Inverter recommendation needed.

Tabaz

goal is to boondock using only solar. I have a Zamp 200W portable and group 27 house battery. My geek friend suggests a 2000W pure sine wave inverter (peak 4,000W). Would like to be able to run the A/C a few hours and very small microwave (separately). Your thoughts on (1) is this a realistic goal and (2) what brand and size inverter?

Nomad

Somewhere (here) it was discussed how much it would take to run the air on solar - as I recall, it was a lot of battery and a lot of solar. Tried a search but couldn't find it.
I have a 400 inverter connected directly to the battery and 120watt solar (group24 battery) and I have no trouble charging my computer/iDevices and keeping my battery charged on a nice sunny day.

mash2

Here is a discussion by technomadia.  http://www.technomadia.com/2015/02/the-almost-fantasy-of-solar-powered-rv-air-conditioning/

Tabaz

The search engine is way smarter than me. I'm sure I'm not the first person to try this.

Tabaz

Great article - thanks Mash2! 

Verna

mash2 said:

Here is a discussion by technomadia.  http://www.technomadia.com/2015/02/the-almost-fantasy-of-solar-powered-rv-air-conditioning/

Thanks for the link. I knew it would take a lot, but I got interrupted awhile ago searching for a link of what it would take.

Great information.

Nomad

How do you guys find that stuff - just have it bookmarked?

mash2

just typed In solar powered air conditioning in RV and this came up (knew that technomadia.com was a pretty good site).

Mr_Mrs_Gnome

@OutbackAZ, I know this isn't quite what you're asking, but have you thought about using a 12v swamp cooler when the humidity is low?

Tabaz

I've lived with swamp coolers here in Phoenix. Didn't know they make a 12V. What about water consumption? I'll definitely look into it.  On another related topic - mash2 - I assume that search was done on Google and not this forum. The search engine here seems to get confused with more than one word in the description.

jkjenn

I wish we could get away with a swamp cooler in the east but the humidity is an issue. The swamp cooler might work along with adjusting your camping elevation in the Southwest, but I think if reliability is important a generator is still the way to go, at this point, unfortunately.

iz6

How about hooking up the inverter to the tow vehicle, instead of solar panels? 

In other words, using the TV as a generator of sorts. If used sparingly, like a couple times a year, only in the hottest days...

Thoughts?

jkjenn

At the cost of the inverter that would be needed you might as well get a generator.

ChanW

iz6 said:

How about hooking up the inverter to the tow vehicle, instead of solar panels? 

In other words, using the TV as a generator of sorts. If used sparingly, like a couple times a year, only in the hottest days...

Thoughts?

Well, let's say the Air-Con unit requires a 1500W surge when starting. That'd be about 125A at 12Volts. That itself would take a pretty durn big alternator in your TV.

Then the continuous operating power at maybe 800W or 900W (guessing here) translates to @ 70A at 12V.

Most automotive generators are intended to output much much lower continuous amperage than that.

Then there's what Jenn said...

iz6

Jkjenn, on Amazon I'm seeing cheap 1000w inverters for under $100, while cheap 1000w generators  are in the $300s..

ChanW, I just assumed that since they are so readily available, and as large as 4000W, that any car could handle the draw.. But maybe not, maybe they are used in a different set up?

To to me it seemed attractive to have a small inverter (plus install a hard start cap on AC) for the unpredictable/unavoidable hot day here and there. With generator you had to lug something that's heavy, plus a gas can, some oil, etc.

Nomad

iz6 - You see the big, monster inverters in big truck stops. Trucks/busses have bigger alternators & battery systems. Have presumed they were too much of a draw for normal vehicles/batteries. I've also noticed all inverters 500 and up that I've come across need to be connected directly to the battery.

Photomom

I had posted this link to a different thread a while back. Much info here. I'd be inclined to give them a call to discuss requirements. https://www.donrowe.com/power-inverter-faq-a/258.htm

Ratkity

My truck driver friend has a bank of batteries that would rival the biggest RV rigs. He runs a refrigerated 18-wheeler and they are also used for backup for that AC unit. I think PXL is right with his inverter info based on what my long-distance trucker friend has mentioned as to what is in his cab, what he runs on his inverter, and the rules for keeping his truck running continuously during down-time (company specific). 

jkjenn

Photomom said:

I had posted this link to a different thread a while back. Much info here. I'd be inclined to give them a call to discuss requirements. https://www.donrowe.com/power-inverter-faq-a/258.htm

Based on the assumption of a 100ah battery and an a/c running at 450w 5,000 BTU (which is about the smallest a/c you could find), you would barely get a full hour out of just the a/c, not including parasitic battery drain.

I would be really surprised if a 1000w inverter would handle even a small a/c starting amps and would think it extremely likely that you would need at least a 2000w inverter, although it would be an interesting experiment. Xantrex, which is widely respected in the power world, has a 2000w true sine wave inverter but it is a little over $350. You would have to also look at upgrading your batteries to support this use.

People who are FT RVers don't consider a/c attainable or sustainable for RVs yet, without a generator or shore power. These are rigs with huge battery power and equally large solar set-ups.

ChanW

Now I think we might be getting down to a solution...

Dalehelman

If you spend time where it is hot and dry. Check out Turbokool. I had one about 5 years ago. It worked very well and I would buy another. They are not cheep about $700 but they are 12 volts well designed light weight.
Sorry we seem to have gotten off topic. Simple answer big inverters need big battery banks which means a lot of weight.

wizard1880

If you want absolute top of the line for inverters, look at Exeltech.  They are used as backup power in all US embassies.  25 year life at 100% load.  But, $1000 for a 1100w model or more for their 2000w models.  Not practical for us, unless you can score a used one on e-bay.

EWizard

How would you hook up an inverter with the stock converter that is already installed in our T@B's?
The 12V part is easy, as that just needs to be tapped into where the 12V from the battery comes into the converter.
The 120V part is what has me stumped.  If you plug into the 120V plug on the inverter, that has to go the the breaker panel somewhere.
Any ideas?

EWizard

I found a couple of things that sort of address what I'm asking.
Does anybody know if this type of install would be attainable with the stock unit in the T@B, minus the transfer switch and inverter?

I found this:
"The most elegant (and of course, most expensive) solution is to connect the RV inverter directly to RV’s AC distribution boxthrough a transfer switch (keep in mind the type of switch used varies based on the power of the RV inverter and if you have a generator). The switch will automatically select shore power if it is available, and inverter power if it is not. If you go this route, you still have to avoid powering the converter from the inverter. The most common method for achieving this is to use a split distribution panel, with the converter on the part of the panel that is not connected to the inverter. If that seems like a more complex RV inverter install than you want to try, read on for how to use a relay."

The thing I'm not sure you can do, is avoid powering the converter from the inverter...

There is also this image I found:

Mercator

There is a really good YouTube video from "Gone With The Wynns" that addresses questions about running air-conditioning on solar. (In case you don't follow the Wynns on YouTube they are a young couple who make great videos about their full-time RV experiences.) Can be done, but not reasonably.

Tabaz

I keep the inverter in the TV and bring it out when needed. Have a quick battery cable disconnect on the house battery and inverter (I'll post pics later). Will be running a dedicated 110v line with 3 prong male from the inverter to the outlet on the driver's side seat pedestal. Will disconnect that outlet from the TAB's electrical system.

Nomad

I also have an inverter connected direct with a Zamp-style connector. It sits in the tub atop the battery. I used to have it in the T@B but the inverter fan drove me crazy so when needed I just plug in an extension cord and run it out behind the tub. If I was real ambitious (and had the tools) I'd probably run it to a dedicated 120 outlet on the side bench.

EWizard

I like that idea a lot @PXLated.
Is your inverter box sealed from the elements?  I noticed a fair amount of water gets into my tongue box when it rains.

Nomad

EWizard - Not that I'm aware of but haven't noticed a moisture problem over the last year at all.
Works great for charging all my toys - Let the solar get the battery fully charged in the morning and then mid-day with good sun I start up the inverter.

EWizard

@PXLated, do you have a photo of this tub?  I'm curious how it looks.

Nomad

Ooops - I lied, it's connected directly to the battery - I didn't do the Zamp type plug.
EWizard - By "tub" I just mean the standard propane cover. The inverter just sits in there on top of the coiled up dump hose. "Oh ick" you say - no, I keep the dump hose nice and clean. Gets dusty in there but the hose is clean :-)