Break In for Nimhs?

[ctdahle]

I just recieved a pair of NiMH packs to upgrade my Cutie. I charged them for 16 hours at 1/10c and then went flying.

No question that they give me more than double the flight time for the same battery weight, but the performance of the model is considerably dimininshed. The plane mushes around the field rather than climbing out with authority. It needs full throttle just to stay airborne and it's a long slow process to get it up to a comfortable altitude.

I had heard that NiMH's have higher internal cell resistance and therefore cannot deliver the same current as comparable NiCd's but I didn't expect such a decrease in performance.

Since I know that people are using NiMH's with good success, I am wondering if they will get better after a few charge discharge cycles, or should I just get along with nicads until I can upgrade to LiPo (which means not only batteries, but new chargers, esc's and gearboxes too I think.)?

[Patch]

I believe (that means I'm not very qualified to answer this) that NiCads are better for high output use, I think that's why they're used in a lot of RC cars. I remember reading a huge article on batteries. If I can find it, I'll post it.

[ctdahle]

Apparently the answer is that "yes" NiMHs do need a break-in period.

I am getting stronger motor runs now and can back off from full throttle.

So the question now becomes "what is the best break in routine?".

Should I have cycled them with a load before flying them, bench run the motor, zapped them with a high rate charge?

[Britbrat]

Yes

[50PlusAirYears]

First NiMH battery pack I bought was a 6 cell Panasonic 3000 pack. Put them in a Kyosho Cessna Cardinal which I had been flying with a 7 cell NiCad pack. With any ofthe NiCads, I had to give a hard toss and let the plane accelerate to flying speed. With the NiMH, the plane climbs out of my hand and has safe flying speed almost immediately. I still have power for one or two go-arounds after 12 minutes, previously I was lucky to be able to extend a landing after 6 with 1700s. Never heard of a break-in till I bought a Megatech P-51. Break-in by their methaod didn't seem to make any difference between the original broden-in pack and a new out-of-box pack. Some people seem to see a difference, some don't.

[Patch]

found it.

members.aol.com/davthacker/nimhfaq.htm