Taildragger

My Feedback: (204)

1C charge rate for a 1600 ma 6 v NiMh battery would be 1.6 ma, right? I'm confused. you would cycle them down to 1.1 v. Correct?

Rafael23cc

My Feedback: (6)

1C of a 1600 mA pack is 1.6 A. Otherwise, I almost never cycled down my nimh batteries. Only nicd. Now I only have LiIon, Lipo, and LiFe.

For cycling, 0.8v to 1.0v per cell seems to be the consensus when I looked in Google.

Rafael

kmeyers

I was told never charge NiMh at a rate higher then 1/3 C.
Why the hurry? Come to think of it, why nimh?

Taildragger

My Feedback: (204)

These are my first NiMh and I've heard a little of everything. Don't know what to think.

countilaw

Taildragger, Everyone has their preference to what type of batteries they use. You will find some people that think LiPo's are the gold standard of batteries. And others will praise LiFe batteries as though they were a God.

But NiMH batteries are good, dependable and a solid investment in a battery. They are a lot better than NiCad because they don't develop memories. However, they won't take the abuse that a NiCad can handle.

You can charge a 1600 mah NiMH battery at 1.6 amps, but it's better to charge it, as it is with all batteries at a slower rate. When charged at 1.6 amps, they will generate a lot of heat and heat is bad news for any battery.

I will usually charge a 1600 mah NiMH battery at .8 Amps or 800 milli amps.

If you feel the battery building up heat, reduce the amps.

Beware of the guy that claims he only uses LiPos for his receiver or transmitter and he only charges them once a year. That guy is an idiot.

Frank

Taildragger

My Feedback: (204)

Thanks Countilaw, They did get hot at 1.6. That is why I asked the question. I am usually in no hury for charging I just thought that was the standard. I'm cutting it down to .4 or .
5 so I don't have to worry about it.

bjw4072

My Feedback: (6)

A 1C charge rate is 1.6 A (not 1.6 mA) for a 1600 mAH batterey.
The usual recommendation is to charge NiMh batteries at a slow 1/10 C rate that takes about 14 hours if the battery
is completely discharged. Usually overnight is enough as the batteries are usually not fully discharged.
Some over charging at the low rate does no harm.

If you use a fast charge (say 1.0 - 1.5 A) you should use a peak detection charger and the batteries will get warm
at the end of the charge.

If you use a fast charger only, the cells in the battery will become unbalanced and the charger will
detect false peaks and prematurely stop charging.

I have found the best approach is to slow charge mostly, to keep cells balanced. Then occasionally
fast charge at the field if necessary. And check state of batteries before flying
with a volt-meter and load.
.

Taildragger

My Feedback: (204)

Thanks bjw4072. That is good info. The ma was a mistype as I often do. I will follow your advice.

Paul Jarvis

My Feedback: (40)

BJW4072 is absolutely correct..........best solution, I believe, is to charge between flights.......it gives you a chance to check roughly what was used on the last flight, see if you have a degraded cell, check how it handles a load (similar to your total servo draw),etc.........I fly only 1/3 scalers and the only Issue I generally have is getting a power source.......so, at contests, i carry a deep cycle 12 volt battery that is on the flight line with me........I do fly a dual battery system, and I can tell you exactly what the entire system draws when the sticks have to moved quickly........remember, nothing is perfect........make it work for you and good luck.......

Paul Jarvis
Team Hitec-Pilot

Taildragger

My Feedback: (204)

Thanks Paul.