T-Pain Is On A Boat: Re: [Electric Boats] Re: 48v diesel battery charger information

Sunday, April 15, 2012

Re: [Electric Boats] Re: 48v diesel battery charger information

excellent ideas but i've begun operating under the assumption that it is better to run a diesel at near it's capacity (85%) rather than very lightly.... i've been given that advice from more than one source.... that advice plus the added cost of the larger engine makes me wish to stick with a smaller one

From: Robert Lemke <robert-lemke@att.net>
To: electricboats@yahoogroups.com
Sent: Monday, April 9, 2012 7:22 PM
Subject: Re: [Electric Boats] Re: 48v diesel battery charger information

Why couldn't this http://www.ebay.com/itm/NEW-25HP-D1105-Kubota-Industrial-Diesel-Engines-In-Line-3-cylinder-1-1-liter-/270944755849?pt=BI_Heavy_Equipment_Parts&hash=item3f1590e089#ht_4711wt_1021 just spin (4) 200 amp 12 volt alternators wired in series for 48 volt bulk charging? Or not in series and each alternator dedicated to a 12 volt section of the battery bank? $2000 for a brand new diesel, $1000 in fabrication for marine use, and $1200 in the (4) alternators comes to $4200 for a 11KW DC gen-set and a lightly loaded (16 hp) 25 hp new diesel engine.

Bob

--- On Mon, 4/9/12, Matthew Geier <matthew@acfr.usyd.edu.au> wrote:

From: Matthew Geier <matthew@acfr.usyd.edu.au>
Subject: Re: [Electric Boats] Re: 48v diesel battery charger information
To: electricboats@yahoogroups.com
Cc: "Eric" <ewdysar@yahoo.com>
Date: Monday, April 9, 2012, 4:21 PM

On 10/04/12 07:04, Eric wrote:
>
> Unfortunately, regardless of random member's analysis of why these units should be cheaper, I'm going to guess that any reliable marine DC generator in the 48V-144V range will be more expensive than an AC generator, primarily due to the limited demand and low production numbers. So I would expect that a Panda, Onan or Kohler AC genset of an equivalent kW output will be cheaper than what you'll find in DC or even what you'll be able to cobble together yourself.
>
> That's just my opinion, but I'm aiming to set realistic expectations. And think of how awesome it would be for all of us if you can prove me wrong...
>

48v DC is also 'Telco Voltage' and there will be a lot of kit around
for it. But Telco's expect and are prepared to pay for, very high
availablity - these gen sets are back up power that just 'has to work'.
So between 'it just has to work' level of engineering AND the 'it's for
a telco mark up', such kit is expensive. It will be absolutely bullet
proof, but expensive.

A DIY really should be cheaper - as you are targeting and entirely
lower level of engineering rigour.

Now you could argue that a marine system should be even tougher than a
Telco spec one - as lives might depend on that system reliably starting
and kicking in, but that's a whole other argument :-)

Now I use a Honda eu20 as backup on my boat - which by any marine
engineering standard is unsuitable for the job - between fumes and fuel
spill potential, but it works for me. (I've never had to use it 'in
anger' fortunately.) I'm aware of the risks and act accordingly. (Like
NOT starting it in the enclosed areas of the boat for starters)

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