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Old 12-20-2011, 10:24 AM   #1
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Default Small lipo + Brushless

I'm toying with the idea of converting my *decomissioned* Edge chassis into a FOFF rig. I can't seem to fit any batteries to the chassis other than the little TP 45c & 65c 3s 850mah lipos from it's crawling days.

I'd be running a Sidewinder with VXL 3500kv brushless motor. Would this kill or shorten the life of those little lipos? I'm not looking for ultimate power maybe I could dial back on the power a bit with the Sidewinder if that would give the battery a break?

I know runtime would be about 5-10 minutes depending on full throttle application but that's O.K. with me. I have three of these little lipos and have a couple spots within a 5 minutes drive I can mess around with it.
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Old 12-20-2011, 10:56 AM   #2
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Default Re: Small LiPO + Brushless

You should be fine with those packs & a BL motor. A load is a load, battery really doesn't care what causes the load.
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Old 12-20-2011, 11:13 AM   #3
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Default Re: Small lipo + Brushless

I know brushless is power hungry and was concerned that it'd overwhelm the battery when it wasn't able to put out what the motor will try to pull, or does it not work that way? I don't know a whole lot about this... I just don't want to destroy these little packs asking them to do something that's beyond their capability.
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Old 12-20-2011, 11:25 AM   #4
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Default Re: Small lipo + Brushless

If they were 20C 850mah 3S you would have issues since the mah is low as well as the "C". What you have is fine, go for it. A lot of the comp guys run similar on a dual brushed motor MOA, so the loads a likely even higher.
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Old 12-20-2011, 02:09 PM   #5
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Default Re: Small lipo + Brushless

I do not know if I would trust those packs with the Venoline Motor. According to the PDF Manual (Page 10):

http://traxxas.com/sites/default/fil...X_manual_0.pdf

....This motor can pull 65amp continuous....and 100amps peak. Those batteries are 850mah 3s 45C and 65C. At 45C that pack can put out 38.25 amps....and at 65C that pack can put out 55 amps.

EVEN if the documentation is specifying the MAX amperage that the motor can handle under whatever conditions....instead of average use amperage draw, I would not trust those packs at even 1/2 the Traxxas rating for the motor. 35amps continuous and 50amps peak would still be at the edge of what the battery is meant to handle. And that is assuming that the packs are accurately rated.

I would not run those packs in this combination of motor/esc. I fear that I would puff/blow one of those smaller packs.
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Old 12-22-2011, 11:19 AM   #6
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Default Re: Small lipo + Brushless

Any other thoughts on the matter???

Are lipos ever supposed to warm up during a run? I did try one of these little packs in my scx with the sidewinder/vxl combo geared 87/16 just cruising around on the (short) lawn with a little full throttle mixed in.. Hit cutoff in 7 minutes (battery wasn't fresh when I started though) and the external temp of the battery was about 82 degrees F. Ambient temp was probably in the 30's or so.
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Old 12-22-2011, 01:28 PM   #7
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Default Re: Small lipo + Brushless

its okay for lipos to get warm from use, just not Hot. i wouldnt suggest that battery and motor combo, but you can try it in a foff as long as you gear it lower than you scx on 1.9s if you plan on running 2.2s. if i were you i would try to fit a slightly larger battery in there so you arent loading the lipo as much
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Old 12-22-2011, 04:21 PM   #8
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Default Re: Small lipo + Brushless

Quote:
Originally Posted by Charlie-III View Post
If they were 20C 850mah 3S you would have issues since the mah is low as well as the "C". What you have is fine, go for it. A lot of the comp guys run similar on a dual brushed motor MOA, so the loads a likely even higher.
Worst. Advice. Ever.

Comp crawlers creep around at low speeds with an occasional split second throttle blast. FOFF rigs run with the hammer down 90% of the time.

From personal experience, I've blown bigger packs (twice) with that motor and a heavy trigger finger.

Last edited by Duuuuuuuude; 12-22-2011 at 04:25 PM.
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Old 12-22-2011, 04:42 PM   #9
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Default Re: Small lipo + Brushless

nominaly those 850 45c packs output at 38.25a not enough for that power system even at 65c thats only 55.25a.

it will run but it's pushing the limits of those packs. I wouldn't do it.
I personaly would want to run a pack that can support about 100a draw

4000mah 25c fits the bill but it's large.

if you could find something like a 2200mah 40c pack it might be your best bet, (88a) its a little larger but could be made to fit with some work i'm sure.

Last edited by fred0000; 12-22-2011 at 04:48 PM.
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