fridge... battery..solar..questions

[colorado matt]

ok My name is Matt. I am trying to learn. Finally getting my off road trailer built. 4x6 box on wheels with telescoping rack for RTT to take advantage of higher tent for annex. I have decided to get a fridge. Not interested in fridge debate. 50 65ish quart range. lithium iron phosphate battery 100 amp hour. 200 watt suitcase solar package with controller. suitcase unit as i have no place to mount. fridge and battery will remain always in trailer.

That is about all i know. trailer will have a 7 pin wiring to take advantage of back up lights...and maybe charge battery while driving. But I always find a spot and stay for days so charging would only be for the ride from home to camp 1-5 hours. So not sure how important that may be.?

Besides fridge there may be a led strip in tent and maybe a few to light up box or cooking area. We are use to the dark and the campfire makes plenty of light for our nightly needs, or headlamps or battery lanterns Usually no laptops or phones need charging. camera batteries ..I carry 3 so that usually lasts the trip.

The few times that we would be at a campsite with power seems to me an extension cord to the fridge would be best and simple.

in my research i have learned that the battery will not or it is bad to charge at low temps. thinking of adding a inverter to the mix and run a heavy load on battery to warm up in morning before solar kicks in. but unsure if that is best way to do that.?

the battery says it comes with a battery management system built in...whatever that means...and solar setup says it comes with controller... would like to know if i am on the right track. trying to keep it simple.

unsure how it all hooks together. is some type of distribution block needed ....am i missing anything that i can add to my research. thinking i would like a longer lead for the panels ...i think it comes with a 15 inch cord. and go easy on the jargon. i can get lost quickly when i read threads and most of what i read is all abreviated versions of equipment .

Thanks for any help .... Matt

 

[colorado matt]

does that mean i should bypass the 7 pin trailer connection and run something strait from vehicle battery to rear of vehicle and then from front of trailer to trailer battery? .... that makes sense

 

[1leglance]

You are on track for a nice simple system....
Yes when you are near "shore" power go ahead and plug in the fridge, all the good ones automatically default to 120v if aval (except newest Dometic, they will catch on fire

If you already have the "suitcase" solar with controller and the Lithium with battery management (BMS) then you are set. Just add fuses between the solar and battery.
Personally I would add something like a Victron Smartshunt (no display just bluetooth) which goes on the negative side of everything and tells you have your battery is doing.

From the battery you just bring power to a fuseblock like you normally would.

I would imagine your setup would be fine for 2 days with no sun, and forever if you get some sun on it each day. The advantage the suitecase has is that you can tilt it and move it to match the sun angle through the day. Lithium takes a charge faster which helps in your setup.

Lots more that smarter people can say but that is my 2 cents.

If you don't already own all the equipment there are other ways to go that might be better & cheaper, but I will wait till you tell us what you currently own.

 

[colorado matt]

I own none of it .... dont mind saving for a great setup.... my limited knowledge and recent research i seem to be stuck about discharge rates and seemed like the equipment mentioned was a good choice for what i want...thanks...Matt

and for distribution block .... maybe option for 3 or 4 things with switches...any suggestions.?

I was leaning dometic....catch on fire?

 

[colorado matt]

 

[colorado matt]

ok lets use this as a base .... fridge will come of of fuse block .....is this a workable system??? i am assuming that controller is what comes with solar panels

 

[dreadlocks]

does that mean i should bypass the 7 pin trailer connection and run something strait from vehicle battery to rear of vehicle and then from front of trailer to trailer battery? .... that makes sense

not really, it still takes ~7-8h of charging at full rate to get a lead-based battery back to full after depleting it, in a trailer you could fix some solar panels to the roof that would give you a decent charge while driving and also when not... the lengths of wire are so long you cant fully charge with any voltage drop, it's really not worth it to count on alternator at all in a trailer setup, when you're out exploring or trail running its not going to be charging anything with the trailer left behind.

 

[dreadlocks]

ok lets use this as a base .... fridge will come of of fuse block .....is this a workable system??? i am assuming that controller is what comes with solar panels

Go get a pair of 6v GC2 Golf Cart Batteries from Sams Club for ~$100 each, a Victron Smart Solar 75/15 or 100/20, and 200-300W of solar panels and you'll run your fridge and camper fine for the most part as long as you don't go overboard on other 12v accessories.. your tow vehicle will keep the battery from going down while in tow, but that's about it.

 

[colorado matt]

sounds simple.... are the lithium iron batteries not worth the money.... getting stuck on cycles and discharge capabilities of different batteries

 

[colorado matt]

ok and using that same diagram above MPPT would just replace one that came with panels.... got it

 

[dreadlocks]

you need a bunch more equipment to support lithium, gets expensive.. we're not there yet.. its hard to beat a pair of 6v Golf Cart batteries in a series if you have the room and weight carrying capacity, which most trailers have in spades.. for ~$200 you get ~220-240AH @ 12V, with lead batteries you only want to discharge em 50% but these GC2's will take abuse if you mess up better than anything else.. your basically making an expensive deep cycle 12v bank your self..

A good fridge will use on average ~20AH a day, with 100AH usable that's 5 days w/out any charge.. 200-300W will give you a good decent charge rate that in good solar conditions will let you go on forever, and in bad solar conditions will at least extend your time a bit before you need to use the shore power charger.

Victron SmartSolar charger will support any battery chemistry you do in the future and gives you great historical and live information about your battery bank via Bluetooth phone app, its worth its weight in gold.

 

[colorado matt]

thats what i needed ...thanks... i'll keep you posted as things progress.....Matt

 

[Martinjmpr]

View attachment 613241

Do you NEED an inverter? For what?

If not I would skip that. No need to add complexity to the system.

 

[Herbie]

Do you NEED an inverter? For what?

If not I would skip that. No need to add complexity to the system.

Agreed. Going on 10 years in my van w/o inverter. I have a 12V adapter for my laptop and everything else runs from a cig. plug or USB.

 

[Charles R]

To me it sounds like you could scale down a number of things. My current setup is just a Renogy 100w panel hard mounted to the roof, plugged directly into a Yeti1000. I use this to run a Dometic CFX-28L. Basically, this system runs 24/7 and VERY rarely sees the Yeti drop below 90%. If I plug in my 1100 watt vacuum cleaner to clean my Heep, it'll drop it to the low 70% range. (it does take more than a single day to fully recharge though)

Recently the heavy smoke in my area, (south SF bay. 30 "spare the air" days in a row!) reduced the panels output to zero for a nearly a week. When there was enough sun, the charge input stayed in the high teens to low 30's watt range for another week or so. Even during all this, I don't recall the Yeti ever dropping below 40%, and the fridge temp never strayed.

So basically, to me it sounds like you could half the size of your system, and still easily meet your needs. Just some food for thought.