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Aug 15, 2005, 09:31 AM
Registered User
Thread OP
Alert

New Traxxas "Blast" boat - motor runs very hot and shuts off


Hi guys,

I took my brand new "Blast" boat made by Traxxas to the lake this past Saturday.

I ran the boat full out for maybe a minute, and no more, full throttle... doing circles with it.

All of a sudden the boat just stops.

I was in my outboard little motor boat thanfully, so drove out and rescued the Blast ( boat ).

I tried the boat and no motor .... so I thought - " I must have burnt the motor out " :\

I drove back to shore, and put the boat on the deck to dry, and about an hour later, turned it back on just to see if it would go, and bingo, the motor was working once again.

Ok, I wonder why it is overheating like this ?

Now, - the battery I'm using is a Venum-Racing 3000 Mah battery - it's a NiMH battery ( metal ) and is 7.2 volts.

Now, would the battery be causing the problem ? ... from what I understand 7.2 volts is a constant, and the 3000 Mah rating of the battery would mean the battery would last longer, but it should not be putting out more power than a 1400 mAh Nicad battery should it ? .... doesn't a larger mAh battery just *last longer * ?

Any ideas, suggestions would be appreciated. Thanks in advance.
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Aug 15, 2005, 09:41 AM
Registered User
bluesy's Avatar

first thought


At first look at your post it sounds like the ESC (Electronic speed control) over heated and shut down. Not knowing exactly what ESC Traxxas put in that boat it is kind of difficult to tell for sure if it has a thermal shutdown as a safety precaution.

Did you notice any other heat buildup in the boat?? Was the battery hot? Was the motor hot??

Is the motor the stock one for the boat? What are the windings? ie. stock, modded.......etc,

I've had the same thing happen with a Monster truck I run and found out the motor was too much for the ESC. Actually the motor was too much for the truck/me combo. So I put a milder motor and got great runtimes with no shutdown.

HOpe this gives you some hope.

Doug
Aug 15, 2005, 10:21 AM
Registered User
Thread OP
Hi Bluesy,

Thanks for the response. Geez, I never thought it could be the ESC. Today,
I'll ride it around in my pool and see if I can get it to shut off once again, then
feel the ESC and see if it is boiling hot.

I do remember touching the motor and it was very hot though. I don't understand something.... - how come a company like Traxxas wouldn't test out their products :-(

I find it very disappointing that I can only run the boat full out for about 45 seconds or so before it dies out. I said a minute in my original post, but a minute is perhaps an over estimation.

The motor, ESC are all the default parts out of the box.

Here is the blurb from my hobby site, which I remeber as being the same as the Traxxas site - :

"The Blast features our powerful, 20-turn, Stinger™ motor; efficient, dependable, shaft drive; and the exclusive Nautica™ electronic speed control. Nautica's digital circuitry provides fully-proportional throttle control and efficient operation. "

I don't know much about batteries and amperage, but something tells me that eventhough the battery I used ( 3000 mAh ) is putting out too much "power" vs a NiCad 1400 mAH battery rated at the same 7.2 volts ? ... I could be totally wrong, but perhaps somebody with knowledge of batteries will jump in on this thread :-)
Aug 15, 2005, 11:08 AM
KC8WPF
CG Bob's Avatar
Quote:
I don't know much about batteries and amperage, but something tells me that eventhough the battery I used ( 3000 mAh ) is putting out too much "power" vs a NiCad 1400 mAH battery rated at the same 7.2 volts ? ... I could be totally wrong, but perhaps somebody with knowledge of batteries will jump in on this thread :-)
I work in the LHS and get questions and comments about batteries all the time. The most common one being "I want a bigger battery for my...". Do you want the motor to run longer or run faster? Increasing the mAH of the battery increases the run time (a larger fuel tank). Increasing the number of cells in a battery increases the Voltage and in turn the motor speed. Theoretically, the 7.2V 3000mAH (21.6 Watts)battery is more powerful than a 7.2V 1400 mAH (10.8 Watts), the difference is noticed in the run and charge time for the battery.

The best explanation I heard was: Battery cells = engine cylinders (more cells/cylinders=more power); battery mAH = fuel tank size (larger mAH = longer run time/more endurance). Not 100% accurate, but good enough for most people to understand.
Aug 15, 2005, 11:19 AM
Boaters are nice people.
Hi Frosty, I replied on Offshore.

Regards, Jan.
Aug 16, 2005, 08:04 AM
Registered User
Thread OP
Hi Bob,

With that being said, then perhaps you are saying that there really is no exta "power" to the motor... I'm not quite sure though. I guess if a battery has extra amperage, as the battery I'm using does, then perhaps it keeps pushing that 7.2 volts for a MUCH longer time than a 1400 mAh battery would. As a battery dies down, so does the voltage from what I understand, so if one uses a smaller battery, then perhaps even 1 minute into a boat ride, that battery could already be dropping to 7 volts, or 6.9 or 6.8 and then I guess in turn this means the motor isn't receiving as much full strength power a battery rated at 300 mAh would ... I would assume this new metal 7.2volt battery I bought ( venom racing ) rated at 3000 mAh will indeed keep the battery running at 7.2 volts much longer than would the smaller battery... and this in theory would be putthing much more strain on the motor ?

Not sure, but I think I'm on the right train of thought here....
Quote:
Originally Posted by CG Bob
I work in the LHS and get questions and comments about batteries all the time. The most common one being "I want a bigger battery for my...". Do you want the motor to run longer or run faster? Increasing the mAH of the battery increases the run time (a larger fuel tank). Increasing the number of cells in a battery increases the Voltage and in turn the motor speed. Theoretically, the 7.2V 3000mAH (21.6 Watts)battery is more powerful than a 7.2V 1400 mAH (10.8 Watts), the difference is noticed in the run and charge time for the battery.

The best explanation I heard was: Battery cells = engine cylinders (more cells/cylinders=more power); battery mAH = fuel tank size (larger mAH = longer run time/more endurance). Not 100% accurate, but good enough for most people to understand.
Aug 16, 2005, 08:05 AM
Registered User
Thread OP
Hi Jan,

thanks I'm heading over there to take a look.

Quote:
Originally Posted by pompebled
Hi Frosty, I replied on Offshore.

Regards, Jan.
Aug 16, 2005, 08:16 AM
Useful Idiot
Overheating shouldn't be a problem until props and motors "get attention" for extra speed. The most usual cause for overheating "out of the box" is the prop shaft(s) binding. Put an ammeter across the motor indoors and check how many amps the motor is pulling disconnected and connected to the shafts, preferably without the props anything more than 1-1.5 A more would indicate a binding power line.
Aug 17, 2005, 12:20 AM
That's a funny word
The two batts will be nearly identical for the first few minute of the run. The 3000 will not noticeably have any more power, well it may , but not from the mah. This is not why the esc is shutting down.
Aug 17, 2005, 05:19 AM
flying thing
lostrider's Avatar
add two cells to your battery- its a sensible solution;
and make sure your esc is will be overcome.
Aug 17, 2005, 05:23 AM
flying thing
lostrider's Avatar
and you will need a water cooling; sure
Aug 17, 2005, 05:24 AM
flying thing
lostrider's Avatar
Quote:
Put an ammeter across the motor indoors and check how many amps the motor is pulling disconnected and connected to the shafts, preferably without the props anything more than 1-1.5 A more would indicate a binding power line.
you must do this first.
Aug 18, 2005, 12:30 AM
Taking care of the pond.
MILLERTIME's Avatar
"I ran the boat full out for maybe a minute, and no more, full throttle... doing circles with it. All of a sudden the boat just stops."

Did you break the motor in? You should not run full throttle till the brushes
have been seated.
Aug 19, 2005, 12:33 AM
Useful Idiot
Have any of the suggestions helped? I'd be interested to know what the basic problem was (the esc shutting own was only a symptom).


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