Introduction: Question

[AlexBen]

Hello to group. Looking for some general guidance.
The project I'm working on is a large truck that I use for motorsports. It is a 36 foot long Ford F650, full 13 foot height with an attic. Technically and by title, its been converted to be an RV.

I've struggled keeping a couple of old school house batteries charged merely by the trucks alternator while driving to and from events. The batteries are used for a 12V hydraulic Liftgate that loads and unload the car from the truck, they are used for the 12V hydraulic 4-post lift that I use to store things over the loaded car, tires gas, etc, and for the 12V winch to assist in loading and unloading the cars. It will run 12V lights and possibly one day an electric awning.

I'm looking at getting a 230 aH Lipo4 battery and something like the Renology 4 panel 40 amp charging package, and some sort of an inverter......

I'm fairly confident that the solar will be more than adequate to keep the battery charged for use as I've outlined, as well as keeping a refrigerator cool on 3-6 hour drives to the track, or during the day at the track and then though the night.

The main question is... on a sunny hot day... how much "more?" would I need to run the AC during daylight hours? Or would that be enough. No need to keep it running over night, most likely I'm back on the road, or in a hotel. But AC during the day, with bright sunlight might be great..... Figure at least a 13500 or possibly 15000 unit either roof or mini split... and I'd choose one over the other if it made a difference to make this work. I do NOT need the batteries to last overnight running AC.... just a small fridge.

I know its a very wide open question, but before I commit to a package that might limit my use, I'd like some opinions from those that have been there, and done that.

 

[Rednecktek]

Well, just a quick couple thoughts to throw at your noodle:

1: anything over 12k BTU is going to need 240v split phase which is going to be pricy. A 12k can be had for 120v.

2: you'll take about a 30% hit to your panel rating between inefficiencies and panel angle, so get as much panel up on the roof as possible. You're going to need some huge MPPT controllers to utilize that much panel but that's one of the trade offs with 12v systems.

3: a 3Kw AIO is going to be the simplest option but won't feed your 12v stuff. You'll have to do a component system to get enough wattage to feed an aircon from 12v.

4: you might want to get something like a DC-DC charger involved to get some real amperage off the truck to charge the batteries in parallel with the panels. A second trailer plug with Anderson connectors would be a good option as the standard 7-pin can't handle much amperage.

5: a 12kw mini-split will likely be eating 1200 watts per hour when the sun is beating down so a bog standard 100ah battery will be empty in an hour.

6: If you want to run all this stuff on 12v to keep your existing system fed you're going to need to get creative on battery placement and have a minimum of 3 batteries to get enough amperage to feed the inverter.

7: You can probably get away with a 2kw pure sine inverter and wires sized for 200a draws, plus whatever your 12v system needs for the hydraulics which is likely pretty beefy too.

It can be done, the 12v system causes a few issues but nothing unsurmountable.

 

[AlexBen]

Well, just a quick couple thoughts to throw at your noodle:

1: anything over 12k BTU is going to need 240v split phase which is going to be pricy. A 12k can be had for 120v.

2: you'll take about a 30% hit to your panel rating between inefficiencies and panel angle, so get as much panel up on the roof as possible. You're going to need some huge MPPT controllers to utilize that much panel but that's one of the trade offs with 12v systems.

3: a 3Kw AIO is going to be the simplest option but won't feed your 12v stuff. You'll have to do a component system to get enough wattage to feed an aircon from 12v.

4: you might want to get something like a DC-DC charger involved to get some real amperage off the truck to charge the batteries in parallel with the panels. A second trailer plug with Anderson connectors would be a good option as the standard 7-pin can't handle much amperage.

5: a 12kw mini-split will likely be eating 1200 watts per hour when the sun is beating down so a bog standard 100ah battery will be empty in an hour.

6: If you want to run all this stuff on 12v to keep your existing system fed you're going to need to get creative on battery placement and have a minimum of 3 batteries to get enough amperage to feed the inverter.

7: You can probably get away with a 2kw pure sine inverter and wires sized for 200a draws, plus whatever your 12v system needs for the hydraulics which is likely pretty beefy too.

It can be done, the 12v system causes a few issues but nothing unsurmountable.

I've seen now a EG4 Mini-Split AC unit that is designed to be fed by solar, and augmented when needed by AC which could be from my battery and an inverter. The AC is 12000 BTU. I think it will suffice. Calls for 1000 to 1600 of solar, but in some modes, can get by with much less. Seems very versatile. Looking at Renogy as a reference for some basic products, it looks like they sell a 175 watt panel, and I can fit 6 of them on my roof, get their 100 amp MPPT controller, a 3000 watt inverter and a 230 ah battery. Looks to be about $2000 plus whatever hardware I need to get to mount the panels. (AC unit is not a part of that, looks to be $1300. Not cheap but designed for just this purpose. Very efficient, and inverter style etc. I think the 12000 may be overkill, but it will run on solar +/- battery pretty well. I'll just have to manage to make sure I don't run down the house battery. Worst case, add a battery at some point. All my 12V stuff is already wired to a pair of old school batteries and functions well, as long as they are charged... but they don't stay charged well, and every time I have to replace them, its another $300 plus in batteries that just don't hold up.

 

[Supervstech]

1050W of pv, will produce about 735W in all but ideal conditions on a flat roof.
Tied directly to the SS mini isn't going to provide much system function.

 

[Rednecktek]

Isn't that unit 48v based? You'll have to get rreeeaaalll creative to power your hydraulics from DC-DC cinverters or have to arrange 2 seperate systems for 12v and 48v.

 

[AlexBen]

Appreciate input. Turns out that EG4 unit is nearly useless for RV as it has no ability to bleed off excess capacity from solar panel to keep battery charged.

Plans have evolved to three stages.
Build or buy a 24V battery, 200ah to 240 range, use 70 watt Victron Orion 24-12 transformer.

I may start with a hybrid 3000 watt 24V MPPT, Inverter, Charger “all in one” that frankly lets me just get those three items, add Solar later.

Need to insulate and finish floor plan anyway before considering AC.

A fully charged 24V 200+ LIPO4 will run my hydraulics and fridge for most events.

 

[Rednecktek]

A fully charged 24V 200+ LIPO4 will run my hydraulics and fridge for most events.

Do your hydraulics run off of 24v natively? My concern is that if they're 12v they're probably going to want to draw more amperage than any converter can provide. Just making sure the math groks on that.