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[John RC]

I need advice on brushless cooling, I'm renovating  a Sar33, The previous owner had used it in salt water and pretty much rotted the old cooling system. I decided to upgrade to brushless, buying a couple of 1700kv Aquastar motors.


Problem, I know very little about running brushless equipment, cooling them even less. The original owner drilled four water cooling takeup pipe holes in the bottom of the hull and three outlets at the side .


I don't know how hot the motors and ESC's will get. Do I need cooling for the occasional burst of speed? If left connected as is, will natural flow be enough to cool, there is a lot of piping.


I was thinking of adding a low wattage water pump for constant flow though all the power equipment. Is this a better idea?

[Tombsy]

I think you’ll be fine, do a drive by to check for water coming from the outlets. You could rotate the water jackets a bit so the outlets are at the highest point just to prevent air pockets in the jacket.

[John RC]

Thanks Brian


I'll do that.

[Onetenor]

Thanks Brian


I'll do that.

Also keep pipes as straight as possible i.e. avoid loops otherwise do as suggested by Brian Pity you already bought motors as Bang Good have just advertised a new watercooled job

[John RC]

Cheers John


Yes, the piping is every where at the moment, what with the motors and the water cooled ESC's. Cutting the pipes shorter and straightening them out is sound advice. The motors and ESC's where a reasonable price around £100.00. The most trouble I had was getting the ESC's to control in one direction as opposed to forwards and backwards in the original set up. The supplied programmer did not want to "chat" to the ESC's first time round. Having to watch a lot of you tube clips for info, Then trying a completely different programmer, which didn't work either. I then returned to the original programmer and suddenly the ESC's started communicating 



I wasn't sure what to expect when I get round to launching Sar33. Which is true for most "new" builds.
The other Sar33 I have has a standard alloy tube coolers on the motors which are pretty effective.
So far I've only run the brushless motors up on 7.4v li-po batteries at the moment. Even at that voltage the brushless seem more powerful than the brushed motors in the standard Sar33 boat on a 11.1v li-po batteries.
I've also noted and like the high pitch whistle as the motors wind up. I'm hoping the 11.1v li-po batteries on the brushless show a marked improvement over the brushed motors and hopefully the cooling comes up to scratch too.
 

[canabus]

Hi John
The motors are good for up to 6S@ 1800 Watts, so I do not think cooling will be a problem.
I run my brushless motors with no cooling, but, only to 4S batteries.

Canabus

[John RC]

Thanks for the advice Canabus, I should be able to get the boat out for a trial run in a couple of weeks.





I'll keep you posted





Just wish the weather would  brighten up.

[John RC]

Well the weather did brighten up. and a lot of weed appeared too.
But thats not going to spoil the fun.
Cooling piping shortened and water jacket inlets and outlets raised to reduce air locks.
Sar 33 was ready for the water.
First run setup with a pair of 7.4v 4000ma Li-Po's, performance of the brushless setup was as good if not better than the Brushed motors running on 11.1v 5500ma Li-Po's in my other Sar 33
The four water inlets and three outlets providing plenty of cooling for motor and ESC

Second run setup with a pair of 11.1v Li-Po's performance crazy fast. Turns at speed projected far too much banking for my liking, most of the crew would have been thrown off the boat with the G force.

I'll stick with the 7.4's