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box for diy eve280ah, what are folks using

rockwind1

Natural selection intervention specialist
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Nov 19, 2020
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57
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Az
to house the bms and the bat packs. will this stand up to the abuse of the rv life,,, dirt roads and bumpy trails?

will these diy packs,, in my case, using 4 of them to make a 280ah 12v ideally i would like to do a 4s3p pack in one box to make a 840ah bat for my rv, is this doable?
 
I just used wood for my 280ah cells. But I was placing them inside under the dinette seating. I made it so when I put the last end on it compressed the batteries together. I can turn the box upside down and they will not come out. Just make sure to pre drill your holes and assemble before you put the batteries in so you don't accidentally run a screw into a cell.
 

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I like how this member did his. I used a similar format and very pleased with it.

 
to house the bms and the bat packs. will this stand up to the abuse of the rv life,,, dirt roads and bumpy trails?

will these diy packs,, in my case, using 4 of them to make a 280ah 12v ideally i would like to do a 4s3p pack in one box to make a 840ah bat for my rv, is this doable?
i just put 16 cells 280 ah each in my Rv. What you’re asking is doable for all 12 of your cells in a box, but practical, I’m not sure. Kind of comes to weight and space. A pre-made abs case would be worth considering.

My install is in a 5th wheel I pass through storage. I have a 2’ x 2’ slideout drawer rated at over 250 lbs i put my batteries in. They were arranged for two 24 volt batteries, 8s each. Between the batteries i put a class t fuse for each battery along with a positive busbar and a negative busbar. That took up that entire 2’ x 2’ area and weighed around 220 lbs. to access the battery, i disconnect the positive battery and slide out.

I’d recommend getting a pre-made abs plastic case designed to fit four 280 ah cells and a BMS. Get one for each battery. Each battery will weigh 50-55 lbs. Those will be annoying but won’t be impossible to move, but grouping all cells in one case at 155-160 lbs would be nearly impossible to easily take in and out of the Rv. Also, even though those abs battery cases are pricey, would make a build easy and you’d have days of your life back. I found i spent more money on hardware for a plywood case than I had expected, and construction took a couple of days after the hands on portion started. Planning this plywood battery case was longer than building.

I Boondock off road so the cases are as strong as you build them. I have a fifth wheel, so i can’t go roads too awful.
 
I'm going to say no. If it's just a typical battery case that would be used for a lead acid battery then you have a few problems.

First is compression. The cells need to be compressed. Often, the increased number of life cycles is touted as the reason for cell compression. In an RV, I think your #1 reason for compression is to keep the cells firmly in place with respect to the other cells. If the cells move at all then there could be stress at the cell terminals. A quality compression frame is probably not going to fit within the typical battery box. I'm not a fan of the strapping tape compression. I want something flat on each end that covers the entire cell case.

Second is a secure attachment. I put my cells in a compression fixture, then I bolted the fixture to the floor of the RV. The battery isn't going anywhere.

My bumper pull toy hauler goes down some rough roads. I've sustained damage to the underside and sides from taking it places that I probably shouldn't. The broken black tank valve was the worst damage. My batteries have survived just fine. I've checked the fasteners on the cells and they're still nice and tight.
 
Compression may not be a factor in some RV cases. My camping battery is doing less than 100 cycles per year. With no compression, these batteries will have like 2500 cycles till the capacity drops to 80% without compression and 6000 cycles with compression. Without compression this is >25 years and with compression it is >60 years. In 10 to 20 years these cells will be outdated and there will be a lot better options - lighter, with higher capacity, and longer cycle life.

So depending on the case, a no-compression option may be better, as it simplifies the build and eases the task of finding a suitable place for the cells.

There are different mechanisms for securing the cell in place. A lead-acid battery case full with foam and a few straps will hold them in place. And you only need to secure the lead-acid case to the RV. A task that may already be solved.

My case will be 3D printed. And will have springs for compression, but only because I want to do it once so I can prepare myself for the next DIY battery that is going to be 10-20kWh.
 
I went the other way and built a box to mount the batteries in, the two 12v 280ah batteries in my truck are in compression fixtures at 11 to 13psi and mounted on rubber dampers. These cells have a lot of mass and I could see them moving around if not secured really well, off road or hitting a good size pot hole at speed.

The other reason is I am putting together twelve 280ah batteries, two in the truck, two in the camper and ten stationary at the homestead. They will all be built and mounted the same for redundancy. Anything you use figure your cell terminals will need checked and possibly cleaned or re-tightened so a plan that gives easier access for servicing makes sense.
 

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