How to discharge a battery fast? A LiPo discharge device

All (or almost all) modern battery chargers have a Discharge option. For all those cases when you want to discharge a battery at home. Useful stuff. However, almost always it’s limited to a relative low current. Max 1, maybe 2 amps. A bigger battery might take hours to discharge to a target voltage.
Some chargers, like Gens Ace IMARS DUAL have an option to use a External Discharge Device and increase discharge current. I’ve built such a device with a help of load resistors, wires, fan and brass sheet. And here is how it works.

0:00 The problem of a controlled discharge of LiPo batteries
1:09 DIY external discharge device
2:38 A quick battery discharge process
5:06 Additional notes
5:49 Summary

[FourthWayRanch]

I've got one of those huge resistors for my VESC, they're cool! the ham radio operators put a resistor in a paint can filled with mineral oil to use as a dummy load.

[MCsCreations]

Brilliant, Pawel! Fantastic work!!! 😃
We need more chargers with this feature!
Stay safe there with your family! 🖖😊

[sgilb]

This seems like a pretty versatile solution. You could certainly add more resisters, perhaps in series/parallel combination. You could also add a female XT60 connector to the resistor bank, allowing you to daisy-chain multiple resistor banks. You could have a small one for modest needs, a larger one for higher power, and both for maximum power!
One might also consider putting the resistors in a tub of water instead of using a fan. It should be safe at these voltages, and water can absorb a lot of energy, allowing you to run it at higher power.

[mihavuk]

Nice one, I'm still using 24VDC halogen car / truck light bulbs, 3 connected in paralell and pulling app. 180W. They do get hot too. But you can illuminate what ever you want during discharge. 😁 Ideal for small chickens maybe. 😉😁

[rasmusg]

Discharge without balance lead is no good. Any charger that can do this with balance lead connected?

[jurikristjouw]

Nice vid and explanation of that feature, not well known, but afaik, that feature exists already on the iCharger back in the old days ;-)

[michapeka]

Hmmm nice. You can use also empty large battery as load, or car battery

[primoziskra]

Some chargers (Junsi icharger) can not just discharge, but also charge battery conected to input. So instead oh heating resistors you can charge for example car battery. Or like I do use 6s6p liion pack to charge my batteries on field and sometimes discharge a battery back to field pack.

[shaider]

Hope you can get an actual heat sink for those large resistors. Best would be to have a thermal engineer model it via CFD to check on best resistive-load cooling config but I guess that's waay to costly at this scale.

[BBFPV]

Buy a 24V coffee machine and do something useful with the energy. 👍

[theflyingsandalrc]

Interesting, I'll have to try this

[UCMusic]

I managed to discharge 2x22000mAh 6S in 25 mins with 1500W 12V RV water heater. Overheating is no problem since resistor won't get much higher than 100°C if you provide enough water. Just be sure to have more than 10L for every kWh of batteries.😂