I just bought replacement batteries for my son's RX and TX. Both are 2500mah Ni Mh packs. My wall wart charges at 100ma for the 4.8v pack and 70ma on the 9.6v pack. How long should I charge these packs? I figure it will be a lengthy charge. 24 hrs - 30 hrs - 36 hrs ????????

You had best check out chargers that will put 250 ma to match the batteries. [8D]

Hi

The standard trickle charge time for a battery charging at 1/10 of its capacity is always stated as 14-16 hours so you can work it out from that.

Assuming 14 hours to err on the side of not over charging. your tx will take 48 hours. and the rx will take 35 hours.

These are of course full charges from flat you don't need to do that every time only put back what you think you have used. overcharging dosn't do batteries any good.

Simon

Fastsky by your reply am right in thinking that I need a charger that will give a charge rate of about 1/10th of the rated capacity? I think simhatus just answered my question

go get a better charger.. they are pretty cheap and will save you alot of hours
if you ask me no battery should be left unwatched when you are charging it.. but well.. that's mostly for LiPo

and matching the battery? noo.. not needed. it will charge anyway.. just slow..

hmm correct me if im wrong..

2500/70 = 35,714285714285714285714285714286
2500/100 = 25

Hi heat yes you are wrong

to charge 1000 ma at 100 ma takes 14 hours

so to charge 2500 ma at 100 takes 2 1/2 times as long

2 1/2 *14 = 35 hours

Simon

1/10 is the best charge rate for the batteries and if you are over the time needed for a full charge by a few hours it isn't going to hurt the batteries. If the rate is higher than this, then you should watch the time closely or have electronic sensing which a lot of the new chargers have. A Triton charger is a good charger. [8D] http://www2.towerhobbies.com/cgi-bin...&I=LXMAJ0&P=ML

Dave Thacker from RADICAL RC www.radkcalrc.com is a known authorith on batteries and their care and feeding.

All of the answers above are both right and wrong for various reasons.

Dave has a web page devoted to questions and answers about batteries and their care, charging, cycling and if they are bad or not. the URL is

http://members.aol.com/davthacker/abattfaq.html

Go there and read up on what Dave has to say. He supports other charger systems and batteries other than what he sells so that adds quite a bit of creditabilty to what he has to say.

Take a look at that and see if that does not answer your questions about batteries.

DS.

I'll second CGRetired recommendation on good info and add one more; www.rcbatteryclinic.com. You will get a lot of not quite correct info on batteries in all the fourums but the two mentioned are quite good and reliable.

Thanks guys - looks like a new charger is in order[]

If you're halfway serious about this hobby a more advanced charger is going to be a must. The wall wort is not very portable.
Triton is nice, I like Hobbico Pro Elite for it's twin outputs.

Andy