Sunday, May 31, 2015

Re: [Electric Boats] Need source for 48v. panel controller and panels-- my next step !

 

I think I will look more closely at cruise amps power needed.  If I can get lower draw, then less amps from the panels and less cost.  The area required is maybe more than I'm willing to have as a sun cover, my boat is not going to look like a barge.  At 6.5 ft. wide I can do maybe 8 ft. long max. would like to be smaller than that.  Flex panels look like what I need all right, and one supplier will sell them for the same as framed panels as they make both for other vehicles.   My cost is about $ 650. plus shipping, for 48 volt, and close to 2 amps, but I will look again to sure.  They are willing to make flex panels to fit my roof design, fasteners that allow maintenance, and secure through roof connections with the controller.
 
I'm assuming I would use 4 to 5 knot cruise power a few hours during the day, with plenty of charge time between uses.  Fast travel, not so much !!  On a week end, I might do 6 -- 10 hours total day use, at a Coots event.  I can almost do that on one charge, but would like extra returning to the battery without a generator.  I found a gen. set that will do a job, but 15 amps charge means that I have to listen to it run during down time.  Not any fun, plus it could be stolen easier.  At most shows, or rental docks I can plug in my 15 amp one,  or two 12v. car type chargers with the bank split, anytime I'm at the dock -- for free.   Dock power is the best, and so this solar array is mainly to cut the last cord at smaller lakes.
 
Thanks Myles, I will keep in touch on this, yours are the first figures that I can use as a comparison.  Best Wishes,  Cal
 
Sent: Sunday, May 31, 2015 11:22 AM
Subject: RE: [Electric Boats] Need source for 48v. panel controller and panels-- my next step !
 
 

Hey Cal-

Good to hear you haven't given up on e-boating. J

For 40amps and 48v, you're looking at about 2kw.

To get the most power per area and to keep things light, you'd want to not skimp on your panels---ie. don't buy 10-12% efficient, $1/watt panels that are framed and heavy.

Rather, you'd want to invest in the 20% efficient, unhoused SunPower flexible arrays which run about $2/watt and available any day, online and on ebay.  For $4k, you can get your 2kw.

For 2kw, at 20% efficiency, you need at least 10sq-meters of solar cells.

And practically, at our latitude, you'd still not get 2kw, but let's say this did tell the whole story.

You'd need a bimini area approx. 6.5ft x 16ft to get your 2kw.  Do you have that much roof space?  How about half of that?

Here's a 135watt Sunpower panel:

http://www.ebay.com/itm/Semi-Flexible-135-Watt-Solar-Panel-High-Efficiency-Sunpower-Marine-Rated-/141262084821?pt=LH_DefaultDomain_0&hash=item20e3e05ad5

Pick up 16 of those and for less than $5k you're cooking with solar.

How deep are your pockets?

-Myles

From: electricboats@yahoogroups.com [mailto:electricboats@yahoogroups.com]
Sent: Monday, May 25, 2015 9:56 PM
To: electricboats@yahoogroups.com
Subject: [Electric Boats] Need source for 48v. panel controller and panels-- my next step !

 

Now that the outboard is done, battery bank hooked up and all works great, I need to look at extending the run time.  Not liking using a generator, so perhaps panels would do that ??  I was thinking of one 48 volt controller, and maybe four decent sized panels on a " Bimini " type top.  I have one top now, but could build anything to fit the panel size. if I could get 40 amps, that would be continuous power at cruise speed.  That might be asking a lot at 48 volts, so maybe half of that would work ??  Batteries are now marine deep cycle lead acids.

What have others done with a reliable controller would be a good start.  Maybe a brand to look for, or a place that could supply a system of panels and controller would also be helpful.  I have done biz in China, so maybe there is a tested system some one has used ??  Flexible panels preferable for an arched top, but I could be tempted to build a flat top with stiff panels, as flat ones are mostly cheaper, higher output.  Need the panels here first, to fit on any top design correctly.

Thanks, I would welcome any ideas on products to buy ----------  Cal 

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