CBP1650's in FM 9AA-3D adapter on Maha II Charger

[Lightedge]

CBP1650\'s in FM 9AA-3D adapter on Maha II Charger

I really don't know where this post belongs but I believe Mag85 owners will be interested.

I just received my new Maha C777 Plus II charger. Very nice. I charged my CBP1650's in the FM 9AA-3D adapter and the batteries got VERY hot. I should have monitored it more closely since I have not used this type of charger before but I didn't. Regardless, one of my batteries blew (no explosion, it just fizzed and stunk for a little while). I thought the temperature sensor would have prevented this. I placed the sensor on one of the batteries in the middle of the pack. I clipped the alligator clips to the adapter that FM provided. I set it to charge for Nimh and let it charge. The charger charges at 800mAh.

Will these batteries not handle an 800mAh charge? I thought this would be a good charger for this application since so many CPFers use it.

Did I do something wrong?

I appreciate your help.

 

[bwaites]

Re: CBP1650\'s in FM 9AA-3D adapter on Maha II Charger

I charge mine regularly at 1.6 amps.

Something very wrong here. My guess, a dead short somewhere in the pack.

Or reverse polarity of the charging cycle.

Bill

 

[js]

Re: CBP1650\'s in FM 9AA-3D adapter on Maha II Char

Lightedge,

Well, first of all, new NiMH batteries should all get a .1C 16 hour slow charge (NOT peak detect or smart charge), and this is especially important if you are grouping them in a battery pack or battery holder. If you insist of peak charging them right from the beginning, you must charge them individually.

So, if your batteries were all at different states of charge, then that confuses the peak detect circuitry. From what I've read, it normally caues the charger to end charging BEFORE all of the cells are fully charged, and not what happened to you. But different circuitry works differently. Perhaps this is what the 777 + II is likely to do. Not sure.

And yes, in the future, it is a very good idea to always keep an eye on a new charging set-up to ensure that it will work as expected.

 

[Lightedge]

Re: CBP1650\'s in FM 9AA-3D adapter on Maha II Char

I did slow charge these batteries overnight on their first charge. This was their second charge and they have all been used equally.

Sounds like the Maha should work with these batteries and this was probably a user error.

I'll spend more time with this.

Thanks for your input.

 

[birderbill]

Re: CBP1650\'s in FM 9AA-3D adapter on Maha II Char

Just how important is this slow charge on a new set of NiMHs? The Maha 777 doesn't not appear capable of doing this. If this is so important why would they design build and sell a $75 (or more) charger with NiMH capability that doesn't support an inherent requirement of NiMHs??

So if I want to get some of the fantastic new CBP 1650s I need a different charger? Can anyone recommend one that isn't an arm and a leg? I guess I can spend a week or so doing the initial charge for 9 1650s one at a time, but I'd rather do something else.

 

[SilverFox]

Re: CBP1650\'s in FM 9AA-3D adapter on Maha II Char

Hello Birderbill,

High performance cells can be a bit "raw" from the manufacturer. The initial charge "forms" the cells and gets them in balance in the pack. For cells that are in "hard use," the forming charge is critical initially and should be done every 10-15 cycles of use. The forming charge is 0.1C for 16 hours.

The Maha charger does not seem to support this, but there may be a work around. If I were using this charger, I would first do a discharge of the cells, let them charge up watching them very carefully for any signs of overheating (good use for the temperature probe), and let them trickle charge at the end of the full charge for a couple of days.

Tom

 

[birderbill]

Re: CBP1650\'s in FM 9AA-3D adapter on Maha II Char

Hi Tom,

The Maha can do the discharge part, although it does apply a 3 min trickle charge to "recognize" batteries. It might trickle charge near the end of the charging cycle, but it will shut off automatically when it detects full charge. It also shuts off after 13 hrs sutomatically.

 

[SilverFox]

Re: CBP1650\'s in FM 9AA-3D adapter on Maha II Char

Hello Birderbill,

I do not own a Maha charger, but usually the cut off timer is for the quick charge cycle. I believe it will continue to trickle charge as long as the battery is hooked up.

Tom