Hi Mike,
I just went and checked on the Alten-Duke products and some of the specs were surprising to me. First off, I didn't expect them to be air cooled, that's a challenge for a permanent marine installation. Given the stated weight range (145 - 275 lbs), I would guess that the electric start version would come in around 200 lbs, maybe more. The overall size is pretty big at 32" x 20" x 27", more than 4 times the volume of a Honda 2000W portable. And to think that I was struggling on where to put lithium cells the size of 4 group 27 batteries....
The fuel consumption spec looks a little funny, both the 48100 and 4850 are listed at about 1qt/hr, I would think that twice the power would take twice the fuel. If we assume a thermal efficiency of 30% (the best turbodiesel engines max out at 42% thermal efficiency), 1 quart of diesel per hour will deliver 3.8hp (2884W) at the crankshaft. For it to deliver 2500W of DC output, the alternator/regulator would have to be more than 86% efficient. Alten also states that the 4850 engine has max HP of 6.8hp (5kW) and that sounds more reasonable for a 2500W output. So I would figure that the 4850 would use at least 0.37 gal/hr at full power, and the 48100 at least 0.75 gal/hr at full power.
So you might figure 2.5 hours per gallon of fuel at 50A rather than 4 hours. Significant? Maybe not, but I think that the "about 1 quart/hour" from Alten-Duke is misleading.
And I agree with you. Running an AC genset through a charger will use more fuel per kWh produced than a direct DC generator. My Yamaha portable uses about 0.3 gal/hr to generate 1500W through my Elcon charger. That works out to almost 5kWh/gallon (about 15% efficient), even using my adjusted rate, the Alten-Duke is closer to 6.5kWh/gallon (17% efficient, the numbers make it look like it should be higher, but diesel has 15% more potential energy than gasoline).
100 gallon fuel tank? What size sailboat are you thinking of converting? My 30' ketch came with an 18 gallon fuel tank and I think that Catalina 30s are around 25 gallons.
Anyway, I hope that your weekend goes well. I hope that you get the chance to get away from the keyboard and get out on the water.
Fair winds,
Eric
Marina del Rey, CA
--- In electricboats@yahoogroups.com, Michael Mccomb <mccomb.michael@...> wrote:
>
> the quote came through on the Alten-Duke4850 at $8,652... this is even a bit worse than i expected..... Â I still believe that i will be able to put an equivalent system together for about half that amount.... Â didn't want to go to the trouble if there was an off the shelf system that would work.... Â these 48v charger systems like the Duke unit are rugged enough but are mainly produced for the telcom companies and the result is no motivation to price compete or keep the prices down....Â
>
> some have suggest generators that produce household current and those are indeed much less expensive however if one does this then you have to go back through an inverter and charger to charge the batteries..... Â you pretty much lose all the dollar savings and then some by doing this AND the efficiency losses associated with running a 48v charger on the other side of an inverter wastes a whole bunch of energy
>
> basically a Hatz can run at power on about a quart of diesel per hour and as with the Duke system produce about 50 amps....  don't know about everyone else but 50 amps would drive my boat at 5 knots....  so a 100 gal or 400 quart fuel tank would drive my boat about 2000 miles at 5 knots  or for 400 hours / 16 days if you want to think of it that way.....  you all understand the rest of the goodies such as charging at the dock or wind and solar while at anchor.... Â
>
> ________________________________
> From: Michael Mccomb <mccomb.michael@...>
> To: "electricboats@yahoogroups.com" <electricboats@yahoogroups.com>
> Sent: Thursday, April 12, 2012 6:19 PM
> Subject: [Electric Boats] info on the Alten-Duke4850 diesel battery charger....
>
> Found someone to speak to about this and they are sending a quote. The 4850 stands for 48v50amps and I figure that 50amps will get me a high percentage of hull speed and at the very least a good deal of rudder effectiveness. The dc gen in the thing is rated for about twice the amps but they run it restricted to 50amps so as to have it be rated for continuous duty. It is direct connected (no belts) and is listed as consuming 1 quart of fuel per hour. It DOES NOT however adjust its throttle as the charge approaches a full state and they explained this as being due to the fact that they do not wish to run the diesel (Hatz) in an unloaded condition. (Cylinder glazing and other bad stuff happens when you under work the thing.) Basically you program the Duke4850 with the charge initiating voltage and the voltage at which the charge is considered full. It then self starts at the initiating point. It runs for an hour and then shuts off. IF the
> charge is below the initiating point it starts again and so on until the point set as being a full charge condition is reached. It is perfectly capable of running the motor at whatever amps the motor demands and utilizing the excess amps, if any, to charge the battery bank. If you were to demand MORE than 50amps via the motor then the batteries would continue to supply what is not covered by the 4850. Since I have always thought in terms of running at between 30 and 40 amps I will always have some left over for bank charging. Being continuous duty it will churn out that 50 amps for days and days as long as you can provide it fuel.  I bet i can intervene so that the system does not shut itself down after one hour if there is still more charging to be done. There is also a 48100 model but I didn't ask as I'm just not interested in 100amps continuous. When I get the quote on the thing I will throw the pricing up here.
>
> This is the same Hatz based 48/50 that you can stumble across as being manufactured in Australia but Alten owns the rights to it in the US and that is probably why I have never received any responses when I queried the Austrailians.
>
No comments:
Post a Comment