Got a Tamiya Hot Shot..

[SteelCityNitro]

Ok, so here's the deal. I'm not an expert on the electric cars. I have been into the nitro stuff for a few years, and my gf wanted to get into the hobby.. so I bought her an inexpensive kit to build, becuse that's what she wanted. So I bought a tamiya hot shot for her to put together and got the radio and all that junk. All said and done, it functions.. it runs. I'm getting about 5 minutes of run time before things go south. I'm using a semi generic battery, a 7.2 volt of course.. but when it gets warm the car just moves in forward or reverse in a jerking motion. I'm guessing that it's becuase the battery is low. What is a simple solution to this problem? Should I find a battery that puts out more MaH or go lipo ? I would imagnine that a Lipo battery would be a little much for a car that was designed 20 years ago.. but I'm sure I could be wrong on that. Any suggestions?

 

[beason]

was it new? maybe the gearing is off? or the battery is bad.

 

[SteelCityNitro]

was it new? maybe the gearing is off? or the battery is bad.

brand new car, gears are fine.. new battery also

 

[abadk9420]

Switch to a high MAH 2 cell lipo all you have be concerned with when buying a lipo is the over all sizeto make sure it will fit in your RC, but if you do go lipo you will also need a lipo specific charger and a ESC that has a lipo cut off. So if you don't want to go that route then just get a high compacity NiMh battery of 4000mah or bigger and it will last a lot longer before it dies out on you. some thing like this would work I think and give yo a good long run time.
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXWZB8&P=7

 

[SteelCityNitro]

Switch to a high MAH 2 cell lipo all you have be concerned with when buying a lipo is the over all sizeto make sure it will fit in your RC, but if you do go lipo you will also need a lipo specific charger and a ESC that has a lipo cut off. So if you don't want to go that route then just get a high compacity NiMh battery of 4000mah or bigger and it will last a lot longer before it dies out on you. some thing like this would work I think and give yo a good long run time.
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXWZB8&P=7

ok, thanks

 

[SteelCityNitro]

Ok, so I tried a new batter that puts out 3600 mah as opposed to one that put out 1200 mah. The 3600 actually performed worse. I was considering removing the drive shafts to the front wheels to see if it will help any

 

[Lessen]

Something is fishy here... what kind of ESC is she running in it?

 

[SteelCityNitro]

Something is fishy here... what kind of ESC is she running in it?

the same as what came with the car. i suppose it's the generic tamiya ESC

 

[Lessen]

Oh ok, I didn't realize it came with electronics. How long did the 3500 last? What was the performance like exactly. Was it bad right from the start or toward the end?

 

[Rolex]

If she did a complete assembly on it, it's possible that the pinion is too tight against the spur, or other parts are binding. That would put quite a drain on the electrics.

 

[Scrogg]

Did it come with a mechanical esc or electronic? I built a Tamiya Dark Impakt a while back. Tamiya's instructions are good if you are mechanically inclined. If not she could have shimmed a diff too tight or something along those lines.

 

[SteelCityNitro]

It's the electronic esc. Performance was great at the start.. got about 41/2 minutes run time and boom, dead. I was going to remove the shaft to the front diff to see if it helps any.. and if that does.. maybe go into it a little deeper

 

[Lessen]

Yeah, somethings gotta be binding there.

 

[SteelCityNitro]

Yeah, somethings gotta be binding there.

That's what I'm guessing now.. The motor was hella hot after one run

 

[SteelCityNitro]

So I removed the 4wd.. and it seems to perform better. There wasn't much binding in the rear diff. assembly, I'm assuming that it's just how the car will perform. I timed the batteries for run times..
on the 1500 mah i get 5 minutes, on the 3600 i'm getting 4. The thing about it is the 3600 batteries heat up everything faster.. It's been my experience that the hotter that electronics get.. the less efficient they perform. So without using a different esc and/or motor, I think this is all the better it will run. Does anyone have suggestions on an esc and motor?

 

[Scrogg]

It is a good possibility the esc connector is not making a good connection. Install deans plugs on everything, that will help loads.
How much you want to spend? I'd definitely say go with a mild brushless system just for the longevity and reliabilty. But that costs more than the car... I had good luck with the
Venom Fireball motors and Traxxas esc'c back when I had a Stampede. The Venom's are only 20 bucks a pop and run for a while.
Stay away from the cheaper LRP esc's and Dynamite Tazer ESC, pure junk.
A 4wd r/c needs a torquey motor and esc to handle it. Proper gearing of course as well.

 

[JettaManDan]

there is something wrong..yes the battery should heat up a little..but not terribly hot..and no way a 3600 will only last 4 minutes...something is not right...bad leads, bad esc, bad motor, bad gear mesh or something draggin in the drivetrain...i'd try to track down what is going on before you drop $$ on a battery and an ESC...