Older Ni-Cd charger for NiMh?

[Wits' End]

I have an Archer (Radio Shack) 23-139 DC battery charger. How bad is it to use occasionally for charging newer NiMh's?
Specs: input DC 11-16v 6W Output DC 2.7V/8.6V 150mA max Date: Jan-Mar 1986
Just found this cleaning my tool area. Looking at this as an extra charger not my main.
TIA

 

[Mr Happy]

From the voltage of 2.7 V it looks like you would need to charge cells in pairs, and from the charge current of 150 mA you would need to charge on a timer.

Since 150 mA is below the 0.1C rate for most AA NiMH cells you could charge them safely, but using a charging time of (1.4 x capacity)/150 it would take some time. For example it would take 1.4 x 2000 / 150 = 18 hours to charge AA Eneloops.

Only you can decide if that's worth it.

 

[richardcpf]

Output DC 2.7V 150mA

150mA charging a 2000mah+ nimh? Dont waste your time... NiMh chargers are cheap, I own the energizer 1-Hour charger and it works wonderfuly.

 

[jerry i h]

Nope. Not for NiMH. However, keep it. I find NiCd AA and AAA to be extremely useful, versatile, tolerant of abuse, not to mention cheap.

 

[45/70]

I think it'll work OK, using Mr H's formula. I have a 6 Bay (2 single + 4 bays that take 2 in series, or 10 cells total) that I occasionally used. It has the same 150mA rate (50mA for AAA's). I figured it was pretty close to a forming charge for 1800's and probably, at least, not damaging for 2000's. Now that I have 3, C-9000's, I probably won't be using it any more.

As long as the charge rate does not exceed 0.1 C, NiCd chargers will work with NiMh's, using the formula. As has been mentioned, it will take a while.

Dave

 

[Black Rose]

I thought the rule was that you could use a NiMh charger to charge NiCd cells, but you couldn't use a NiCd charger to charge NiMh cells.

 

[Mr Happy]

Rules are made to be broken.

 

[Mr Happy]

More specifically, fast NiCd chargers that rely on -dV termination should not be used with NiMH, but slow chargers that use a constant charging current less than 0.1C are fine, as long as you stop charging at about the right time.

NiMH cells can take a 0.1C overcharge for quite a long time (hours, not months) without damage.

 

[TakeTheActive]

Not "As-Is"!

I have an Archer (Radio Shack) 23-139 DC battery charger. How bad is it to use occasionally for charging newer NiMh's?

I just GOOGLE'd the Part Number you gave (to see if I could find some 'Tech Specs' or a Manual) and it came back with:
3.7V/1000mAh Li-ion Battery for Sanyo 8300 (Red).

Is 23-139 the correct Part Number?

On the other hand, based on it's age (~23 years), is it TIMED or DUMB?

• If it's TIMED, you'll (probably) have to RESTART it (one or more times) to fully charge CURRENT NiMh cells.
  .
• If it's DUMB, you can safely pump 150ma into a 1500mAh cell for 16 hours, or into a >1500mAh cell (i.e. a 2000mAh LSD) for a bit longer (2000mAh / 150ma * ~1.6 = ~21.3hrs)

Personally, based on my recent reading of the ARCHIVES here at CPF, I just dug a few old DUMB / TIMED chargers out of storage in an attempt to rejuvenate / de-crystalize some NEGLECTED 1300mAh, 1600mAh and 2000mAh cells. You can use an OLD charger to recharge NEW cells *IF* you understand WHAT you're doing. BUT, personally, I wouldn't use an OLD charger on a regular basis. I'd use a NEWER charger that could provide 0.5-1.0C with -dV termination...

 

[Wits' End]

Re: Not "As-Is"!

I have a DC charger I can use, this is just an extra. It sounds like the dumpster is the best place for this. Charging at -20 F probably isn't the best anyhow

 

[45/70]

Re: Not "As-Is"!

Charging at -20 F probably isn't the best anyhow

Probably not, eh?

Dave