Checking myself before I wreck myself - pricey battery system

[dbsoundman]

Hi all, I've been trying to plan out the electrical supply and distribution for my skoolie and I think things have escalated a bit farther than I had intended, so I call on your collective wisdom.


The basic setup will be a recreational vehicle setup, so we will have a full sized (9.8 cu ft) fridge, toaster oven, 2 burner induction cooktop, two 12,000btu mini splits, water pump, lighting, and possibly an electric water heater running on our house system. My goal is to have enough battery capacity to keep the lighting and refrigerator going while mobile, then connect to shore power or a generator to have enough capacity for everything else. Eventually I'll add solar once we plan some more serious national forest boondocking.


Given that 12 volt refrigerators are somewhat uncommon and really expensive compared to their 120vac counterparts, I will definitely need an inverter to go along with my battery setup, along with the normal alternator charging and shore power charging options.



Here's where things start to get expensive: I'm not interested in taking a chance on cheap crap from Amazon, so I've settled (for now) on Victron components. I'm looking at a 3000 watt inverter/charger, to the tune of over $1k, plus all the other bits to go along with that.


Then, moving on to batteries...whoa. AGM vs Lithium. I know that AGM batteries don't last as long, but I'm not sure all the "benefits" of AGM will really do me any good given that we don't even know how often we will go camping just yet (hopefully often but life happens), and I'm worried that the Lithium batteries will not do well during the winter, when we could have prolonged periods of subzero temperatures - even here in Ohio we've had one week periods of temps below 0 the last couple winters. Not to mention lithium batteries are like twice as expensive.


I've been in contact with AM Solar out in Oregon, and they've recommended a setup that includes kits that would cover basically all of the AC and DC power distribution (fuses, boxes, wiring to the AC circuit breakers), inverter, battery charging components, and even the batteries, but it's looking like it will be $6-7k. This is all Victron components and name brand items so I understand that adds to the cost, but I just wasn't expecting that much cost just for the components without the solar charge controller or panels. They're recommending 300 Ah of Lithium batteries to start, or 800 Ah of AGM batteries for my use case, noting that I can always add Lithium batteries, but I can't add AGM batteries until I replace all of them, so I think the Lithium estimate is a little low.



My big question is, am I overthinking things, or is this really the right way to go? I mean don't get me wrong, I would love to try to run the mini split while going down the road on a hot day (yes I know, not recommended, all that, but happy wife happy life), but all I really wanted was to keep the refrigerator going. I am a fan of "buy once, cry once" philosophy, but this is quickly becoming more expensive than I had ever imagined at the start.

[magnakansas]

I bought a 1800 watt pure sine inverter by Magnasine... for $50.... I see a 3000 watt pure sine by sensata... same company used $600 when new would be around $2700.

I think if you look around carefully you can buy most of what you are looking for in near new condition for 25% to 50% the cost of new.

The down side is possible bad equipment and no warranty.

I feel fortunate so far... no deals gone sour for me.

I spend hours looking at face book market place, ebay, and craigslist for the deals....

air compressors, tools, busses, welding equipment. blah blah blah...


william

[BeNimble]

Generally it is good advise to get a camper and go camping and see what you really need vs what looks/sounds good on paper.

[Bert06840]

A $150 dorm fridge uses 1kWh a day when used hard.
Lights and internet a couple hundred Wh. Say you need 2kWh. 400 Watts of solar can give you that during SUMMER.

Hot water on solar is crazy. Forget that.

Running an A/C from batteries while traveling is crazy. Use an engine-driven compressor.

Do you need A/C while parked? Only occasionally? Much smarter to use the generator.

[kazetsukai]

Originally Posted by dbsoundman

My big question is, am I overthinking things, or is this really the right way to go?

Based on this:

Originally Posted by dbsoundman

...all I really wanted was to keep the refrigerator going.

YES.


$6k-$7k seems pretty outrageous for running a fridge, don't you think?



First, back to goals. What do you want to do? Give us a list, like so:

• Keep this fridge: (link) running 24/7 for up to X days overcast
• Laptop, 3-4 hours a day, mostly during daytime
• TV, 1 or 2 hours a day, mostly during nighttime
• etc

Second, how much roof space do you have for solar? Batteries are expensive, panels are cheap. A very modest battery bank may fit your needs combined with a large-ish solar array for a lot less than what you've been quoted.



An example if you DIY I'm pretty confident you could get 2000W of panels, 400Ah of AGM batteries, an appropriate charger and inverter and at right around $2000, maybe $3000 with some more bells and whistles. Those batteries might just get your fridge through a single night, and that might be enough for you.

[dbsoundman]

Originally Posted by kazetsukai

An example if you DIY I'm pretty confident you could get 2000W of panels, 400Ah of AGM batteries, an appropriate charger and inverter and at right around $2000, maybe $3000 with some more bells and whistles. Those batteries might just get your fridge through a single night, and that might be enough for you.

This is basically what I ended up doing. Purchased a couple 200Ah Renogy AGM batteries, Bogart engineering charge controllers, a victron battery protect, and various other bits and pieces. Haven’t purchased the AC electrical panel yet and some other details (like wire), but I got the bulk of it. I’ll make a complete list later.

I did not purchase solar panels just yet as I want to do more research on them and make sure I actually know how I want to mount them first. Too many other moving pieces in my build for me to have the mental bandwidth to figure that out just yet.

[kazetsukai]

If you live near populated areas, local Craigslist listings can have panels available for very cheap. Last 3000W I bought for $0.30/W.