519ah 12v lifePo4 DIY project. Alibaba cells.

Cavendish

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Nov 29, 2021
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Hello.
* Not sure if this should be in the newbie corner?!
I decided to make the decision to purchase x12 EVE 173ah 3.2v lifePo4 cells, and x3 JBD 200a smart BMS from Daisy at Docan technology (Shenzhen) co., Limited.
The reviews were good, and Daisy Efest was very helpful to guide me through my first purchase.
Will try and update this post with progress on the project.
I should state that this will be my first build. If all goes well I'll end up with a 12v 519ah battery pack.

* Please comment if this in inappropriate or in the wrong place.
 
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Cavendish

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Nov 29, 2021
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11
Tested and waiting for shipment
 

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Cavendish

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Nov 29, 2021
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Balancing and capacity test.

So my cells should hopefully arrive February. I'd quite like to be ready for then. Minimising single use items would be great.

Questions first:

1) My ideal capacity test idea. I'm going to purchase a victron smart shunt 500a, and JBD smart BMS 200a. So my question is this:
Can I use these two for capacity test? (Battery -> shunt -> BMS -> load (load - should this be via inverter? Or can I attach any 12v appliance? Such as LED lights))
If I understand correctly this wiring will allow the shunt to stay on when the test is done, I also plan on having a live screen record video to capture the final stages of the test from the shunts bluetooth, so I can see Ah and get my final capacity (screen record is necessary, because I understand the shunt/ Bluetooth won't store the data).
BMS set to 10v LVD. If this isn't a smart plan, i have listed below a more traditional method(or so I believe).
My main reason for doing it this way, is because I don't want to purchase more stuff, it saves money and is more environmentally conscious.
- If this yields unsatisfactory results I may have to purchase a tester and start over.
- Will this shunt record the total ah? I guess this is my biggest concern!

2) Car battery jump cables..! Is this a good idea to use for capacity testing?
As I'd rather not cut wire and put lugs on for temporary tests.

https://www.amazon.se/dp/B0856PHNLX...t_i_RTDW7P6REMN06QEXGJ9W?_encoding=UTF8&psc=1


Balancing:
- If they seem low SOC, Divide the 12 cells into 4 4s packs in series, charge them with the 8amp charger I use for my car battery (it has a fast charge option, maybe someone can say if that's a good idea to use or not).

-Connect all 12 cells in parallel and charge with a power supply @ 3.6v 10a, until the amps drop down to Zero.
https://www.amazon.se/dp/B071HW378T...t_i_SD8WCHCHBF11PBENPV68?_encoding=UTF8&psc=1
• This step seems fairly straight forward.. or so I hope 🥴

Capacity test
*If using the smart shunt doesn't work!
-Split the cell up into 4s 12v packs.
-connect capacity tester. Set at zero before connecting to battery. then up the power from the tester and wait until it cuts out and gives a final report. https://www.amazon.se/dp/B09DF7V98Y...t_i_ZAXB796F2NA21FMXPQXT?_encoding=UTF8&psc=1


I am curious to know if this is a good way to do it.. as most people capacity test each cell, from my YouTube searches. But having 12 cells and 1 tester seems very arduous to test one by one.
- * should I, for some reason top balance again after capacity test? Does the capacity test effect the balancing?

I do hope this makes some sense.
 
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