how fast should a dual cell be?

jedclampit · #1 03-06-2003, 12:55 PM

I'm not sure that my QFM dual cell mod has added crazy fast speed, shouldn't this thing be travelling 2x as fast as a normal stock bit? I've checked my surgical procedure and I know they are hooked in series. Is it possible that I cooked my stock batteries with a 3volt 600mA charger-having left it charging for no more than 5min? I did hear a faint 'ticking' from one of the batteries after charging, but didn't see any leakage or whatnot. How fast should a dual cell go with a 2.6 motor compared to a stock bit?

jedclampit · #2 03-06-2003, 01:53 PM

ok me again, how important is it to solder the negative from the second battery directly to the ground terminal on the board vs. the negative terminal in the 'tub' of the car? the negative battery terminal has a wire already going to the ground on the board so this should work fine right? I know QFM and http://foy.foy.com/minircmod/moddocs...attinstruc.htm have the negative of the final battery going straight to the board what's the difference? Anyone, anyone, Bueller... Bueller? Thanks!

jedclampit · #3 03-06-2003, 02:03 PM

I forgot to mention as you've probably deduced: I soldered the negative of my second cell to the negative in the tub of the car. This car is a runner, don't get me wrong but it doesn't have CRAZY fast speed or anything just above average I think.

Coyotekat · #4 03-06-2003, 02:12 PM

5 mins??? Thats way too long. Should have only been 1 to 1 1/2 mins. May have damaged a cell. Connect the ground to the board, not to the well. Thats the ground for the motor. Hope this helps

Good Luck

jedclampit · #5 03-06-2003, 07:16 PM

thanks for the response Coy, I'll solder to the board's ground and i've also discoverd that one battery is 100 mAh and the other is 70 mAh, so it's probably safe to assume that I fried the little sucker eh?

jedclampit · #6 03-07-2003, 05:50 PM

ok here goes, two cell charging: time= battery cap/charger output

I have 2 batteries coming in the mail they are each 1.2V 150mah that I'm charging with a 3V 600mah charger. How long?

(two cell rig) time=.150A/.6A=.25hours , so 15 minutes to charge no way!

Coyotekat · #7 03-07-2003, 06:12 PM

When I got mine, I charged it for 2 mins and it ran for about 20 mins. But a few days later I didn't drive it and it took 5 - 6 mins to fully recharge to its full power. Its not good to have two different batts hooked up togather, so most likely the lil one is cooked.

Let me know how it goes once you hook everything back up.
Good Luck

jedclampit · #8 03-07-2003, 06:21 PM

What I'm after is a dam formula cuz 15-20 minutes can't be right. Anyway Coy what are you charging with, you're telling me times etc. for charging but what are you using to charge so i can figure out a comparison to what I am using.

Thanks for your replies by the way, ya the disparity between the battery capacities was just rookie excitement assuming they were close enough, but the little guy is fried i think. As soon as you here it hiss I think it's done, which I did hear.

Racer9 · #9 03-07-2003, 06:32 PM

Hissing will make it bad! Only charge till the batteries get warm on the car!

jedclampit · #10 03-07-2003, 06:47 PM

Roger that! I was waiting for warmth when suddenly warm was too warm. What I need is to be able to do is some reliable calculations to figure out my charging time with my setup which is described above. A 3volt charger pushing on a 2.4 volt battery pack needs to be accounted for because that would decrease the time for charging I think, along with the amperages listed above.

jedclampit · #11 03-07-2003, 06:56 PM

Ya what I meant was once you hear the hiss the batt is 'done' as in 'toasted'