To invert or not too? that is the problem

[Dirtdoctor]

I used OUTBACKPOWER.comThey set everything up and did a great job. Remember they have everything designed and tested for the long haul.

[ThePimentals]

Keep doing research. Re do all your numbers. Something isn’t right. Read handy bobs solar. If you are doing full solar and you haven’t read that then you can just kick yourself in the face now

[Ernst]

Hi Kiwi Bus,


Maybe most has been said already, but I can add my two cents worth:

I think you are on the right road with choosing 48 V, if you intend to do so much electrically.
I decided on 230 V AC for most appliances in my last three projects. Especially a fridge draws energy, not because of the current, but because of the time! An additional advantage is that domestic fridges (energy class A++ or A+++) use much les energy than DC fridges - even if you take 5 to 10 % loss in the inverter into account) and are much cheaper.
I'd prefer a real sine wave inverter, although the fridge may well run on a "modified sine" (which in reality is a modified block wave).
It may be worth while to have a spare inverter stand-by. An Ali Express purchase will be less than half the price of an A-make (like Victron), so you should be able to afford a spare one.

Good luck. Please report your progress.

[MambaJack]

Originally Posted by Iceni John

I have 2kW of PV to charge about 850aH of golfcart batteries for a 12V system, and that's at about the top end of the recommended charging rate to ensure I can get a good charge into them even on a winter day.

John

Hi John, I have also been attempting to figure out how to size my system, have been reading a lot on solar forums, and am very interested in how you came up with your numbers. Do you have a build thread somewhere, or more detail on your electrical?

[nicolasuribe]

"AC is a huge load, the modern inverter driven split systems can be easily powered by a 3+kW inverter with good surge capacity, but they'll pull amp hours out of your battery bank very quickly."

Question: Why aren't there any propane-powered AC units? If you can run a refrigerator on propane, one would think that a propane-powered AC would be doable!

[john61ct]

Very common, but built into propane-powered vehicles.

In reality a spinning engine can run a compressor, the rest is not too thirsty.

Check out truck APUs, run off pony engines, just usually diesel.

It is not a technical challenge, but there must be enough of a market to attract the investment money.

[littlekiwibus]

So after everyone pretty much singing the same tune (aircon is a crazy big load ), and us taking some time to measure actual drain for our items (thanks for the tip). We have revised our needs and spreadsheet/pdf.

No More A/C , we decided you guys were correct, over 50% of our daily needs on A/C, just wasn't worth all the money we would have to spend on extra panels, batteries and wiring. Once we removed the 5400W load from our system, our total daily dropped... a lot.

We may make wiring provisions for an A/C unit that can only be run from shore power or a generator, but for now, we are factoring it out.

We also managed to measure the real power drain of some of our household items (we have measured appliance names with an orange background)

With all this in mind, we are now thinking of going with a 24v 500AH bank , as it goes nicely with our 24v starter system. Plus 24v appliances are much cheaper and easier to buy. We're planning for about 1750-2000W of solar, plus a beefier 24v alternator for emergency situations.

See attached PDF for our changes.

Thank so much for all your advice, it has helped us see the error of our ways, and yes we need to do a lot more research into solar setups, but I think, we are now in a better position to know what to look for.

Originally Posted by Ernst

I decided on 230 V AC for most appliances in my last three projects. Especially a fridge draws energy, not because of the current, but because of the time! An additional advantage is that domestic fridges (energy class A++ or A+++) use much less energy than DC fridges

Thanks for the advice , this advice is what we were after before everyone picked our numbers apart , we're starting to think cheaper, efficient household appliances behind a quality (big) invertor, with as much 24v as possible, is our direction forward