NOOB Questions: 12V Fridge, Solar, Boondocking

[ChiliDog]

Hello,
My wife and I just purchased a 2021 Rockwood 2911 Bunkhouse, our first RV. To say we and the kids are excited is an understatement.

It has an Everchill 10.7 cuft 12v Reefer, with 190 Watt Solar system, Two deep cycle Group 27 batteries. I have an 1800w generator I can bring, or may buy a Predator 3500W generator that will run my AC. Highs will be upper 70s so AC not crucial on this trip, but refrigerator is!

We are planning on boondocking for 5 days in the Mojave desert in a small town with limited resources, but some should things really go south. Have friends in the area in cabins so could do showers else where. Tanks are 60 fresh, 40/40 on grey/black

My question is should I expect my batteries and solar to keep up with the refrigerator or not? I have read alot saying it won't keep up, and some saying it should be OK for four days. I'll have unobstructed sunlight.

If not how long will I need to run the generator to bring batteries up to spec?

I know alot of speculation on anyone's part but not sure how this will go with the solar recharging batteries with running limited lights, water pump etc. I'll for sure bring the small generator, not sure the big one is required as AC shoudnt be needed in October where we'll be. I know I can only run one 15K AC with the big generator, small geny would be just to recharge batteries for survival.

For info we were plugged into 30 amp power last weekend and woke up after the power popped off for the whole park sometime in the night and batteries showed at 60%, but by 9am in smoky and tree obstructed sun I was back to 100%, power had been restored about 1/2 hour


Thanks all much appreciated, I've searched a bunch but would prefer n engaged conversation for answers to my specifics.

[eye95]

Originally Posted by ChiliDog

Hello,
My wife and I just purchased a 2021 Rockwood 2911 Bunkhouse, our first RV. To say we and the kids are excited is an understatement.

It has an Everchill 10.7 cuft 12v Reefer, with 190 Watt Solar system, Two deep cycle Group 27 batteries. I have an 1800w generator I can bring, or may buy a Predator 3500W generator that will run my AC. Highs will be upper 70s so AC not crucial on this trip, but refrigerator is!

We are planning on boondocking for 5 days in the Mojave desert in a small town with limited resources, but some should things really go south. Have friends in the area in cabins so could do showers else where. Tanks are 60 fresh, 40/40 on grey/black

My question is should I expect my batteries and solar to keep up with the refrigerator or not? I have read alot saying it won't keep up, and some saying it should be OK for four days. I'll have unobstructed sunlight.

If not how long will I need to run the generator to bring batteries up to spec?

I know alot of speculation on anyone's part but not sure how this will go with the solar recharging batteries with running limited lights, water pump etc. I'll for sure bring the small generator, not sure the big one is required as AC shoudnt be needed in October where we'll be. I know I can only run one 15K AC with the big generator, small geny would be just to recharge batteries for survival.

For info we were plugged into 30 amp power last weekend and woke up after the power popped off for the whole park sometime in the night and batteries showed at 60%, but by 9am in smoky and tree obstructed sun I was back to 100%, power had been restored about 1/2 hour


Thanks all much appreciated, I've searched a bunch but would prefer n engaged conversation for answers to my specifics.

Man, you jumped into the middle of something here. 12V fridge discussions are raging as manufacturers are going whole-hog in this direction.

Some questions:

How many amp hours can your batteries provide? Remember some batteries can only provide 50% of their rated capacity.

What kind of generator is your 1800 watt? Hopefully, it is an inverter generator. I don’t know if Predators are available as non-inverter generators. If they are, make sure you get an inverter generator.

Do you know how long the power was out? That will give you some idea how much charge drains from your batteries per hour. Of course, battery consumption from your 12V fridge at night will be less than during the day.

Three tips: Keep the fridge as full as possible. Fill it with cold food. Don’t make the fridge chill your food. Get your fridge to temperature before setting out.

[tomkatb]

Batteries are the weak link.

Solar on the roof can, on a good day, produce 25 amps per 100 watt panel.

Your batteries likely have 80 or less amps Available in storage. Got to check.

Likely best case, you will consume 100 amps a day. Pure guess. Likely more.

So the generator will need to run daily. Run the coffeemaker and watch tv. Have breakfast.

To be sure you need 400 amps(200 available) of batteries and 600 watts of solar. Need overkill for Rainey days and trees.

Would not work well in the Midwest

[ChiliDog]

Ok thanks for the input,

I plan to purchase the 3500w predator since it’s gonna be hot and need AC for brief periods and also to charge battery. Now wondering how long I ll need to run Geny to keep up the 12v deep cycles, changing those out to 6v as soon as they die.

Sounds like this setup isn’t ideal but I ll put it to the test and have some real world data to add to the discussion. The fridge does get to operating temp in about 2 hours from sitting open in storage and doesn’t draw down power on batteries when the truck is charging in transport, so that’s a plus.

Yeah the more research I do the further down the rabbit hole it goes!

[babock]

Hopefully you meant 25AH per day and not 25A.

Originally Posted by tomkatb

Batteries are the weak link.

Solar on the roof can, on a good day, produce 25 amps per 100 watt panel.

Your batteries likely have 80 or less amps Available in storage. Got to check.

Likely best case, you will consume 100 amps a day. Pure guess. Likely more.

So the generator will need to run daily. Run the coffeemaker and watch tv. Have breakfast.

To be sure you need 400 amps(200 available) of batteries and 600 watts of solar. Need overkill for Rainey days and trees.

Would not work well in the Midwest

[babock]

When I finally get a 12v fridge, I will allot 100AH of battery to it along with 400 of solar. And that is just for the fridge. Anything less and you will be very dissatisfied.

[ChiliDog]

I looked up the spec of my batteries and they are 64 ampH each x2

So to keep above the threshold of 50% drain I can't use more than 64aH.

My solar is a 180 watt panel so if we figure its producing avg 7 amp between 8 and 5 thats a net gain of approx 56 amp? Given no clouds overhead, say ideal solar situation.

From what I've read the Everchill will draw 11A on startup then run on 2.5A. Does that 11 hit every time the compressor kicks on like an AC with startupp vs running draw?

Excuse my butchering of terms, still very new to this!

[babock]

You will get closer to 40A assuming flat mounted with an MPPT controller. If you have a PWM, much less.

Originally Posted by ChiliDog

I looked up the spec of my batteries and they are 64 ampH each x2

So to keep above the threshold of 50% drain I can't use more than 64aH.

My solar is a 180 watt panel so if we figure its producing avg 7 amp between 8 and 5 thats a net gain of approx 56 amp? Given no clouds overhead, say ideal solar situation.

From what I've read the Everchill will draw 11A on startup then run on 2.5A. Does that 11 hit every time the compressor kicks on like an AC with startupp vs running draw?

Excuse my butchering of terms, still very new to this!

[rsdata]

Although you are not out in the Mojave at home, maybe you could setup in the driveway and at least fill your fridge with water bottles and try things out for a couple-3 days. Monitor your battery power closely while home and don't let voltage of the batteries ( not hooked to any power source or drain) drop to less than 12VDC or you will lose some permanent capability.

I will bet you will need genny power to supplement battery/solar power, so bring some gas along. The 1800 should work well as long as you are not doing AC out there.

[ChiliDog]

Babock I do not know which type of controller I have. The hardware is advertised as a 1000w sine inverter but doesnt specify the controller. Not sure what Forest River would outfit these with.

RSData thats a great idea, will try that soon

[babock]

Take a picture of it and post it.

BTW an inverter has nothing to do with solar.

Best thing you can buy is a battery monitor that measures current. For around $130 you can buy the Victron smart shunt and it will tell you how much capacity you have left in you battery bank.

Originally Posted by ChiliDog

Babock I do not know which type of controller I have. The hardware is advertised as a 1000w sine inverter but doesnt specify the controller. Not sure what Forest River would outfit these with.

RSData thats a great idea, will try that soon

[rsdata]

don't let voltage of the batteries ( not hooked to any power source or drain) drop to less than 12VDC or you will lose some permanent capability.

Without spending a lot of money, buy a $5-$10 voltmeter ( multi-meter) at any hardware store. Watch a youtube video to train yourself on how to use it.

When making a battery voltage measurement, it is important to do so in a NO-load or NO-charge configuration... in other words, disconnect either the POS+ or the NEG- lead from both batteries before making a measurement of BATTERY VOLTAGE ( VDC). By measuring without anything hooked up you will get a truer indication of where the battery voltage is without any outside interference ( a load or a charge situation). It WILL take 10-20 minutes for a battery to stabilize, disconnected before a true reading can sometimes be made... depends a lot on the battery. Also make sure, by popping off the top caps that each cell is filled to the bottom of the ring with DISTILLED water... any cell low, top it up.

Fully charged the battery ( each individual battery) will measure at least 12.6 VDC... maybe higher if they have been recently charging. HOWEVER, if when disconnected the battery(s) should never measure below 12.0 VDC, as at that point, further use or discharge will shorten the life and capacity of the battery(s) permanently. At 10.1 VDC, the battery is considered DEAD, and although it will ( probably) charge back up again, it will rarely get back all of it's power capacity again. So check the battery(s) often until you get a feel for what fridge power is pulling out, and what SOLAR power is putting in.

Look up youtube videos from Will Prowse... (TRY THIS ONE...
https://youtu.be/fFHn_xoMsAs

he has MANY that explain SOLAR... a few start at the beginning and explain the basics... if you are lost when watching one, try another one of his to learn basics first, before watching his more advanced ones.

Keep asking questions and you will learn much from many on this forum... I presented a lot if info here, as well organized and understandable for a SOLAR rookie as I could...

babock's suggestion to get a battery monitor is a good one, but before you jump that way, I figure you should do some manual work to help understand HOW YOUR battery system reacts doing things manually...

PS... make sure you understand this info BELOW ALSO before going much further... in regards to your Charge Controller...

Should one connect the controller to the battery first than the panel or the other way around? Or does it make any difference?
It makes a lot of difference for some charge controllers, not so much for a smaller number.

Most CCs instructions tell you to connect to the battery first before applying any PV voltage to the controller panel input(s).
For some this is necessary to detect what battery voltage is being used before trying to send any charging current into the battery bank.
For others it is necessary to properly power up the processor and initialize the operating system firmware.
In either of those case if you apply power to the panel input first they may freeze with an error indication or they may just not work properly and give you no indication why.
A few allow you to apply panel voltage first. I do not know of any that require the the panels be connected and producing power before the battery connection is made.