Choosing a Solar Setup

michaelroyy · July 2020

I am a new owner of a 2015 320S Boondock. I am looking at adding solar to run off-grid, but without using air conditioning or the heater (much). Maybe hot water, lights, and maybe refrig... What are the thoughts of the Renogy 100 Watts 12 Volts Monocrystalline Solar Starter Kit with a 30a PWM controller? Thanks. Lots reading all your questions and responses!!!

jkjenn · July 2020

michaelroyy said:

I am a new owner of a 2015 320S Boondock. I am looking at adding solar to run off-grid, but without using air conditioning or the heater (much). Maybe hot water, lights, and maybe refrig... What are the thoughts of the Renogy 100 Watts 12 Volts Monocrystalline Solar Starter Kit with a 30a PWM controller? Thanks. Lots reading all your questions and responses!!!

If you are running the fridge via LP, that setup might not be a bad place to start, based on what you have stated. The biggest challenge people run into is battery capacity.

Congrats on your new T@b!

We would love to see pictures!

michaelroyy · July 2020

Thank you for your response. Should I be thinking of a lithium or (2) 6-volt marine batteries or ?...

jkjenn · July 2020

michaelroyy said:

Thank you for your response. Should I be thinking of a lithium or (2) 6-volt marine batteries or ?...

To be honest, dual AGM deep cycle would be my recommendation. Lithium is still over-priced and unless you are camping frequently for more than 3-5 days at a time, you really won't get your return on investmemt at this time.

CrabTab · July 2020

We use a 100W Renogy Eclipse briefcase to recharge the battery when boondocking. It came with a 20A PWM controller. Our battery is the stock battery. Usually it takes just a few hours in the sun to recharge. I felt it was a good place for us to start learning our off grid needs, wanting to know before spending money on lithium or add the weight of 2 6V batteries.

Our heat and fridge run off of propane (no AC, as you're planning too) when boondocking.

We can usually find sun and haven't found a need to upgrade from this simple setup. There are, of course, instances where we might long for more capacity (i.e. camping during a monsoon). We've just gone to 'tent camping' mode in those few situations and done without the luxurious extra power, or headed down the road to find fairer skies (and the battery charges from the alternator).

pthomas745 · July 2020

The Renogy panel will be fine. But, if it is just "hot water, lights, fridge on propane" the dual batteries may be overkill. Do you know what battery is in your trailer? How many amp hours is it? How do you intend to monitor your battery?

Camp first. Figure out how to monitor your battery. Realize how hard it is to use a lot of power in the trailer. Then make these pricey decisions.

I have a 100 watt panel and a stock battery. I can boondock til I run out of water.

Jackie_Dave · July 2020

We also have the 100 watt briefcase from Renogy. Works great for what we need. We have gone into tent camping mode during a stay in northern NY. Camping in nothing but trees. Right now we have no plans to upgrade anything for the length of our stays.

ScottG · July 2020

I've been using a Renogy 100W suitcase with a 10A PWM controller coupled to a single group 27 wet-cell marine battery for the last five seasons. My electrical usage is similar to what you are planning. I've camped for up to eight days straight with this system and could probably go indefinitely.

Depending where you camp, the biggest limitation may be getting your panels into the sun (or at least facing a bright sky) for at a short time each day. One of my first mods was to extend the reach of my panel so I can optimize its placement as needed. On one occasion, I had to use almost 40' of tail to get my panels out from under the trees. Ultimately, it's all about the light! :-)

michaelroyy · July 2020

Thank you all for your sharing your info and experiences. Very much appreciated. pthomas: I have a Champion Marine Battery (24M-625CH) that came with the trailer.

pthomas745 · July 2020

That battery is most likely an 80 amp hour battery. (Champion doesn't list the amp hour capacity for this battery, for whatever reason...) The way batteries work, if you try not to "discharge" a battery below 50 percent of the usable amp hours, you can extend the life ("cycles") of the battery. So, you have 40 amp hours to play with.

GC3 · July 2020

I'm going to try to calculate how much exactly, but I'm guessing it doesn't take adding too many actually useful devices like a cell signal booster to justify adding "headroom" capacity in the form of more panel/battery (and maybe a small inverter) to the factory solar package. I am thinking even another permanent panel would increase flexibility in where to park. Waiting on delivery of a 2021 Tab 320S

pthomas745 · July 2020

I use a small inverter inside the trailer, and carry a small 25 ah battery for laptop work when I'm out taking pictures. 12v chargers for the laptop save power for those times I use the 12v plugs from the camper battery. If you know how many watts/amps a device uses, and can calculate the amp hour use, you will be way ahead when you start thinking about power upgrades. I use a Kill-a-Watt to measure everything I use in the trailer.

GC3 · July 2020

pthomas745 said:

I use a small inverter inside the trailer, and carry a small 25 ah battery for laptop work when I'm out taking pictures. 12v chargers for the laptop save power for those times I use the 12v plugs from the camper battery. If you know how many watts/amps a device uses, and can calculate the amp hour use, you will be way ahead when you start thinking about power upgrades. I use a Kill-a-Watt to measure everything I use in the trailer.

Something like this for the inverter, where to plug in?

https://www.amazon.com/dp/B082V5TC11/ref=cm_sw_em_r_mt_dp_sLXiFbB21CM25

DougH · July 2020

@GC3 ; Hi... many of us have bought pure sine wave inverters instead of modified sine wave models, or models that just don't say. Supposed to be much gentler on electronics, and I've had several small appliances that just don't work at all if not on a pure sine wave inverter. Everyone has their fave brands based on reliability, cost, quality of construction and components, features. So you may get several PSW inverter recommendations. I've had several, and my current larger Giandel has been trouble free for me... but I have it shock mounted, ventilated, and all inputs / outputs fused.

https://www.amazon.com/Inverter-1200Watt-Control-Outlets-Emergency/dp/B07G36Z2TH

pthomas745 · July 2020

I should have been more specific: inside the trailer, the 12V "cigarette lighter" plugs are on a 15 amp fuse. So, the absolute limit for those plugs would be an appliance that would draw less than 180 watts. I've never approached that limit, so "less than 180 watts" is probably safer. (My laptop draws about 45 watts max, or about 4 amps per hour from the battery.)

There are many small "pure sine wave" inverters these days. I charge phones/batteries, run little fans, etc. I have one of these:

https://www.amazon.com/gp/product/B07KQ4Q2L5/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Inverters have a "efficiency" factor, so if you can find a 12v power adapter for your device, it will save a bit of power from your battery.

For those bigger inverters, for things over 180 watts, the inverter has to be wired directly to the battery. Many owners have installed them inside the trailer. I carry one that will attach to the battery with alligator clips. It works, but care must be taken to make sure not to overdo the power use: Your 700 watt appliance will draw 'roughly" 3 amps per minute from your battery.

druthazer · August 2020

If you want your batteries to recharge while driving between overnight off grid stops don't you need installed solar panels?

pthomas745 · August 2020

If your tow vehicle charges your trailer as you drive, no.

ChanW · August 2020

We have our panels attached to the 'roof rack' on our TV. While on the road, in good sunny weather, the solar system recharges our Tab batteries more quickly than the TV alternator does.

On one trip, before we'd installed the solar, we discharged the Tab battery way too far (left the three-way on battery by mistake). The TV's alternator took forever to get that charge back up.

We now have 200W of solar and 220 Ah of battery. Very glad we do, for those many shady or cloudy eastern campsites.

druthazer said:

If you want your batteries to recharge while driving between overnight off grid stops don't you need installed solar panels?

Tundra57 · August 2020

If you fit a dc to dc charger between the TV and your tab battery, it will charge way faster than the solar panels while driving. You also should uprate the wiring in the TV. Modern vehicles monitor the TV battery and when charged, reduce the voltage to save over charging the TV battery. This leaves a low voltage which drives a very small current to the tab.

The dc to dc charger boosts this voltage at the expense of more input current from the TV and provides the correct charging cycle to the battery. It has the added bonus of preventing the Tab from discharging the TV battery if you forget to unplug. Also it charges in the dark.

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