I haven't considered what load this system will be sustaining, I've simply done a bit of research (enough to be dangerous) and selected what I can afford thinking ahead to expansion. It may be much larger than my current needs but thought I'd post it to see what comments or suggestions ya'll would offer.4 Renogy 12v 100 watt Monocrytalline panels into a Renogy Tracer 4210 40 Amp MPPT Charge Controller charging 4 Trojan T105?RE 225 Ah, 6v deep cycle batteries connected in series to produce 12v which are further connected to a Go Power GP-SW1500-12 1500-Watt Pure Sine Wave Inverter. As well as a remote Renogy MT-5 monitor.I have to sit down and calculate amp hours to determine how long this would run my air conditioner. More out of curiosity than intending to run it.

It may take longer to run the calculations as to how long the A/C will run than how long it will actually run.Bill

Hi,With that size inverter you will be lucky if the air conditioner starts. If it does start then run time might be about 20 minutes.

Does MPPT offer any advantage with 12V panels? I thought that it did not.I don't think that inverter could start the air conditioner compressor.

Battery powered Air Conditioning is an oxymoron, you know, like jumbo shrimp. :)Try calculating how many lbs of lead you would need.Many have problems running AC with a 2KW genny.Please don't buy yet. And welcome! HTH;John

Hi,While a pure sine wave inverter 'can' run a small air conditioner, the one on the roof of a RV is about 13 amps at 120 volts, or a little over 1,500 watts running load, and probably 4,500 watts momentary start up load. I know someone with a MCI bus, and it has a 24 volt alternator for the starter motor, and 12 volt for all the lights and other things. He installed a Trace 4000 watt 24 volt inverter to run his rooftop A/C unit. He can run one at a time. Before changing to 24 volts, he could not run the A/C from the 12 volt inverter.So if it is a sunny day, and you had a 2,000 watt inverter with a 4,500+ watt surge rating, then you could run the A/C for about 1 hour daily with a 400 watt solar system. This would consume about 1,200 watts from the batteries, along with all the output of the solar panels during that one hour. You would require #000 wire between the inverter and batteries. Your RV will consume about 35 AH daily to run just the refrigerator and CO and propane detectors. This is about what one of my 120 watt solar panels will collect in one day. You can take the amp rating of one of the panels, and multiply by 5 to get the daily 'average' amp hours collected per panel. You will have exceptions, where you might collect some more power, such as a really long day way up north, or at a higher elevation. But a really warm day, then the solar output will be less as the panel temperature warms.My suggestion? Get a 300 - 500 watt MSW inverter and run the generator when you want to microwave something, or run the A/C unit. It is a whole lot less money to invest in the RV.I would also recommend using the much less expensive PWM controllers. By using 12 volt panels, you can use PWM and collect about 5% less power than a MPPT controller will deliver to your battery. What you might have spent in the MPPT controller, but saved with a 20 amp $15 controller, you can spend on solar panels, and save overall costs.SunElec.comI saw a 140 watt panel with aluminum frames on sale at this place a few weeks ago for $229. I would not recommend a panel larger than 150 watts on a RV, even finding space for my 120 watt panel was difficult, while a larger panel is just more sail area, and more difficult to locate between the vents, A/C and antenna and roof edge. Making sure that the A/C will not shade part of the panel is a problem. With my first system, the panels where close to the antenna, so when it was up, unless parked with the antenna to the north of the panels, it would shade them during parts of the day, so I had to put it down to get the most amperage.I have a 415 rated watt system on my RV. Today it's replacement cost would be around $1,000 while I spent over $2000 back in the 90's for mine. My 120 watt was $429 back in 1999, when wages where much less than today.Good luck,Fred.

Our under installation solar system for our Montana

djgodden
Explorer
Jan 02, 2016
OK, looks like the overwhelming opinion was the 1500W inverter was insufficient given hair driers, microwaves, convection, etc... So, I returned it and have the 3000W. No, I'm, not going to run the A/C, it was me being curious.
rjsurfer
Explorer
Dec 19, 2015
I have an identical solar/battery setup except I have 700 watts of solar and there is no way I could run my rooftop AC.

I'm lucky if I get 15 to 20 minutes on my 1,500 watt microwave without going into low voltage shutdown.

You may have the solar and battery guts to run it if you go by the specifications for the individual components but that low voltage (usually 11.5) shutdown of the inverter will bit you in the ass every time.

Ron W.
pianotuna
Nomad III
Dec 18, 2015
Hi,

That depends--my microwave draws 1591 watts.

zb39 wrote:
1500 should run your microwave also.
zb39
Explorer
Dec 18, 2015
1500 should run your microwave also.
pianotuna
Nomad III
Dec 18, 2015
2oldman,

two words

hair drier.

*grin*
2oldman
Explorer II
Dec 18, 2015
djgodden wrote:
Meaning a TV for a while, BlueRay, charge phones, use a computer, etc.
Then you don't need a 1500w inverter.
djgodden
Explorer
Dec 18, 2015
Thanks for all the replies. As I indicated, I don't really intend to run the AC but was curious if it would run at all or if so, for how long. Looks like a beefier inverter would be needed as well as more batteries. Which is fine, I expect my setup to be able to sustain me easily for "normal" use. Meaning a TV for a while, BlueRay, charge phones, use a computer, etc.
lasttruck
Explorer
Dec 18, 2015
djgodden wrote:
I haven't considered what load this system will be sustaining, I've simply done a bit of research (enough to be dangerous) and selected what I can afford thinking ahead to expansion. It may be much larger than my current needs but thought I'd post it to see what comments or suggestions ya'll would offer.

4 Renogy 12v 100 watt Monocrytalline panels into a Renogy Tracer 4210 40 Amp MPPT Charge Controller charging 4 Trojan T105?RE 225 Ah, 6v deep cycle batteries connected in series to produce 12v which are further connected to a Go Power GP-SW1500-12 1500-Watt Pure Sine Wave Inverter. As well as a remote Renogy MT-5 monitor.

I have to sit down and calculate amp hours to determine how long this would run my air conditioner. More out of curiosity than intending to run it.

Have the Renogy panels, MPPT and monitor like you, but am using Costco GC2 batteries and a Samlex inverter. Panels are wired series/parallel as are the batteries.

Just for kicks, I plugged in a 5200btu window AC and ran it for a couple of hours with direct, overhead bright sunshine. After two hours, I had a 8% net battery bank loss per the Trimetric battery monitor.

I am not able to remember if I had the AC set to high or low cool, but it was sitting outside, in the shade and did not cycle off.

An option, but only in full, overhead sun for a short period.
time2roll
Nomad
Dec 18, 2015
If you are getting MPPT you may as well save money on panels and get 24v models. Easier to mount 2 large than four small. Run in series to simplify the wiring.

24v panels, 65 cents per watt
pianotuna
Nomad III
Dec 18, 2015
Hi John,

I should have qualified that and said "at least 8%, under most conditions".