Maha C777-Plus II Charging issues

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lordsaryon

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Mar 10, 2005
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40
Location
Saint Louis
I recently acquired a [email protected], and haven't been able to test it yet.

I plugged in the Maha, plugged in the pac. Had a few problems, but it finally started to charge.

When it "cut-off" saying it was full, it read 8.2V, 100maH.

Now when it charges, it jumps to around 10.5V, and slowly drops.

I never do get a full charge. I have hit the discharge button to see if maybe something was wrong, and it seemed to do nothing (well, it discharged, and re-charged to those low levels.)

Does anyone have any ideas for me to try?

Thanks.

(BTW: The cells are 1500maH cells.)

Edit: I sat and watched it this time. The charger will go for about 6 minutes, and beep, and reset to a state as if there was no battery pack connected. The 9AA-3D pack was extremly warm where you plug the charger into. It's almost as if it's shorting. Does anyone have anything I can test, or a way to see if something is wrong with the battery carrier?

Re-Edit: When testing the cells, I have 6 at ~1.4v, and 3 at ~.050V, and the + and - are reversed (The 6 have the "crease" at the + side). Maybe bad cells? Did i measure wrong?
 
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Shark

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Feb 7, 2003
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200
Location
Oswego, IL
Cell reversal usually happens when the pack was discharged too low. I dont think there is a cure for it either.
I have had my C777-Plus for years and never had any problems.
Your problem with the batt pack may not have been caused by your charger, have you charged any other packs with it?
 

pertinax

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Oct 27, 2005
Messages
219
Get a battery holder that holds, say four batteries. Through a process of elimination, isolate the bad cells. If they're really not charging, pitch them.

I find that it works better to cycle all new batteries through the Maha (or equivalent) for four or five cycles before putting them in the battery pack for the light. Then do a full burn on the light. If it shuts down prematurely, pull out the pack, and feel the batteries. Some will probably be MUCH hotter than the others. Mark them as suspect. Yank the cells out of the pack (quickly), and check their voltage individually. You'll probably find that the hot cells have much lower voltage (tenths of a volt lower) than the others. Replace the problem cells. Repeat until you get an acceptable burn time. Demote the suspect cells to lighter duty.

I'd recommend buying 12 cells to get nine good ones for a Mag-85. Such may not be necessary with the high-current ones (CBP1650 and so forth), but it does seem to be the case for Energizer 2500s.

Pertinax
 

bcwang

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Feb 5, 2002
Messages
456
Location
California
pertinax said:
I'd recommend buying 12 cells to get nine good ones for a Mag-85. Such may not be necessary with the high-current ones (CBP1650 and so forth), but it does seem to be the case for Energizer 2500s.

Pertinax

You've had bad consistency with the 2500s? The HR stamped 2500s are my most consistent cells compared to all the other ones I've used. I haven't had a bad one yet with over 24 in use, and they're all about the same capacity.

lordsaryon,
I do think doing some cell matching before using them in packs is a good idea. Cell reversal is not a good thing, however you said you only charged the pack and haven't even used the flashlight. Maybe you do have some incorrectly installed cells, I can't imagine any cells being reversed polarity while others are almost fully charged unless they are installed backwards.
 

PaulW

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Mar 23, 2003
Messages
2,060
Location
Laurel, Maryland
lordsaryon,

As Shark suggested, your problem might be with the holders for your cells. I used to have to have similar glitches when trying to charge my Mag85 cells with my Maha C777-PlusII. I could get a charge for only a short period of time, whereupon it would stop and then start over again. And when it finally quit charging completely, the charge was not full. I had to resort to using a radio shack 10-cell holder, which did the job -- but, of course, did not fit in my Mag85.

This problem was when I was trying to charge the nine cells in three 3AA-to-D holders. After I got a better 9AA-to-3D holder the problem went away, and the charging process was effortless. Fivemega was the supplier and they are beautiful holders:

http://candlepowerforums.com/vb/showthread.php?t=107769

I don't think he has any more for sale. But, if you're interested, you might be able to pick one up in the B/S/T forum.

Paul
 
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