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-   -   6v charging for a dual-bat bit? (say that drunk!) (http://tinyrc.com/forums/showthread.php?t=9561)

ph2t 03-17-2003 08:36 PM

6v charging for a dual-bat bit? (say that drunk!)
 
Guys,

if you are to charge a dual bat modded bit (2.4V on car) with a 6V supply (4*AA bats) won't you blow the board?

When first charging the car, the batteries are flat. The 6V supply pretty much sees this as a low resistance circuit (almost short circuit?) therefore the voltage across the changing terminals would be low. But when the battery is charged (after a couple of minutes going by info I've seen here) it is seen as almost an open circuit.

Wouldn't this mean that then there is 6V going across the terminals of the car, the very same terminals that go to the circuit board. Wouldn't this blow the RX2 IC? I've heard that the max voltage that the circuit board can handle is around 5V......

Please correct me if I'm wrong...

Thanks,

ph2t.

sessiz10 03-17-2003 08:49 PM

It wouldn't be an open circuit until you gave the board power by pressing the controls. I don't know if this is true but I've done 6 volts to my triples without any problems.

ph2t 03-17-2003 09:05 PM

The board always has power, that's why the battery drains on the car even without using it.

RabieS 03-17-2003 10:57 PM

Ok, I dont know why but the first time a ever did a dual cell it worked perfectly. Now every car I dual cell seems to loose its power. They still go fast but no torque. I changed it back to a single cell and now it is worse then it wuz before I dualed it. I made a 6AAA charger and while on charge I hit the buttons is this what cause it because I didnt hit the controls the first time i ever did one.

sessiz10 03-17-2003 11:01 PM

Quote:

Originally posted by RabieS
Ok, I dont know why but the first time a ever did a dual cell it worked perfectly. Now every car I dual cell seems to loose its power. They still go fast but no torque. I changed it back to a single cell and now it is worse then it wuz before I dualed it. I made a 6AAA charger and while on charge I hit the buttons is this what cause it because I didnt hit the controls the first time i ever did one.
I think you fried something on the board.

RabieS 03-17-2003 11:05 PM

well ****z :) at least I know what I did wrong now. Im scared to try again on my new rx8 :|

chelboed 03-17-2003 11:16 PM

I'm not sure what you did, but I have used up to 6 cells on a board and not fry'd it. I didn't get good performance with 6, though. I run 3 cells all the time. I charge with 7.5v. I charge my 2cell cars with 6v 800mah. I have done this for a long time, and I have NO PROBLEMS. Sorry to hear about the run of bad luck.

ph2t 03-18-2003 06:36 AM

RabieS: I found a graph about performance for DC motors in the back of a **** Smith catalog. I've gotta scan it in , but I'll post it soon for your info.

Otherwise thanks everyone for you feedback!


ph2t.

ph2t 03-18-2003 06:43 AM

:D damn! that's funny! The board censored my post. D1ck Smith is one of the biggest electronics chains around in Australia!


ph2t.

hogjowlz 03-18-2003 10:09 AM

just say horse**** smith.

i use a 4aa charger all the time on several dual cell cars and have had no problems. i recommend this just dont let it overcharge.

sessiz10 03-18-2003 10:31 AM

Quote:

Originally posted by ph2t
The board always has power, that's why the battery drains on the car even without using it.
I'm no electrical engineer but all baterries discharge they don't need something to drain them.

hogjowlz 03-18-2003 11:28 AM

you are both right but sessiz is less right

your car is always on because the reciever has to "listen" for a signal from the controller. this does drain over time.

and yes batteries do drain slowly even when not hooked up into a circuit. this is very slow and a fully charged battery that is stored out of a car will hold a charge for months probably.

sessiz10 03-18-2003 11:39 AM

Thanks for the info hog (and yeah makes sense) but How am I less right?:confused:

How would you test to see how much the pcb draws?
I think what this guy was worried about was was sending 6v to the board while charging and I still don't think the board does that. The pcb may draw some juice from the bat inorder to listen for the Tx but i'm sure it's limited.

hogjowlz 03-18-2003 12:10 PM

oh when i rev it up while charging it sounds like an air ratchet.

also remember when you rev it while charging there isnt any load.


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