NiMH for ignition batteries?

Ed,

Lots of guys are running NiMH batteries for ignition with good success.

Thanks. It's good to know that others have success with them.

I kind of remember some debate about them, but none of the details. It may have had to do with pack impedance when using the same mah size packs as nicads. I was going to use 2,000 mah NiMH packs instead of 1,200 mah nicad packs, thinking that may alleviate the problem.

Ed Cregger

Ed, I was at a recent IMAC contest and lots of people are running NiMH ignition _and_ receiver packs. The technology is becoming more and more accepted. You just need to quit asking these damn fool questions. Oops, group mentality again :).

Rein

That's the only kind of questions I know, Mitch. 8>)

Ed Cregger

Thanks, J. I'll give the websites another gander.

Things are a changing when it comes to batteries. I also like the idea that I can just throw them in the trash when I'm finished with them and not have to worry about special disposal methods, in addition to the added capacity for the size and weight.

Ed Cregger

Thanks, Mark. Maybe that is where I saw the reference. Anyway, nothing succeeds like success. I'll give an NiMH pack a try and see what happens.

Now to find an individual willing to be an R/C caddy. 8>)

Ed Cregger

| Thanks. It's good to know that others have success with them. | | I kind of remember some debate about them, but none of the details. It may | have had to do with pack impedance when using the same mah size packs as | nicads.

That's exactly it.

| I was going to use 2,000 mah NiMH packs instead of 1,200 mah nicad | packs, thinking that may alleviate the problem.

You could look up the internal resistance of your 2000 mAh NiMH cells and compare them to that of the 1200 mAh NiCd cells, and if they're somewhere close, they'll be just fine. And I suspect that the values for a 2000 mAh NiMH and 1200 mAh NiCd are fairly close.

One other potential problem ... NiMH cells self-discharge 2 or 3 times as fast as NiCd cells. I don't get to go flying as often as I'd like, and often when I do I'm flying gliders or electrics, so my glow igniters tend to last a long time between charges, sometimes several months. A NiMH cell would be almost completely discharged within a month. Not really a big problem if you fly a lot, but if you don't it might be annoying.

Le 9/07/03 11:44, dans ouROa.35960$ snipped-for-privacy@newsread1.prod.itd.earthlink.net, « Ed Cregger » a écrit :

In term of battery use, it's interesting to know the wattage neccessary for the ignition system. I read somewhere that the drain was around (to be confirmed 200ma/h). Any battery in the capacity range over 600 ma would be fine in this case.

As soon as the drain is moderate, any type NiCd, NiMh, Li-ion or polymer would be used.

I hope so because i'm on my way for a "Petit Gros" (french in the text) with a kawasaki RD33 weed eater engine and Electonic ignition system. (8000 t/mn with a 18*10).

Marc.

Under normal battery conditions (using a nicad pack), the manufacturers recommend using a 1,200 mah pack at a minimum, if I'm not mistaken.

Cliff Griffin, a former newsgroup participant, had experimented with using much smaller packs and found that some ignition systems were particularly frugal in their consumption of power, while other ignition systems depended upon a heavy dump of electrons in order to keep everything tidy. This is why I asked if it was still a problem.

I miss that rascal, Cliff.

Ed Cregger