PWM vs MPPT

[Mooree]

Either PWM or MPPT charge controllers can recharge solar batteries safely. However, there are several substantial differences. Both controllers charge batteries in three stages: bulk, absorb, and float. Unfortunately, PWM controllers bulk-charge batteries at a constant voltage value. On the other hand, an MPPT controller automatically adjusts the solar panels’ output voltage to recharge the deep cycle batteries. As a result, the MPPT controller ensures more efficient solar energy utilization.

If you need to run power-hungry RV appliances and devices, an MPPT charge controller is a better choice. While it is more expensive than a PWM controller, you can enjoy savings from its robust features and exceptional solar-to-electricity energy conversion efficiency.

 

[BrunoMTP]

On a related note, if your rig doesn't already have LED interior lighting, it's probably worth spending a few dollars swapping out the most used incandescent bulbs for led bulbs. Replacement led bulbs have become relatively inexpensive and use a fraction of the juice of the older style incandescents. You can save a lot of amps usage when running on battery power with LEDs.

 

[John From Detroit]

Either PWM or MPPT charge controllers can recharge solar batteries safely. However, there are several substantial differences. Both controllers charge batteries in three stages: bulk, absorb, and float. Unfortunately, PWM controllers bulk-charge batteries at a constant voltage value. On the other hand, an MPPT controller automatically adjusts the solar panels’ output voltage to recharge the deep cycle batteries. As a result, the MPPT controller ensures more efficient solar energy utilization.

That is almost exactly what I was going to say.
Also thePWM controller sends what amounts to square waves (Retangular0 to the battery
On/off/on/off/on/off the length of the ON varies to control the charge.... You do not want to listen to an AM radio near that and FM may be affected as well
MM\PPT.. are kind of DC-DC buck boost converters..
So the panels are ALWAYS charging when exposed to enough light.. Even if the panel's output voltage drops below the battery charge voltage. MPPT Maximum Power Point Transfer.
Always on, never off. They adjust voltage instead of chopping it up,.