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sailor4life7777 · 08-07-2022, 04:07

Hi guys, I've been really going through a lot of different options for my 34' power catamaran setup and I recently discovered the Hangkai electric outboard motor (48V, 2200 watt) that are going for $485 on amazon. I was thinking of putting two of these electric outboards (one on each hull) and also mounting a gas 9.9hp-20HP outboard centrally as well.

I will have 1650 watts of solar panels dedicated to the motors and 2x24vx100ah lithium batteries wired in series to charge the 48V motors. With this setup, I know I won't be going very fast with the dual electric motors (4-6 mph at best most likely), but I should have pretty good range. If I need to go longer distances, I can fire up the gas outboard engine as well. The dual electric outboards would be great for steering. To be honest, I won't be crossing oceans or going too far with this setup, I just want to be able to go to nearby islands that are 30-40 miles away at most. I won't have any sails, so I would be relying just on my 3 engines for getting to the islands. I figure the electric engines would be great for fishing as they will allow me to troll for fish without using any gas and I would have pretty good range just with the electric engines. I want to reduce my reliance on gas since prices are going through the roof!

What do you guys think of this setup? Any potential drawbacks that I'm not thinking about? Also, anyone with firsthand experience with the hangkai electric outboards? I read all the reviews and watched all the videos I can find about these electric outboards and although they are not the greatest quality, I figure I can fix or repair any issues and electric brushless motors are pretty reliable (and low maintenance).

Thanks in advance for any advise!

**StuM** · 08-07-2022, 04:59

Do the numbers:
Electric motors 2200 x 2 = 4400W (about 6HP)
Solar 1650 x 3 or 4 full sun equivalent = 5000-6600Wh per day
i.e. solar will provide enough energy to run maybe 2 hours at 4HP equivalent.

That should be good for 3 knots or so. So range of maybe 6 NM.
Batteries 2 x 24 x 100 = 4800Wh. That's about the equivalent of your full daily solar output. So you can run for 2 hours on your batteries and then need a full day to recharge them.

You're going to be doing almost all of your runs to and from the islands on your 9.9HP outboard and just use your electrics for manouvering at either end.

I'd guess that you may be able to push your cat at 5-6 knots with your 9.9HP in good conditions, but that will be about the limit and it will be less going into weather.

sailor4life7777 · 08-07-2022, 05:03

Thank you for your reply! Sorry I misstyped, I will have 3300 watts of solar panels. Also, I don't plan to use the engines at 100%, most likely will run them at 50% so that I can increase the range (and I don't mind going slow since I will be trolling for fish as well). Does that make more sense?

sailor4life7777 · 08-07-2022, 05:04

I also was thinking I could use all three motors as the same time when I need to go long distances to save fuel costs. Would I actually get fuel savings by using all three motors at the same time?

**StuM** · 08-07-2022, 05:28

Quote:

Originally Posted by sailor4life7777

Thank you for your reply! Sorry I misstyped, I will have 3300 watts of solar panels. Also, I don't plan to use the engines at 100%, most likely will run them at 50% so that I can increase the range (and I don't mind going slow since I will be trolling for fish as well). Does that make more sense?

OK, so it will only take half a day to recharge the batteries.
If you are running at 50% (3 HP), I doubt that you will get close to your. 4-6 knots.

(I don't know where you are fishing and what for, but for off-shore 6-8 knots is a good trolling speed range. That's going to need your gas outboard.

)

Ifitsworthdoing · 08-07-2022, 22:45

Interesting @sailor4life7777 - we are currently commissioning a 34ft 5ton all-electric powercat equipped with twin ePropulsion 6kW Evo pod motors plus a 10kW Propel S1 outboard in the lazarette. Our dinghy tender will have twin Remigo 1kW motors that can also serve as emergency rudders and supplemental propulsion for the mainship in case of Orca attack having damaged our main propulsion and/or rudders. We will have up to 2 x 27kW propulsion LiFePO banks plus 18kW house bank and around 3.5kWp solar with additional triple wind turbines. The project will be covered in a series of articles in Powerboat & RIB magazine. Similar size boat to yours, so would be good to stay in touch to exchange experiences and data!

Manateeman · 10-07-2022, 06:53

We love our huge solar panels and house battery but we find there are days ...or a series of days...when we must turn on our diesel generator.
We can understand the why of electric motors but not the how.
Especially on catamarans that choose to count every ounce.
Please explain what system you will use after a lightning strike or three days of rain. Are you certain you have enough thrust to push against a storm for days.
This crew sailed for years without any engine. We built catamarans and we love Chris White designs. So these are sincere questions.
Captain Mark and the manatee crew.

KTP · 10-07-2022, 07:26

I am really warming to the idea of electric drive with a reasonable battery bank (we have 18kWh currently) supplemented by a small 160 pound 3.5kw diesel generator. You get all the advantages of electric (low maintenance, super quiet operation, instant startup) and the diesel generator from my research should provide about 10kwh per gallon of diesel, so with 20 gallons onboard, you have 200kWh of energy storage there.

If you use two 6kw electric outboards, each with a static thrust of 279.4 pounds (Navy Evo 6.0 specs) that gives you 559 pounds of static thrust. On our sailboat with a internal electric motor and the original prop, we were measuring about 180 pounds of static thrust at the dock with a strain gauge at 3000 watt input, so the numbers seem to check out. We would get about 4 knots at that 3000 watts, so I would expect at least 6knots from 12kw.

With a 18kWh battery and the genny running, you could motor at 12kW for about 2 hours, long enough to get you up a channel or well away from a dangerous shore. At a slower ~5kts, about 5kW to the motors, you could go for 12 hours with the generator running....60nm. At 4kts you could motor until your 20 gallons of diesel run out, about 70 hours or 280nm, of course depending on conditions.