Oceanvolt Hybrid Motor

[rpmbnsf]

Well, looks like i'll be sticking with motors/sail drive and smallish generator along with a fairly large lithium battery bank and as much solar as practical for my setup. Don't think i'll even go for a wind generator, I've never heard a review where owners are ecstatic with the performance of wind generation, seems like they're merely okay or they can't stand them. But that's a discussion for another thread.

Thanks all for your input.

[Just Another Sa]

Originally Posted by rpmbnsf

Well, looks like i'll be sticking with motors/sail drive and smallish generator along with a fairly large lithium battery bank and as much solar as practical for my setup. Don't think i'll even go for a wind generator, I've never heard a review where owners are ecstatic with the performance of wind generation, seems like they're merely okay or they can't stand them. But that's a discussion for another thread.

Thanks all for your input.

If you consider a fairly large lithium battery bank, you should also consider fuel cell as an alternative. Both cost a lot, but the latter might turn out to be the better option.
If a smaller battery would do, the fuel cell would be too costly option.

[transmitterdan]

Is fuel cell actually viable in an ocean crossing cruiser?

[Paul Elliott]

Originally Posted by transmitterdan

Is fuel cell actually viable in an ocean crossing cruiser?

I'm curious about that too. I looked at the EFOY product, which uses a methanol/water fuel, and it uses about 0.25 gallon / kWh. This is pretty comparable to what my 50 hp diesel engine burns when charging my 12V batteries at 83A (1 kW) (with the transmission in neutral because we're racing). If I didn't already have the engine I might consider a fuel cell as a way to keep my batteries charged, but on my boat I would need to carry roughly the same volume of special fuel cell methanol as I would diesel fuel.

The fuel cell sure would be quieter though, and would produce less heat and smoke. The biggest EFOY cell provides up to 210 Ah (12V) per day, although their fuel cartridge only holds 2.64 gallons. This is enough fuel for about 11 hours at full output.

[Stumble]

One major problem with fuel cells is that the catalyst is only good for some numbers hours. I can't remember specifically for the EFOY but if I remember it basically doubled the cost/kwh compared to just the fuel. Making it a very expensive way to generate electricity. As with everything there is a use case, but its pretty narrow.

[Just Another Sa]

Originally Posted by transmitterdan

Is fuel cell actually viable in an ocean crossing cruiser?

Depends on how you define viable.
It is certainly far more cost effective and far more practical than an idea of crossing an ocean using an electrical motor with only the energy stored in any kind of battery pack!
Neither comes anywhere near as good as using sails & wind or ICE & propeller & fuel.
In addition fuel cells used in space vehicles or submarines are very reliable.

[scooter.john]

I am building a 14m cat with two Oceanvolt SD15's. The motors and batteries are 48 volt so my initial plan was to reduce power loss by choosing as many 48 volt accessories as possible with dump load diverter(ie) hot water heater, eutectic refrigeration,watermaker.
This leaves me with a 24 volt circuit for toilets, shower pumps, anchor winch, electric cockpit winches and a 12 volt circuit for auto pilot, waste macerator, radar instruments and lighting and a 240 volt circuit for dive compressor, galley appliances and power points.
I feel this is too many circuits and am considering moving the 48 volt equipment to 24 volt. Any advice would be appreciated.

[myocean]

It is not always most important to have best efficiency. Optimize from case to case: Check in detail which of the consumers are really relevant because they consume lots of Ah per day (better Wh per day due to your different voltage levels). I assume these are autopilot, watermaker and fridge.
If you install about 1 kW of solar you have already a pretty good base supply.
The autopilot, running while sailing, can be powered by hydrogeneration if solar is not sufficient on cloudy days. So there should be no issue.
When autopilot is covered and you have the 1 kW solar, you have pretty much no problems anymore. Water maker should be one of the efficient models with energy-recuperation and for the fridge, check if yours is really most efficient. We had a European residential fridge consuming only 30 Ah (at 12V) a day in hot climates. (with dedicated small AC inverter).
The great thing with electric propulsion is that you have no energy issues while sailing due to hydrogeneration.

[valhalla360]

Originally Posted by transmitterdan

Is fuel cell actually viable in an ocean crossing cruiser?

The EFOY is $6k for 105w output and you need to source methonal to power it.

If you have an electric motor operating at even a modest 5kw output, you are going to need 2 units running 24hrs just to replace 1 hr of run time.

No idea about reliability in a marine environment but that doesn't look viable.

[44'cruisingcat]

Originally Posted by scooter.john

I am building a 14m cat with two Oceanvolt SD15's. The motors and batteries are 48 volt so my initial plan was to reduce power loss by choosing as many 48 volt accessories as possible with dump load diverter(ie) hot water heater, eutectic refrigeration,watermaker.
This leaves me with a 24 volt circuit for toilets, shower pumps, anchor winch, electric cockpit winches and a 12 volt circuit for auto pilot, waste macerator, radar instruments and lighting and a 240 volt circuit for dive compressor, galley appliances and power points.
I feel this is too many circuits and am considering moving the 48 volt equipment to 24 volt. Any advice would be appreciated.

Don't really see that doing that would offer much benefit. You have to have 48 volts for the drives anyway. If you want a biggish inverter, running that off 48 volts would make sense. Big reduction in current. I'd probably be looking to use the 48 volts for as many big load items as possible, for that reason. A 48 volt windlass might be nice....

Maybe you could skip the 24volts circuit, if you really want to eliminate one?

[Octopus]

Originally Posted by scooter.john

I am building a 14m cat with two Oceanvolt SD15's. The motors and batteries are 48 volt so my initial plan was to reduce power loss by choosing as many 48 volt accessories as possible with dump load diverter(ie) hot water heater, eutectic refrigeration,watermaker.
This leaves me with a 24 volt circuit for toilets, shower pumps, anchor winch, electric cockpit winches and a 12 volt circuit for auto pilot, waste macerator, radar instruments and lighting and a 240 volt circuit for dive compressor, galley appliances and power points.
I feel this is too many circuits and am considering moving the 48 volt equipment to 24 volt. Any advice would be appreciated.

Our situation is not dissimilar to you. We've owned a Lagoon 420 Hybrid for ten years, so our experience may be of value to you.

Our Lagoon 420 Hybrid has a 72V lead acid propulsion bank charged by a 16.5kVA 230VAC generator and 12V lead acid house bank charged from the 72V propulsion bank via a DC-DC converter, plus we have a 4kW 230AC inverter off the house batteries. None of this is ideal and it is quite complex.

The 72V/12V DC-DC converter is not three stage charging, so it canes the lead acid house batteries, which the inverter also canes, and isn't particularly efficient (circa 80% on top of losses to charge the 72V bank).

I'm in the process of switching to LiFePO4, but haven't yet decided on configuration yet.

I assume that you have a generator and your batteries will be LiFePO4.

We don't have any 24V accessories and I'm not sure why you would need them, especially if you have LiFePO4 house battery, where there would be virtually no voltage drop from operating 12V windlasses and winches. We don't have any 72V devices, although I have just purchased a 72VDC/230VAC inverter.

In your situation, to keep things simple, I'd consider having a single 48V LiFePO4 battery bank with multiple (always on) 48VDC/230V AC inverter/chargers (linked together to synchronise the wave form in inverter mode), with combined charging capacity sufficient to power your two SD15 motors. In inverter mode you would want combined AC output sufficient to operate your dive compressor and a high output AC watermaker, although typically I think you would want to have the generator on when running these. Then power your 12V low-load circuit (and 24V if necessary) off a switch mode power supply powered by the (permanently on) 230VAC inverter (s).

For short duration high-load 12V accessories, like winches, windlasses and generator starter, you could look at using fit-and-forget supercapacitors, charged by your 12VDC low-load circuit, located close to the point of use, to provide the oomph required.

We use 230VAC appliances for everything possible (oven, microwave, toaster, induction hob, fridge, freezer, washing machine, watermaker, power tools, vacuum cleaner, hot water heater etc.), becuse they are cheaper,
more efficient and more ubiquitous than their 12VDC cousins

Chris

[BigBeakie]

"For short duration high-load 12V accessories, like winches, windlasses and generator starter, you could look at using fit-and-forget supercapacitors, charged by your 12VDC low-load circuit, located close to the point of use, to provide the oomph required."

Where could I find out more about these high load caps? Are you sure they would handle the load from a loaded 1,500W windlass? Have you done it?

At this point it seems prudent to have a separate 12V bank for high loads for that equipment. I cannot find a 48V/12V DC converter that can handle the load reliably.

[ranchero76]

In my opinion - 48V as much as possible. I would invest in converting as many motors from 12/24V to 48V as possible (or even to 220 AC where it's safe!). Easy on wiring - HUGE difference when long cables are used, and once it's done - you know how it was done, you can replicate/keep spare motors as needed.

[scooter.john]

Thank you Chris for your valuable experience. You have got me thinking about 240 volt for high load circuits. How is this more efficient than 48 volt.

[scooter.john]

Thank you Ranchero and Octopus. Your input confirms my initial thoughts. It is very valuable to have it confirmed.