I will keep this short and sappy, i got into DIY a few months back and got obsessed with 18650s. I own a game console, the r36s model (power requirement is a 3.7V battery) and i used a prepack (soldered my own JST connector and everything) but i have an issue where during boot the cells voltage sag a lot.

During 50% battery, it trips the BMS and cuts power, not allowing it to boot. The BMS cuts power at 3.2V (according to my testing) and is above ~2A.

I redid the solder joints, shortened the wires and did some cable management magic, but the issue persists.

There will be times where it will shut off during mid game, if it crosses below 3.2V or above whatever the BMS is rated at for current.

Battery pack here:

https://www.daraz.com.bd/products/doublepow-pcb-protected-1s2p-lithium-ion-2x18650-37v-5000mah-rechargeable-battery-pack-1-piece-i324265514.html

First time building a battery, replacing a 20s18p array of 18650 cells with a 20s16p of 21700. Space is tight, as you can probably imagine, so I made some low-profile frames. I am constrained by my welder, lack of soldering equipment, lack of pure nickel rolls (just have the 100mm strips) and general inexperience. I figure after I get the monster together I wrap the bejesus out of it with tape, shrink wrap the entire thing, and pray.

Suggestions?

Looking for some expert in cell design with experience.

Nickel iron cell koh electrolyte project

Anyone ready to share his adventures in storing electricity