battery charging question

[seanycozzie24v]

another question i have a 9.6v 3700mah battery and a charger that charges at 300ma. how do i know the batterys actually charging? because if i plug the charger int the wall with out a battery no light comes on but if i plug a battery in it turns red. the funny thing is though. if the charger is unplugged and i plug the battery in the red light comes on??

heres all the info from the charger

constant current source

model bt02340

pri 230v~50hz 11.3w

SEC 1.2v~12v...~

50ma-80ma-120ma-180ma-240ma-300ma 3.6VA (MAX)

 

[RR01]

The easiest way is to either borrow or buy a multimeter to check the voltage (try Maplins if you don't have one). Take a reading before you charge it and another after. If the voltage has increased then the charger is working. A fully charged 9.6V battery should give a reading of about 11.2V.

The equation for working out the total charge time is: mAh of battery x 1.5 (if a NihM) divided by charge rate = hours, so for your battery it's 3700 x 1.5 / 300 = 18.5 hours (from fully discharged). If the voltage was, say, 9.8V before charging then you could probably knock 4-5 hours off that time.