Diesel Electric Hybrid power

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blakej59
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Diesel Electric Hybrid power

Post by blakej59 » Thu Jul 25, 2019 8:11 am

I've loosely followed publicly available info on various company's R&D efforts to develop diesel/electric hybrid power for yachts. The day will come that a system will be available for re-powering using electric motor drives (rather than Yanmar) with one engine generating the power for both electric drive motors as well as house power. This may also allow for removal of the generator.
There will be the risk of operating with only one engine vs. the safety of having 2.
The future is interesting. If this happens, I expect the fuel consumption will be much improved. You'll be able to drive for short distances without the diesel engine running so you'll be able to quietly leave the marina.

For engineering types, get's you thinking.

Best, Jim

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AMCarter3
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Re: Diesel Electric Hybrid power

Post by AMCarter3 » Thu Jul 25, 2019 8:59 am

Very interesting topic, indeed. It's too bad that the original PDQ company did not make through the 2008 recession. I imagine they would be moving down that path.

As a by the way, my 2006 PDQ does not have a generator and, as far as I can tell does not need one. Instead, we have a Webasto diesel hydronic heating system located in the Starboard bow locker. We also added last year a single solar panel (over our aft bimini). I am quite amazed at how much energy is generated by this panel. With our long summer days in the Pacific Northwest, I suspect we could go for 5-6 days on-the-hook without turning an engine on. (Granted, we don't have high draw devices like a washer/dryer).
Mac Carter
2006 34' PDQ PowerCat "All Heart"; MV 98; twin 100 HP Yanmars
Home Port: Bellingham WA 98229
Member of San Juan Sailing & Yachting Charter Fleet: http://sanjuansailing.com/charter-detai ... .php?id=35

deising
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Re: Diesel Electric Hybrid power

Post by deising » Thu Jul 25, 2019 9:05 am

Hi, Jim. This might sound negative, but here are a few thoughts –

To preserve the current boat performance, the motors would have to produce the same torque and RPM needed now (propeller mods might allow for some differences/improvements). Given the inefficiency of creating electrical power from the single diesel engine to supply the motors, that one engine might need to be somewhat larger than the current combined propulsion diesels (say 2 x 100HP, plus some additional), so 250 HP might be a reasonable guess.

The current engines weigh about 490 pounds each and a single 250 HP engine about 800 pounds, so there’s a savings near 180 pounds. In the hybrid, however, you would need a generator hanging off the big engine and two motors, so I think your overall weight would likely increase. The idea of eliminating the 5kW generator and using the big (only) engine for house loads like A/C or battery charging while away from shore power means running the large engine at extremely light load – not good. Saying instead that you would have a huge battery bank and massive inverter (4kW or more) to handle the house loads would add a lot of weight and cost. So much weight that the boat performance would not be even close to the same.

I realize you were not specifically looking to refit the PDQ, but if you did, where would place the larger engine? It surely would not fit in our engine spaces. In any catamaran design, having just one large engine (basically a genset) in either hull would require a careful redistribution of weight within the hulls.

Finally, while many boats only have one propulsion engine and get by just fine, I have had a few issues come up that made one engine (always the port, by the way) inoperative. I was sure glad to be able to continue to a safe location with the other engine.

Regardless of the above, I applaud the research folks are doing and hope it bears good fruit along the way.
Duane Ising
m/v Diva Di
Punta Gorda, FL
2006 PDQ MV 34 - hull 91, 75HP, 3-blade

deising
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Re: Diesel Electric Hybrid power

Post by deising » Thu Jul 25, 2019 9:12 am

To Mac's point, the boat's environment and owner requirements play a big role. A/C is not often desired in the Pacific NW, and heating can be provided via fossil fuel as Mac does. Not having the A/C units to consider makes living off solar/battery/inverter practical most of the time.

In FL, however, for at least half of the year almost everyone craves the A/C. If you are not connected to shore power, you often run the genset for a few hours in the evening to cool things down for sleeping. Sometimes you get lucky and have decent breeze, but not that often.
Duane Ising
m/v Diva Di
Punta Gorda, FL
2006 PDQ MV 34 - hull 91, 75HP, 3-blade

duetto
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Re: Diesel Electric Hybrid power

Post by duetto » Thu Jul 25, 2019 11:14 am

a few years back i had lengthy discussions about this with dick vermullen (maine cat) when he was designing the prototype powercat. his plan was just as described, a constantly running generator powering 2 electric motors. after a couple of years of changes he gave up and went with diesels. he found, again as noted above, that he couldn't get the speed he was looking for.
john & diane cummings
duetto mv34 #23

dstrecker1
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Re: Diesel Electric Hybrid power

Post by dstrecker1 » Wed Jul 31, 2019 9:46 am

Probably they only way it will work with electric drives and still get the same performance is with fuel cells.

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