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diy solar

diy solar

Build a Battery … Where to start?

More than I got out of my eve 'b' 304ah cells.

Usually, a straight edge shows the jelly rolls when running across the cell and a bit more towards middle. In that one pic, #276, all I see is shadow.
 
OK great thread!

So WHAT are you guys with a DIY box doing for the main terminals connecting to the MPPT/inverter? I there's got to be terminals for passing the juice THROUGH the side of the box... When I look at the pre-fab boxes they have these terminals already there but on Andy's accessories page I don't see any and on AliExpress I have to deal with stuff like this...
 

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OK great thread!

So WHAT are you guys with a DIY box doing for the main terminals connecting to the MPPT/inverter? I there's got to be terminals for passing the juice THROUGH the side of the box... When I look at the pre-fab boxes they have these terminals already there but on Andy's accessories page I don't see any and on AliExpress I have to deal with stuff like this...
Didn't need anything like that in my diy box.
1736714202063.png
 
OK great thread!

So WHAT are you guys with a DIY box doing for the main terminals connecting to the MPPT/inverter? I there's got to be terminals for passing the juice THROUGH the side of the box... When I look at the pre-fab boxes they have these terminals already there but on Andy's accessories page I don't see any and on AliExpress I have to deal with stuff like this...
I just found this on AliExpress: $13.63 | 2PCS 200A All-Copper Lithium Battery Energy Storage Terminal Battery Connector Battery Storage Terminal Post

I went with these, which are very similar in style to what Luyuan includes with their kits.

I’ve never passed 200a through them, but 50a has’t been any issue.
 
Each of these is going to take some time, I am thinking of testing compacity of 4 (1 of every 4) they all started at 3.385v… should I test them all for a starting point or what sampling do you sggest?

image.jpg
 
You waited so long for the cells to arrive to your door don’t waste anymore time too balancing or doing capacity tests, assemble the battery and put it to use.


On the first charge keep an eye on the cell delta and this will tell you quality of the cells.
 
Will have 9 of 16 charged by morning..once they are all done anything that don’t hold charge same as others I will test them.. but they all came exact same charge voltage .. 3.385v all seem to be taking 255.5 or so AH of charge..

I’m sure once they are charged it will take me a few days to get everything built for compartment, I can test a few then …
 
I just put the JK BMS with 2A active balancing on the cells in series and charge them. As the cells get closer to full charge, I just cut back on charge rate or stop charging until cells balance, then charge again until I get all cells close to 3.60V with less than 0.008V delta.

 
I just put the JK BMS with 2A active balancing on the cells in series and charge them. As the cells get closer to full charge, I just cut back on charge rate or stop charging until cells balance, then charge again until I get all cells close to 3.60V with less than 0.008V delta.

So easy and simple, days of top balancing or capacity testing are long gone

(unless you enjoy the time and effort, I can kinda see an ASMR kick out of it if that’s your thing)
 
Yeah I should have done it that way .. I have 9 finished and might as well go all the way at this point .. so far charging them is been easy, and it is cold here(ok not your cold my cold at 44-52f) .. so I really did not want to go outside, came back from my trip with a stupid cold .. so giving me something to do … IMG_1410.jpeg
 
Yeah I should have done it that way .. I have 9 finished and might as well go all the way at this point .. so far charging them is been easy, and it is cold here(ok not your cold my cold at 44-52f) .. so I really did not want to go outside, came back from my trip with a stupid cold .. so giving me something to do … View attachment 272426


Won't this cause stress on the posts as the cells charge?

Battery cells swell as they discharge and as they charge - the mid-point is when they are the smallest.
 
If those are stacked short busbars, I was wondering about the angle the busbar must be at contacting the terminal, and the terminal has small enough landings as it is.
 
note - I realize this is just for a top balance charge - and that won't be the final assembly - but would suck to damage them while preparing them for use.
 

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