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Old 06-20-2012, 11:02 AM   #1
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Default Shorty Lipo in TC?

I'm curious if anyone has played with running a short lipo for 190mm TC racing. It seems like you could cut some weight and play with weight bias a bit more, but the lower mAh means you'd lose voltage faster, etc. Anyone have any experience with this? I'm thinking I may want to try it in a 17.5 car, but don't want to be seriously down on power, etc. Main reason I ask is I've seen a few cars built for shorty packs and a few that are shorty compatible and I wasn't sure if some people were using these packs or if it was a "hey, you could also run a shorty" type situation. Any thoughts would be appreciated.
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Old 06-20-2012, 11:40 AM   #2
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I'm curious if anyone has played with running a short lipo for 190mm TC racing. It seems like you could cut some weight and play with weight bias a bit more, but the lower mAh means you'd lose voltage faster, etc. Anyone have any experience with this? I'm thinking I may want to try it in a 17.5 car, but don't want to be seriously down on power, etc. Main reason I ask is I've seen a few cars built for shorty packs and a few that are shorty compatible and I wasn't sure if some people were using these packs or if it was a "hey, you could also run a shorty" type situation. Any thoughts would be appreciated.
I'm just now starting back into on-road... but in all my testing in 2wd buggy, the weight savings of the shorty doesn't give enogh of an advantage compared to the better voltage of a larger MAH 2 cell lipo. In mod it wouldn't matter as much (if at all), but in 17.5 blinky where every MPH really counts, I always go with the larger, but slightly heavier, mah lipo.

I would imagine the same would apply in 17.5 TC.
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Old 06-20-2012, 05:55 PM   #3
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I saw a guy use a short lipo in 17.5 TC with the esc behind it on the battery side of the car. It was a 4400 MaH 2 cell pack. He had no problem at all, he also tried 13.5 blinky and had no issues still. He was a little leery to try it in MOD due to the high drain rate of the motors, he was afraid it wouldnt have enough power to keep up at the end of the race. heres a couple links, one is the order website and the other is specs and pics of the lipo. First one is order site.

http://rocketrcspeedshop.webstorepow...Rank=salesrank

http://team-powers.com/index.php?thispage=viewproduct
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Old 06-20-2012, 06:17 PM   #4
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i have been running shorty packs these past 2 months and found no runtime problems with it. i use the ORCA VX ESC and unboosted with a ratio of 5.7 i get about 10mins of runtime. Boosted with ratio of 7.0 i get 8 mins runtime ,all at voltage cutoff of 6.9V.

here is a link to my blog. read the entry about shorty packs.
http://kawada-alcyon.blogspot.fr/
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Old 06-21-2012, 02:31 AM   #5
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Short answer... Yes!:

http://www.rctech.net/forum/electric...ect-tc6-c.html

I run them with 13.5 boosted in my project car above.

Another guy at our club runs them in 17.5 blinky and is only a fraction off the lap record.
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Old 06-21-2012, 08:38 AM   #6
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As Dale says i run a shorty lipo in my Schumacher Mi4CXL in the 17.5 blinky class and my best time is just 8/10ths off the new track record. That record will be mine .
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Old 06-21-2012, 10:01 AM   #7
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Originally Posted by weekendracer_uk View Post
As Dale says i run a shorty lipo in my Schumacher Mi4CXL in the 17.5 blinky class and my best time is just 8/10ths off the new track record. That record will be mine .
Which brand of lipo are you running John? I'm running the Reedy 4000/60C which are working very well and standing up to the heat/stress of boosted.
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Old 06-21-2012, 10:16 AM   #8
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A shorty battery should have no problem in terms of power and duration and can lighten the car substantially. But if you have to ballast the car up to the standard minimum weight, you pretty much lose any advantage.
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Old 06-21-2012, 08:44 PM   #9
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Quote:
Originally Posted by Cpt.America View Post
I'm just now starting back into on-road... but in all my testing in 2wd buggy, the weight savings of the shorty doesn't give enogh of an advantage compared to the better voltage of a larger MAH 2 cell lipo. In mod it wouldn't matter as much (if at all), but in 17.5 blinky where every MPH really counts, I always go with the larger, but slightly heavier, mah lipo.

I would imagine the same would apply in 17.5 TC.
Agreed, I did try a little experiment with my shorty LiPo in my VTA car(TA05v2 with a 25.5 motor & no boost), & noticed I just didn't have much grunt compared to other cars, so I tried a few other packs I have(a 25C 5200mah pack & a 40C 5000mah one), & the higher capacity packs DEFINITELY ran better, had more punch & was on an even keel with the guys I was racing(& my lap times in practice improved by about a half second)....
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Old 06-21-2012, 08:45 PM   #10
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Quote:
Originally Posted by Rick Hohwart View Post
A shorty battery should have no problem in terms of power and duration and can lighten the car substantially. But if you have to ballast the car up to the standard minimum weight, you pretty much lose any advantage.
That also might explain my experience with it in my VTA car, since my TA05v2 is definitely NOT a lightweight....
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Old 06-21-2012, 09:14 PM   #11
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Originally Posted by daleburr View Post
Which brand of lipo are you running John? I'm running the Reedy 4000/60C which are working very well and standing up to the heat/stress of boosted.
Running Vampire 4400/50C , did want the reedy shorty myself but when i went to buy some i had left it to late and no one had any stock in the UK.
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Old 06-22-2012, 07:22 PM   #12
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We have a TC6.1 running in 21.5 blinky that was 50grams overweight.
So by fitting the shorty @100g less then original battery we could add ballast(50g) forward/ back etc as needed to balance the car.
The battery was also moved 3mm out and small amounts of double sided tape used to lock battery in.

With this the car was now 3 grams over the min weight, perfectly balanced with electrics and 0.5sec a lap quicker.

I'm not saying 50 grams equals 0.5sec per lap but in taking the time to balance everything and possibly the new ORCA 60c4500(hootrc.com.au) pack it was faster on the clock.

Only downfall is run time at end of pack. We run 5min qualies so best to do one warmup lap then race time only. The drop off at end actually made the car easier to drive and therefore the times at end were similar.

Same observations in my T3 2012 in stock 17.5 boosted but i use the full size ORCA6500's now.

Not the easiest to see in this photo but only one i have.
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Shorty Lipo in TC?-tc6.1shorty-copy.jpg  
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Last edited by davo705; 06-22-2012 at 07:23 PM. Reason: add photo
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Old 06-25-2012, 12:29 AM   #13
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I am currently running a shorty, and feel it has a big drop in voltage after restarting either because a crash or hot laps before the race. My car comes off the track after a 6min. race at 7.8 volts and warm. Shortys are not a good choice for blinky racing.
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Old 06-25-2012, 01:57 AM   #14
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I've been running the Reedy shorty in boosted 13.5 for about a month. The car definitely handles better, but I am starting to notice a drop off in top end speed after about 4 minutes (losing about 2 metres on a 40mtr straight). I have also noticed that although the amount of mah being drained over 5 minutes is the same, the voltage of the battery is lower. For the first few meetings, the voltage was 7.8 after a run but I am now seeing 7.5. I suspect this is the reason I am noticing a slower top speed towards the end of a run.

I'm not sure I'll stick with shortys. I've noticed that at the start of the final, the car almost lifts off the ground and wheelspins for a short period. This could be due to the lighter weight of the car or just a poor setup for getting off the line, but having tried more droop on the front and softer springs on the rear, nothing has made a difference.

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Old 06-25-2012, 05:08 AM   #15
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So Tim, maybe change your gearing ever so slightly (drop a pinion or two). That way not so much wheel spin at start and better at the end?

Its funny how its all about the 6845-6855mah packs at moment when you can get away with a 4000-4500 pack.
Its a racing thing, getting the right compromise etc.

My car can often feel so much faster out of corners and at end of the straights, yet i can be lapped by a slower car with better lines and corner speed (i'm no master)

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