Charging & Balancing before battery build..?

I’m getting ready to put together a 18650 10s3p and a 10s4p pack. This will be my first time. It made sense to me to check the capacity, balance the cells and charge them first. Im using an opus BC-C3100 charger on hg2. It takes 5-6 hours to discharge and about the same to charge. I have 70 cells so it’s taking a while. Is there a better way to do this?

thanks in advance!

12 down 58 more to go…

normally if you buy from places like, the batterys are all at the same voltage level, only a few mV to each other. So there was no point for me to balance them first. I could start soldering after measuring all cells

I got them from ebay off an sellers abandon project. They’re seemingly unopened packs. And all pakaging looks legit. So far, the first randomly picked 12 are good averaging about 3100mah.

I connected up TP4056 's to each of my parallel cells when I got them to balance them, before I wired up the BMS. Didn’t take that long to balance, left it over-night basically…

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Can you link?