TinyRC.com

TinyRC.com (http://tinyrc.com/forums/index.php)
-   Bit Char-G Mods and Projects (http://tinyrc.com/forums/forumdisplay.php?f=63)
-   -   Baffling dual cell problem (http://tinyrc.com/forums/showthread.php?t=8509)

crazydave 02-17-2003 01:10 AM

Baffling dual cell problem
 
Ok, I have the + and - ends of 2 batteries soldered together, and taped over, and I have a wire coming off of the ground on the opposite end, to go to the ground on my car. The positive makes contact with the clip in the car.

Basically it's wired exactly the way the QFM site shows, except I believe the are mislabling the tabs in the car, so even though they say connect the - from the battery, to the positive in the car, and I'm saying - to the -, I'm still attaching the negative to the clip on the right hand side of the car (the drivers side). Look at the diagram and see if that made sense.
http://tinyrc.com/qfm/racing/mod_07.htm#25

So here's where I need your help. When I check the batteries out of the car they read 1.75 volts. Which is about right for 2 drained cells, because all my other empty batteries read .70 - .80, but as soon as I put them in the car they read .85, like only one battery is connecting. I thought maybe some how it was making contact through the electrians tape I covered the end of the batteries with. So I even went so far as to cut off the negative contact, leaving only the part the charger connects with, and the tab I have my wires soldered too, but it still reads .85.

I'm wracking my brain trying to figure why the batteries output voltage changes as soon as the car's + clip touches the positive of the battery. I'm reading the voltage from the same spots, and I'm just completely baffled why it changes when I install them in the car.

Dave

Clint 02-17-2003 04:41 PM

i havent checked the voltages on my dual cells but, once the bateries are in the car
they are under some load...they are constantly listening for a signal to move...
remeber there;s no on/off switch on the car..so they are always "ON"

scottyboyfun 02-18-2003 11:23 AM

If u look down on a bit, and it is facing forward, the RIGHT side is the positive

The Left side is the negative

2fst4u 03-21-2003 03:49 PM

qfm's diagram shows the batteries wired in series. this is the correct way to do a dual cell. if i understand correctly, you are attempting to wire the batteries in parallel. just a guess. hope it helps.

nbnby 03-21-2003 10:38 PM

1 Attachment(s)
I think 2fst is right. It sounds like you are wiring in parallel which will give you more amperage and longer run times. You need to wire in series to double the voltage. From reading your thread it sounds like you did whats on the right. If that's the case, you need change it to the connection on the left.

I might be misinterpreting your post. If so, sorry. Hopefully this helps.

nbnby 03-21-2003 10:43 PM

Hopefully that diagram works. If not, let me try to explain it. You need to wire the pos. of one battery to the neg. of the other battery. Then you take the unconnected negative and connect that to the negative in the car. Then you take the unconnected positive and put it on the positive of the car.


All times are GMT -5. The time now is 02:11 AM.

Powered by vBulletin® Version 3.7.3
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.