charge during certain hours then discharge during certain hours. Ideally, putting the charger on a timer so it’s just automatic. Thanks!
I charged it with an ISDT Q8 and a 24v power supply. However, that would need manual re-setting. If it's in a permanent location you could run a solar panel to it with a charge controller.
Anyways, to your question, probably this: amzn.to/2T5jqp9
DavidPoz thank you!
I think you are correct about ring terminals conducting more than threads on bolt.
The military uses this T.O. 1-1a-14 for electrical practices its about 1300pgs i think happy reading
AWESOME build and attention to detail....they don't make them like that in China! ...would be so kind as do a follow up after the battery has had maybe 500 cycles and show us how its capacity is holding up? Keep up the great work, Cheers Pete
David, glad to see you implemented some of the changes people were mentioning from the last video. Hope the battery has a long and safe life.
For the temperature sensing - Thermistors on the BMS board are necessary to ensure the electronics do not get too hot. It would be nice if the BMS manufacturer had a couple of inputs for thermistors that were attached to a couple of the cells. Cells and BMS board will heat up at different rates. For the battery safety and performance, you care more about the actual cell temperatures. If you demo some of the simple power tool batteries, they have sensors attached to the outside of the cells as an example (those NIMH or NICAD cell BMS use the cell temperature as a secondary input to control the end of charge).
Dave - Keep up with your battery builds! Good work and good videos too. (Have to comment on the battery in the family freezer. My wife hates it when I do that kind of stuff)
Love your channel + comment about sharing / FUN! Agreed!
Great set of experiments. I agree with you on the Loc-tite, the threads would be a bad path for current flow and the surface of the lug to connector would be the path of lowest resistance.
Love your content Dave. Really appreciate your reception to feedback, it helps all us DIYers.
Great follow up. Nice and QUICK
Low Temp is all because Will P, I bet!
I'm also a big fan of renewable / alternative energy so I really like your vids and your sharing of knowledge. Thanks for the vids keep em coming.
If you load the battery and touch from the ring terminal to the brass with a test light, you will know if it's an issue. The test light will light up if you have too much resistance in the connection. If it does not, the connection is fine. That's the test that has been being used in the automotive industry for longer than I have been around. Takes opinion out of it. Keep it simple.
Exactly. Good catch - I mean damn... I face palmed myself when I read your comment. Could also use vom on millivolt setting.
I’m pleased you sorted that main wire out mate. Happy days 👍🏽😁 I wouldn’t want that 🔥 to happen mate. Take care and your family 👍🏽
The battery looks really good for a diy. After I looked for quite awhile; i ended up with the Battle Born. (which was not my first choice by any means). I would have gone with the Fortress or the Simpliphi lithium batteries, but the cost, weight, and shipping cost was a deal breaker for me.
Battle Born ended up giving me a good deal on the cost per battery, so I took it. Also the ten year warranty helps too.......
Gonna see these on the market soon? BattlePoz, DavidBorn. ;-). Both videos are super informative! As always! Note: My Valance batteries all had Locklite on the bolt threads...and that was from the factory.
For the nickel saltwater test, some cross validation would be to put a bit of steel in the same saltwater bath-but in a separate container for the same duration.
Good idea, thanks.
I'd say you're correct that most of the current will go in the terminal to the brass (preferred indeed). i'd put a Belleville washers over the terminal below the bolt to keep mechanical tension tight on the terminal with vibration, and voilà.
@Thomas Chrombly
This issue must be related to the wires jerking on the tab welder in the first video. I suppose using the battery really can loosen bolts.
I think if you put the loctite on the bolt it could run out/squish and coat the surface of the brass part that is in your circuit, potentially not great. Solution, just put the loctite on the inside screw thread (not the bolt), and not have so much that it would squish out. Then the brass surface stays clean!
Nice! Currently building an approximately 100AH lithium for a trolling motor, I can't see spending $900+ for a dang battery! But for less weight and FAR less cost (half the size of your battery) I can DOUBLE my water time! Certainly blows away using 18650 batteries!!
You could also use Nordlock washers instead of loctite, though I don't think the loctite would cause any problem. I have some CALB large format 100 Ah LFP cells which came with a dry type of thread locker already on the threads so at least they don't think that type would cause an issue.
It would be useful to know how many man hours you expended on this project. Obviously, subsequent battery builds would be faster. If someone were to build 4 to 8 batteries, an estimate could be made regarding total man hours, with an estimated efficiency increase in later builds. This provides a useful aid in deciding whether or not to build your own, or buy Battleborn. Victron, or other brand batteries. Some have more time than money. For some, the satisfaction of DIY is worth it both for knowledge and competence, even if buying would make more sense. For those less technically competent, buying is obviously the better option. Those choosing to watch these videos likely have higher competence in attempting DIY. Thank you for helping feed our technical curiosity.
I wouldn't mind building another as a speed test, but these builds get expensive. $440 in parts. I need to wait for the views, and next months ad revenue before buying more materials.
Thank you David, great job
Fantastic build. And love your workshop!
I always used locktite when I competed in car audio 5 farad cap and 3 batteries with 2 150 amp alternators. Needed it or everything would come loose. Busted the front window and blow the sunroof out a few times
you gotta be kiddin me right? That's insanity!
The only problem i see with the lock tight would be i would put it into the hole rather then on the stud... that way if there is any "extra" lock tight it would be pushed into the connection rather then building up at the top maybe building a small film between the brass and your ring connection
Great follow-up! I'm gonna check out that video of the gentleman from VT that you recommend. I just moved to VT from MA and I would like to go off grid next spring.
In regards to not wanting the bolt to come out, and with how "built to last" you've done everythying... .once you are happy and ready to close it up for good.. they make conductive epoxy... you could use that rather than threadlock
Great video, I just want to add that you need oxigen, not just salt water, to rust any steal element. Just saying.
Correct.
The bolt you are using is a locking bolt. That's what those ridges on the flange of the bolt are for. I'm not saying you shouldn't use the locktite, I'm saying you probably just don't need to.
That is a great looking battery for under 500 dollars. A person can make 2 batteries for the price of 1 battle born battery.
on the nickle test just use a dremel tool grinder if no sparks then no steel
All fine, your builds are low voltage and amperage ones there this simply not matter. Good job, nice engineering. Electrons like to travel as close as possible to surface or even on the surface of conductor all depends on voltage and amperage. My apologies for non-professional wording but i tried to dumb it down for average as possible.
very nice video, gonna copy your process, including the locktite, sheesh!
a quicker way to test nickel strip is to use a grinder, or a grinding wheel on a drill, or a dremel with a grinding wheel. if you see a lot of sparks, it's nickel plated steel. little to no sparks it's pure nickel.
or... try a magnet.
@@glensmith766 Nickel is also ferromagnetic so that won't help.
To me, the number 1 question is what’s the total cost (products & tools) required for complete assembly?
By the way, never use different metals at the cable connectors, as there is building up a bandgap and due to this thermogenerator effect the connection will get warm and wastes energy.. so better try to use only copper connectors...Hope this helps..
Electricity flows through the path of least resistance. IE from the brass to the ring terminal or vice versa.
There's only 1 thing I could add to this. Your only single point of potential failure is the battery terminals themselves. As time goes on environmental effects on crimped components (especially high current), will become exponentially detrimental. Solder them after crimping. Problem solved. (High current component failures are one of my specialties - and I see it all the time on conductors like this). No problem with the loctite. If that thing EVER comes loose under high current loading, it will generate a LOT of heat that you do not want anywhere near those batteries.
Thanks for the follow up.
Cool video. But at $477 for 1 battery? I understand that LiFePO4s are expensive. Last summer I used 1450 KWh in one month. I would need MANY of them to do what I need. Good luck with yours.
6:13.. You are absolutely correct David. BTW... Great tests..
After getting the battery so cold, I'm concerned that there will be some condensation inside the case. Let it completely warm up for 24 hours. Then open the case for another 24 hours to allow any moisture inside to evaporate naturally. Just don't open the case when it is so cold. Check the humidity in your house. Based on the appearance of frost, I'm going to guess it is in the neighborhood of 40%. Of course, I have no data on how long after you removed the battery from the freezer that you photographed the frosted case. In the winter, inside your house (cold climate up North), your inside humidity may be more like 25% or even less unless you humidify your house. I realize this was only a one time test.
Have you considered using spacers and using a fan to circulate air through the battery? Wouldn't batteries in the middle be most likely to get hotter than the outside due to insulation? A Simple PC fan could keep things cooler - or warmer depending on the setup..?
Sure. There is nothing wrong if you want to incorporate some form of cooling. Most electric vehicles have to do this since they are trying to push 300+ amps out of the cells. In my case I built this for small off grid stuff, like lights and mini-fridge. I just won't be pulling enough amps to create excess heat.
Hello, where did you order the battery box from? I did not see a link posted.
I wondered that too -he said it was Ali-Express but a search for "Battery Box" doesn't narrow things down very much.
Re Loctite: These aren't precision parts, and so there's no expectation that there will be contact outside of the small area where the threads make contact. As long as there's not so much Loctite that you get hydrostatic lock before the bolt head makes full contact, I don't see the harm. Besides, you really don't want the threads to be carrying much or any load, you want the current to flow through the flat surfaces. Being unlike metals, you might want to put a dressing on them to prevent electrolytic oxidization. You can't prevent the thread stress area from having continuity, but you don't want that to be your primary contact. Imagine if a spark welded the threads together!
Re nickel strips: I don't know if immersion in a salt water bath is a good test, as it's the oxygen in the air that causes rust. An acid bath would provide faster and more conclusive results. How deep you scratch depends on the depth of the plating. If it's supposed to be solid nickel, that depth would be unknown. Iron is about 2/3rds as conductive as nickel, and as long as you have enough total conductivity I don't see a problem either way.
The threads have 2x2^-1 the surface area of flat surfaces, of course you want them to carry current, you want all of the bolt surface you can carrying current. You cover them in grease afterwards, not during construction, to keep out moisture. The softer the metal of terminals, the more deformation you can achieve and the lower your terminal resistance.
Please patent your battery switch idea good work
The locktite is a non issue as were the metals from inner and outer threads contact, locktite would be push out and only be were there is space between the two surfaces and the current woundn't be going there anyway. If locktite is conductive, it would only improve flow of electrons. It maybe another story if we were talking real high voltages.
Kapton tape is not what you want to use in a rubbing situation on a busbar. Kapton is great for high temperatures, and is also very insulating electrically but it has very poor wear resistance and is implicated in aircraft accidents when the Kapton wiring insulation failed. There are much better things for seperating out that busbar - hotmelt glue blobs are pretty good and easy to place.
I noticed you didn't put Locktite in all the threads leaving part of the threads clean to conduct power. Since it doesn't cover all the threads I doubt conducting power in the threads will be a problem. Especially as you point out a lot of power can pass through directly from the side of the terminal. The only way I can see it could possibly make a difference is with extremely high current loads.
I was taught long ago a little goes a long way.
For Solar power application, what's the most optimal charging setup? Panel/charge controller/wiring.
Just use a brass bolt on under side, with flat & lock washer (brass too twice)
Iron and steel are both magnetically attractive, but not sure about a Ni coating on it.
I'm not sure you fixed the potential short issue with the card under the positive end. The nickel was bent over the edge of the cells so at the very edge it could still rub through the shrink wrap. Your insulation should have gone around the edge of the cells.
The ends of the cells are protected by the plastic cell holders...
Time and effort and the price to suspend is not worth it I recommend you should buy from the reliable factory with the five or 10 years warranty what do you think?
For sure. I'm amazed how fast prices have dropped the last couple years. I would buy a pre-built one for $500 today.
Well done David. Yeah, I went a bit on the defensive for you in that last video. Did not like that one guy with the scare tactics method.
I have seen cases under heavy load and high frequency applications where lock tight started acting like a capacitor. We did a lot of testing on our avionics equipment to certify the use of loctite.
The capacitance issue was more on HF equipment like DME and radar, but this only happens when there was over application of the loctite and there was surface seepage. High current was the same deal.
The other thing that we tested was split and star washer applications, turns out, for longgevity of electrical connections that over the space of a year that star washers outperformed split washers, reason being there was more metal bite when tightening the bolt head down compared to the split washer that only had metal bite in one place. This test was done over a year where our measurements were taken over a year on high current parts like smoothing caps and HF parts like clystrons. All was checked twice a day by two teams around the clock.
Not white papered but our personal testing done for our local on this little blue ball.
Nice video, and we'll done with the feedback.
Thank you. I love the feedback. For the star washer, any preference to stainless steel, or something else?
@@DavidPozEnergy I would say look for galvanized as it has better conduction, but, if there is going to be a lot of vibration then go stainless, the conduction does not really play that big a part as long as the terminal has good adhesion to the stud through the case, we also found when using female studs like on heavy current caps that applying a drop of loctite to the stud rather than the bolt worked even better as it would run into the female thread and not seep out onto the face of the stud, we just wiped off the face after application to make sure that there was no contamination between the surfaces.
David, great job and excellent format. Would love to see you do more of this type of video on some of your builds. I have a question. When you use DALY BMS'S, is there some way or program you can use to check the cell levels?
The newer Daly's have a bluetooth option, but not older ones. I have plenty of older Daly BMS's in service. Take a look at my Ammo can build. I soldered in two extra JST-XH connectors. They allow me to manually check the cells fast with a little device called a Batt-Go cell checker. I do that once in a while because it's fun, but the BMS is the protection 24/7
Glad everything works fine and I sincerely hope you never get to learn the lesson about cell level fusing the hard way. But consider this - regardless brand, batch number etc - every cell is slightly different because of manufacturing process and tolerances. Even though there are no obvious differences some will last less time than others. When the time runs out and if the failure results in a short, the energy of parallel cells will rush to discharge through the faulty cell (potentially fairly dramatically). Imagine a plausible worst case scenario. I hope you are doing the smart thing and keep this battery in a fire-safe enclosure away from the living space.
Nice video, thanks for producing this. I was the build video and now I know how my nevt build looks. Just one question. Is there a limit to how many of the batteries you can connect in parallel?
Great videos! Thanks bud...
12:50 Fun fact and a money saver... Go to Big Y and purchase their store brand of ice cream. Is the exact same stuff as the Friendly’s, just with Big Y packaging. 👍🏻