bagged97

So I got to my local spot to make a few passes and low and behold, both my RotoStart batteries are dead. Not to worry me none though. I just took the test leads off my voltmeter and put them into the battery jack of the ol rotostart then put the other ends on my cars battery. I know 12 volts is a little much, but when you wanna run, you wanna run! Plus I've never seen my motor kick over so quick! Anyway, what kind of electric motor is in the rotostart, and what kind of voltage can it handle while still being reliable?

Roadhog2K4

you are going to kill your rotostart AND your engine...

bagged97

I can see the rotostart getting destroyed, but how would the engine?

Roadhog2K4

well since a stock rotostart can tear the engine apart if it floods, I cant imagine what one with 12v to it would do.

bagged97

True. 12volts was a kick in the pants, but it didn't spin any faster than if it was idling.

Roadhog2K4

yes, but it has more power...

bagged97

Would more starting power hurt the engine any more than spinning it up to 30,000 RPM when it's running?

Roadhog2K4

well you dont get it... The engine is less likely to flood when it is running. If it does flood when it is running, it will just stop. Since there is nothing trying to keep it turning you wont break anything. If it floods when you are trying to start it, and you have an uber powerfull rotostart. You will likely break the connecting rod or something else.

CR500rider

i think the oneway bearing would give before a conrod or anything would break....the oneway bearing is the weakest link in the whole system

bagged97

I agree with the oneway being the weak part of the rototstart, and that was what I new would break if something was going to. I didn't worry about the engine cause I haven't flooded one in forever so that wasn't an issue. Plus a touring car bump starter spins alot faster that my 12 volt rotostart. Those guys don't seem to be ruining engines.

DaveG55

bagged97, You can do what you want, it's your truck. But what Roadhog2k4 told you is right. IF you flood the truck while using a Rotostart hopped up on 12v you can indeed destroy and engine, not just the owb. Here are two threads that show what can happen, one is an old engine and one is new.
http://www.rcuniverse.com/forum/m_3657424/tm.htm
http://www.rcuniverse.com/forum/m_3602080/tm.htm
Also, your bump start analogy is off. If an engine floods w/ a bump start, all that happens is the rubber wheel slips on the flywheel. With a roto start, nothing slips, something dies.
The Roto start itself is designed to work on 7.2v not 12v (almopst twice as much). If you keep using it on 12v then it's only a matter of time before the motor in it fries. Either the brushes will self distruct or the windings will get hot and short out.
But, hey, it's your truck.............

On a side note, This is why I don't care to buy used rc stuff. You never know what people do to this stuff.

CR500rider

if i went to my bashing spot and my rotostart battery was dead i would have done the same thing if i would have thought of it lol, i dont see why you guys are harping on him....what he did worked, it didnt break anything and he got to drive his truck. my theory is if it works in a pinch go ahead and do it. its not like he is using his rc truck as a source of transportation, that would be a different story....its just a toy

DaveG55

I'm not harping on him. Just trying to dispell the myth that the owb is going to break first. It doesn't always. Others have had trouble and broke engines and I just posted those links.
He also asked about the rotostart motor and how much it could handle and I gave my opinion that it probably won't last long if he keeps using a 12v battery.
Like I said, it doesn't matter to me if he (or you) does use the 12v, there not my trucks. If you want to take the risk, go ahead, just know that there IS a risk.
And, you're right, it's just a toy. Unfortunatly not everybody can afford to run out and get a new motor at $100 - $250 because they imitated somebody doing something risky and broke theirs.
Not everybody can afford to take some risks.

blindguy

The HPI rotostart uses a stock 540 size motor that will run fine on 12v. You could run the risk of having the rotostart button get stuck on more easily when running it at 12v. The older rotostarts uses a wimpy 1A switch where as the later rotostarts have a 5A switch. A freshly charged 7.2v stick pack, like the rotostart uses, can easily put out 8.5v or more, but not the 12.5v to 13v like a car battery.

I'm sure it will function just fine on 12v, but like everyone has said, you run a greater risk of damaging the oneway bearing, crankshaft, or conrod due to the increased torque of the rotostarter.

bagged97

Thanks CR500rider. I wasn't trying to figure out a way to destroy my engine. My take on it is that if someone knows how to start an engine, flooding it shouldn't be an issue. That is why I wasn't too concerned with breaking it I was just adding a bit more starting power to get me runnin.

Whoa G

true about the 540 size motor, the motors in the E-maxx are 550's, and they run on 14.4V (two 7.2's in series), so i would think 12V would be fine for a 540, but i know i wouldn't take the risk with mine

MBX5T Maniac

My Feedback: (-1)

Whoa G, the E-maxx motors are designed differently. They are specially made to handle the high voltage. Most motors can't take more than 10 volts or so. This being said, the extra torque provided because of almost double the torque will destroy any flooded engine. I suggest buying a new battery, as it sounds almost dead to me.

Whoa G

I guess that's what the larger armatures are for (duh). Thanks for that clarification. still i think the owb would go before the con rod if you flooded it but like i said - i wouldn't risk it

Neil E

Way to go bagged97. What ever it takes to keep running instead of going home early. I will keep this in mind if I ever have a dead battery. I do what ever it takes to keep running and bashing. I hate to go home early.

Just a note: The Volts are not a problem its the 80+ amps in a car battery that will kill the Roto start. Hope it didn't mess yours up. Always remember to charge your batteries the night before, I know I don't LOL

Cheers
-N-