A MUCH better charger

[Admin]

I measured the current my remote was charging the battery with and it was about 300mA and went up and down like it was cycling it or something. I also measured 2.7 volts without the car charging and dropped to 1.9V when charging so I decided to make a better charger. 300mA seemed like a lot to come from 2 AA batteries. I also noticed when I put it on the charger for the second time (not running the car at all) it took about the same amount of current again. This means the battery is capable of storing a lot more energy.

OK, here it is. I took a 3V 700mA transformer power supply (Radio Shack #273-1756 with a 5.5mmOD, 2.5mm ID tip) and hooked it up directly to my battery. The voltage was perfect 2.1V. The current was 400mA (the batter will only draw what it needs so don?t worry about the rating on the transformer being high). I watched the current for over 2 minutes and it never dropped below 250mA. I didn?t want to charge any longer so I took it off and WOW. It sure stayed peppy for a long time. You know how on a single charge it?s peppy for about 30 seconds. This was peppy for 1.5 minutes and lasted 10 minutes driving with throttle on constantly and 2.2 motor. So, time to make a nice charger. I used 2/56 very small screws and nuts sticking out of a plastic project box from radio shack. Just drilled the holes the right distance apart and used nuts to hold them however high I wanted. Then I made another hole for a jack (Radio Shack 274-1576) to plug the transformer in. I put a Blue 5V LED (Radio Shack # 276-311) in parallel with the terminals so I could determine if the car was charging. When the car is placed on the terminals the LED goes out since it drops the voltage down to 2.1V and when the car is off or not making good contact the LED is on since the transformer produces 3.6V when open. So, the LED is just there so I know I have a good connection to the car NOT AS A TIMER! I have to watch the time and take if off when I feel it?s ready (apron 1.5 minutes.). I also added a switch just to turn the light off without having to unplug it.

Anyway, the charger works great, give it a try!

http://www.geocities.com/pfabersac/bitcharger.html

[mcojoc]

EXCELLENT!!!!!!!! I’m going to try one asap.

[Admin]

ooh. can anyone figure out one that uses the original charger, but modifies just the electronics because i have a feeling i’ll forget the car on the charger and have more spare parts. b

[Admin]

I was going to put a timer in mine or something to turn off under a certian amprage but didn’t have time. But, yes, you have to watch it. I left my car on and forgot it. 15 minutes later it started smoking and sizzling. I took it off and I could bend it back and forth because all the plasic was soft from being so hot. I bent it back to as best I could so I would cool properly. Needless to say the battery was fried but I had a switch on the bit to turn off the batt when not in use so it didn’t damage my electronics. It’s till a little warped around the battery area but runs just fine!

-Peter

[Author]

Posts