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Jul 21, 2014, 05:58 PM
Three Mile Pilot
kernelsandirs's Avatar
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Discussion

Homemade 8.4 NiMH batt, not powerful enough for ESC?


Hey there gang, So I am fairly new to RC cars, the other day I made my own 8.4V NiMH pack which is 7 AA 2400 mAH batteries in series.

When I place this pack in my new RC car and give it full throttle off the line, the car jumps like a couple inches then stops. if I get the car rolling at a slow speed and increase the throttle slowly I can get it up to full speed.

when I measure the pack with a multi-meter when fully charged it says it has like 10.5 Volts, I am not clear on a way to measure what the output of the pack is as far as max draw.


I have a battery pack that came with the car and it runs fine it is a 7.2Volt pack at 1800mAH.

and a friend's 8.4Volt pack in my car works fine as well.

So I guess my question is, should I be able to get the proper draw from a pack made from 2400mAH NiMH batteries? the pack work fine in my plane,
I am guessing the resistance from wheels on the ground Vs. turning a prop has a big difference in how many amps are being drawn.

Should I rewire the pack with a larger gauge wire? I am not positive of the guage now but it is fairly thin.
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Jul 21, 2014, 06:43 PM
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Mark Wood's Avatar
This forum is for Electric Airplanes. Try here: https://www.rcgroups.com/electric-power-cars-50/

mw
Jul 21, 2014, 07:33 PM
Registered User
Quote:
Originally Posted by kernelsandirs
So I guess my question is, should I be able to get the proper draw from a pack made from 2400mAH NiMH batteries?
I sincerely doubt it. AA NiMH are good for ~5A if they're really good cells. You need Sub-C (or better) cells that are specifically designed for high power applications.


Quote:
Originally Posted by kernelsandirs
Should I rewire the pack with a larger gauge wire? I am not positive of the guage now but it is fairly thin.
No, this would be a waste of time as the cells are inadequate for this particular application. The wire is perhaps a secondary issue.
Jul 21, 2014, 08:43 PM
Three Mile Pilot
kernelsandirs's Avatar
Thread OP
Quote:
Originally Posted by Mark Wood
This forum is for Electric Airplanes. Try here: https://www.rcgroups.com/electric-power-cars-50/

mw
Sorry I did a Google search for battery forum, didn't look at the breadcrumb that shows it's an aircraft group. Thanks
Jul 21, 2014, 08:44 PM
Three Mile Pilot
kernelsandirs's Avatar
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Quote:
Originally Posted by mrforsyth
I sincerely doubt it. AA NiMH are good for ~5A if they're really good cells. You need Sub-C (or better) cells that are specifically designed for high power applications.




No, this would be a waste of time as the cells are inadequate for this particular application. The wire is perhaps a secondary issue.
Thanks, just gonna get a good rc car pack, I will keep the 8.4 for my old ezstar 😁
Jul 21, 2014, 08:46 PM
Registered User
Eeeekkkk



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