I am having problems with my Hammer EP.
It will run fine for 5-7 minutes(with 3000 mah batteries) then it will stall out for a few seconds then start for a few seconds, then stall again.
Dont think its radio problem, since it will do this even at very close range.
The motor is staying cool, the water coil seems to work well.
Wondering if the ESC could be going into protect mode and shutting off power to the engine.
The boat is stock, have tried different batteries, but that is not the problem. The batteries do seem to get a little on the hot side of warm.
The boat seems to still have plenty of power left when it does the stop and start routine.
I greased the shaft and oiled the engine.

Also wondering if some boats do this when the batteries start to drain, normally a boat will just gradually slow down, so you know to start bringing it back to shore. My boat starts stalling befor I notice it slowing down.

Any help will be appreciated.

Hi,

Can you tell if the ESC is hot after it shuts down (hard to do if the boat is out on the water, I know...)?

If it's not overheating, it's possibly an manufacturers error, contact your supplier.

If it does get hot, it's possibly the long runtime from the 3000mAh that causes it.
Do you run full throttle when it happens, or do you run a lot half throttle (which will also heat up the ESC)?

Making the ESC the first watercooled object in your watercooling circuit is the next thing to do.

Regards, Jan.

Thanks for the response Jan. I ran it at full throttle, and I need to invest the money in a watercooled ESC. Its just hard to drop $80-90 for an ESC to put on a $130 boat.

The ESC did seem to heat up, but not so much as to burn it up. I called Hobbico/Aquacraft and talked to one of the techs, he said it sounded like a bad ESC.
They are shipping a new one.

Could a bad battery cause an ESC to fry out?

I could not resist the bargain basement NIMH battery packs at Tower Hobbies. They get hot when they charge and they get hot when they run, not sure if that factors in to the ESC going poof. Gonna test with Nicd's when I get the new ESC. Not sure if I should try my NiMH pack again or not.

Does anyone know if any local hobby shop should have the equipment to test a battery pack?

Do you refer to the EPIC 3000 mAh batteries?

Tower does not give technical specs on these cells, so it's hard to say if they're any good.
These cells are probably what's left, after the good cells are selected, so take care not to overcharge or drain them excessively, or the weakest cell(s) will die.

If you want to spend the money, try the GP3300 SCHR-U cells (Pushed & Matched), you'll be amazed...

Temperature: NiMH's are supposed to go hand warm into the boat, preferably fresh from the charger, charging them the day before running them is damaging to the cells (to say the least...).
You should be able to charge them with 3A, using a Delta Peak charger.

As far as I know, a bad pack can't damage the ESC.

Good to hear Tower is sending you a new ESC.

Another unwanted source of heat are the Tamiya connectors, replace them with goldplated connectors like Deans, when the Tamyia's have started to corrode, you'll have instant improvement.

Regards, Jan.

Just make sure, the heat from the packs can't get to the ESC directly.