Nihm temps
 

So i still use rechargeable nihm cells for my tx and receiver pack. Right now they are charging and at 120F. Is that a normal temp? is this too hot? they are AA size 2650 mah and i'm charging them at 2.5 amp rate? Is everything kosher with this? Sorry if this answer is already some where in here

RE: Nihm temps
 

For TX batteries you are charging at way to high of amp rate i would not go above 800mah on the AA batteries!! you probably just shortened the life of your AA,s the rate you are using is meant for sub C size RC pack batteries the smaller AAA and AA's 500mah to 800mah is a good charge rate.

RE: Nihm temps
 

I am not sure, but I would think you would be able to charge at 1C, and you are charging at just less then that.  It wouldn't hurt to charge slower every once and a while.  heat is always the enemy.

RE: Nihm temps
 

Shenlonco is right.
1C is too high for AA & AAA batteries.
I charge mine at no more than 400mah. I've been told that 1/10C is the propper rate.
This is a good read.
[link]http://servaas.com.au/blog/index.php/recommended-battery-charge-rates-in-mh-c9000/[/link]

Cheers.
Paul.

RE: Nihm temps
 

120* is a tad to much.. 110* is the max you want when charging Nimh batteries
and you can charge at 1c but the charge in the batteries will not last as long if you charge at 0.500amps ;)

RE: Nihm temps
 

The charge rates on my charger is measured in Amps, not mAh. I charge a battery with a capacity of 5000mAh at 5Amps.

High Discharge cells can be discharged at 1C. Low discharge cells such as the cells you probably have are typically charged at a much lower rate. I do believe I looked in to this at one point and they are no more than 2-4C discharge rate.

However, I have some Energizer AA cells around that capacity that is charged on the Energizer 15min charger. After looking at the specs on the charger I couldn't believe they were being charged at 7.5A. That is nearly 3C. They are 5 years old and still somewhat work.

To answer the question, I would charge them at a lower rate to keep the temps off of them. Those batteries don't need to be turned around quickly as they last for several hours at a time. They should be topped off before a day of racing/fun run and should be good for all day.

Ryan

RE: Nihm temps
 

To be exact 120 deg is perfect!
a perfectly peaked NIMH battery temp is 119 they say.

RE: Nihm temps
 

and I've been told 110* is the max for peak charging and this was from a racer in Denver who wins :D
to each his own ;)

RE: Nihm temps
 

thank you for the feed back everyone, I found a sweet park with a nice size pond the other day, can't wait to get my sv back in the water, she will have some new fiberglass and fresh paint when I finish her up. The seam was splitting pretty bad on mine so i ran a sheet of fiberglass over the sides and a strip down the center of the bottom. Hull has a lot of abuse and use on it.