T-Pain Is On A Boat: Re: [Electric Boats] Solar panels on the boat deck: what are safe voltage level?

Wednesday, October 8, 2014

Re: [Electric Boats] Solar panels on the boat deck: what are safe voltage level?

Hey Bendik,

I understand your concern. I have house batteries at 12v charged from an
inverter on the solar system that runs on a 24v system. The system keeps the
house system fully charged all the time.

You could opt to run a capacitor bank for your 110v system and a inverter to
keep it there. The problem with such a system is capacitors have a quick high
amp discharge should anyone come in contact with it. You can protect the
circuitry however to keep such a mishap from happening. Your complete battery
bank could then be at 12/24/36/48 volts depending on desire and equipment you
scavenged. I would keep the capacitor bank charged vs. discharged to avoid
startup surge.

Just a thought.

Kevin Pemberton

On Monday, October 06, 2014 04:15:33 PM you wrote:
> Thanks for your reply and comments Kevin!
> One comment on voltage: I undestand that charging voltage is different from
> system voltage (battery voltage). The motor I am planning to use is a 120V
> (might work fine on 96V). But I want to keep the voltage level on the
> *boat´s deck *as low as possible (higher voltage in the "machine room" is
> ok - there are no kids down there:)
> Regards Bendik
>
>
> 2014-10-06 15:35 GMT+02:00 pembertonkevin@gmail.com [electricboats] <
>
> electricboats@yahoogroups.com>:
> > Hello Bendik,
> >
> > Charging voltage is not system voltage. The cables that come out of the
> > panel
> >
> > have connectors that are both water tight and safe around water and
> > people. A
> > 48 volt system will have anywhere from about 70 volts to over 100 volts
> > from
> > the panel but that is after they have been hooked up in series to produce
> > it.
> > This will depend on the controller. MPPT controllers are the best bet.
> >
> > My system consists of 4 panels producing 1120 watts at peak bright full
> > sun
> > day. On the water using reflection from the water this could be higher on
> > some
> > days. The panels produce 49volts open circuit and the cheap MPPT
> > controller I
> > imported converts the voltage to a 24 volt system.
> >
> > Because the controller input voltage is the most important voltage of the
> > system (No matter what voltage you choose) consider shopping for the
> > controller first, then find suitable panels for it.
> >
> > My crystaline panels cover an area of roughly 8 square meters, maybe a
> > little
> > more. Morph panels will require more space.
> >
> > My panels weigh in at over 50 lbs per panel. This makes using them as a
> > shade
> > difficult on a boat but if the bank is low in the boat may work.
> >
> > Any shade on even one panel connected to a single controller will reduce
> > output considerably. For this reason I do not suggest deck mount but
> > rather as
> > a shade over the cockpit, or davits. I have used small panels on my canoe
> > for
> > shade and to extend the range. I would never be caught in a storm with the
> > configuration but if prudent would work for others.
> >
> > Final point.
> >
> > Controllers are cheaper in the 24/12 volt variety than for higher voltages
> > at
> > your wattage. Higher wattage and the 48 volt systems shine. The lower
> > voltage
> > panels are more per watt. A controller that works on 12/24 volts will not
> > produce 12 volts with panels that are above about 28 volts ( this is a
> > gray
> > area). The controller for 24 volts will handle about twice the watts as it
> > will if used on 12 volts.
> >
> > Considering the above information I would likely choose a 24 volt system
> > for
> > the size of 1000 watts. Because of space limitations on boats I would only
> > consider crystaline panels for a system of 1000 watts. I would keep an eye
> > on
> > the kids and keep them off the panels. If working with a sail boat I would
> > make
> > sure no shackles ever found their way to the panel surface. I would set
> > chores
> > for the kids to take care of those panels so they would take pride in
> >
> > them.
> > This could be the morning dew removal with a squeegee, and have them see
> > the
> > increase from the panel from their effort, and give them a slap on the
> > back.
> >
> > All in all every watt you do not need to pull from the bank will save you
> > the
> > resistance the bank charges in interest. May the sun and wind always be at
> > your back.
> >
> > Kevin Pemberton
> >
> > On Tuesday, September 30, 2014 09:33:17 AM you wrote:
> > > Hi!
> > > What is safe voltage level for solar panels mounted in the "traffic
> >
> > zone" on
> >
> > > a boat deck? ...Kids playing around with wet hands...
> > >
> > >
> > > 12-20V?
> > > Or higher?
> > >
> > >
> > > I am planning a ~1kW array to power electric propulsion (120V motor)
> > >
> > >
> > > What are your opinions/experiences?
> > >
> > >
> > > Bendik