"Taps"

[kevinmccune]

an older Eahora XC 100 I gave away will not take a charge now,don't know how long it sat without a charge,any ideas?

 

[6zfshdb]

It's possible the cell voltage has dropped below what the charger needs to "recognize" the battery. Using a charger with a force start option is one possibility. Another is to wire a charged battery of the same voltage in parallel with the dead one. This can raise the cell voltage to the point where the charger will start charging.

Use caution when attempting this. A short, or reversing the polarity can cause damage.

 

[RunForTheHills]

Yeah, one or more cells have dropped below the low voltage cutoff and the bms is doing its job. Some people have revived such batteries by opening it up and individually charging the cells with an rc charger. But I would definitely charge it outside after that.

 

[harryS]

When the BMS is stopping the battery from charging, it often isolates the cells from the discharge port. leaving no access to recharge thru the output, The safer approach is to open the battery and measure the internal cell voltages.

Even then, I think this is why NYC had so many ebike fires. Too many users that could not afford to replace their low cost batteries. Then you had people with enough tech knowledge to open batteries, find discharged cells and perhaps recharge them, but without the knowledge to know when this becomes dangerous, Often, users were forcing recharge on cells that should have been retired.

Sure, if you know how to tinker on batteries, you might run across a few that can be revived safely. But I doubt that will be the case with a Eahora XC 100, made with low cost cells that have a short service life.

,

 

[kevinmccune]

When the BMS is stopping the battery from charging, it often isolates the cells from the discharge port. leaving no access to recharge thru the output, The safer approach is to open the battery and measure the internal cell voltages.

Even then, I think this is why NYC had so many ebike fires. Too many users that could not afford to replace their low cost batteries. Then you had people with enough tech knowledge to open batteries, find discharged cells and perhaps recharge them, but without the knowledge to know when this becomes dangerous, Often, users were forcing recharge on cells that should have been retired.

Sure, if you know how to tinker on batteries, you might run across a few that can be revived safely. But I doubt that will be the case with a Eahora XC 100, made with low cost cells that have a short service life.

,erers

thank you,I believe this bike carcass may now become a"tinkerers" front pocket find,I could get a new battery and related electronics,the trouble is,new ebikes are so cheap now,I have just about finished putting together one of my old favorite bikes,that means I may save myself some frustration.