ABN Hoosier

iTrader: (20)

Problem: battery very hot, battery connector melting.

Conditions: running stock RTR car. Motor, ESC everything RTR. Pinon and SG stock.

Battery: Traxxas 3300 MaH 7 cell, Venom 3000 MaH 7 cell


I run my sons truck before the race in the street in front of my house. I get 12-13 minutes easy with power starting to decrease around the 11 min mark. No issues. The battery has 7 cells, ( know this may be a factor, but the ESC isn't burning up) and I run a Taymia/Traxxas adapter beween the Battery and ESC (ESC has Taymia and the Battery has Traxxas connector.) This might be a resistance gate for the current. I don't know. My son runs it two 7 min qualifiers and both of them the truck dies out. I check it and the battery and connector/wires are extremely hot.

Any suggestions, experience or guidance is appreciated.

Do the wires come out of the stock RTR ESC because I need to put a new end on it and was just wondering.

Thanks,

-Hoosier

2wdMod

iTrader: (42)

Hoosier, the Tamiya style connectors are VERY poor for handling current, and they get a poor fit after only a few battery changes which makes them heat up quite a bit. The best bet would be to solder up a Traxxas connector onto the ESC lead and just skip the in line adapter.This will require some soldering skills.
In adition to the connector, check the gear mesh between the pinion and spur. a hard landing can cause the motor to move and make the mesh tight causing high current draw from the battery, and high motor/ESC temps.also while you have the gear cover off I would back the motor away from the spur and spin the drive train to make sure it all rotates freely with no binding.RTR's are great , but alot of the time they need to be gone through to make sure screws are snug,there are no binds in the suspension or drivetrain, shocks are full of oil and all the things like that that you have the chance to "tune" as you build a kit.I generally look at RTR's like I do buying a used vehicle for the above mentioned reasons.They are great because everything you need to run them is in the box, but you should still make sure that the guy that assembled it did a good job at it.

Also On the SC10 gear diffs, you might want to tear it down and make sure it was properly shimmed . We have had a few guys show up with new sc10 RTR's that ended up stripping out the gear diffs within a few runs because the diff wasnt shimmed properly out of the box. You can find instructions on how to properly shim the diff in the SC10 thread here on RC tech. Good luck.

ABN Hoosier

iTrader: (20)

Thanks for the quick response. So, the connector is the culprit. I believe that because it had a poor connection and was cutting out intermittently and I guess after time the poor connection built up more resistance and heated up the wires/battery. I run a RC8T and new to the electric stuff, but am enjoying the SC class for my son. The diff is not making the clicking sound yet. I ran about 12 packs through the car, still good. The kit came with the shims and instructions so I am good on that.

So, couple of quick questions:

I am running a 20T pinion and an 87T Spur. If the motor is running hot, to go easier on the motor do you go more or less teeth on the pinion?

Is the gear ratio the same ideal as Nitro CB/SG? Less teeth on CB/Pinion more bottom end, more teeth on CB/Pinion more top end?

I don't know what the target range of temperature on motors, what are they?


Thanks

2wdMod

iTrader: (42)

Target temp on the motor is going to be around 130*F after a good 5-7 minute run(give or take 20* for track size and conditions).If you run nitro I am sure you have a temp guage, so just temp it after a run.It sounds like your gearing is in the ball park, I dont know with the 7 cell pack though,the additional voltage may cause the motor to run a little warm even with a good ratio.Gearing is the same as with nitro.Lower teeth on the pinion = more torque, also lower motor temps. More teeth on the pinion = more top end, but also higher motor temps.Like i said running a 7 cell pack it may be hard to find a happy medium for gearing in relation to motor temps.We(my son and I ) race 1/10 buggies and trucks , so we run 6 cell/7.4 lipo in all our stuff. So I am betting running the 7 cell pack you will see higher average temps .Also pick up a couple extra sets of motor brushes,Comm cleaning stick, and some good bushing oil for the 17T motor in the truck.Getting on a good after race maintenance regimen will help get your moneys worth out of the RTR 17T motor.

Rick Hohwart

The 20T os too high to begin with so I would run a 16 or 17. And you are not supposed to run 7-cells with the RTR motor which makes the problem even worse.

6-cells and a 17 tooth pinion will be much better.

ABN Hoosier

iTrader: (20)

Thanks again guys, some of the other forums I get 100 views and no replys.

7-cells... you know what sucks about that, they guy at the LHS never said anything about it. The 7-cell 3000 mah battery ran me about 40 bones each and I bought 2. So I figured since I have 4x's the money invested over the cost of a new motor I would roll the dice until this motor is done.

Which leads me into the next question. I would like to upgrade maybe to a BL system for his SC10. The whole thing is pretty confusing to me. What would be a good ECS/Motor combo for the SC10. A bit faster than stock, and maybe on the edge of uncontrolable. Some one have the short answer? Any links would be appreciated.

gashuffer

iTrader: (48)

^ Tekin RS with a 13.5 will do you just fine

bcrazy

iTrader: (9)

I have been running Novak brushless motors with Novak Havoc and GTB ESCs in all my cars with a lot of success. I understand that the LRP ESCs and motors work very well also.
I would recommend a 17.5 or 13.5 brushless motor for the SC10.

Cain

iTrader: (294)

what legal to run by you? If its pretty much an open 2wd class, I would give the castle sidewinder or Mamba Max 4600Kv combo a look. lots of power, but controllable and can be tuned easily. These units can be found pretty cheap, especially used ones. The Mamba Max was durable enough that with slight mods we used it in 1/8 scale electric before the Mamba Monster max ESC came out.

I run this unit in my Academy 1/10 2wd GV2T truck and I am quite happy with it. Loads of power including top end but I can tune it to work just like I want. with the right settings, cogging has not been an issue. (motor stutter at start throttle)

If you are concerned about cogging however, give the various sensored units out there a look. Or, if you need a race legal system for a spec class (some spec 13.5 or 17.5), you will need a sensored unit.

vwjuice

iTrader: (5)

A good brushless kit isthe Novak Sport kit. It is designed as an rtr upgrade kit. It's $160 and provides way more power than stock and is really good for the track.

ABN Hoosier

iTrader: (20)

Thank you for the guidance everyone. Just realized that I was taking a temp reading at the end of the motor where the rotor is and it is substantially higher in temp than the temp of the can. I temped it at the end bell I guess its called and it was 245 and the can was 190. I changed the pinion gear to 17T down from 20T. I started hearing for the first time the clacking sound in the diff, so I installed the shims under each sun gear, which is two shims total under each. I think the added torque of the 17T might have been causing the clicking in the diff. My question is where exactly to you take the temp of the motor?


Thanks

Hoosier

BuggyKing

iTrader: (17)

I would recommend that you change out ur connectors to deans. A much better connector then the standard Tamiya ones. Just IMO>

KidAgain

iTrader: (5)

Check the temps at the endbell. And you cant go wrong with novak especially their customer service.

ae rat

get castle mamba max 4600 brushless and reedy 35c 5000 mah lipo batteries.

Don Sholes

I'm almost positive it's the Standard plug. I would recomend getting a Traxxas plug. It will handle 8.4 volts alot easier the the one you have.