Monday, February 27, 2012

[Electric Boats] Re: motoring with ,quickcharge 48/V 25 amp,6V agms,and a honda 2000

 

Hi eric thanks for the info I am running this set up already on my
boat.I did a test run a few weeks ago. I ran an average of 3.75 knt for
5.5 hrs at a 32 amp draw on my electic yacht meter, close as I can
figure from that run I should be able to go appx 10.5 hrs and that will
bring my 200 amp hr bank down to around 50% I am ok with that for what I
do. thanks again for the in put bill.
--- In electricboats@yahoogroups.com, "Eric" <ewdysar@...> wrote:
>
> I'll assume that you're talking about a Quickcharge SCO4825 Select a
charge on-board charger. On their website they provide the following
specs, 48V, 25A, 12A@117VAC. If all this is true, then I don't see a
problem. But I don't believe these numbers.
>
> Lets look at the energy input, 12A x 117V = 1404W. That's easy enough.
>
> You know that your 6V batteries don't charge at 6V, the peak charge
voltage for your AGM batteries is 7.2-7.3V. So your peak pack charging
voltage for 8 batteries in series is 57.6V. Let's call it 54V for the
bulk of your charging. 25A @ 54V = 1350W. The Quickcharge website
doesn't mention the technology that they use, but at the bottom of their
promotional PDF, they mention "100% copper transformer heavy duty
rectifiers..." These types of chargers have traditionally operated at
80-85% efficiency. So being generous, 1350W output will take only 1600W
input (assuming 85% efficiency). 1600W/117V = 13.7A. Not a big deal you
say, it's only a difference of 1.7A, but let's read on.
>
> Now let's look at your generator. A Honda eu2000i is rated for 1600W
continuous output, so now you're right on the line. If your charger only
pulls 13.7A while charging, you're good. But it might pull more. If it
does, your Honda will shut itself down when the load getts too high. My
Yamaha 2000 will do the same.
>
> Maybe the SCO4825 only puts out 1200W (48Vx25A), if so, then the
output at 54V will be around 22A. If that is the case, then the Honda
should handle it fairly well, but you won't be getting 25A.
>
> If you have access to one of these chargers, then the simple way to
check it's power requiremetns is to run it through a Kill-A-Watt meter
while charging your batteries. I have a P3 model, they are available at
Radio Shack for less than $30. If you don't have access to the charger,
you have to take the manufacturer's word, but their published specs are
suspicious to me. At almost $500, that could be an expensive experiment.
Of course, if you buy it somewhere with a good return policy, your risk
is lower.
>
> I went through the same debate and I chose an Elcon PFC2000+ charger
for around $600. The manufacturer specs were more believable and they
were able to load a charging profile that was perfect for my LiFePO4
battery pack, AGMs are even simpler. My measured thoughput effieincy is
close to 93% with the fully electronic (no transformer) PFC charger.
Elcon's spec of 14A@115V nominal input turned out to be right on (as
measured with a Kill-A-Watt monitor)during the bulk charge phase for my
batteries. This 14A exceeds my Yamaha generator's continuous rating of
13.7A, but I've run the charger for an hour from the generator and it
hasn't missed a beat, I would expect the same from a Honda. I've also
verified that I'm getting a consistant 27-28A at 55V from the
charger/generator combo. This powers my 30' 10,200 lb boat at 4.2-4.3kts
without using any battery at all.
>
> Most of the other peoplpe in this group that have electro-motored on
their portable generator (Myles, Mike, etc.) are running chargers with
lower input/output so their generators are not as close to the limits.
So your proposed setup might work, and it might not.
>
> After all of this work, I've never had to use my generator to get
home. I motored the boat for an hour on the generator as a proof of
concept, and it worked fine, but I've never needed it in real life.
>
> Perhaps someone else in the group has more hands on experience with
the specific charger that you're looking for. If so, hopefully, they'll
jump in.
>
> Fair winds,
> Eric
> 1964 Bermuda 30 ketch, 5.5kW Propulsion Marine drive, 8kWh Lithium
batteries
> Marina del Rey, CA
>
> --- In electricboats@yahoogroups.com, "Bill Falk" fsailing35@ wrote:
> >
> > anyone using this set up? if so how is it working for you and what
charge settings are you using? any info thanks
> >
>

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