inexpensive panels

If the system in your trailer is 12V then you have to use a 12V solar panel with a PWM controller. A PWM controller will not drop the output voltage down to 12V when using a 24V solar panel.
An MPPT controller will drop the voltage down to 12V when using a 24V solar panel.

Tom_M wrote:
That controller is a PWM. You need an MPPT controller.

Is it truly REQUIRED? Or is it just a preference?

I understand that the MPPT controllers might be a little more efficient. But the system I'm creating is probably an overkill anyways for my needs so I'm not worried too much about squeezing out every bit of efficiency.

-Chris

That controller is a PWM. You need an MPPT controller.

pianotuna wrote:


The 250 panel may be 24 volts--so you would have to move to a 24 battery bank.

This is where I'm getting a bit confused about solar panels and controllers...

The 250w panels in question have the following:
Max power voltage (VMP): 30.3 V

But doesn't the CHARGE CONTROLLER take care of converting the input voltage (and current) to be used to charge your 12v lead acid batteries at the proper voltage and current??? (provided the maximum input voltage isn't greater than that allowed by the charge controller).

Looks like the charge controller I referenced above has the following:
Max input power and voltage: 390W /12V; 780W/24V
But I'm not sure what the maximum panel voltage is.

But it looks like this one would, right?
https://www.amazon.com/Flexzion-Controller-Multi-Function-Adjustable-Regulator/dp/B08BP8P2MP/ref=sr_1_9?dchild=1&keywords=solar+charge+controller&qid=1607213851&refinements=p_36%3A-4000&rnid=2661611011&s=lawn-garden&sr=1-9
It mentions: Max. PV Voltage: 50V Is that max from the solar panel???

-Chris

S-J,

The 250 panel may be 24 volts--so you would have to move to a 24 battery bank.

Short answer is a qualified "No"

An MPPT controller would work.

They do sell a 250 watt kit with a used panel:

https://store.santansolar.com/product/1-250w-solar-panel-kit/

I would recommend bumping up to a larger capacity charge controller.

Would a simple $16 charge controller like this:
https://www.amazon.com/Controller-Regulator-Intelligent-Adjustable-Parameter/dp/B07STZSG9J/ref=psdc_2236627011_t3_B07G1PL1B9

work with one (or two) 250w panels like this:
https://store.santansolar.com/product/santan-solar-t-series-250w/

I'm a little confused about the requirements of the charge controller vs the output VOLTAGE of the solar panels.

If that combo worked, then you could put a 250w solar system on your RV for:
- 250w solar panel: $50
- 30a charge controller: $16
- Z-brackets + wiring + misc: $50(?)
Total: ~$120 (or 500w for ~$190)

I bought a 200w WindyNation system off Amazon for ~$260 recently and will install it on one of my RVs. If you convince me that the above 250w setup would work, I'll probably add that to my other RV just for fun. I'll have a nice Aili battery monitor on each so I'll be able to see exactly how each performs.

I guess where it gets really interesting is if you are creating a 500w or 750w system. 500w solar system for less than $200 seems pretty amazing. Unfortunately (I guess...lol) I only have ~200AH battery bank and no real need for a 500w system.

Shipping of the panels becomes an issue. BUT...I happen to be traveling near Gilbert AZ (where they are located) in about a week and I could pick up the panel(s) in person.

Am I missing anything here?
Chris

Youngsters do not factor that to seniors, a 20 year guarantee is as useless as a two thousand year guarantee.

ty beemerphile1

Santan is very highly recommended on several solar Facebook groups I watch. Apparently there are many happy customers.

mr_andyj,

Panels are generally warrantied for 80% of oem output after 25 to 30 years.

Mine, after 15 years, are still outputting their oem wattage.

I'd love you to post a link to inexpensive ebay panels.

It would be great if you provided a link to the article that suggests panels are 50% "used up".