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Old Dec 31, 2009, 12:43 PM
Steve Chamberlin
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Bay Area, CA
Joined Oct 2009
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Question
Battery run-time and LiPo cuttoff for Traxxas VXL-3s

Hi everyone,

I recently bought a used Traxxas Slash with the Velineon brushless power system. I'm getting what feels like abnormally short battery life, but not having used a similar car before, I'm unsure what's normal.

With a 2S LiPo 2200mAh 25C, I got maybe 5 minutes of medium-speed tooling around the street before the VXL-3s ESC went into reduced power mode. I drove it maybe another 10 minutes after that, but it was less fun without full power. I finally came back in, and the red light on the ESC was blinking slowly. Took the battery out and tested it with my multimeter, and it's still at 7.4v! I use the same battery on my plane, and routinely run it down to 6.8-7.0v, so it seems like maybe the ESC's low-voltage cutoff is engaging too early.

I also tried a 3S LiPo of unknown size/rating. It's possibly a bad battery, so this may be a bogus test, but on the 50% power "training" mode I only got 9 minutes of medium-speed street driving before it shut down completely. Again, the red light was blinking slowly. Testing the battery on the multimeter afterwards, it was still at 12.4v.

Is this normal? What kind of run time do you get from your batteries on similar systems?
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Old Dec 31, 2009, 03:04 PM
I feel the need for speed!
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Southern U.S.
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Thats about right for a 2200................get a Turnigy 5000mah 2s 20c from hobby city.............they're $19.............get two!!

http://www.hobbycity.com/hobbycity/s..._20C_Lipo_Pack
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Old Jan 01, 2010, 09:30 AM
Steve Chamberlin
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Bay Area, CA
Joined Oct 2009
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Are you sure only 5 minutes before entering 50% reduced power mode sounds normal? In other threads, I see people claiming 25-30 minutes runtime with 4500mAh NiMH batteries, so I expected my 2200mAh LiPo to last 12-15 minutes.

From the VXL-3s ESC manual:
When the battery voltage begins to reach the minimum recommended discharge voltage threshold for LiPo battery packs, the VXL-3s will limit the power output to 50% throttle. When the battery voltage attempts to fall below the minimum threshold, the VXL-3s will shut down all motor output.
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Old Jan 01, 2010, 12:36 PM
I feel the need for speed!
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Southern U.S.
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4500 is still a little more than double your mah.............mah is mah, doesnt matter if its nimh or lipo. A 2200 is very small for the VXL system, plus your batts can only provide 55 amps continuous..........your straining them. The VXL can pull 70-80 easy. Your batt amperage output should exceed the amperage pull from your motor. You would see MUCH longer runtimes on the lipos i posted.
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Old Jan 01, 2010, 01:18 PM
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Hackettstown, New Jersey
Joined Feb 2008
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I have a couple of 2200 mah packs that I run in my ducati bike, its running a mamba 5700 and run time is about 20 minutes... but its much lighter and I can't hammer the throttle... It will backflip.... I wouldn't recommend running that in the rustler.. My friend runs those in his kids xl-5 stampede and they run for about 15 minutes or so..
As Scorpion said... run a 4000 or 5000 battery and you should get about 25 minutes of good bashing or longer if you take it easy.. Mah is Mah, but lipo's also brushless also require power .. amps.. and those batteries are too small to deliver...
Another thing is the VXL esc is known for tripping the lvc before it needs to.. that could be why you are still seeing 7.4 volts or 3.7 per cell... best advice.. get larger batteries... or turn off the lvc and monitor the pack.. but you have to be careful with that as it will drain that battery quickly... going below 3.0 volts can and will harm the pack...
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Old Jan 02, 2010, 01:18 PM
Happiness is a belt fed weapon
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Do you know what your gearing is? That may be a deciding factor also. I've run 2200 mah 3 cells in my Slash with a Mamba max Pro 5700 for at least 10 minutes. Granted the voltage is higher, but the Mamba system will draw more amps than the VXL.
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Old Jan 26, 2010, 10:47 PM
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Boise Idaho
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I'm running two 2S 25C 2350mAh Rhinos in parallel and getting ~15min run times, WOT not more than about 30% of the time. Just bashing in the dirt with a couple of jumps with the LZ on grass. Its a VXL3s in a 1/10 2WD Losi Desert truck, 14T pinion. It will pull wheelies (backflip) if you can get the clutch to lock up, its still set factory stock.
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Old Jan 26, 2010, 11:15 PM
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USA, MN, Minneapolis
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his problem is the packs inability to supply amps. when you mash the throttle its pulling alot of amps and because of the low C rating the voltage drops too causing the LVC to trip.
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Old Jan 27, 2010, 09:19 AM
Air, Ground & Water
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Canada, ON, Rockland
Joined Aug 2008
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Their were early issues with the VXL-3 LVC triggering but I think its mostly having to do with the battery not being able to supply the amp draw from the Velineon 3500kv motor.
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Old Jan 29, 2010, 04:30 AM
Team Daedalus
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Joined Jun 2008
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Can I run 2 2250 Mah 11.1 lipos in Series?That would be 22.2 volts with a 35C
Is it possible to run this amount of volts or do I need to run them in parallel.

I have a ton of Turnigy and Ryno batteries all around 22Mah and 35 c and would like to use them instead of ordering more.

Todd
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Old Jan 29, 2010, 05:32 AM
Air, Ground & Water
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Canada, ON, Rockland
Joined Aug 2008
23,290 Posts
Whats wrong with checking the manufacturer website for information on SPECS.
VXL-3s (WATERPROOF) ESC SPECIFICATIONS
Input voltage: NiCad/NiMH 4-9 Cells (4.8 to 10.8 Volts DC)
Input voltage: LiPo 2-3 Cells (7.4 to 11.1 Volts DC)
http://www.traxxas.com/products/acce..._vxl3s_h2o.htm
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Old Jan 31, 2010, 08:05 AM
Happiness is a belt fed weapon
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Ventura, CA
Joined Oct 2009
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Quote:
Originally Posted by Wolveslayr View Post
Can I run 2 2250 Mah 11.1 lipos in Series?That would be 22.2 volts with a 35C
Is it possible to run this amount of volts or do I need to run them in parallel.

I have a ton of Turnigy and Ryno batteries all around 22Mah and 35 c and would like to use them instead of ordering more.

Todd
Run it parallel. Then you will still be running 3 cells (within allowable limits) and you will increase your capacity to 4500 mah. That will be plenty to drive it at least 20 minutes. Maybe even more. If you want to really scratch the itch to run 6 cells, you will need something capable, like the Mamba Max Pro. The ESC is rated for 6 cells lipo. You will also need a very low kv motor. I've used a 4 cell lipo in a Slash with this setup. The power was absolutely ridiculous. The esc is still fine to this day. The Mamba 5700 motor is in the landfill though.
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Old Mar 18, 2014, 06:37 PM
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United States, PA, Broomall
Joined Jan 2012
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I am having the same problem with my vxl system. I am running a 5000mah 25c two cell lipo that should be able to supply plenty of current. I suspect the cold weather may have something to do with the lvc coming in too soon. I will wait for warmer weather and see if the situation improves. Either the battery is getting old or the cold weather is affecting current flow. Or both. Just my take on it.
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