Hi Jonny,
I answered the disconnect the batteries already as well. It is fine to disconnect them--but even better to let a solar system maintain and recharge them.
MPPT allows the use of cheaper per watt higher voltage panels. It also harvests 8 to 10% more energy per day, and may work better in low light situations. The extra watts collected only become important when you run out of roof real estate. At the time I did solar it was a no brainer to use MPPT. Now with cheap panels, it may be more inexpensive to use pwm technology. I'd still favor a controller that is 60 amps. That will allow up to about 800 watts of panels.
To do an energy audit simply use your behavior at home for the number of hours items are used. Life in an RV should not be much different than at home. I believe you are underestimating how much you will use as far as energy goes. It is always better to have too much--than run short and have to start a generator at 2 a.m.
Also, more and more campgrounds are limiting the generator run times. British Columbia, for example allows only from 8 a.m. to 10 a.m. and then again from 4 p.m. to 6 p.m.
Jonnygsx wrote:
I didn't ask if 120volts would be enough in storage tuna. I asked if it was ok to leave the batteries connected in storage or disconnect them. (cycles was my concern, didnt know if constant trickle was better than just letting them sit with no load).
An energy audit is pointless. This is my first trailer. I've never used it. Ive already told you want I want to use. Furnace in the evenings and morning and laptop charger and a few leds. It doesn't require an audit to figure out thats a low number of amp hours each night.
MPPT is unnecessary from my research. I am trying to work on a budget here. For the cost of MPPT it is better to simply use a PWM controller and buy another panel.
