Adding 32700 cells to existing TalentCell 24Ah LifePO4 battery

[matttelz]

Hello all! First time post here. Glad to see this forum has quite the life to it. I'm new to the LifePO4 world and energy storage. I live just outside of DC in a suburb of Maryland. I'd like to slowly build up an energy storage system. I originally purchased a TalenCell 24Ah battery to replace a lead acid battery for a backup sump pump system in the basement... I realized that probably wasn't the best purchase but anyway, it's what I have.

To give you a little background. I have extensive knowledge of liion batteries as I build a couple of battery packs for my now stolen ebike. I eventually upgraded from recycled batteries to genuine panasonic cells in an actually organized pack... Always on the cheap side fyi....


I even did some fun modifications to my ebike charger to ensure the voltage was correct and add a meter:


SO back to this 24AH TalentCell pack... I'm looking to expand upon what I already have. I recently took apart the pack and realized they're using cylindrical 32700 cells. A quick search and I find some VariCore cells like this: https://www.aliexpress.us/item/2251...NU&mp=1&gatewayAdapt=glo2usa&_randl_shipto=US
Looks like the cells are halfway decent according this the tests here: https://lygte-info.dk/review/batteries2012/VariCore 32700 LiFePO4 6500mAh (Gray) UK.html

So my idea is basically to just add to the 4S4P setup in the TalentCell pack to get it to around 100Ah to start. I'll also be upgrading the BMS with a DALY brand. I know the cleanest look would be to also use the 32700 cell holders but I'm considering going the hot glue route and gluing them all together to also reduce pack size... Very curious to know your guy's thoughts. I don't want to make a bad purchase or start building something without collaborating my idea, especially with those way more invested in LifePO4 than myself.

Thanks!
Matt

 

[DThames]

If the original battery is working okay, I would consider building a second battery with its own BMS and using them in parallel. I would also suggest you look a the JBD BMS. For about $6 you can get an app to adjust all of the battery parameters in the BMS via your phone. You can also monitor the battery on your phone. I have several of these of different voltages and types, both Li-ion and LiFePo4, which all owrk with the same app.

Also, get a tester and cycle test each of your new cells so you can build cell groups with similar capacities. You will keep your new battery in balance much better if the cell groups are closer to the same value.

If you can afford it get a good battery welder and use the cell spacer/holders and nickel strips. You will produce better results than soldering wires to the cells. Example build.

Edit...US stocked cells.

 

[matttelz]

Thanks for the advice. I think what I'm more concerned with is the price per kw. I've done what feels like extensive research and it doesn't seem like I can even get under $200/kw at current prices. Even with building my own pack with cylindrical cells, some come out to be more expensive that current prices of 100ah batteries on amazon...

 

[DThames]

Thanks for the advice. I think what I'm more concerned with is the price per kw. I've done what feels like extensive research and it doesn't seem like I can even get under $200/kw at current prices. Even with building my own pack with cylindrical cells, some come out to be more expensive that current prices of 100ah batteries on amazon...

I purchased 100 cells from Basen via Alibaba a couple of years ago. Shipping was a big part of my cost.