What ESC

[Chris PearceParticipant @chrispearce30862]

Hi all,

After many trips with the 36" woodern Sea commander, using a Graupner speed 600 with a sonik marine ESC ( Drawing 20 Amps) ( Cheers Ashley)) and a 6V 8 A SLA, and always coming away with a over heated engine and esc and not much speed/planeing?.

I now in the right frame of mind! to get a new ESC, it has been suggested a 40 amp Viper, but I would like to have something a bit more, any advice?

I also would like to reduce the weight of the battery and use something else 7.5v 5000 or twin 6V 4A SLA.

ChrisP

[KiwimodellerParticipant @kiwimodeller]

Chris, I have a 46" Sea Queen, fitted with the old Taycol Double Special motor from the 1960’s. To this I have fitted a modern radio set and an Electronize ESC with a 12v 7AH SLA battery. Even though the battery is quite heavy she still needs extra lead ballast. This set up comes close to planing, looks good on the water and does not come anywhere close to oveheating. It seems to me that if you are experiencing overheating it is likely that the motor is having to work too hard to even get to the speed it does now. My suggestion would be to go to 12volt, still with a SLA battery (the smaller batteries in some of my other boats do not give much of a run time and the batteries also get hot). The current draw on 12volts should then be less resulting in less heat. The other thing to play with is prop size and pitch. A smaller prop or one with less pitch will allow the motor to run at less load, draw less current, perhaps rev more to be in a range where it works more efficiently and produces better power to get up to planing speed. Hopefully my ideas will give you some thoughts to start with and some others will chime in with their ideas which is why the forum exisits! Cheers, Ian.

[Chris PearceParticipant @chrispearce30862]

Hello Ian,

I have used another prop this being a Brass 35 3 blade, the last was a race prop 2 blade, I have used other batts like Lipo! 5000 it went very well but the engine was very hot for several minutes unable to handle and lasted for several minutes on that.

I will look at the 12v batt idea using twin 6v 4AH, The sea commander is an old aerokit 30+ years.

Cheers ChrisP

[KiwimodellerParticipant @kiwimodeller]

Chris, I am familiar with the Commander having had one thirty years ago! The Sea Queen is its big sister, looks very similar and is now re – released by Jotika. I like to use the original type of motor in my older boats just for the sake of nostalgia but that does not extend to the radio gear as I suspect the old gear would probably interfere with every other boat on the pond. Best of luck with your experimenting.

[ashley needhamParticipant @ashleyneedham69188]

Dude. I cant remember if you had a speed 600bb or just an ordinary speed 600? the bb is ok to 12v but the ordinary ones only to 7.2 or 9.6. None of them draw more that 10 or 12 amps a best efficiency. Your ESc must be shot. I think you had a 10Ahr 6v batt sla type? get a viper marine 25A ESc and this will be more than enough for the motor, without anything getting hot. (the motor will get warm with proplonged thrashing)  I would buy a 30,35 and 40mm 2 blade ( NOT x-pitch) props to try out. Generally speaking these 2-blade props are better at higher revs. Get perhaps a few 3-blade plastic ones to try as well, they are cheap enough,same sizes. The only way to decrease weight is to use a NiMh pack, this will be half the weight of yer SLA batteries. I would stick to the lead ones for now, as high capacity NiMh cells are reasonably dear, and you have a boat big enough to carry a big batt, and a big battery already.

Over running the 600 on 12v will knacker it to short order. A definite solution may be to swap the 600 for an MFA 850, running 12v on a 50mm 2-blade prop, the combination MFA recomend. This is a proven package for boats your size. About £25 for a motor. runs at about 10A current draw..you would need a 12v battery, or get another 6v one.     Ashley. 

[Chris PearceParticipant @chrispearce30862]

Hi Ashley,

I can always rely on you for info, I will get a 25A esc and take it from there, I have a speed 600, I will have alook for some plastic props, should I be looking for race/performance style?

cheers

Chrisp 

[ashley needhamParticipant @ashleyneedham69188]

CP. Twin bladed ones, not x-pitch (as this is the extreme pitchyness). Apart from a small difference in style due to being made by different  manufacturers, all the plastic 2-blade ones you are likely to encounter are all v similar. Possibly a 30mm is too small, so get a 35mm and 40mm to start with. Unfortunately they will be in red or black plastic so not necesarily a great compliment to the boat, but it should give you the best performance on the 600 and new ESC. A small selection of plastic  3 blade props might be good for your spares box. they are likely to be used at some time or another, if nothing else for experimentation. Ashley

[Penny LeeParticipant @pennylee76979]

Key your data into this and see what you get,Chris.

[Chris PearceParticipant @chrispearce30862]

Hello All,

I have put in a 25 amp ESC, with the speed 600 and then a 37.5 mm race twin prop, this combo has stopped the engine from over heating.

I used a 6v 4mA SLA battery but doesn’t last for long, the larger 6v 7mA is ok but the performance isn’t great due to the weight.

What type of NimH would anybody suggest 7.2V 3500?

 Cheers

 ChrisP 

[ashley needhamParticipant @ashleyneedham69188]

CP. So it was the ESC as suspected!  The NiMh batteries are about 1/2 the weigh capacity for capacity (ish) so the bigger the better. Probly 3700`s are an economic buy, although if you are considering getting something else, or making something, then Maplins are selling those 6v 4.5Ahr SLA batts at only £3.99 at the moment, so an alternative ploy may be to get a few of those and simply change them out when the performance drops, or a little before so you dont knacker them. The only other consideration is that NiMh batts deliver a lot more current, together with a small increase in voltage may make you go a bit faster. Hey, what the hell….get 3 x  7.2V  3700 MaHr NiMh batteries and have done with it !  You are not going to have too much running time anyway with that heavyish boat and a speedy motor! (could try a slightly smaller prop, would take slightly less amps and so increase running time, at a small loss in performance)    Ashley.

[Chris PearceParticipant @chrispearce30862]

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