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Friday, June 10, 2011

Still More Engine Musings: DC Gensets

So, if you check boating forums on the Internet, this parallel hybrid stuff seems to be a hot topic of debate on the internet. One of the arguments against hybrids is cost. Example, I got a quote for the Beta60 and the Beta60 Hybrid, and the hybrid version was about 75% more expensive. Seems like a lot, but the question is, compared to what?

On this build I do plan on having a DC genset to help charge the large battery banks. Any large AC loads will be run off inverters. As a parallel hybrid propulsion engine can be operated as a DC genset, is the cost of a straight diesel propulsion engine + separate genset more than the cost of a parallel hybrid? Not sure, as I haven't priced DC gensets, but here are a few of them (prices published on the internet if available).

WhisperGen stirling engine DC generator. About $10,000+ (?)
Volvo diesel based 5.5kw DC generator. Cost? Not Sure, but green Volvos always cost a lot in my experience.
AmplePower DC Generator with smart controllers. 8.5kW. Cost $16,000
Then there is the cost of the consumed engine room space for the genset. As with most boats, space in the engine room on a Westsail 42 is at a premium.

As I haven't really calculated power requirements, I may be able to get by with dual high capacity alternators on the propulsion engine, the cost of which will very likely be cheaper than a hybrid (even after special brackets, pulleys and charge controllers).

220 Amp 24v DC Alternator. Two of these would total about $3000 (without controllers).
As the word "musings" in the title of these posts suggests. Nothing has been decided and I am just thinking out aloud while examining the possibilities.


Tate said...

Ouch! I see why you were saying the beta hybrid didn't look so bad. I didn't realize the gensets were so expensive. I suppose I'm naive still when it comes to boat equipment. ;)

Patrick said...

I saw Nigel Calder at the Seattle Boat Show and he was doing some hybrid math and he was saying at that time that the hybrid engines don't cover their costs of wear and tear on the engiens (running at idle, etc). He was saying that until you ad passive systems (solar, wind, tow) then you start to see the whole system "working". He might have some slides on this he'd be willing to share or to chat with you about.

robert s said...

Thanks Patrick. Yes I have followed Nigel's writings on the subject for some time (he has a number of articles in past issues of Professional Boatbuilder). Suffice to say, hybrid power on boats is not as straight forward and easy if you really are pursuing more fuel efficient propulsion, compared to automobiles. There are much more variables to consider.