Charging C or D batteries in AA/AAA charger?

[oronocova]

I have a ROV PS1 charger I use for aa/aaa. Eventually I will get a better charger but for now would it work to make an adapter (i.e. wire leads) and charge C and D cells with the same charger. Would it work, but only take longer? From what I have read the PS1 is not a smart charger. It reads 2VDC 200mA x 4 on the back. Would it make a difference if the charger was smart or trickle?

Thanks in advance, I only have a few applications for C/D cells but would like to convert them over to rechargeable as well.


-Jon

 

[SilverFox]

Hello Jon,

If you can live with 40 - 80 hour charge times, I don't see any reason why it won't - eventually - work.

Tom

 

[jayflash]

Tom, the "chemistry" of the cells would benefit from a .5C or 1C charge rate, correct? I was thinking of upgrading my old, dumb, 400mA charger for my new 5Ah and "7Ah" NiCd cells to improve their performance. Do I have this right? Thanks, again, Tom?

 

[SilverFox]

Hello Jayflash,

The primary reason to charge at 0.5 - 1.0C is to generate a strong and reliable end of charge signal for -dV termination.

A secondary theoretical reason is that if you discharge at higher rates, charging at higher rates will allow better performance during the discharge. The RC people adhere to this, and there is some substantiation of it in plating performance. However, there are a lot of variables and loose ends in this theory.

Tom

 

[jayflash]

Tom, thanks so much for your ongoing help. I appreciate the time you take for all of us.:twothumbs

 

[Al Combs]

Hello Jayflash,

The primary reason to charge at 0.5 - 1.0C is to generate a strong and reliable end of charge signal for -dV termination.

A secondary theoretical reason is that if you discharge at higher rates, charging at higher rates will allow better performance during the discharge. The RC people adhere to this, and there is some substantiation of it in plating performance. However, there are a lot of variables and loose ends in this theory.

Tom

Do they make a D cell charger with 10 amp charge rate? I was looking at the MAHA MH-C808M with 2 amp rate. But I didn't want to spend $90 on the charger. I ended up with a Vanson BC1HU from BatteryJunction for $26. To get around the 20 plus hour charge time for a 10 AH D cell for my MagLite 3D-P7, I bought 2 sets of batteries to rotate them.

The back of the charger says 14 hour timer mode for the 9 volt cells and -deltaV for the rest. It does take just shy of a day to charge D cells. As you say, I wonder how they are able to detect the voltage drop at such a low charge rate of only 0.07C? But it seems to work OK. One by one the LED's switched to green as it went into trickle charge mode. Maybe as the batteries get older it will be a problem.

I saw another member's post saying the BC1HU flagged several brand new LSD cells as being bad. I guess I got lucky by buying the cheaper Tenergy cells from BatteryJunction. Or their was a problem with his charger.

 

[SilverFox]

Hello Al,

To get 10 charging capability you need to move up to the high end hobby chargers. If you didn't like the price of the C808M, you probably won't like the prices of these high end hobby chargers either.

The BC1HU has a safety timer built into the main charging too. I believe the current model switches over to trickle charge after 14 hours for D cells. The older models switched over after 11.5 hours. There have been reports of C and D cells venting on the BC1HU due to missed termination. These are usually caused by topping off the cell after a charge cycle.

A 10 Ah cell charged at 0.1C (1 amp) will take around 14 - 15 hours to fully charge from empty. This means that the BC1HU would have to run for around 20 hours charging at 700 mA to fully charge your cell.

The C808M only charges at 2 amps, but it has a back up method of termination. It terminates on -dV, but also on peak voltage. If the charger misses the -dV signal due to the less than ideal charge rate, it will keep charging until the cells voltage hits a peak value that occurs before overcharging damage occurs.

Tom

 

[Al Combs]

Hello Al,

To get 10 charging capability you need to move up to the high end hobby chargers. If you didn't like the price of the C808M, you probably won't like the prices of these high end hobby chargers either.

I figured as much.:devil:

The BC1HU has a safety timer built into the main charging too. I believe the current model switches over to trickle charge after 14 hours for D cells. The older models switched over after 11.5 hours. There have been reports of C and D cells venting on the BC1HU due to missed termination. These are usually caused by topping off the cell after a charge cycle.

The Chinese/English directions were so vague I specifically checked for this. It took over 20 hours for the first of 3 D cells to green light on my BC1HU. The directions on the back of the charger say only the 9 volt outlets are timer terminated.

Thanks Tom!

 

[SilverFox]

Hello Al,

I only have 2 of these chargers, and I am sure there are many more revisions out there. My first one actually lists the 11.5 hour timer for D cell charging. My second one did not list the timer value, but I was informed of it when I contacted the manufacturer. At that time I was told that Vanson will license the charger for private labeling and will tweak some things according to what is specified by the buyer.

After having a few C and D cells get hot on my BC1HU, I decided it was false economy to keep using it and moved on to the C808M. My cells don't get hot, or vent, with that charger, so I consider it money well spent. D cells can get expensive. I had 2 D cells and 2 C cells go south on me using the BC1HU. Since I moved to the C808M, I have had no further problems.

However, I must say that I have been using the BC1HU to try to revive some 10 year old NiCd D cells...

Tom

 

[Al Combs]

Hello Al,

I only have 2 of these chargers, and I am sure there are many more revisions out there. My first one actually lists the 11.5 hour timer for D cell charging. My second one did not list the timer value, but I was informed of it when I contacted the manufacturer. At that time I was told that Vanson will license the charger for private labeling and will tweak some things according to what is specified by the buyer.

After having a few C and D cells get hot on my BC1HU, I decided it was false economy to keep using it and moved on to the C808M. My cells don't get hot, or vent, with that charger, so I consider it money well spent. D cells can get expensive. I had 2 D cells and 2 C cells go south on me using the BC1HU. Since I moved to the C808M, I have had no further problems.

However, I must say that I have been using the BC1HU to try to revive some 10 year old NiCd D cells...

Tom

I'm not sure if it matters, but I ordered a BC1HU from BJ and received a BC2HU by mistake or as a replacement. Not just a matter of including a 12V cigarette lighter adapter, it charges at 700ma instead of 820ma. Long and longer didn't matter to me at the time. The BC2HU definitely terminates by charge completion and not time.

 

[oronocova]

Thanks for the input all. I was looking at the same Vanson charger. Sounds like a good buy for the money, I'll probably end up with that one so I don't have to wait half a week for charging.
Thanks again, Jon

 

[VegasF6]

I had a post about this charger with the LSD cells, I don't think it was me you were referring to though? In my case it didn't "flag" the cells as bad, but it never terminates properly. Well, that's not true. Sometimes it does, sometimes it doesn't. The recomendation was to get the Maha, but even that doesn't charge at .5 - 1C for these 10 amp batteries. As far as I know, to get anywhere near the recomended charge rate, you are going to have to use a hobby charger, something like a Triton or a Bantam. I don't want to post a link as it seems to be frowned upon lately, but you may want to do some reading at a site like RCgroups.com. I recall when I was doing some research on Emoli and A123 battery I saw a very respected member from here asking technical details about them. It was enough to convince me they must know what they are doing over there