Is it enough?

[CJMainer]

I'm building a skoolie and will have 3 24v 280Ah batteries assembled with 1640 watts of solar panels on the roof. My question is. Will this be enough to run a small fridge , mini split(when needed) and a tv? I can't judge my current usage in my house because I have a family of 5 that blasts AC , TVs , PC's and anything else you can think of 24/7. My wife and I are separating so I don't want to be burdened down with rent so I'm going this route. Oh i also have a 5000 watt generator to charge said batteries on poor solar days.

 

[snoobler]

Congratulations. I'm on my second marriage. Divorces are painful, but ultimately, people almost never get out of good marriages, so congratulations are indeed in order.

Get the best energy star fridge you can find, and they can get down to 1kWh/day, but more typically, you're looking at 2X that, 2kWh for 20cu-ft.

12000BTU/h 20 SEER minisplit burns about 600W full blast. We'll assume 8 hours of this., 4.8kWh

TV, 80W, 8h/day (kids), 0.64Wh

Inverter, 30W, 24h/day = .72kWh

2+4.8+.64+.72 = 8.16kWh

8.16kWh/.85 (inefficiency) =9.6kWh TOTAL NEED

Battery: 3 * 8 * 3.2V * 280Ah = 21.5kWh TOTAL BATTERY

Solar: 1640W * 4h = 6.56kWh TOTAL SOLAR PRODUCTION/DAY

You solar will only provide about 2/3 of your estimated daily needs.

Estimated need: 9.6kWh/4h = 2400W of solar

 

[CJMainer]

Thank you for your answer

 

[Alphacarina]

Note that the above answer assumes your A/C running full blast for 8 hours per day - That's the elephant in the room and you can largely control that. If it's running full blast for every minute of those 8 hours, it's pretty darned hot outside. If you can get by with less A/C, you may be just fine. It wouldn't be easy to expand the 1640 watts of panels on your roof I suspect (unless you have a very big bus) so conservation may be your best bet. A heavy duty battery charger which could replace lots of amps into your battery pack with only an hour or two of genset running time might be the best addition you could practically come up with . . . . unless you can find a way to add lots more solar. There will always be days when you get less solar than expected, so something to make up the difference from the genset would be a wise expenditure, IMO

Don

 

[CJMainer]

It's a 38' international. I have a 3000 watt growatt all in one. It can only have a max of 2000 watts solar in. thats why i went with 4 410 watt panels. I have a 5th panel because i had to order 5 but that's ok because I'm installing a secondary 12v system for my lights , Maxxair fan and and diesel heaters. I had thought about putting all 5 in series but then I would be over my max voltage. I think my max voltage is 145 vdc . If I put them in series I think it would be around 200 volts. And I dont think I could have a 2 series of 2 panels and then one single panel in parallel.

 

[MisterSandals]

It can only have a max of 2000 watts solar in.

Really? That sounds odd to me.

And I dont think I could have a 2 series of 2 panels and then one single panel in parallel.

Correct. But you could put the 5th panel to use with its own charge controller. Redundancy is a good thing to have too.
EDIT: okay i reread and see you are using the 5th panel for a 12v system. Cool. It could just as easily charge your 24v bank so you'd have just a single battery bank (less redundancy, doh).

 

[CJMainer]

Really? That sounds odd to me.


Correct. But you could put the 5th panel to use with its own charge controller. Redundancy is a good thing to have too.
EDIT: okay i reread and see you are using the 5th panel for a 12v system. Cool. It could just as easily charge your 24v bank so you'd have just a single battery bank (less redundancy, doh).

yea , It's a 24v system. 2000 watts . The 48v can have 4500. I don't think I could put near that amount of panels on the bus so I went with the 24v system.

 

[CJMainer]

Will having 2 different charge controllers be an issue? If i can fit more panels on my roof I have no problem adding more. If i means just adding another cc.

 

[drifty325i]

Yes you can run as many SCC as you like, just get a nice small one to run that separate panel for the 24v system. And have a 24-12v converter to run DC loads

 

[12VoltInstalls]

I don’t know what region you are in (thinking about AC) but managing air conditioning use is huge a benefit, and you can get a reasonably inexpensive 10/11cubicfoot 120V that runs on like 1A or less.

Also, I like the idea of the 12V standalone. Once you get to as many watts as you’ll have, 12V looks less attractive. However, bulk 12V led lights (not retail packaged or priced) and stuff are so inexpensive and they use so little power it is hard to argue against fully outfitting for 12V convenience and comfort lighting. Plus there’s excellent 12V water pumps and stuff from the RV and upfitter world.

 

[CJMainer]

I don’t know what region you are in (thinking about AC) but managing air conditioning use is huge a benefit, and you can get a reasonably inexpensive 10/11cubicfoot 120V that runs on like 1A or less.

Also, I like the idea of the 12V standalone. Once you get to as many watts as you’ll have, 12V looks less attractive. However, bulk 12V led lights (not retail packaged or priced) and stuff are so inexpensive and they use so little power it is hard to argue against fully outfitting for 12V convenience and comfort lighting. Plus there’s excellent 12V water pumps and stuff from the RV and upfitter world.

I live in Maine . I purchased a 12k MRCool 22 seer mini split heat/ac pump. It should cover upto 800sq ft. I think my bus at most when done will be 250sq ft. I like the idea of adding another SCC and adding more panels. San tan has a some good deals so used panels might not be a bad investment for this.