I don’t think they allow the thruster to run without the motor running no.
My thought was a 12V to 50V booster but I can’t find one with enough umph to do this job.
Alternators does not charge that much at idle, at least leisure boat bow thrusters can usually be used without main engine running(usage is anyway restricted to short periods only) . One of the challenge using a direct drive is the gearing. Even at 100kv and 24 you will have much more rpm than you need to…the “target” speed is extremely low in this application, so to work well the pitch of the prop need to be much much less than on a e foil.
In their video about the thruster Supra say that they are running it at 24V.
I’ve found a few potential motor motors that may work at 24V.
The question is now how to get 24V in the boat while still using the 12v alternator to charge the individual batteries and not compromising the 12V systems.
That’s very cool haven’t seen one ready built like that.
Going back to the lithium battery idea what size battery would I need to power 2 of these guys:
Probably limited to 5 continuous minutes of run time.
I would say you just need a higher KV and run at 12V solves a bunch of problems. What about this?
At 3080kv and 12v doesn’t that yield 40k rpm? Don’t I want a lower RPM?
Sorry I’m still learning how all this works!
Considering insurance and other related safety issues, would not use any DIY (lithium)batteries in my own boat. Think you would be fine with 24 volt max, and that can cheaply and simply be achieved by using 2 car size led acid batteries in series. If want to spend some money, there are also approved 12v lithium packs …You can probably charge them in the marina, so they can be a separate system from the boats default battery pack. Typically the bursts required for bow /stern thrusters are closer to ten seconds than a minute, and you should not need too many bursts to more the boat.
I agree avoiding the lithium is the ideal scenario.
I’m mostly hoping for a recommendation on where to start with motors in the 24v area.
I’m just not well versed in how brushless motors work.
For example I see several motors with plenty of thrust at 50v but what happens if I feed it 24v? Does the thrust go down proportionally or does it go down slightly and amp draw goes up?
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How all this work :
Volt and kv = rpm
Max amp ( so motor size) = torque = thrust
Speed= high rpm or big size prop ( and pitch )
For instance : A given 50A motor can give 1100w at 12v , 2200w at 24v …
Bigger motor can run at low rpm and can be made at lower kv and still give enough torque and not to much rpm ( cavitation …)
So aim for the highest voltage , lower kv , motor and prop size according to needs
Boat weight will give you thrust needed
Thanks!
So max amp draw is going to be independent from voltage (or mostly so)
A motor will draw 50a at 12v for half the torque of 50a at 24v and so on so it’s directly proportional to voltage.
the T140 model 2KW (170 amp 12V), gives a thrust of 38 kgf This is considered to suit boat in the range of 8-10 meters. If 24 volt, the amp would be more reasonable, only half. Guess this power would be sufficient for your boat? Tunnel is 140mm, the 5blade propeller is only a few millimeter smaller. For sure Lewmar have invested plenty in RD so would not challenge their design. Considering the application we need different properties than on a foil, we are here lookin for max “pollard pull”, max kgf in a practically stationary status, whereas a e foil is moving relatively fast . my 5 cents:
-24v
- low Kv
- big diameter of motor( more torque) 80mm. Utilizing only part of max rater power
- big diameter of prop,(160+mm this comes from that the hub(motor) is bigger than in a regular unit
- large blade area ( 5 blade)
- low pitch( no gearing)
.
I get that traditional thrusters have their place, but as I’ve already elaborated on I’m not interested in them for a variety of reasons. Telling me repeatedly to use one is not going to change my opinion, I’m well aware of all of the thruster options available at the moment and several in development.
I’m here trying to get advice from folks who are using small high power DC motors to accomplish a similar task to what I want to do. I’ve seen plenty of videos of efoils, kayaks, sups etc with more than enough power to accomplish what I want to but there are never enough details for me to figure out exactly what they are using to accomplish it.
I was hoping to eliminate some trial and error by getting some info from people actually building things and pushing the limits, not get told to go to west marine and buy a thruster.
My suggestion would be to go to a supra dealer and measure the width, length of motor and then width of duct. That way you wil be able to gain a good idea of what’s needed and look for a similar sized motor.
I suspect they are using 250-350kv range and the thruster around 150mm.
Tailored for ROV or RC boat needs, several would be needed: small with 9x9x12 cm so a 8cm diam propeller, 1000w and sold 350GBP / 500USD:
Voltage: 24V
Max. Current: 43A
Max. Power: 980W
Max. Pull: 9.2kg
Cable: 1m/39.4in 14AWG silicone cable with 4.0mm male banana connector
Size: Approx. 9 * 9 * 12cm/3.5 * 3.5 * 4.7in
https://www.amazon.co.uk/VGEBY1-Underwater-Propeller-Brushless-Waterproof/dp/B07V8NSGS1/
Think you got my post totally wrong. The first part just showing for comparison, what a traditional thruster has for specs. Starting from the "low Kv ", the suggestions in my post has nothing to do with a traditional thruster, but mainly how to possible achieve the same with a high power direct drive motor.
Considering the propeller you have different need than for kayak and e foil…moving a heavy hull sideways is different story. If You look at Malibu ski boats stearn thrusters, that also looks relative large diameter? If You want small units, You need a few to get the same thrust, good idea from SoEFoil, a handful of those ROV motors might do the job.
Hi
DW54135 (12mm shaft diameter version) is equipped with a propeller developed and designed by ourselves, and the maximum thrust can reach 50KG (voltage 56V). The propeller price is US$749 (including: motor, ESC, fairing, propeller, etc.), and reservation is required.
The current will be relatively large, thus shortening the single use time of the battery.
Wondering how is your build doing now? welcome to try the new 65111 160kv 3000W Amphibious motor made by Flipsky, for more details, you can check this link, https://bit.ly/3lEnmw9
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