Charging Through the "Output" Connector

[2old]

Accidentally (of course) I connected my 52V charger to the "output" connector of my 52V battery for three or four hours. It fully charged the battery with no excess heat or any problems. Did I do any damage to the battery or charger?

 

[john61ct]

That would only matter if the BMS were designed to prevent it.

Many designs, doing it that way is how you bypass the BMS restrictions.

Without a BMS they both go to the same points

 

[2old]

Thank you.

 

[docw009]

You bypass the overvoltage circuits behind the charging port when you come in via the output port. The hoverboard makers were doing that in 2017. With 100K units out in homes, all you needed were a few dozen chargers to go over voltage and cause a rash of exploding batteries. I believe they fixed it by switching to a single port BMS.

Having overvoltage protection saved my bacon when I was shipped a 52V battery/charger in 2016 by mistake when I ordered 48V. The 52V charger lived in my garage for a year, charging my 48V packs too. I eventually bought a 52V pack on purpose, and now I had to look at my chargers. One day I found I had two of them? Wow.

FInally, thru pilot error, I did connect a 48V charger to the output of a 36V pack. I did not burn my garage dowm, but I had to chuck the battery in a pail of water to kill it when I came back. It was so hot.

 

[john61ct]

Wow!

13S 46.8-48.1Vnom, 52-54.6Vch

14S 50.4-51.8Vnom, 56-58.8Vch

Anyone unknowingly using a charger designed for 14S on a 13S pack IMO should get a different hobby.

I never fully trust any charger, even if they cost thousands

always check Volts & Amps, with known-good instruments separate from anything "built in" to any device

ideally every charge cycle.

Over reliance on a BMS is worse than doing without one.

 

[2old]

You bypass the overvoltage circuits behind the charging port when you come in via the output port. The hoverboard makers were doing that in 2017. With 100K units out in homes, all you needed were a few dozen chargers to go over voltage and cause a rash of exploding batteries. I believe they fixed it by switching to a single port BMS.

Having overvoltage protection saved my bacon when I was shipped a 52V battery/charger in 2016 by mistake when I ordered 48V. The 52V charger lived in my garage for a year, charging my 48V packs too. I eventually bought a 52V pack on purpose, and now I had to look at my chargers. One day I found I had two of them? Wow.

FInally, thru pilot error, I did connect a 48V charger to the output of a 36V pack. I did not burn my garage dowm, but I had to chuck the battery in a pail of water to kill it when I came back. It was so hot.

Thanks, DW; probably I'm safe since only charging to 80% and checked the output of the charger which was accurate.

 

[2old]

Wow!

13S 46.8-48.1Vnom, 52-54.6Vch

14S 50.4-51.8Vnom, 56-58.8Vch

Anyone unknowingly using a charger designed for 14S on a 13S pack IMO should get a different hobby.

I never fully trust any charger, even if they cost thousands

always check Volts & Amps, with known-good instruments separate from anything "built in" to any device

ideally every charge cycle.

Over reliance on a BMS is worse than doing without one.

Thanks again; checked the output of the charger when I received it and it was correct. Plus, by charging to 80%, probably safe. Reconfigured system so the mistake can't be repeated. All things considered will charge battery outside and store it "safely".