NiMH pack failure
 

Hi. What do you suppose caused this pack to self destruct? I'm guessing I drew more amps than it could deliver, but that's just my guess.

It was a Great Planes 7-Cell 8.4V 1200mAh 4/5AA NiMH Panasonic plugged into a Great Planes ElectriFly T-600GD ESC System w/Gear Drive. I have no idea how to find out what the discharge rating of Great Planes packs are. I even checked the Panasonic site. I 'm under the impression that I need a pack that can deliver 25 to 30 amps and I have a feeling this pack was probably rated around 8C or 10C although I have no way of knowing. 10C would only be 12amps and I'm sure I exceeded that.

Thanks, David

RE: NiMH pack failure
 

It would appear from the picture that there may have been a bad solder joint or bad weld on the interconnecting strap, causing it to heat up and burn through the sleeve. I doubt if the cells were at fault in this case.

RE: NiMH pack failure
 

Thank you, Red. I know I need to break down and buy a watt/amp meter to find out what my electric systems are doing. But, until I get around to that (I'm new to electrics) is there a way I can find out what the discharge ratings of NiMH packs are? I've noticed that almost all Lipo packs provide such information: 15C, 20C, for example. The motor I have came with a 30amp ESC so I'm assuming it's capable of yanking over 20 amps out of a pack. With a 2000mah NiMH pack I would probably need a rating of at least 15C (30 amps).

In the meantime I will send my photo to Great Planes and see if they will replace it. My experience is that they are very good about taking care of people.

Thanks again.
David

RE: NiMH pack failure
 

Well, I got a pretty fast response from Great Planes tech support. I was told by them that most sub-C NiMH cells can safely discharge at 20C. That's much higher than I expected.

RE: NiMH pack failure
 

Did they offer to replace teh failed pack?

I had an issue that I sent to Great Planes and I didn't hear back from them for a couple of weeks. I sent my issue to them by e-mail. Did you telephone them?

Regards, -K01s [8D]

RE: NiMH pack failure
 

I emailed them and they responded withing 48hrs.

I was instructed to mail the pack to them. I'm sending it out tomorrow.

A month or so ago I purchased a GP motor that did not come with the caps and diode. They mailed them to me free of charge within 10 days.

With a giant distributor like GP, I feel like that is good service. To honest I was sceptical. They deal in such high volumes that I was prepared to be at the end of a very long list. Either they have a good number of techs working for them, or they work very efficiently, or both.

One thing I never do is sound angry in my requests. I always try to be polite and considerate. You see, I did a bit of computer tech support once and the angry emails got pushed to the bottom. When you're busy and the boss is bothering you and you're tired and hungry, the last thing you want to deal with is a troublesome client. I know what it's like to be in their shoes and I remember the people I was happy to help out.