Electric: how much power did you install?

Ladies.andthe.camp · 05-10-2023, 05:05 PM

Question about battery banks/power:

We are doing all the calculations for our power needs. We are two people who have full time remote corporate jobs, so having computer/internet power is important. And then we have the dogs so $$ AC will be a must. But we were curious: what has everyone ended up needing for power? Just trying to gauge if our numbers are pretty normal, or if we are just out of control with the amount of power we THINK we will need when we are boondocking. So any info on how many watt hours you're using or amp hours would be helpful. And/or what your electrical set up is i.e. how many battery banks did you end up installing and how that is panning out for you. Thanks Skoolie peeps!!

cadillackid · 05-10-2023, 06:05 PM

one thing to think about is if you are boonbocking away from quiet zones you can alwasy facxtor a generator into some of your needs.. if its a hot day and you are both indoors working on your computers with the A/C on, a generator can run outside helping to produce power, charge batteries, etc.. allowing you to shut it down later when you want to be outside or have quiet time to sleep at night..

Ladies.andthe.camp · 05-10-2023, 07:23 PM

thank you! we actually JUST landed on going down the black hole of generators. so this suggestion def helps since that seems to be kind of a good idea in general!

TucsonAZ · 05-11-2023, 04:49 AM

I mean, this question is sort of like asking us your favorite color. There is SOOOO much more needed information with a question like that. For example, when I had about 1,800 watts of solar and a 6,000 watt hour battery bank with flat mounted panels I could collect between 100-1,200 watts of solar during the same time of day depending on where I was and weather.

Then you have to account for really bad times where you may collect very little solar for a day or three followed by a lot of sun. There's size of your bus, color and thermal gains and so much else to factor in.

I will say this in general, go way way overkill, as much as you can reasonably afford. My solar is 15k for my bus, that's brutal but I need a lot of power and I need redundancy and to be able to count on it. Get a good LifePo4 battery system and run things at 48V and you really can't go wrong. But running ac is brutal so make sure you're running something with inverter technology.

Ladies.andthe.camp · 05-12-2023, 09:53 AM

this is very helpful, thank you! I feel like with a lot of our first round of research, we saw a lot about 12v inverters. but fairly recently when looking up big electrical systems, and then we saw some stuff about 24v, but now that we are asking people on forums that can hone in on specifics and attest to what they did for their electrical system that needed a lot of power, its looking like 48v inverters are more so what we are looking for.

in your skoolie, what kind of electronics are you running and how long can you go boondocking? I was having trouble figuring out how many amp hours things like a fridge and AC use, since these things turn on and off based on the temps. If you have any resources that help determine how much power those types of things are using, I'm all ears!

HamSkoolie · 05-12-2023, 09:46 PM

Our build (still in process) includes a 9000 BTU and a 12000 BTU AC, one front and one rear.
We have 10 ea 290W mono panels for 2900W total which will be 6s2p into our 6.5kW EG4LL inverters built in mppt charge controllers then off to the batteries at up to 120amps charging. The batteries are a pair of EG4LL rack mount lithium batteries with 5.12kWh per 101 pound battery (avail in 12, 24, 48 volts). We are starting with 2 ea 24V batteries and can expand up to 2 more batteries in the rack that will hold the batteries. So we're starting with 10.24kWh of lithium expandable to 20.48kWh. The batteries then feed the inverter input.

The inverter is 6.5kW with 13kW surge and in addition to the built in MPPT charge controllers has a relocatable monitoring and control screen.

We will also have a residential refrigerator, computers, HAM radios, and hope to be able to cook with electric when sunlight is ample while also having propane cooking backup. Worst case, we will have a 3500W Harbor Freight inverter generator.

I am working on a document for calculating power needs including accounting for inverter inefficiencies and such. That will be posted on our website when complete but it's going to be a while as I'm busy with the build, teaching, and other life interruptions.

incubus · 05-23-2023, 10:02 PM

Though it seems rather unpopular I use absorption refrigerator which is powered by a propane Flame the size of a pilot light. One of the highest amperage uses is the refrigerator which has to run 24/7. I did a volumetric comparison a fuel used by the refrigerator. Found out the energy used to create one solar panel not including the energy used to temper and heat treat the panel would run my refrigerator for over 19 years. The Harbor Freight generator running the AC during the day when the heat is that it's worst is a good way to back up your solar. Also split systems are much more energy efficient than the old rooftop units. Many are 120 volt. I guess what I'm saying as many people try to build systems of batteries and solar to run every convenience of a normal home, computers TVs refrigerators and electric stoves. Seems to never quite work out and the cost becomes astronomical

HamSkoolie · 05-25-2023, 03:50 PM

Quote:

Originally Posted by incubus

Though it seems rather unpopular I use absorption refrigerator which is powered by a propane Flame the size of a pilot light. One of the highest amperage uses is the refrigerator which has to run 24/7.

Nothing at all wrong with an absorption refrigerator. In our case we'd love a three way or two way (have one in our 5th wheel and it works just fine while sipping propane) but we want a full size refrigerator but can't justify the insane prices wanted for them (we could afford it, we just refuse to pay insane prices). So we're going with the standard residential fridge and taking the kW hit to our system.

Quote:

Originally Posted by incubus

I did a volumetric comparison a fuel used by the refrigerator. Found out the energy used to create one solar panel not including the energy used to temper and heat treat the panel would run my refrigerator for over 19 years.

Wait, I thought solar panels were "green" (sarcasm off). Yep, solar (and wind) have been "green washed".

Quote:

Originally Posted by incubus

The Harbor Freight generator running the AC during the day when the heat is that it's worst is a good way to back up your solar. Also split systems are much more energy efficient than the old rooftop units. Many are 120 volt.

An HF 3500 inverter backup is our backup plan during shakedown though our system is being built with the ability to double our battery bank by simply removing two draws in the battery rack and sliding in two more 5kW batteries. We'll have two 120VAC mini splits (one front, one rear) for redundancy and to deal with high heat in the southwest or humidity in the south.

Quote:

Originally Posted by incubus

I guess what I'm saying as many people try to build systems of batteries and solar to run every convenience of a normal home, computers TVs refrigerators and electric stoves. Seems to never quite work out and the cost becomes astronomical

Cost can be controlled by watching for sales and choosing better products. We initially budgeted VICTRON gear for our solar processing. Good stuff but not the best bang for the buck. GroWatt "all in one" inverters are a good deal if they fit your system size. We went with the same inverter as our batteries and got 2 MPPT controllers, 120A charger, and relocatable monitor/settings screen with 6.5kW cont/13kW surge full sign wave inverter for less than the price of just the Victron MultiPlus. Then again, we have 2900W of commercial takedown panels and a 40' rig building for full time off grid. Still, under 6K total for the system which isn't bad at all for the size.

incubus · 05-25-2023, 09:28 PM

6K isnt bad. I got very lucky with my solar panels. Was able to pick up military panels after testing was over at work. You know the price," just get rid of them"

incubus · 05-25-2023, 09:36 PM

If you go with a Residential Refrigerator make sure you can turn the automatic defrost on it off. It goes into defrost cycle it uses a huge amount of energy. I had a residential in my GMC, added extra insulation to the top and sides, vented the coils on the back to outside. It worked very well

HamSkoolie · 05-26-2023, 08:22 PM

Quote:

Originally Posted by incubus

If you go with a Residential Refrigerator make sure you can turn the automatic defrost on it off. It goes into defrost cycle it uses a huge amount of energy. I had a residential in my GMC, added extra insulation to the top and sides, vented the coils on the back to outside. It worked very well

That's a great point I'd never considered. Added to spec sheet "fridge defrost must be able to be disabled"

TaliaDPerkins · 05-27-2023, 10:53 PM

replied to wrong post, sorry

TaliaDPerkins · 05-27-2023, 10:54 PM

Installed yet I can't say. Intended plan was tilt up along one side and along the roof for 6.4kw of panels for an all electric bus. I have those panels. Currently working out how to power assist tilting up the panels on the side and how to shield them from impact during movement.

David from Ontario · 05-28-2023, 05:10 PM

Cheaper, smaller fridges may not be "frost free." The 6 cubic foot apartment sized fridge I bought for my skoolie for $398 CAD isn't. And that's a good thing. No built in heaters for defrosting. Since I'm not living in it full time, when I'm back from a trip and power down the fridge, it will defrost.

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