"C" size rechargables

[smknman]

I need 8 rechargable C batteries for a boombox, I don't care about chemistry only capacity. The highest capacity I have found NiMh at ~3300, however a normal alkaline is more like 8000mah. Is there a rechargable cell that aproaches this?

 

[Meduza]

3300 from a NiMh C-cell? thats not good...

here you got some real NiMh C-cells:
http://www.thomas-distributing.com/cbatteries.php
http://www.batteryspace.com/index.asp?PageAction=VIEWCATS&Category=227

5-6000mah is normal for NiMh C-cells...

 

[smknman]

I may not kow much but at least I know where to ask questions. Thanks Meduza!!

 

[john2551]

Also if you see something higher that 6000mah on eBay sold directly from China beware that most of those are frauds. 2500mah with labels that say a lot more.

 

[tino_ale]

AW is going to sell C-size protected li-ion very shortly (end of fev. is the ETA). Check out his thread in dealer's corner here Those should be 3200mAh.

Don't forget that the capacity is not all, you must also consider the voltage...

In the end, those li-ion will have roughly the same Wh in them as alcaline do.

 

[Thujone]

If you use the lithiums you will have to reduce the cells used in order not to blow up the 'boom'box... So even if the cell contains the same energy as an alky one you would still be cutting your cap in half by dropping half the cells. May as well stick with the NIMH at least he wont have to come up with dummy cells that way.

 

[smknman]

HHHMmmmmmmmmmm. The boom box takes 8 c cells in series giving 12v. 4sets of parrelel pairs of Liths in series gives 14.8v. Is this safe? that would give me the capacity I'm looking for I believe with only a ~3 volt increase. Am I in the right ballpark?

 

[Thujone]

If the cells are 4.2v off the charger (they will be) you would have 16.8v with 4p2s. Seems a bit strong to me, YMMV

 

[smknman]

Thanks for the warning, I guess its 6000mAh.

 

[TigerhawkT3]

What are the contacts inside the boombox like? If they stick out a bit, you could go with SLA - just get a pair of alligator clip wires and hook it up. You'd need the right charger, though.

 

[Thujone]

What are the contacts inside the boombox like? If they stick out a bit, you could go with SLA - just get a pair of alligator clip wires and hook it up. You'd need the right charger, though.

This is the lightest equiv to him doing 6ah NIMH and it weighs 3.1lbs. If it doesnt move then sure go for a huge external SLA like this otherwise just get the NIMH they will fit internally and work well.

 

[Brighteyez]

Those boom boxes that take 8 batteries generally also have a 12VDC input for use with a car lighter jack. A coaxial power plug connected the a 12V 7A SLA battery would indeed do the trick if that is the case; no real need to fool around with alligator clips.

Personally, I think I'd be inclined to try and stay with 4500-5000 mAh cells, given what has happened with the increased self-discharge rates from the higher capacity AA sized batteries.

This is the lightest equiv to him doing 6ah NIMH and it weighs 3.1lbs. If it doesnt move then sure go for a huge external SLA like this otherwise just get the NIMH they will fit internally and work well.