* CAUTION * CAUTION * First let me say I really like what you are doing and follow your channel more than any other. I feel that I have to comment on the terminal blocks/connectors that you made with a bolt through the plywood. Any increase in resistance from a bad or loose connection will transfer the heat from the bad connection directly to the plywood. Defiantly a fire hazard. Considering the precious cargo inboard, maybe an upgrade to a more “thermally” insulated junction block is warranted. Something like this www.ebay.com/itm/Red-Black-Junction-Block-Power-Post-Set-Insulated-Terminal-Stud-3-8-Stainless-/152076469422
Hi Fred - thank you for the kind words and the concern, I really appreciate comments like this. You make an interesting and valid point that piqued my curiosity. I can see a possibility that there could be a resistance from a bad or loose connection that would transfer heat to the wood and be cause for alarm. Sorry for getting "nerdy" with these numbers but this kind of stuff interests me a great deal and I tend to over-research things especially when safety is involved. So your comment got me to thinking - how hot would the screws need to get to ignite the wood? Turns out there is a term for this - it is called the "flash point" of a material. The flashpoint for wood is variable and depends on moisture content, humidity, ambient temperature and a bunch of other "science" stuff but is generally considered to be about 500-600 degrees F. Then I wondered about the wire terminal junction blocks. The wire terminal junction blocks are made of stainless steel bolts encased in glass reinforced nylon. So I couldn't find a flashpoint for the glass reinforced nylon but I did find a melting point temperature: 491 degrees F. So this got me thinking: 500-600 degrees is REALLY hot and that resistance load would probably be high enough to blow every fuse in my fuse blocks and probably also trigger my breaker. The circuit breaker is rated to pop at 185 degrees F. Also if the bolt got hot enough to reach the flashpoint of the wood (and somehow did not trigger the circuit breakers or the fuses) wouldn't the bolt melt right through the glass reinforced nylon and likely make contact with the wood anyway? Thanks again for the comment - I love having extra sets of eyes that consider things that I clearly did not think of. It also made me realize that I don't have the "backup" chassis 12V system fused!
Wow, I take of my hat for you. Your wire management is outstanding. I have a ton of videos about (re)building camper vans, mostly done by Americans, and in all of them wire management is crap, it is terrible. But you, although not an electric engineer as you say so yourself, know how to do it. Fantastic. One thing I noticed when the board was placed in the van: the 48-12 converters should have been turned around 90 degrees so the cooling ribs are vertical instead of horizontal. It makes the cooling process more effective. Think of a chimney which sucks in cold air at the bottom and releases it hot at the top.
Thank you De Mus - great eye on the cooling fins! I actually had not even thought of that but what you are saying makes perfect sense! Thank you for the insightful and kind comment!
such an impressive job as usual . admittedly, this on a whole turns my brain to mush . granted, if i concentrate on one piece at a time i can understand and get through it .
I am the same way Richard - one small piece at a time :). Showing it all at the end it looks much more overwhelming than it really is. Thanks for following along
You can also use well nuts. The trick is to screw the set screw into the insert and then use the nut to pull and compress the fastener. Good for low vibration small fastener applications.
I would suggest to get one beefy, adjustable DC/DC converter. Most of the car equipment require 13.8V (float voltage of a car battery), they all work with 12V but for example some ham radios for cars have reduced transmit power when running at 12V, and 13.8V will accumulate the voltage drop over longer cables under load. But maybe most important you eliminated a lot of point of failures by getting rid of the relays, multiple dc/dc converters and the separated 12V lines. I could be a nightmare to troubleshoot a failure on the road, I think. But don't get me wrong, I know these (industrial) dc/dc converters can be expensive and most of all, your "current" 12V panel looks really really beautiful :)
We thought about doing this and didn't find anything in the 1200W (ish) range. I agree with you about the higher voltage. We will keep our eyes out for this problem and report back if we run into issues with this setup. Thank you for your kind words - we are not experts and are trying to make things work.
@@BeginningfromthisMorning Yeah, in my looking for something I see the 48VDC to 12VDC converters top out at around 60A and I have a 1000 watt inverter. Instead of doing (6) 20A, I may do (2) 60A like the guy who posted suggested. Less potential failure points. Maybe I missed it, but why didn't you just configure you battery for 12V to begin with? Would have skipped the step down converters entirely.
@@danadurnfordkevinblanchdebunk We have been runnign this system for about 4 years now I guess. In that time we have had 2 of these buck converters fail (they cost about $18). I am pretty sure one was my fault (I shorted it accdentally while soldering a wire - whoops!) but the other was due to too much load because of our Diesel heaters - we fixed that by just running the diesel heaters off the starter batteries. We are glad we went with 48V for a few reasons. Number 1 is that all our big loads are AC - the air conditioner, microwave, cofee maker, heated floors, compressors, welders etc ... everthing we run that is BIG is AC. Our DC loads are tiny - lights, phone chargers and fans. We typically have less than 200W total DC loads. Running at 48V gives several advantages in needing smaller wire sizes, smaller fuses, etc. It runs at 1/4 the Amps of a 12V system meaning it runs cooler and more effeciently. The big savings are in the solar depertament. To run our array we would have needed 3 more Solar charge controllers at 12V - because we are 48V we run our entire 3500W array (and often 4250 W when using our ground deploy panels) on a Single Victron MPPT 250/85 (these cost about $850 each).
Good stuff. It's a bit over engineered, but it absolutely will work. Nice separation of your load using multiple converters. The only thing I'm missing or did not notice is the fuse into your panel for Master power. Great content, looks great.
Thank you Travis - By the time power reaches these 12V fuses it would have gone through a 300Amp Class-T fuse, followed by a contactor controlled by the BMS, and finally a 100A Blue Sea circuit breaker. If you have not discovered the blog - we provide many of the more "technical" details on there. www.beginningfromthismorning.com/house-batteries-part-7/
I'm going to look on your blog to see if you have listed all the 12VDC draws. By the way, well nuts are rubber and work for an installation such as the board to aluminum body. But the riv nuts are perfectly suitable.
Great work, Juan, and very inspiring for me. You have great ideas and your implementation is so meticulous. Have you considered using 120VAC for all your "house" systems? It should make it cheaper and less complicated. If you need to step down to 12VDC, I would recommend this good (and inexpensive) HP blade enclosure power supply - DPS-1200FB (it is so small and givs you 100A; also adjustable, if you open it up and get to the right trimmer). Your approach for "house" systems is also perfectly valid. If you have anything sensitive connected to 12VDC circuits in parallel with the relay coils, I would recommend putting diode(s) in reverse to the coils, to safely guide any reverse currents induced by the coils. Since you have so many coils triggering at the same time, those reverse currents could have voltages and currents enough to damage sensitive electronics. Other than that, tt will be interesting to see what your impressions are when you get to use your system in the field. I have also been converting an RV, incrementally, for years now. It is based on a 32' semi trailer and I pull it with my semi truck. Roof is covered with solar panels and I use an older AGM battery bank with 24 x 2 volt GNB cells. I have opted to use 120/240VAC everywhere. If my main inverter/battery fails, I have a separate battery and inverter on my truck, which can power most everything (except A/C and water heater, mainly due to insufficient source power). So very similar situation to yours, but solved differently. By the way, for the solar string configuration, for higher conversion efficiency, you have to keep the PV array voltage not too much higher than the battery bank voltage. This way there is less loss in the MPPT controller. I am planning to rewire mine like that as well (from 3 panels in series to 2). Your solar panel sliding system is perfect. You gave me some great ideas. My last two 300W panels are above a skylight, so I want to slide them apart to expose the skylight to the sky. Best wishes to you and your family.
I have one of those Buck Converters and I find that they output 12V exactly. the issues with that for me is that most 12V equipment works better at about 13 V like pumps and fans so I have chosen to get an adjustable higher Amp rated Buck for my system. Mine will allow me to set my Voltage to 13.7 at the Camper (not the output since you can get resistance in some of the trailer wiring)
Thank Jason - these do indeed put out exactly 12.1V. We tested these with our Maxx Aire Fans, A water pump that came with the rig, and a couple different LED lights - no issues so far but we will report back if we see any strange issues. Thank you for the input.
One thing you won't be able to do at only 12.1V is charge a 12 volt battery - should the need arise. A lead acid 12 volt battery needs a charging voltage of about 13.8 volts. So, for instance, if your 12 volt starting batteries needed to be charged, you could do so using your lithium battery pack and the buck converters. I realize that you've done a tremendous amount of work and done a fantastic job, as usual, but I would suggest that, at the very least, you acquire a buck converter that will give you 13.8 volts for those times when you might really need it. Maybe, give it its own circuit? Or, wire it so that at the flip of a switch you could be charging your starting batteries from your lithium battery pack? Because, 12.1 volts isn't going to do the job, for that particular application. Thanks, for the great video!
We have two converters that will push out 13.8 volts on order. I don't think it will be a big deal with the LED lights - but for the fans and motors we are putting in the higher voltage ones. Thank you for the suggestion and the kind words.
Just a safety note. I would consider adding a non-conductive barrier between your pos and neg terminal lugs. Both 12v. and 48v. Use plexiglass or plastic and go about an inch higher than the lugs. As they are now, it would be very easy to contact both lugs with a tool or anything that is conductive. Arc flash is no fun.
I have my backup system relays running in reverse to yours. Basically...the relays are powered on (NO) at all times with the primary power. If the primary power fails...the relays turn to NC...which is my backup power circuit. That way if I am not around if the primary fails I still have the power through the backup automatically.
Interesting! And I like your logical reasoning for wiring it the way you did. Here is how I was thinking about it: I was thinking more along the lines that running off the 48V Lithium battery would be the "default" (NC) and since it is protected by the BMS it would not allow it to drain further than it needed to if something was accidentally left on. Once all the battery's voltage gets too low, everything just turns off If I wired it the way you describe and something got left on it would reach the low voltage cut-off for the BMS which would then turn off all 48V power and transfer the DC power to the "back-up" batteries. This would result in having both my 48V battery completely drained as well as my starter batteries completely drained. It is a tradeoff either way - I like your take on it - Thank you for commenting.
Very true that the fail-over might drain both on your setup. My backup batteries are separate from my starting ones though. Yup...I got 3 systems...gotta make everything complicated :)
The Buck Convertors generate a lot of heat, I put mine in the open near the appliance. Also according to ADAM WELCH the fixed voltage ones are very efficient. If yours are Chinese keep some spares.
Yes they are supposed to be around 96% or so efficient - which seems pretty good. I have not tested the efficiency yet. As for the durability, I will report back - I have about 4 spares since I had to reorder some at a slightly higher voltage - If they make it a couple years I will be pretty happy with them.
LOL - far far more innocent than that I am afraid. When I was a bit younger I loved to fly model airplanes - There is a model called the 'slow stick' that was one of my favorite: amzn.to/2Cl5T7Q - look a the decals on the wings :)
I understand not having the output from the converters parallel, but I see no reason why you can't tie the grounds to the chassis. It would certainly make your wiring a lot easier.
The buck converters use a floating ground and only provide 12V between the wires. So chassis ground to buck ground could be +/- 48V potentially and same with the chassis ground to buck positive and you shouldn’t force buck ground to chassis ground to prevent damage to the converters. In other words chassis ground to buck ground could be 5V with chassis ground to buck positive 17V giving you a potential to feed 17V into your appliances. Which would be fine for 12/24V appliances BUT could fry the reference circuitry that calibrates the 12V on the bucks allowing 48V across the output and a hefty replacement bill.
Hey guys! Just wondering if you have your 48v system hooked up somehow to charge from your alternator? I've also got a 48v battery and am trying to figure that part out!
Hi Darren - we do not charge our battery from the alternator that for a few reasons. We are working with a 56 year-old bus with an engine that was designed in the 1930s. We want to put as little stress on that poor engine as we can. We put a massive amount of solar on our roof and a giant battery so we wouldn't worry about it too much. I do have a solution that is a little convoluted but a buddy of mine has successfully implemented. What he does is run a 12V inverter (~2000W directly off his alternator). He then wired the A/C side back into his main inverter (he has a couple Victron 3000s) as a "generator". One thing to be cautious of is not to fry your alternator (he ended up putting a dedicated one for charging) so he put a temperature sensor that shuts it down if things get too hot (which they do after a little bit). The Victron inverters can switch so quickly that he doesn't even notice when it cycles off. We are not 100% sure we are going to go this route yet but if we do decide to charge from the alternator this is how we will be doing it.
’12VDC' vehicle electric equipment is really designed to operate on 14VDC which is what the entire vehicle is receiving from the vehicle alternator. When the engine is off, system voltage is between 12.0-12.6VDC (depending on battery state of charge) which is really an absolute minimum to operate and at that, they generally operate poorly. By designing your buck converters to deliver 12.0VDC, you will find that most of your '12VDC' accessories will perform poorly. You could benefit by using a 12V converter that had an adjustable output that you could tune achieve 14V.
Hi Steve - thanks for the comment. Interesting points. I tend to think you are likely correct - but let me play devil's advocate for a minute. My thinking goes like this: Most electrical equipment has an operating range it is designed to work within. When the battery is charging it is subjected to Voltages over 14V or sometimes even 15V. So devices need to be able to have an operating range where 14V or 15V is at the "high" end. However, I would think that most if not all of these 12V devices are designed to work when the batteries are not being actively charged. A 12V battery is said to be at "full charge" when it is higher than 12.6 Volts. 12.4V = 75%, 12.20V = 50%, 25% = 12.00V 0% = 11.8. The measured output of the converters was 12.13 so it would look like the battery was at somewhere between 25% and 50% capacity - surely this is within a reasonable operating voltage for most devices. Anyway, I have emailed both the maker of our Fans (Maxx air fan) and the water pump we will likely be getting (Flojet) and asked specifically about my 12.1 output - to see if it would affect performance in a negative way or affect the lifetime of the product. I am not really worried about our LED lights but I will obviously keep an eye on them.
Brilliant that was a lot of work my friend most people don't even think about doing what you've done so like I said you should open a work shop building a bus conversion the right way or bus builds for dummies Lol Are you sure you don't work for Boeing down there in Mesa Your wiring looks so nice I bet they would hire you buddy Anyway great video as usual Keep them coming!
Beginning from this Morning I totally hear you my wife would do the same but that's a part of being married right as I get older its clear for me it's easier to ask for forgiveness than ask for permission Lol.love your work brother its going to be a beautiful coach when your done and all yours and Michelle's hard work will pay off so keep up the fight your on the home stretch, really Well done.
I would be concerned about the 12 Volt output as most 12V appliances really like 13.5 Volts (an alternator puts out somewhere around 14 volts). Motors in particular. Fans (bathroom, roof, vent)., water pumps. If these motors are run on less they tend not to run as fast and burn up the motors. I love to play with relays (my era maybe) The relays you used should be double pole and will isolate the two circuits. I just did this a while back. I put a set of LED loading lights on the rear of my trailer. I also wanted them to come on with the reverse lights on the tow vehicle. The loading lights have a switch in the rear of the trailer. They now light from either source with no feed back to the other source (make sense?) There is a nice wiring diagram in the post. www.lever-family-racing.com/lever-family-racing-home/family-vehicles/2006-car-trailer-2/ramp-loading-lights-2017-09-26-2 I have never been a fan of the rivet nuts. Even after they are seated what can happen is when you go to remove the bolt the rivet nut will start to spin and you cannot get the bolt out unless you can get to the back side of the rivet nut. Not sure what the alternative is. Nice wiring job. I like neat wiring. I think you will like the rewire of the dragster (if my back will heal). Glenn Lever
Hey Glenn - I always appreciate hearing from you and have been enjoying your videos. I tend to agree with you on the higher voltage (13.5 or even as high as 14.4) - we did test our fans, a pump, and some lights on these converters before we bought them to be sure they would work OK. They seemed to work OK - I will report back if they die prematurely or we experience some weirdness from them. I love playing with relays (and electronics in general) - it was really fun to do this project. Unfortunately, with as much work as we have ahead of us I am not too sure I will often have the luxury :) I did not like the rivnuts at first but the more I worked with them the better they became - I think with the proper tool they will be better. The rivnuts were a last minute addition to the project and I didn't have time to order the right tool - live and learn. I am sorry to hear about your back - I will keep you in my prayers for a quick recovery. I am excited to see what you do with the wiring on the dragster.
Yes, I am still thinking that one through - We should be moving enough that it shouldn't be an issue. However, I want to have a plan in place if it does become something I need to look out for.
Read more details on the Blog: www.beginningfromthismorning.com/dc-power-part-1/
* CAUTION * CAUTION * First let me say I really like what you are doing and follow your channel more than any other. I feel that I have to comment on the terminal blocks/connectors that you made with a bolt through the plywood. Any increase in resistance from a bad or loose connection will transfer the heat from the bad connection directly to the plywood. Defiantly a fire hazard. Considering the precious cargo inboard, maybe an upgrade to a more “thermally” insulated junction block is warranted. Something like this www.ebay.com/itm/Red-Black-Junction-Block-Power-Post-Set-Insulated-Terminal-Stud-3-8-Stainless-/152076469422
Hi Fred - thank you for the kind words and the concern, I really appreciate comments like this. You make an interesting and valid point that piqued my curiosity. I can see a possibility that there could be a resistance from a bad or loose connection that would transfer heat to the wood and be cause for alarm.
Sorry for getting "nerdy" with these numbers but this kind of stuff interests me a great deal and I tend to over-research things especially when safety is involved.
So your comment got me to thinking - how hot would the screws need to get to ignite the wood? Turns out there is a term for this - it is called the "flash point" of a material. The flashpoint for wood is variable and depends on moisture content, humidity, ambient temperature and a bunch of other "science" stuff but is generally considered to be about 500-600 degrees F.
Then I wondered about the wire terminal junction blocks. The wire terminal junction blocks are made of stainless steel bolts encased in glass reinforced nylon. So I couldn't find a flashpoint for the glass reinforced nylon but I did find a melting point temperature: 491 degrees F.
So this got me thinking: 500-600 degrees is REALLY hot and that resistance load would probably be high enough to blow every fuse in my fuse blocks and probably also trigger my breaker. The circuit breaker is rated to pop at 185 degrees F.
Also if the bolt got hot enough to reach the flashpoint of the wood (and somehow did not trigger the circuit breakers or the fuses) wouldn't the bolt melt right through the glass reinforced nylon and likely make contact with the wood anyway?
Thanks again for the comment - I love having extra sets of eyes that consider things that I clearly did not think of. It also made me realize that I don't have the "backup" chassis 12V system fused!
Good catch Fred. I agree, terminals of some type should be used.
Love it brother. Thanks for letting us be a small part.
Thank you yankey4 - thanks for following along
Your wiring job looks very neat and clean. Good job!
Thank you Average Joe
Wow, I take of my hat for you. Your wire management is outstanding. I have a ton of videos about (re)building camper vans, mostly done by Americans, and in all of them wire management is crap, it is terrible. But you, although not an electric engineer as you say so yourself, know how to do it. Fantastic. One thing I noticed when the board was placed in the van: the 48-12 converters should have been turned around 90 degrees so the cooling ribs are vertical instead of horizontal. It makes the cooling process more effective. Think of a chimney which sucks in cold air at the bottom and releases it hot at the top.
Thank you De Mus - great eye on the cooling fins! I actually had not even thought of that but what you are saying makes perfect sense! Thank you for the insightful and kind comment!
such an impressive job as usual . admittedly, this on a whole turns my brain to mush . granted, if i concentrate on one piece at a time i can understand and get through it .
I am the same way Richard - one small piece at a time :). Showing it all at the end it looks much more overwhelming than it really is. Thanks for following along
and as you know 2 is 1 and 1 is none. Good job on the backup power and the explaining it.
Once again Juan you show your skills. I thank you for the knowledge.
Thanks er1073 - I appreciate your kind words
Beautiful work, as always!!!
Thank you Bill!
You can also use well nuts. The trick is to screw the set screw into the insert and then use the nut to pull and compress the fastener. Good for low vibration small fastener applications.
I would suggest to get one beefy, adjustable DC/DC converter. Most of the car equipment require 13.8V (float voltage of a car battery), they all work with 12V but for example some ham radios for cars have reduced transmit power when running at 12V, and 13.8V will accumulate the voltage drop over longer cables under load. But maybe most important you eliminated a lot of point of failures by getting rid of the relays, multiple dc/dc converters and the separated 12V lines. I could be a nightmare to troubleshoot a failure on the road, I think. But don't get me wrong, I know these (industrial) dc/dc converters can be expensive and most of all, your "current" 12V panel looks really really beautiful :)
We thought about doing this and didn't find anything in the 1200W (ish) range. I agree with you about the higher voltage. We will keep our eyes out for this problem and report back if we run into issues with this setup. Thank you for your kind words - we are not experts and are trying to make things work.
@@BeginningfromthisMorning Yeah, in my looking for something I see the 48VDC to 12VDC converters top out at around 60A and I have a 1000 watt inverter. Instead of doing (6) 20A, I may do (2) 60A like the guy who posted suggested. Less potential failure points.
Maybe I missed it, but why didn't you just configure you battery for 12V to begin with? Would have skipped the step down converters entirely.
@@danadurnfordkevinblanchdebunk We have been runnign this system for about 4 years now I guess. In that time we have had 2 of these buck converters fail (they cost about $18). I am pretty sure one was my fault (I shorted it accdentally while soldering a wire - whoops!) but the other was due to too much load because of our Diesel heaters - we fixed that by just running the diesel heaters off the starter batteries. We are glad we went with 48V for a few reasons. Number 1 is that all our big loads are AC - the air conditioner, microwave, cofee maker, heated floors, compressors, welders etc ... everthing we run that is BIG is AC. Our DC loads are tiny - lights, phone chargers and fans. We typically have less than 200W total DC loads. Running at 48V gives several advantages in needing smaller wire sizes, smaller fuses, etc. It runs at 1/4 the Amps of a 12V system meaning it runs cooler and more effeciently. The big savings are in the solar depertament. To run our array we would have needed 3 more Solar charge controllers at 12V - because we are 48V we run our entire 3500W array (and often 4250 W when using our ground deploy panels) on a Single Victron MPPT 250/85 (these cost about $850 each).
Very impressive work. Riv Nuts are a great asset on a vehicle such as yours - but only if you use the right setting tool. 👍
LOL Thanks Norman - I have since purchased the right tool and I plan on doing the door panel with riv nuts
Good stuff. It's a bit over engineered, but it absolutely will work. Nice separation of your load using multiple converters. The only thing I'm missing or did not notice is the fuse into your panel for Master power. Great content, looks great.
Thank you Travis - By the time power reaches these 12V fuses it would have gone through a 300Amp Class-T fuse, followed by a contactor controlled by the BMS, and finally a 100A Blue Sea circuit breaker. If you have not discovered the blog - we provide many of the more "technical" details on there. www.beginningfromthismorning.com/house-batteries-part-7/
@@BeginningfromthisMorning will check out the blog. Thanks.
I'm going to look on your blog to see if you have listed all the 12VDC draws. By the way, well nuts are rubber and work for an installation such as the board to aluminum body. But the riv nuts are perfectly suitable.
Thanks Kevin - I did see those well nuts recently and thought exactly what you had said. As always thanks for the great input.
Very nice, great work, why not snubber or feedback protection diodes for those relay banks?
That actually sounds like a great idea! Thank you!
Great work, Juan, and very inspiring for me. You have great ideas and your implementation is so meticulous.
Have you considered using 120VAC for all your "house" systems? It should make it cheaper and less complicated. If you need to step down to 12VDC, I would recommend this good (and inexpensive) HP blade enclosure power supply - DPS-1200FB (it is so small and givs you 100A; also adjustable, if you open it up and get to the right trimmer).
Your approach for "house" systems is also perfectly valid. If you have anything sensitive connected to 12VDC circuits in parallel with the relay coils, I would recommend putting diode(s) in reverse to the coils, to safely guide any reverse currents induced by the coils. Since you have so many coils triggering at the same time, those reverse currents could have voltages and currents enough to damage sensitive electronics. Other than that, tt will be interesting to see what your impressions are when you get to use your system in the field.
I have also been converting an RV, incrementally, for years now. It is based on a 32' semi trailer and I pull it with my semi truck. Roof is covered with solar panels and I use an older AGM battery bank with 24 x 2 volt GNB cells. I have opted to use 120/240VAC everywhere. If my main inverter/battery fails, I have a separate battery and inverter on my truck, which can power most everything (except A/C and water heater, mainly due to insufficient source power). So very similar situation to yours, but solved differently.
By the way, for the solar string configuration, for higher conversion efficiency, you have to keep the PV array voltage not too much higher than the battery bank voltage. This way there is less loss in the MPPT controller. I am planning to rewire mine like that as well (from 3 panels in series to 2).
Your solar panel sliding system is perfect. You gave me some great ideas. My last two 300W panels are above a skylight, so I want to slide them apart to expose the skylight to the sky.
Best wishes to you and your family.
Excellent suggestions - Thank you Diyan.
I have one of those Buck Converters and I find that they output 12V exactly. the issues with that for me is that most 12V equipment works better at about 13 V like pumps and fans so I have chosen to get an adjustable higher Amp rated Buck for my system. Mine will allow me to set my Voltage to 13.7 at the Camper (not the output since you can get resistance in some of the trailer wiring)
Thank Jason - these do indeed put out exactly 12.1V. We tested these with our Maxx Aire Fans, A water pump that came with the rig, and a couple different LED lights - no issues so far but we will report back if we see any strange issues. Thank you for the input.
One thing you won't be able to do at only 12.1V is charge a 12 volt battery - should the need arise. A lead acid 12 volt battery needs a charging voltage of about 13.8 volts.
So, for instance, if your 12 volt starting batteries needed to be charged, you could do so using your lithium battery pack and the buck converters.
I realize that you've done a tremendous amount of work and done a fantastic job, as usual, but I would suggest that, at the very least, you acquire a buck converter that will give you 13.8 volts for those times when you might really need it. Maybe, give it its own circuit? Or, wire it so that at the flip of a switch you could be charging your starting batteries from your lithium battery pack? Because, 12.1 volts isn't going to do the job, for that particular application.
Thanks, for the great video!
We have two converters that will push out 13.8 volts on order. I don't think it will be a big deal with the LED lights - but for the fans and motors we are putting in the higher voltage ones. Thank you for the suggestion and the kind words.
WOW, that is so good wow. thank ya.
Just a safety note. I would consider adding a non-conductive barrier between your pos and neg terminal lugs. Both 12v. and 48v. Use plexiglass or plastic and go about an inch higher than the lugs. As they are now, it would be very easy to contact both lugs with a tool or anything that is conductive. Arc flash is no fun.
Thank you Tony B. I am actively looking for some plastic covers that should also provide a nice way to label the bolts.
I have my backup system relays running in reverse to yours.
Basically...the relays are powered on (NO) at all times with the primary power.
If the primary power fails...the relays turn to NC...which is my backup power circuit.
That way if I am not around if the primary fails I still have the power through the backup automatically.
Interesting! And I like your logical reasoning for wiring it the way you did.
Here is how I was thinking about it: I was thinking more along the lines that running off the 48V Lithium battery would be the "default" (NC) and since it is protected by the BMS it would not allow it to drain further than it needed to if something was accidentally left on. Once all the battery's voltage gets too low, everything just turns off
If I wired it the way you describe and something got left on it would reach the low voltage cut-off for the BMS which would then turn off all 48V power and transfer the DC power to the "back-up" batteries. This would result in having both my 48V battery completely drained as well as my starter batteries completely drained.
It is a tradeoff either way - I like your take on it - Thank you for commenting.
Very true that the fail-over might drain both on your setup.
My backup batteries are separate from my starting ones though.
Yup...I got 3 systems...gotta make everything complicated :)
Gregory Thomas love it!
I put my buck convertors near the load. This allows thinner wires and swithes off convertor.
That's a good idea - the only downside is it might make tracking down where you put the buck converter a little more tricky
The Buck Convertors generate a lot of heat, I put mine in the open near the appliance. Also according to ADAM WELCH the fixed voltage ones are very efficient. If yours are Chinese keep some spares.
Yes they are supposed to be around 96% or so efficient - which seems pretty good. I have not tested the efficiency yet. As for the durability, I will report back - I have about 4 spares since I had to reorder some at a slightly higher voltage - If they make it a couple years I will be pretty happy with them.
Interesting to see the Deutsches Kreuz may someone is a hardcore biker.
LOL - far far more innocent than that I am afraid. When I was a bit younger I loved to fly model airplanes - There is a model called the 'slow stick' that was one of my favorite: amzn.to/2Cl5T7Q - look a the decals on the wings :)
I understand not having the output from the converters parallel, but I see no reason why you can't tie the grounds to the chassis. It would certainly make your wiring a lot easier.
While you can do it and it makes wiring easier there is peace of mind with having a dedicated ground to each device.
The buck converters use a floating ground and only provide 12V between the wires. So chassis ground to buck ground could be +/- 48V potentially and same with the chassis ground to buck positive and you shouldn’t force buck ground to chassis ground to prevent damage to the converters.
In other words chassis ground to buck ground could be 5V with chassis ground to buck positive 17V giving you a potential to feed 17V into your appliances. Which would be fine for 12/24V appliances BUT could fry the reference circuitry that calibrates the 12V on the bucks allowing 48V across the output and a hefty replacement bill.
Hey guys! Just wondering if you have your 48v system hooked up somehow to charge from your alternator? I've also got a 48v battery and am trying to figure that part out!
Hi Darren - we do not charge our battery from the alternator that for a few reasons. We are working with a 56 year-old bus with an engine that was designed in the 1930s. We want to put as little stress on that poor engine as we can. We put a massive amount of solar on our roof and a giant battery so we wouldn't worry about it too much. I do have a solution that is a little convoluted but a buddy of mine has successfully implemented. What he does is run a 12V inverter (~2000W directly off his alternator). He then wired the A/C side back into his main inverter (he has a couple Victron 3000s) as a "generator". One thing to be cautious of is not to fry your alternator (he ended up putting a dedicated one for charging) so he put a temperature sensor that shuts it down if things get too hot (which they do after a little bit). The Victron inverters can switch so quickly that he doesn't even notice when it cycles off. We are not 100% sure we are going to go this route yet but if we do decide to charge from the alternator this is how we will be doing it.
Can i use the output 12v dc into 240v ac?
Rivnets or tac weld nuts to the back of the metal?
’12VDC' vehicle electric equipment is really designed to operate on 14VDC which is what the entire vehicle is receiving from the vehicle alternator. When the engine is off, system voltage is between 12.0-12.6VDC (depending on battery state of charge) which is really an absolute minimum to operate and at that, they generally operate poorly. By designing your buck converters to deliver 12.0VDC, you will find that most of your '12VDC' accessories will perform poorly. You could benefit by using a 12V converter that had an adjustable output that you could tune achieve 14V.
Hi Steve - thanks for the comment. Interesting points. I tend to think you are likely correct - but let me play devil's advocate for a minute.
My thinking goes like this:
Most electrical equipment has an operating range it is designed to work within. When the battery is charging it is subjected to Voltages over 14V or sometimes even 15V. So devices need to be able to have an operating range where 14V or 15V is at the "high" end. However, I would think that most if not all of these 12V devices are designed to work when the batteries are not being actively charged. A 12V battery is said to be at "full charge" when it is higher than 12.6 Volts. 12.4V = 75%, 12.20V = 50%, 25% = 12.00V 0% = 11.8. The measured output of the converters was 12.13 so it would look like the battery was at somewhere between 25% and 50% capacity - surely this is within a reasonable operating voltage for most devices. Anyway, I have emailed both the maker of our Fans (Maxx air fan) and the water pump we will likely be getting (Flojet) and asked specifically about my 12.1 output - to see if it would affect performance in a negative way or affect the lifetime of the product. I am not really worried about our LED lights but I will obviously keep an eye on them.
Brilliant that was a lot of work my friend most people don't even think about doing what you've done so like I said you should open a work shop building a bus conversion the right way or bus builds for dummies Lol
Are you sure you don't work for Boeing down there in Mesa
Your wiring looks so nice I bet they would hire you buddy
Anyway great video as usual
Keep them coming!
LOL - Michelle would kill me before I even got the idea for building buses out of my mouth :). Thank you for the kind words
Beginning from this Morning I totally hear you my wife would do the same but that's a part of being married right as I get older its clear for me it's easier to ask for forgiveness than ask for permission Lol.love your work brother its going to be a beautiful coach when your done and all yours and Michelle's hard work will pay off so keep up the fight your on the home stretch, really
Well done.
I would be concerned about the 12 Volt output as most 12V appliances really like 13.5 Volts (an alternator puts out somewhere around 14 volts). Motors in particular. Fans (bathroom, roof, vent)., water pumps. If these motors are run on less they tend not to run as fast and burn up the motors.
I love to play with relays (my era maybe) The relays you used should be double pole and will isolate the two circuits. I just did this a while back. I put a set of LED loading lights on the rear of my trailer. I also wanted them to come on with the reverse lights on the tow vehicle. The loading lights have a switch in the rear of the trailer. They now light from either source with no feed back to the other source (make sense?) There is a nice wiring diagram in the post. www.lever-family-racing.com/lever-family-racing-home/family-vehicles/2006-car-trailer-2/ramp-loading-lights-2017-09-26-2
I have never been a fan of the rivet nuts. Even after they are seated what can happen is when you go to remove the bolt the rivet nut will start to spin and you cannot get the bolt out unless you can get to the back side of the rivet nut. Not sure what the alternative is.
Nice wiring job. I like neat wiring. I think you will like the rewire of the dragster (if my back will heal).
Glenn Lever
Hey Glenn - I always appreciate hearing from you and have been enjoying your videos. I tend to agree with you on the higher voltage (13.5 or even as high as 14.4) - we did test our fans, a pump, and some lights on these converters before we bought them to be sure they would work OK. They seemed to work OK - I will report back if they die prematurely or we experience some weirdness from them.
I love playing with relays (and electronics in general) - it was really fun to do this project. Unfortunately, with as much work as we have ahead of us I am not too sure I will often have the luxury :)
I did not like the rivnuts at first but the more I worked with them the better they became - I think with the proper tool they will be better. The rivnuts were a last minute addition to the project and I didn't have time to order the right tool - live and learn.
I am sorry to hear about your back - I will keep you in my prayers for a quick recovery. I am excited to see what you do with the wiring on the dragster.
I'm running mine on 16 volts and no problems so far. Another great video Juan.
Lever-Family-Racing
Yes?
The price of the tool definitely outweighs the aggravation.
100% agree - we bought a proper rivnut set tool
Did u consider runnning from 12v batteries and having a permenant trikle charger to 12v batteries?
Yes, I am still thinking that one through - We should be moving enough that it shouldn't be an issue. However, I want to have a plan in place if it does become something I need to look out for.
over kill. over $$$$$$$$$$ . and lots of time. " KISS " dan t palm springs ca USA
Why would you not just buy a riv nut gun? It's only $30 and sets the riv nuts in seconds rather than 5+ minutes per riv nut doing it this way.
I should have and I have one now. At the time I thought "oh it's only a couple rivnuts" - I really should have just bought the right tool
Hidi me
Wow more wiring.......yeah...smh
There is even more next week! It takes a lot of work to re-do a bus