It depends on the voltage panels and what your goal is.
When I upgrade to a 40amp mppt controller I will be able to fit another panel.
My current eco worthy $99 controller only accepts 50 volts max.
ECO-WORTHY 20A MPPT Solar Charge Controller 12V/24V |Eco-worthy
The new 40amp model I want accepts 100 volts.
https://www.renogy.com/rover-40-amp-...#tab_prd-specs
So rule of thumb from what I know is try to pump the max volts into the controller for what its rated for.
Thoughts.
If you want to charge your batterys @ 14.7 volts, which is the standard bulk charging voltage, At what time of day will you reach that voltage with a 17 volt panel? ( 12 volt panel)
With higher voltage panel, or panels in series you will reach 14.7 volts way way earlier in the day with the sun break.
But it all depends on what type of camping your doing.
I have a generator but never use it. Its for if an emergency arises. I dont want no noise when Im camping in the state lands.
If your just doing weekends then your batterys will probably get you by and a pwm system will supplement.
If you do longer dry camping youll see PWM will not keep up .
But I guess its subjective to your power usage.
I have 1100 watt inverter
I run coffee maker in morning.
Toaster oven
Charge cell phones, laptop
Run TVs, one during day and two at night
Box fan or two in summer
Heater in winter.
I can run my fridge off the inverter if needed in a rare case I run out of propane.
ect ect
Just my opinion though
Serious boondocking " Go MPPT or go Home"
Linear Mode
