Portable Solar Plan

OK, does that controller have a monitor or just by phone app? What else do I need? I like the panels on Amazon with the stands already attached (the stands if purchased separately are $50 each).

Controller - Grape 40 amp from Home Depot
Panels - Windy Nation with stands and fuses (2 x 100 watt)
Wiring - from panels to controller and controller to battery bank
Y Fitting (1 for each panel)
Fuse - from controller to battery?
Batteries - 2 Sams Club "Duracell" 6 volt AGM (220ah each)

The higher the voltage of the panel, the more benefit from an MPPT controller.

An PWM controller will only deliver the maximum amps the panel can drive (panel watts/panel voltage) while a MPPT control can deliver almost the full wattage of the panel. So a 100 watt 17V panel will only delivery a max of 5.9A with a PWM controller while a MPPT controller can deliver 7A (assuming charge voltage of 14.2V). With 2 panels and 10 hrs of daylight, that is 20A/hr or almost 1/2 of available power from a single battery. A 100 watt, 21V system will deliver the only 4.8A with a PWM, but the same 7A with a MPPT controller.

All that said, when I dived into solar, I went with a single 100 watt panel and PWM controller. It exceeds all of my power demands including charging two laptops, phones, several hours of fluorescent lights, and a night of running the furnace. I never really considered a portable panel because of fear of theft combined with no room to store them. Another advantage to the panels is on a full moon night, I get over 0.5A going to the battery. And as soon as the sky begins to lighten, the panels start putting into the battery. By just after sunrise, I'm already getting .75A.

Hi Tizi,

Look at the cost per watt. The only time MPPT makes financial sense is when there is no room to add more panels. The Grape Controller can do 40 amps, so it may be likely that one would run out of roof space before running out of controller capacity. Plus the Grape is extremely programmable and temperature compensation.

Back when panels were $5.50 per watt MPPT made great sense. But with panels as low as 0.39 cents per watt that is no longer true.

Plus the Grape can do 24 volts to a 24 volt battery bank. All for $50.

Tizi wrote:

pianotuna wrote:
Hi,

Roll your own is almost always cheaper.

MPPT is overkill on a 200 watt system that has nominally 12 volt panels. Look at the Grape 40 amp controller at Home Depot. (Don't get me wrong, the Victron is a heck of a good controller).

http://www.solarblvd.com/ has better prices than the Windy Nation kit (but does not include the frame).

For my detailed thoughts on solar surf here:

https://freecampsites.net/adding-solar/

Is it overkill if I will be adding 2 more panels eventually? I want the system to be expandable.

I'm looking forward to the outcome of this thread. I was thinking about something similar!

pianotuna wrote:
Hi,

Roll your own is almost always cheaper.

MPPT is overkill on a 200 watt system that has nominally 12 volt panels. Look at the Grape 40 amp controller at Home Depot. (Don't get me wrong, the Victron is a heck of a good controller).

http://www.solarblvd.com/ has better prices than the Windy Nation kit (but does not include the frame).

For my detailed thoughts on solar surf here:

https://freecampsites.net/adding-solar/

Is it overkill if I will be adding 2 more panels eventually? I want the system to be expandable.

Hi,

Roll your own is almost always cheaper.

MPPT is overkill on a 200 watt system that has nominally 12 volt panels. Look at the Grape 40 amp controller at Home Depot. (Don't get me wrong, the Victron is a heck of a good controller).

http://www.solarblvd.com/ has better prices than the Windy Nation kit (but does not include the frame).

For my detailed thoughts on solar surf here:

https://freecampsites.net/adding-solar/