Solar questions for new TT

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New member
May 16, 2024
We are taking delivery of a new 2024 Grand Design XLS 22MLE next week. It has the 12v refrigerator which concerns me for the times we dry camp (maybe 20% of the time for 3 or 4 days max). The trailer comes with a 165watt solar panel and MPPT controller. I plan to either transfer 2 newer 6volt batteries from our old trailer, or bite the bullet and buy a new 200Ah (or 230Ah?) lithium. We are very conservative with our power usage when dry inverter, no tv...just refrigerator, lights, water pump, etc. I can add a 165w panel on the roof, but am thinking I'd rather get a Renogy 200watt suitcase so i can move it around as necessary? It would have its own separate controller. My questions....Would this set up take care of my needs? The suitcase panels i see come with PWM controller, should I upgrade to another MPPT or will the one MPPT and the PWM work ok together? And finally, is there any difference or advantages to getting one 200Ah lithium battery compared to two 100Ah batteries? This is an amazing forum and thanks for any advice!
Have learned from my solar system on mine, 300 watts, is it’s good enough to keep refrigerator going until you get to your destination to plug in. Have an electric only refrigerator. The lithium batteries can extend your power source. Only have 2 panels on my 5th wheel. Can ad a 3rd on the ground. Am considering a solar generator. But I do bring my Honda 3200 when boondocking.
Figure the refrigerator will draw about 1 kWh (80 amp-hours) a day from your batteries. That's how much power you'll have to replace while boondocking, either from solar or from running a generator.

If it was me, I'd go with the lithium batteries. Prices are ridiculously low right now.
A big unknown here is how much you can count on solar. One cloudy day turns just enough solar into not even close. Unless you camp on a barren plain, shade from trees limits your daily net. Yes, a portable panel mitigates that but only if you are there to move it around and ensure it doesn't walk off. Yes, solar can work but it's not a given, so requires a plan B or being OK with running low.

Mark B.
Albuquerque, NM
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