i have a nimh batteries and how long should i be charging it for ?

Most 'smart' chargers have automatic cutout feature once the battery is charged

what size MAH is it and how many Volts?

charging a 4200MAH 7.2V battery at 3 AMPS should take around 40-50mins form flat, but could take longer depending on the condition of the battery

Some more info on your battery and your charger and that will help us out a bit

all it says is the input and output .no lights to tell you if it is done. the input is 220v 50/60 Hz and the output is 9.6v 250ma.and the charger got no brand on it or the battery. if that helps

What size battery are you using?

it is a 7.2

What is the mah rating?

umm i don't know

That what you need to find out.

then you can work out approximate charge times

mate does it have anything at all written on the battery?

i have a 2 5000mah batteries, and my "smart" charger has a cut off after 90 min so i acautly have to charge each battery twice to get a good charge into them....or so it seems

This is by far not a smart charger, not to mention the wrong voltage for your battery. This is the kind of thing that comes with dick smith Rc cars.

your charging at .25 AMPS, so id guess around 6 hours for a full 4200 battery

Do yourself a favour and get a decent charger, please. This one will end up killing your battery.

Chargers are cheap these days, you can get an advanced B6 style charger from ebay for less then $80 delivered that will do most type of batteries including LiPo's up to 5Amps. If you dont have this kind of cash or dont need LiPo charging, discharging etc then at least head down to your local hobby shop and pickup a NICD/NIMH charger, every hobby shop i have ever been too has these things in stock and you should get away with $40 or under.

Most chargers are 12v input, so you need to use a 12v powersupply or choose one that has 240v input either built in or power adpater (usually sold seperate)

How much money can you spend on a charger and we can recommend you one?

John

thanks my dad ask a guy a the shop and was told to change it for 10 hours

umm the math is wrong there, remember that it takes 110-120% of input current to get output current. so 6 hours at .25 gives a total of 1.5 ah and doesnt charge a 4.2 ah that would need around 4.5 ah in to get full charge in.

the best charge for any battery is about a 10 hour charge rate if the charger allows it.

Im sure this has been sorted considering no1 has posted since Feb b4 you did, try telling joe bob on christmas day that he has to wait 10hrs each time his battery needs charging & see how long he stays interested in RC

I wasnt using any advanced maths, I was merely stating my experiences. Ive never heard of anyone charging an R/C battery for 10 hours though since around the late 90's