HELP PLEASE I think I may have some bad cells

[Moltensurf]

If you have a BMS hooked up, it is safe. Be aware that the state of charge is unknown, so charge the pack until one cell is at high voltage disconnect, then parallel them to get them all fully charged before testing as a pack. Sounds like you got what you paid for.

I picked up a 12 V/24 V charger, so I may charge the pack with the BMS connected. I have them on a small bench charger right now, waiting for them to top balance.

 

[Gazoo]

I picked up a 12 V/24 V charger, so I may charge the pack with the BMS connected. I have them on a small bench charger right now, waiting for them to top balance.

Did you get a smart BMS? I am a little lost here and don't know which BMS you purchased? And what charger did you buy?

 

[Just John]

If I test them as a pack, with the BMS hooked up. I will get a full read out of each individual cell? Will I be able to tell if there is a problem with a cell? Or do I need to drain them all down one at a time?

You really should take them apart, top balance them, and then test as a pack. The good news is that charging as a pack is faster until you have to parallel them. Even then, likey 90% of the balance is done, so shorter wait. Until you do that, they are all really at a random state of charge.

 

[Moltensurf]

Did you get a smart BMS? I am a little lost here and don't know which BMS you purchased? And what charger did you buy?

I do have a BMS. It’s a 24 V overkill solar. The charger I got is just a little smart charger it’s called Foxsur It’s a 12 V/24 V charger. I hooked up the BMS, but when I connected the charger it did not want to charge. I rewired the cells in parallel and I am once again charging with my bench charger. I set the bench charger to 3.65 V, but when I connect the leads to the battery terminals it drops down to 3.5 V. 8.77a. It’s been charging for about 24 hours now.

 

[Dzl]

[edit: wrong thread, sorry]

 

[Moltensurf]

Did you get a smart BMS? I am a little lost here and don't know which BMS you purchased? And what charger did you buy?

I do have a BMS. It’s a 24 V overkill solar. The charger I got is just a little smart charger it’s called Foxsur It’s a 12 V/24 V charger. I hooked up the BMS, but when I connected the charger it did not want to charge. I rewired the cells in parallel and I am once again charging with my bench charger. I set the bench charger to 3.65 V, but when I turn it on it drops down to 3.5 V. 8.77a. It’s been charging for about 24 hours now

 

[Just John]

I do have a BMS. It’s a 24 V overkill solar. The charger I got is just a little smart charger it’s called Foxsur It’s a 12 V/24 V charger. I hooked up the BMS, but when I connected the charger it did not want to charge. I rewired the cells in parallel and I am once again charging with my bench charger. I set the bench charger to 3.65 V, but when I turn it on it drops down to 3.5 V. 8.77a. It’s been charging for about 24 hours nowView attachment 35558

My advice would be to hook them up in serial again with the BMS. Then set your power supply to 29 volts and use it instead of the battery charger which doesn't appear to have a lithium setting. At 10 amps, looks like your power supply is more powerful than the charger anyway.
Likely the charger thinks (without a Lithium setting) that your battery is already charged.

This looks like your charger, and I hate to say it, but it will not work for Lithium cells, only lead acid and AGM.

Having said that, 8 times 3.65v is 29.2 volts, and 10 amps at nearly 30 volts would be running the power supply all out. In other words, you might wish to limit the current to 8 amps rather than 10, simply because these Chinese power supplies like to die when run at 100% for extended periods of time. Your power supply will work better and faster than the charger. Overkill makes a quality BMS, just make sure the cell high limit is set to 3.65 volts, and it should stop the charge the moment the first cell is full. Then you can parallel the cells for the last top balance (in the meantime, charging as a pack means 1/8th the time, because each cell is getting 8 to 10 amps, rather than 8 to 10 amps divided by 8).

 

[Gazoo]

I do have a BMS. It’s a 24 V overkill solar. The charger I got is just a little smart charger it’s called Foxsur It’s a 12 V/24 V charger. I hooked up the BMS, but when I connected the charger it did not want to charge. I rewired the cells in parallel and I am once again charging with my bench charger. I set the bench charger to 3.65 V, but when I connect the leads to the battery terminals it drops down to 3.5 V. 8.77a. It’s been charging for about 24 hours now.

I have that BMS too and when I first hooked it up wasn't able to get any current to the load.

Within the app settings there is a setting for driving mode. In driving mode a padlock (protection lock) is displayed on the main display. When tapped, it turns the BMS on or off. It didn't work until I uninstalled the app and reinstalled it. Then the BMS started to pass current and the protection lock worked like it's supposed to.

The other setting is monitoring mode and that's the setting I prefer. Next time you hook up your BMS check these settings and see if you can get it to come to life. If not try uninstalling the app then reinstalling it.

 

[Gazoo]

The charger I got is just a little smart charger it’s called Foxsur It’s a 12 V/24 V charger.

Regarding the charger the people reviewing it on Amazon say it doesn't work well for 24 volts. At most it may charge a 12 volt battery to 13.8 volts. Whatever you do don't use the pulsed mode feature. I think that's the same as disulfate/equalize settings and should not be used with these cells.

 

[Moltensurf]

Regarding the charger the people reviewing it on Amazon say it doesn't work well for 24 volts. At most it may charge a 12 volt battery to 13.8 volts. Whatever you do don't use the pulsed mode feature. I think that's the same as disulfate/equalize settings and should not be used with these cells.

Thanks for the info, I will be sending that charger back.

 

[Gazoo]

Sorry I forgot to mention I am using the Android app with the Overkill.

 

[Moltensurf]

My advice would be to hook them up in serial again with the BMS. Then set your power supply to 29 volts and use it instead of the battery charger which doesn't appear to have a lithium setting. At 10 amps, looks like your power supply is more powerful than the charger anyway.
Likely the charger thinks (without a Lithium setting) that your battery is already charged.

This looks like your charger, and I hate to say it, but it will not work for Lithium cells, only lead acid and AGM.

Having said that, 8 times 3.65v is 29.2 volts, and 10 amps at nearly 30 volts would be running the power supply all out. In other words, you might wish to limit the current to 8 amps rather than 10, simply because these Chinese power supplies like to die when run at 100% for extended periods of time. Your power supply will work better and faster than the charger. Overkill makes a quality BMS, just make sure the cell high limit is set to 3.65 volts, and it should stop the charge the moment the first cell is full. Then you can parallel the cells for the last top balance (in the meantime, charging as a pack means 1/8th the time, because each cell is getting 8 to 10 amps, rather than 8 to 10 amps divided by 8).

OK I got the BMS hooked back up. 29 V 8 A. I have my BMS online on my iPhone

 

[Moltensurf]

Sure appreciate all the help, I sure am learning a lot.

 

[Moltensurf]

Sorry I forgot to mention I am using the Android app with the Overkill.

Hey having trouble with my bms. My cells are 216 amp hours. 100 amp hours is programmed into the bms. The BMS will not charge past 100 amp hours without changing some settings. I bought the app where I can reconfigure parameters. I figured 216000 miliamp hours for cycle capacity. If the design capacity is 200 amp hours. In this portion would I put 200000?
Another question once you have those numbers where they’re supposed to be plugged in how do you hit enter so it actually changes?

 

[Dzl]

Here is a to link to the manual I believe they outline each settings parameter.

 

[Moltensurf]

Here is a to link to the manual I believe they outline each settings parameter.

I’ve been looking at this, it explains how you calculate the numbers, but not actually how to enter them; unless I am missing something.

 

[Gazoo]

I don't know anything about the iPhone app.

When I installed the android app, the app asked me to enter the designed capacity and the cycle capacity using ma's. If you uninstall and reinstall the app, the app should ask you for those numbers if the iPhone app works like the Android app. Once the app is installed the nominal capacity can be changed and that value is entered in Ah's.

 

[Moltensurf]

I don't know anything about the iPhone app.

When I installed the android app, the app asked me to enter the designed capacity and the cycle capacity using ma's. If you uninstall and reinstall the app, the app should ask you for those numbers if the iPhone app works like the Android app. Once the app is installed the nominal capacity can be changed and that value is entered in Ah's.

Bummer, it doesn’t work the same way on my iPhone

 

[Gazoo]

Maybe @HRTKD would know. I think he uses the iPhone app.

 

[Moltensurf]

I got it, check out this short video.