I have two choices - bypass the controller on the portable panel & parallel it with the solar panel
on the roof or add a connector on the outside of the trailer that feeds to the electrical
system on the input side of my battery
monitor and use the controller built into the portable panel.
My choice is to go with the second solution - individual controllers, unless sometime in the future I decide to switch to an MPPT controller
. Both the portable & built in controllers are PWM
which are not as efficient as the far more expensive MPPT controller. The problem is once you get above a 15 amp MPPT controller, the price jumps high enough that an additional panel or two may be a less expensive solution (provided you have the room).
If you really want to know the state of charge of your battery
, I strongly suggest purchasing a monitor in addition to the readout on the charge controller.
A real monitor such as a Trimetric 2025
will keep track of actual amp hours in & out, rather than just give a voltage measurement. For example, right now both the LED's built into the trailer's basic battery
monitor & the GoPower solar
controller show the batteries at 100%, however the Trimetric 2025 shows that I am still down by 8 amp hours from a fully charged batteries.