lynper52

My Joysway Wildcat Electric Catamaran looses speed after 1-2 min driving. It slows to aprox. 3/4 of full. The batteries should be in good shape; showing 12,5V+ and each cell: 4,19. Could it be the speed controller or somthing getting (too) hot...??
Any suggestions? I am using 2x 3s 5200mAh in series.

rgburrill

Could be the motor getting hot. Check to make sure you cooling lines are clear.

lynper52

Thanks! But the I could see cooling water coming out, and the motor felt not to be hot.

Got RPM

How hot are the packs? Is that voltage after running or before? Is the shaft freshly lubricated?

The Saylors

Ya i would think that something is binding or your speed controller is malfunctioning since it isn't happening the moment you turn it on. i would work the parts by hand and see if anything feels off. What is the temp of the esc when this happens? Doesn't sound like its trying to thermal out but excess heat can be a sign of a fault.

lynper52

Thanks to you both! Now I have something to check out...
First; I have to lubricate the shaft, because I have baught a "demo", and it could have been in the shop for a while. I have not lubricated the shaft. (First I have to find out how... The batterie-packs hase not been hot, the warmest area has ben the "T-plugs".

The Saylors

When you say the t plug is hot how hot do you mean? a hot plug is normally a sign that there isn't enough touching surface area in the plug causing some energy to be lost in the form of heat or poor solder. Even if it isn't the problem it would still be a good idea to upgrade them to ensure good energy/heat management. They are very inexpensive, i like the castle brand plugs (good surface area and quality metal) and the traxxas ones (cant be plugged in backwards).

lynper52

Thank you! I will check those traxxas plugs. Presently waiting for some marine-grease to lub. the prop.-shaft.

lynper52

I recogniced that the flexshaft was worn out (+rusty). I have changed it with a new, but still there are speed problems. Todays morning with an outside temp. near freezing point, the problem was there from the start. I guess that the temp. is not a issue. (All cables was cold). Have recharged the batteries; Voltage of cells and total (4,20 -4,20 -4,20 ) 12,6. Next step...?? May be the speed-controller?

lynper52

I think I go for a new speedcontroller/ESC. Have actually bought one.., but after a conversation with the seller, not sure if it fits the motor.
The problem is: I can find no specs on the motor, maxs amps etc.

Got RPM

Cold batteries have higher resistance and do not put out the power that hot batteries will, so the boat will be slower. But that does not explain your original issue of slowing down as the electronics heat up.


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lynper52

Understand; batt., and temp. But I olso understand that I have a lot to learn about rc-electronic. I did not realise the challenges about to cange from 120amps esc to a 130 amps from the same produser. (From present: Hobbywing, Seaking 120 A-R til Seaking 130A-HV 5-12s Lipo). I am using 2 x 3s, 5200mAh, 35c in series.

lynper52

Have studied a little during the weekend... The ESC I intends to change has a built inn "Super BEC"? Is that a linear or a switching BEC?
Regardless, the new ESC (130A-HV from Seaking) has no BEC. So I have to purchase a BEC, preferably a switching BEC (UBEC).
Any suggestion? : 2 x 11,1v (3s) 5200mAh in series, engine: 4pole 4074 brushless aprox. 100amps max.