I did my first duel cell conversion this week and it didn't quite go according to plan.
I used a senfa charG clone to convert and used another that I had as the donor for the second cell. I modified the chasis quite a lot so I could get both cells under the body and everything appeared to be going well.
I carried out the controller mod so I could charge my new beast and couldn't resist blipping the throttle whilst charging. It worked!!
Imagine my shock, when after about a 60 second charge I put my bit on the floor and........ nothing!
I worked out there could be a loose connection and checked everything. All fine. I then figured I might need a higher charging rate so hooked up the bit to 4 AA cells to charge. After 60 sec still nothing! Why would my car not charge!!!
I was beginning to think that I could have damaged the cells in soldering them but couldn't see how cos I was carefull to ensure that I made the joints quickly so they didn't heat up much.
After a couple of days scratching my head I and thinking I had ruined 2 perfectly running cars
I blagged a Digi meter off a friend to check out what was going on.
THE CELLS WERE WIRED IN THE WRONG WAY ROUND!!!!
It seems that in my haste to get the cells out of the cars i didnt take note the polarity. Not a big problem cos the inside of the clone chassis was stamped with a + and - near the contacts. Only problem is THESE MARKS ARE THE WRONG WAY ROUND!!
So, when I was attempting to charge the cells I was actually shorting the car's cells and the charging cells in one big short circuit!! surprised I didn't start a fire!
The most amazing thing about all this is that I re - soldered the cells the right way round and now it works!
Guess these little NiCads can take a lot of abuse!!
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