Advice Please -- Newbie Designing Full Solar System w/ Chest Freezer

This is my first time working with electric, off grid, solar, everything … here’s where I’m at (and humbly looking for guidance). Sorry, wouldn’t let me post links.

Just bought a ’95 Chevy G30 15-psgr van (used as a nursing home transport van), with a hightop and only 60,000 original miles. Converting to a DIY budget campervan, but we’re only planning on using it for vacations: maybe one weekend/month, and two 2-3 week trips each year, so like 50-60 days per year. When we are on these trips, we will probably be driving an average of 2-3 hours/day. We are NOT living in it, so we are only looking to install a minimal to moderate solar system that can power:

2 laptops, 1 iPad, 2 cell phones, 1 hot spot, 1 cellular booster, LED lights, MaxxFan Deluxe … AND

110V Freezer Chest!

I know that there is a lot of debate about the pros/cons of doing a freezer chest conversion vs. 12V DC fridge. When we go camping, we drink a lot of adult beverages . . . we’re on vacation. This seems like to cheapest way to get a big fridge that will keep those drinks cold. And it sounds like the power usage can be comparable or less than a 12V fridge, as long as I don’t have the inverter running 24/7.

The system I have designed is basically built from the starting point of getting this freezer and figuring out how to power it without keeping an inverter on all day.

Koolatron Kool 3.5 cubic ft Chest Freezer ($200 at Home Depot).

Importantly, this particular freezer has a thermostat that can go up to 32 degrees, so we’re thinking that drinks and any non-produce food can stay cold, without freezing too much. If that doesn’t work, and it is too cold, we will try and manually alter the thermostat like the home brewers suggest:

If either of these methods work, I would not need an external thermostat to regulate the freezer temp: it will either be factory set at 32, or I will manually adjust that upwards, closer to 40.

Because the fridge will be plugged into an inverter all day, I looked for an inverter with a Power Save mode, so that it will only turn on when there is a draw. GoPower inverters have that option:

“Power saving mode enables the inverter to turn itself on and off looking for a specific sized load, yet draw less power than standard operation. When power saving is enabled and the inverter senses a load, it may take one second for the load to become active. This one-second wait will be fine for loads that draw continually, such as televisions and stereos. However, it may not be suitable for loads that are intermittent such as bread makers, power tools or blenders. Power saving will continually draw a small amount of power from the batteries, so if the inverter will not be in use for longer than a day, it is advisable to turn the inverter off using the on/off switch located on the front of the inverter or remote.”

My hope is that when the fridge thermostat goes to turn the compressor on, it will wake the inverter up to provide power. This should only happen a couple of times an hour, and should only run for a few minutes each time.

Another option, would be to follow this poster’s advice, he used a few more components to be able to basically do the same thing—automatically turn the inverter on, only when the thermostat turns on:

So, with the freezer chest conversion as my starting point, I need an inverter that will only turn on when the compressor turns on. After that, I am just trying to install the most cost-effective and efficient components for the rest of my system. I thought we could try to get by with 200W solar and 100Ah lithium. But, I want to make sure that my components can support an expansion to 400W solar and 200Ah, if it turns out that we need more power. Here is where I am at:

Rich 200W Solar panel ($200)

SOK 100Ah 12V LiFePO4 ($570)

Renogy 50A Solar MPPT Controller w/ DC-DC Charger (alternator charging) ($260)

Renogy Bluetooth Controller ($40)

GoPower PSW 1500W Inverter ($450)

GoPower 30A Transfer Switch ($80)

OR GoPower 1500W Inverter with Built-in 20A Transfer Switch(this would cost almost $100 more than buying the inverter and TS separately, and give me a 20A TS versus 30A). ($610)

GoPower PSW Inverter Remote ($90)

GoPower DC Inverter Install Kit ($190)

All in, before I buy wire, fuses, etc. this brings me to about $1,900 (everything except for the battery is available on Amazon Prime).

Again, I have no experience. Can y’all who have done this before, and know what you’re doing, please offer me advice on any issues you see with my design/goals? Thanks in advance!!

I don’t think your solar panel and battery combination are big enough for a 110 volt fridge and the inverter to run it. It’s big enough to cover everything else you listed, but not the fridge. If you have to drink cold beverages and you’re not living in the van anyway, why not get a nice big super-efficient ice chest and use block ice? A couple blocks of ice, two or three gallons each, could keep things cold for weeks.

Greetings & Welcome!

I have to agree that a simple ice chest sounds like a more practical solution for you. I’m a full timer, and wouldn’t trade my ice chest for an electrical fridge or freezer. Now for a fuel powered one, maybe.

You’re starting with a passenger van, so that means factory finished floor, walls, & ceiling. A huge plus, keep them. Since you should have opening windows, a ~$20 fan will give you far better ventilation than a $250+ roof vent.

I’d start off cheap with a ~$20 junk yard deep cycle battery and a cheap isolator. I wouldn’t spend money on solar or lithium batteries until you have a lot more experience under your belt.

I prefer to start saving money to begin with, then upgrading if necessary later, which 99.9% of the time, there is no upgrade necessary and I just saved myself BIG BUCKS.


"Always avoid complicated solutions to solve simple problems." ~ OffGrid