Who is still building DIY batteries

[Rednecktek]

I've got 2 of the 8s battery packs from the BatteryHookup sale last year waiting to get finished out. Some steel plate, a basic shunt on each, some thermostats and pet heating blankets and I'll triple my capacity for less than what I spent on the first battery.

I have it on my "To-Do List" to get a 48v AIO for my pump house so I can run the well pump without running the generator. When that happens I'll do my own battery build. Current prices give me 304ah of 48v with a JBD BMS and basic shunt for about $2000 which is 30% less than a pre-built for more capacity AND the fun of building. Having no desire for communications and off grid internet monitoring and fancy display screens saves a fortune.

 

[JJJJ]

AND the fun of building

SO well spoken!

 

[JJJJ]

A couple of years ago I was intrigued with the prebuilt boxes that were out there. Packaging was nice, easy to use, etc, etc.

On the other hand, the knowledge and experience I have gotten with the DIY path has been invaluable. If I have a bad cell for some reason I can trade it out. My first batteries consisted of CATL cells. I had some that were a little less cooperative than others during stress usage. I sourced some replacements and this encouraged me to perform the resistance testing. I sourced a YR1035+ which is a cool item to have on board. Using a EBC-A40L I am able to walk each cell through different voltage levels. In my current path I am taking resistance levels at 3.4, 3.3, 3.2 and 3.1 and then adding up total resistance. I then place a label on each cell showing this resistance level. My plan is to batch the cells by resistance level so each battery case has "like" cells. This will reduce the stress on the BMS and help the batteries to work better together. Nothing is more frustrating than having a "runner" spoil the show.

 

[chilidillo]

16ah cells rated for 400-800a discharge? I have to wonder at what voltage sag is acceptable for that kind of test.

I’d love to see a Will video testing these specs!!!

I'd love to see Will show Wheel-standing golf carts for effects, lol

 

[JJJJ]

So when I purchased these CATL cells one of the "hot topics" was the use of an aluminum "crush" washer to expand the terminal contact size at the welded stud. There was concern about possible pitting or corrosion.

I chose to use the washer approach. I did NOT put anything on the washers but was careful to clean them properly with an alcohol wipe to remove any possible oil deposits or dirt.

Well I don't have microscopic vision, however in inspecting the washer and tops of the terminals I am not seeing any pitting or breakdown. Granted this is not a scientific examination but I find it encouraging.

 

[timselectric]

So when I purchased these CATL cells one of the "hot topics" was the use of an aluminum "crush" washer to expand the terminal contact size at the welded stud. There was concern about possible pitting or corrosion.

I chose to use the washer approach. I did NOT put anything on the washers but was careful to clean them properly with an alcohol wipe to remove any possible oil deposits or dirt.

Well I don't have microscopic vision, however in inspecting the washer and tops of the terminals I am not seeing any pitting or breakdown. Granted this is not a scientific examination but I find it encouraging.

Here's the thing.
It's not increasing the contact point. You still have the same amount of contact with the terminal.
But, it does add another contact point in the circuit. One at each terminal.
The only change is more resistance throughout the circuit.

 

[JJJJ]

The only change is more resistance throughout the circuit.

Not installing them in the rebuild would actually make things easier this being the case.

 

[740GLE]

Only thing I can think of is if the washer is tight on the threads, and the bus bars is loose with large slots. The total surface are if you just used a sloppy bus bar would stink, but with washers it’d maybe stink less.

 

[JJJJ]

Here are two photos, one without the washer, one with. These are crush washers.

 

[JJJJ]

Shouldn't be too difficult to check the resistance across the bus bar. Since the bottom edges are tapered, I suspect the contact surface is less than I thought.

 

[timselectric]

That washer isn't sized correctly to help.
The hole is too big, and/or the washer is too thick.

 

[JJJJ]

The hole is too big, and the washer is too thick.

Just like a poorly fitting lug LOL. Good point!

Thank you for taking the chance to look. Will omit the washer in the next build. As said earlier, it will make things simpler.

 

[timselectric]

Just like a poorly fitting lug LOL. Good point!

Thank you for taking the chance to look. Will omit the washer in the next build. As said earlier, it will make things simpler.

Just use the proper sized lug, for the most contact area.

 

[jdbauman]

I bought 16 brand new EVE 280s 2 weeks ago from U.S. warehouse stock, drove to Houston and picked them up, $115/cell w/copper busbars and nuts incl. And of the 3 tested so far they each have tested over 280AH from 3.45v. Valid QR codes. Grade A. Apexium 48v 280 DIY case kit (basically the Mason kit) for 600, 205 for the ebc a40L Charger/tester, and $54 for the cable that goes from case to Inverter. That was $2,700 total.

As a comparison, I had a quote from Seplos direct (from China) of Mason 48 DIY 200A BMS 3.0, LCD, BT, $475, 2M 50mm2 battery cable $60, (16) 'Grade A new 280AH cells' $99/e ($1584), RS485 Adapter $10. but add the month? wait and $456 for shipping! = $2585.00. That's w/o the EBC A40L tester. And of course, as always we would be at their mercy to actually provide new cells as promised.

Does anyone know if the eg4 6000xp can be used with an EEL 48Volt Diy Battery?

 

[jdbauman]

I have three DIY 16S, two DIY 8S, and four 14S-5P DIY EBike packs.
I got into the DIY batteries long before solar, building EBikes for my grand-kids from scrap 5 & 12 speed bikes I got for free. Was a hobby, something the GK looked forward to working on while they visited, gave us something to talk about (to bridge that 50plus year age gap) and once built, we would go out riding - without killing myself. (yeah my own Ebike got a double battery pack).

Ditto! and what better way to understand how everything works then to actually have a hand in putting it together.


I sure liked the cheaper part! and as Tim says, easy to have a spare cell on a shelf that could be used in any similar battery. I have (so far) three DIY 16S packs all built on the same 280K cells, although my next two packs in the process will be built with 304A cells, so I should actually have a 280 and a 304 cell spare - I can steal a 304 from one of the 8S packs in a pinch.

I was too, but clearly I was not as courageous as you, I bought two factory server racks first, then moved on to DIY packs - LOL.

The cells in the factory packs do not look too easy to remove or replace individually, but I know exactly how to remove and replace a single cell in my packs.

Playing with the packs taught me a lot about balancing, both in one pack, and between various packs, even when the packs are very different capacity - 100Ah factory racks and 280Ah DIY packs, this was good to learn and I am happy to know now a lot more than I did a couple years ago.

Does anyone know if the eg4 6000xp can be used with an EEL 48Volt Diy Battery? I purchased a DIY kit from EEL and would like to make sure it is compatible with the EG4 6000xp inverter before I purchase one. Any advice?

 

[SomethingAppropriate]

Does anyone know if the eg4 6000xp can be used with an EEL 48Volt Diy Battery? I purchased a DIY kit from EEL and would like to make sure it is compatible with the EG4 6000xp inverter before I purchase one. Any advice?

If the bms is JK inverter BMS then you should have no problem.

If it is not, just run in lead acid mode. No communication but it will work fine.

There are other, more complex, options but we will leave that for later.

 

[jdbauman]

Thank you for your help.

 

[SomethingAppropriate]

Thank you for your help.

I have an EEL box with JK inverter BMS hooked up to dual 6000xps.
I love the eel box. I got a cheaper one also and the EEL is better.

 

[SomethingAppropriate]

My other is a Luuyan

 

[houseofancients]

Does anyone know if the eg4 6000xp can be used with an EEL 48Volt Diy Battery? I purchased a DIY kit from EEL and would like to make sure it is compatible with the EG4 6000xp inverter before I purchase one. Any advice?

if your EEL battery supports pylontech ( both seplos and JK bms support this and are used by EEL) , you will have no problem