Ready to buy a NEW Class B...but need advice on solar Amp-hours

[tmreeves]

I am fully committed to buying a new Class B, and it WILL HAVE the latest solar/lithium technology.  Based on my shopping research, so far, the Thor models offer systems with different capacities:  200 vs. 400 vs. 800 Amp-hours.  My question is:  How does someone select one of these?  This RV will be used by me and my wife for weekend trips and occasional 5-6 day adventures (usually nights with plug-in power).  I am willing to spend more on a larger capacity system, but don't want to just spend money on power we are unlikely to need.   Any rules of thumb?  Any experiences with solar power:  likes/dislikes, blessings/curses, pros/cons?

Thanks for any advice?  Tom.

[sandsys]

On my last van I had 400 amps each solar and AGM batteries for an all electric/diesel van in which I often boondocked for a week or more in Arizona with no electrical hookup. I also spent three months (Oct-Dec) in North Carolina with no hookup, but free showers, by driving every now and then to charge my batteries if they got lower than I liked. The furnace was diesel but everything else, including my water heater and induction burner, was electric. I was the only one living in it, though. Given that you said you will be plugged in most nights and mostly going for weekends, I wouldn't spend a lot on solar. If you think you might go full-time in this rig in the relatively near future, then I would definitely do a bunch of solar for the freedom that gives you.

Linda Sand

[lappir]

Have you spoke with any aftermarket installers? I think that's what I would do. You could make sure the vehicle had the necessary space, pathways and alternator for the system, but I don't think I'd spend a lot of money on a system put in by the builder without extensive knowledge of every part of the system they propose.  With aftermarket you know you will be able to work on it if needed and where the wiring will be going. With a system built into your vehicle there could be multiple things that would have to be removed to have access. 

Rod

[Randyretired]

Sizing a solar system is somewhat complicated.  It depends on how much you need or want to power.  For instance what appliances will need to be powered.  In our RV we have a residential refrigerator and we use a drip coffee pot.  We also have TV but the big draw is a mini split AC.  So our power requirements are substantial and we often spend months boondocking.  If your requirements are modest then of course a smaller system will do.  Another consideration is the time of year and general location.  Short winter days only produce limited power but long summer days are solar friendly.  It may be helpful to try and figure out what you will want to power and what time of year you plan on powering these things and talk with some professionals.  Often the limiting factor on an RV is the amount of room for solar panels.  If you have more than just modest requirements I usually recommend to install as many solar panels as will reasonably fit.  The panels have come down in price and are relatively inexpensive.  Batteries and the electronics are not inexpensive and can get very expensive quickly.

[Chad Heiser]

With a little more information, I can provide some better feedback.  What do you expect to power in the van when you don’t have shore hookups?  This answer in conjunction with how long you want to be able to power those items will better answer how big the system needs to be.

Generally speaking a 3KVA inverter will run any appliance in any size RV.  This usually means one large draw appliance at a time though.  In other words don’t try to run the microwave and coffee pot and hair dryer all at the same time from the inverter.  A 3KVA inverter might be bigger than you need in a van, but it is a good starting point for discussion purposes.  Typically a 3KVA inverter requires a minimum of 400 amp hours of battery capacity.  A good rule of thumb for solar is to be two to three times the battery amp hour capacity in solar watts.  If you have 400 amp hours of battery then that is 800 to 1200 watts of solar (generally) to keep it charged up.  With lithium batteries I like to be closer to the three times mark because they can charge faster than AGM or lead acid.

 

[sandsys]

10 hours ago, lappir said:

With a system built into your vehicle there could be multiple things that would have to be removed to have access. 

!!! In my van, they installed the furnace then built the cabinet around it. The guy who needed to service my furnace did a very good job of NOT swearing.

Linda

[sandsys]

7 hours ago, Randyretired said:

Short winter days only produce limited power but long summer days are solar friendly.  It may be helpful to try and figure out what you will want to power and what time of year you plan on powering these things

And where. There are a lot more sunny days in Arizona than there are in Oregon.

Linda

[Sky King76]

Great question. Just bought a 2022 Thor Sequence and all the way up to the walkthrough I didn’t know it was lithium, I thought it had a generator because I’d just seen one earlier in the day that was a year older. Thank God Thor has some really good videos on YouTube about these models, in hour long detail.

When I realize it ran on lithium, I remember seeing one of the Thor videos and the reps said the batteries were an upgrade over the generator AND you could run the A\C all night easily on the batteries. They were NOT talking about the little 200Ah setup we have. We don’t anticipate being part of the RV lifestyle to any degree and wanted to boondock as much as possible but as someone said we’re go aftermarket for way more amps. Compare the cost of adding after purchase vs already on the vehicle. I know they use some better batteries on the bigger setups. No clue if we’ll replace or add or even how that works.

Oh…for example I went out and turned on the power, inverter…and A\C. It was pulling 76Amps! I didn’t even know that was possible. So if I would have left it on…I don’t know what temp the A\C was set on, it showed about 2.5 hours of battery before I’d have to start the engine.

Edited June 12, 2023 by Sky King76

[Randyretired]

The conversion from 12v to 120v requires 10 times the amps from the batteries. When on shore power there should be a circuit that patches the 120v through instead of the inverter using batteries.  This means the amps will be reduced by a factor of 10.

Edited June 12, 2023 by Randyretired

[jalann]

Considering your plans for using the RV, a solar setup with 200-400 Amp-hours should suffice for weekend trips and 5-6 day adventures, especially if you'll have access to plug-in power during your journeys. The larger 800 Amp-hour capacity would be more beneficial for extended off-grid stays. Keep in mind that the amount of solar power you need also depends on what appliances you'll be running in your RV and during which seasons. While a smaller system will save you money upfront, if you anticipate more extended off-grid adventures or powering energy-intensive appliances, a larger capacity system might be a wise investment. 

Edited October 17, 2023 by jalann