Rechargeable batteries not charging consistently

[Jerry1]

I have an issue that has started with my rechargeable batteries that I'm not sure how to resolve. It has happened with both AA and AAA batteries but this example is with some C-cell batteries I have. I have a unit that needs 6 C-cell batteries. It stopped working so I recharged the batteries. Three of the batteries seemed to recharge fine and according to the charger, that took 2647, 2524 and 2184 mAh. The three other batteries took 1100, 829 and 650 mAh. The batteries max is NiMH 1.2V 5000mAh. Given that the unit stopped working, I would have expected that the batteries would have taken on closer to 4000+mAh but I suppose that the problem is with the three batteries. Unfortunately when this has happened with some AA's, the next time I charged them I didn't have the problem with the same batteries. So, it seems somewhat sporadic. I have put the batteries that didn't take a full charge back on the charger and it seems like they're taking more power but I don't think I should keep dong that without knowing better what I'm doing.

My charger is a pretty good charger (OPUS BT-C3100) and I see other functions:
Charge
Discharge
Discharge Refresh
Charge Test
Quick Test

But, I'm not sure what these functions actually do and whether or not I should use them. I feel like I should do a discharge refresh but I'm not sure how to proceed. Looking for some input before I go further.

 

[Aerides]

How old are the batteries? I think some can become less effective after several years. Still far better in the long run!

 

[ncbill]

I have an issue that has started with my rechargeable batteries that I'm not sure how to resolve. It has happened with both AA and AAA batteries but this example is with some C-cell batteries I have. I have a unit that needs 6 C-cell batteries. It stopped working so I recharged the batteries. Three of the batteries seemed to recharge fine and according to the charger, that took 2647, 2524 and 2184 mAh. The three other batteries took 1100, 829 and 650 mAh. The batteries max is NiMH 1.2V 5000mAh. Given that the unit stopped working, I would have expected that the batteries would have taken on closer to 4000+mAh but I suppose that the problem is with the three batteries. Unfortunately when this has happened with some AA's, the next time I charged them I didn't have the problem with the same batteries. So, it seems somewhat sporadic. I have put the batteries that didn't take a full charge back on the charger and it seems like they're taking more power but I don't think I should keep dong that without knowing better what I'm doing.

My charger is a pretty good charger (OPUS BT-C3100) and I see other functions:
Charge
Discharge
Discharge Refresh
Charge Test
Quick Test

But, I'm not sure what these functions actually do and whether or not I should use them. I feel like I should do a discharge refresh but I'm not sure how to proceed. Looking for some input before I go further.

I would do the discharge refresh.

If the device that uses the C-cell batteries is low-drain (e.g., a radio) you could substitute AA rechargeable batteries in C-cell size adapters.

 

[Jerry1]

How old are the batteries? I think some can become less effective after several years. Still far better in the long run!

The batteries were bought/put into use October 2022.

I would do the discharge refresh.

If the device that uses the C-cell batteries is low-drain (e.g., a radio) you could substitute AA rechargeable batteries in C-cell size adapters.

I do have an adapter and am using it now while I recharge the batteries, so yes, that works no problem but, the C batteries last a great deal longer than the AA's. The device is my touch faucet at my kitchen sink. The C's last about a year as I have only charged them one other time. They came initially charged, so this would be the third cycle.

 

[braumeister]

I feel like I should do a discharge refresh but I'm not sure how to proceed. Looking for some input before I go further.

I think you need to run them down to zero charge, then put them on the charger. That should reset them.