Replace Battery, Controller, or Something Else?

[ronaldrodgers]

@ PCeBiker (family break) "...I'd suggest not trying to revive your battery any longer.
It seems to be making things worse?"
I will see what happens this next ride.
When I charged the battery on Sunday for 12 hours the battery read 54.3v. Today it read 54.0v. Yep, I think it is time to buy a new battery.

Take care all, talk to you later.

 

[PCeBiker]

@ PCeBiker (family break) "...I'd suggest not trying to revive your battery any longer.
It seems to be making things worse?"

I mistakenly thought that you had only riden your ebike a block with a fully charged battery and it shut down.

I will see what happens this next ride.

You only need to take note of the voltage when your BMS shuts down.
If you lose your data from your Watt meter, do what @harryS said and plug in your charger for a few seconds to wake up the battery, and check the voltage.

If your cut-off voltage is the same as before you started all this, then reviving your battery isn't working.

When I charged the battery on Sunday for 12 hours the battery read 54.3v. Today it read 54.0v.

I think that it's possible that the fully charged cell groups leaked some voltage through the BMS over to the partially charged cell group, and that's why your voltage dropped?
(That is complete speculation on my part though.)


I say keep charging it back up to 54.3 before you go for your next ride.
You may possibly be "forcing a balance" by doing so?

It's generally considered hard on a battery leaving it at full charge, but in your case, with your battery being out of balance, it might actually do some good.

Yep, I think it is time to buy a new battery.
Take care all, talk to you later.

My new BMS testing equipment arrived.

I hope my battery goes out of balance.
Then I'll have a chance to use it.

I don't want to tear into my healthy battery just to try it out.

 

[PCeBiker]

Here's a good explanation about balancing a battery,..

Are old battery packs safe?

I read a article that was saying that a battery pack that was loosing its ability to charge all batterys in pack, from use and recharging, over time,can catch fire. The article says the battery maintenance system only works to prevent over charging, but not to monitor the whole battery pack. It...

forums.electricbikereview.com

 

[ronaldrodgers]

I mistakenly thought that you had only riden your ebike a block with a fully charged battery and it shut down.



You only need to take note of the voltage when your BMS shuts down.
If you lose your data from your Watt meter, do what @harryS said and plug in your charger for a few seconds to wake up the battery, and check the voltage.

If your cut-off voltage is the same as before you started all this, then reviving your battery isn't working.



I think that it's possible that the fully charged cell groups leaked some voltage through the BMS over to the partially charged cell group, and that's why your voltage dropped?
(That is complete speculation on my part though.)


I say keep charging it back up to 54.3 before you go for your next ride.
You may possibly be "forcing a balance" by doing so?

It's generally considered hard on a battery leaving it at full charge, but in your case, with your battery being out of balance, it might actually do some good.




My new BMS testing equipment arrived.

I hope my battery goes out of balance.
Then I'll have a chance to use it.


View attachment 168315


I don't want to tear into my healthy battery just to try it out.

You must be a good person, because Santa brought you a great gift.

 

[ronaldrodgers]

Here's a good explanation about balancing a battery,..

Are old battery packs safe?

I read a article that was saying that a battery pack that was loosing its ability to charge all batterys in pack, from use and recharging, over time,can catch fire. The article says the battery maintenance system only works to prevent over charging, but not to monitor the whole battery pack. It...

forums.electricbikereview.com

Thanks for the link. I appreciate your attitude about fire safety. It is also a concern of mine.

 

[PCeBiker]

Thanks for the link. I appreciate your attitude about fire safety. It is also a concern of mine.

Post #10 explains how balance charging works, and post #13 shows how a regular plug in Watt meter can show you when the balancing is finished.

 

[ronaldrodgers]

Last night I charged the battery for three hours and the charger indicated it was fully charged. I am continuing charging today. I plan to use itThursday 12/28.
I charged the battery for 3 hours on 12/26. The battery was charged to 54.4 v. I continued charging on 12/27.
12/26 Charged for 3 hours
12/27- Charged for ? hours (I will enter the actual time on the spreadsheet later.)
When tested with Multimeter on 12/27/2023
1st Reading 55.5v
2nd Reading 54.8-9v
3rd Reading 54.8v

I am going to end this thread for the most part. I am going to add to the spreadsheets. I will be adding comments to the spread sheets as well. I will be charging the battery longer than needed, trying to balance the cells. I assume I will be purchasing a new mount that will hold the battery from my other ebike. I will add to this thread sporadically.

PCeBiker and harryS thank you for your assistance with this project.

 

[PCeBiker]

I think that it might be working.
Your voltages are getting higher.

55.5 Volts is kinda high though.
Anything over 54.6 can overcharge the battery.

You should be OK if you only do it once a month or so to balance the battery.

Check for heat or smells or any signs of overheating when it's at 55.5 volts.

Of course it's not good to leave a battery sitting at full charge for a long time, but you're doing maintenance that may really help to revive your battery.
Some people only do it once a year.

 

[ronaldrodgers]

Thanks, I watch charging batteries like a hawk.

 

[ronaldrodgers]

Someting new just happened. I went on a ride. I thought I was going to able to go 10 miles, but no the motor shut of at about six. That was a surprise,but not the biggest. The voltage left in the battery after the ride was 3.6v. Do you think the BMS went bad?

 

[harryS]

No. The BMS is probably working. You're out riding with a weak battery. One or more of the 13 cell groups discharged below its minimum value (about 3 volts), and the BMS shut off the battery, If you were to check it with a meter, it likely will have recovered a bit and be sitting around 3.3V, while the other twelve are closer to 4V,

Charge it back up and it will happen again.

Crappy day for riding in central midwest, but it is warmer, around 40F.
.