Solar panel watts&amp output

Hi,
I have 2 130 watt panels on my RV for a total potential of 15amp output per hour if my battery is low in the morning.
A friend recently installed one 260 watt panel on her van that is rated for about 8amps output per hour.
Can you explain this?
Edited.
I have 2 130 watt panels on my RV for a total potential of 15amp output per hour if my battery is low in the morning.
A friend recently installed one 260 watt panel on her van that is rated for about 8amps output per hour.
Can you explain this?
Edited.
Comments
You probably have a PWM charge controller--Which is fine for your installation
Power = Volts * Amps.
A PWM controller "lets through Amps"... I.e., (forgetting losses), 15 amps in is 15 amps out.
A MPPT charge controller is a "down converter"... A DC switching (buck mode) power supply. Again, ignoring losses, the MPPT controller takes Watts in and outputs the same Watts out:
- Power = Voltage * Current; Current = Power / Voltage
- 260 Watt / 14.5 volts charging = 17.9 amps out
- Including losses: 260 Watts * 0.77 panel+controller deraiting * 1/14.5 volts = 13.8 amps typical maximum current
A PWM controller:- 260 Watts * 1/18 volts Vmp = ~14.4 volts Imp (current maximum power)
Realistically, if both installation are properly designed and installed, they have about the same output.-Bill
Well, I found out now that her controller is a PWM Sunsaver 20 by Morningstar. So, she is getting only the 8amp rating to the battery?
2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 700 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.
https://www.solar-electric.com/mosumpsochco.html ($200 + RBTS cost)
There are a lot of larger MPPT controllers to pick from out there...
-Bill