diy solar

diy solar

Built a DIY 20A/cell 8 cell charger for the BYD modules.

Maast

Compulsive Tinkerer
Joined
Oct 31, 2019
Messages
773
Location
Washington State
Made a 20A/cell 8-cell charger so I can charge all the cells up to the same voltage. I was having a hell of a time getting a balanced charge for these used BYD modules so I can test them.

Built my own because I couldnt find a 8 cell charger that would charge individual cells separately that had a decent amperage to it. Or it was stupid expensive. Put this one together for about $200-250.

This is version 2, version 1 went up in a amazingly large and thick cloud of white smoke when I found out the RSP-100-3.3 power supplies arent reverse protected like I thought and I left them connected while powered off and I started discharging the battery. This version has two paralleled shotty diodes on the positive lead to keep that from happening again. Diodes get (literally) blistering hot w/ 10A each going through them so I thermal epoxied a heatsink to it which drops the temps down to about 150F. Still too hot so I'm adding another heatsink to the other side.

MacGyver as hell but it works really well. The best thing is I can set it up and walk away - no more watching it like a hawk for runaway cells and burning off charge with makeshift resistors of stainless safety wire or adding a power supply charger to a lagging cell. I was taking days to get a single module set up before I could test it, now I just strip the module, hook it up and go to work and then test it the next day. Huge time saver.

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