Solar component(s) help needed

johnm1 wrote:
I keep bouncing back and forth on what to get and need someone to point me in the right direction ... please.

I have a new TT toy hauler. All LED lights, don't want to run 120AC stuff. Have (2) 6v gc batts (new). Camp in shaded areas (not deep shade) in upstate NY and I'm planning on starting with a portable system of 100 to 200W.

I was thinking a MPPT charge controller was better for me, since it supposedly harvests the sun better in shaded areas but I've been reading that the MPPT units don't work as well as the PWM units with smaller PV systems. I don't mind spending more $$ on something like the MPPT but I want it to do what I need it to do.

Which would people recommend for me with the above criteria?

Thanks and I know there will be follow-on questions!

Buy a generator and extension cord and call it good.

Solar panels and shady camping, not a good mix.

One must ask themselves just how much lugging and tugging do you REALLY want to deal with for portable solar panels..

Decent panels that will net you a fair amount of wattage are LARGE and EASY TO BREAK. A 100W panel is about 4ft x 2.5ft and supply a mere 5.75A a peak sun!

You will need some sort of "stand" that is easy to build/break down and store.

You will need one heck of a lot of expensive and not to mention heavy wire to get any appreciable distance away from the shade.

Then you also have to take into account storing and hauling big panels.

Sure you can buy "portable" panels, but they will cost more and you will need panels of them since they are often smaller in order to make them portable.

HERE is a portable Renogy "suit case" for $200

or you can get a 100W regular Renogy HERE for $139

Hi,

The smaller the battery bank the greater the need for lots of watts of solar to get the charge back to 100% on a daily basis. A larger bank doesn't do as deep a cycle.

For twin golf cart jars, I'd go for 400 watts on flat installation. That should nearly eliminate generator use for charging.

About the maximum battery bank size for 400 watts is about 600 amp-hours.

If you're using 12V nominal panels, both styles of controllers, PWM and MPPT will be very close in efficiency. MPPT has the advantage of taking higher voltage and converting that to current to the battery. It operates on the "knee" of greatest power efficiency from the panel. MPPT sometimes suffers loss in extremely high temperatures.

For 200W of portable panels, buy the cheaper PWM controller. When you tire of lugging solar panels in and out or have one fall over and break, you'll be ready for serious solar mounted on the roof.

FWIW, I actually use one 24V nominal panel mounted on the roof with an MPPT controller. It fits my current needs.

Ok ... but, is the PWM more efficient with smaller watt systems or do I have that wrong? I don't think I'll need more than 300 watts (though time will tell).

Portable might be a long wire back to the RV. You might do well with a 24 volt panel in 200 to 270 watt range and a small MPPT controller. Large panel might be awkward at times but at least it is only one. With higher voltage your % losses in the wire will be cut about in half as compared to the same wattage through the same wire.

If you might mount a panel on the roof (I recommend this) consider a 30 amp Morningstar MPPT. The portable can be used in parallel with the fixed roof mounted panel.

Lots of ways to implement solar, this is just my random thought of the day.

Morningstar 15a MPPT 1 panel $240

Morningstar 30 amp 2 panels MPPT $335

Buy PWM by Bogart or Mornigstar. Put the saved money in more panels. If you go over 600 watts or so use mppt.