Reply
 
Thread Tools Search this Thread Display Modes
 
Old 04-17-2014, 11:23 PM   #1
2 Rivet Member
 
2014 22' FB Sport
Mill Valley , California
Join Date: Mar 2014
Posts: 26
Using inverter and generator together?

The A/C unit requires something like 3.5 kW to run right, but does not actually draw that much all the time. The little Honda 2000 generator can not start it, but could almost keep up once it is running

An inverter can be used which will run the A/C, but the draw will empty the batteries quickly. I want to use the batteries and inverter to run the A/C and at the same time use the generator to charge the batteries to the best of its ability.

The question is what kind of inverter and charger to use? It appears to me that the combo units can only invert or charge, but not both at the same time, right?

Anybody done this before?

Thanks, Andrew
__________________

__________________
awiegel is offline   Reply With Quote
Old 04-18-2014, 12:25 AM   #2
Rivet Master
 
dkottum's Avatar
 
2012 25' Flying Cloud
Battle Lake , Minnesota
Join Date: Jun 2009
Posts: 7,716
I would think the inverter and generator outputs would not be in phase with each other so it could not work.

Also trying to run the generator to charge the batteries to power the inverter at the same time as running the generator to power the air conditioner, could only be worse than running the generator to power the air conditioner by itself, because of power losses at the inverter and the associated wiring.

There is nothing to gain. You need a larger generator.
__________________

__________________
Doug and Cheryl
2012 FC RB, Michelin 16, ProPride 1400
2016 Ram 1500 Laramie Crew Cab 4X4 Ecodiesel 3.92 axles

The Truth is More Important Than the Facts
dkottum is offline   Reply With Quote
Old 04-18-2014, 12:32 AM   #3
Rivet Master
 
J. Morgan's Avatar

 
1972 31' Sovereign
1975 31' Excella 500
Currently Looking...
Benton , Arkansas
Join Date: Mar 2013
Posts: 5,040
Images: 11
I am working on something like you are proposing... But not exactly...

I should have an answer as to if this will work sometime next week.... and a longer term test over the summer...

Click image for larger version

Name:	ImageUploadedByAirstream Forums1397799143.906671.jpg
Views:	170
Size:	826.3 KB
ID:	209880
__________________
The fact that I am opinionated does not presuppose that I am wrong......

J. Morgan is offline   Reply With Quote
Old 04-18-2014, 12:33 AM   #4
Rivet Master
 
dkottum's Avatar
 
2012 25' Flying Cloud
Battle Lake , Minnesota
Join Date: Jun 2009
Posts: 7,716
But most buy a second "Companion" Honda 2000 to help the other one.
__________________
Doug and Cheryl
2012 FC RB, Michelin 16, ProPride 1400
2016 Ram 1500 Laramie Crew Cab 4X4 Ecodiesel 3.92 axles

The Truth is More Important Than the Facts
dkottum is offline   Reply With Quote
Old 04-18-2014, 12:38 AM   #5
Rivet Master
 
J. Morgan's Avatar

 
1972 31' Sovereign
1975 31' Excella 500
Currently Looking...
Benton , Arkansas
Join Date: Mar 2013
Posts: 5,040
Images: 11
Using inverter and generator together?

To answer your question more directly, I think you could use a large battery charger run by the generator to charge your batteries while the batteries run the air conditioner, but battery chargers can be hard on a battery if left.on high charge for extended periods of time without a balanced load. (like if the a/c didn't come on for a long time).

Even charging at 50 amps will only deliver 600 watts of run at a given time, and even if the a/c were to only 1/2 time, effectively you only have 1,200 watts to consume before you lose ground on your battery charge, not counting the efficiency losses of the inverter and the efficiency losses of charging a battery.

It might be a little risky. I wouldn't sleep well with this setup, nor would I leave it unattended, overcharged batteries can on occasion catch fire.
__________________
The fact that I am opinionated does not presuppose that I am wrong......

J. Morgan is offline   Reply With Quote
Old 04-18-2014, 12:39 AM   #6
Don't forget your cat nap
 
Ag&Au's Avatar
 
Port Orchard , Washington
Join Date: May 2009
Posts: 4,464
Images: 1
This reminds me of a perpetual motion machine I once saw at a carnival when I was I kid. It looked great until you got out a pencil and paper and did the math. (we didn't have calculators then).


As far as I know, the only reasonable solution for running the A/C in a modern Airstream for any length of time without shore power, is two Honda 2000W generators with their cabling kit, or any single generator of sufficient wattage rating.


Welcome to Airforums,


Ken
__________________
Ag&Au is offline   Reply With Quote
Old 04-18-2014, 08:16 AM   #7
Rivet Master
 
1988 25' Excella
1987 32' Excella
Knoxville , Tennessee
Join Date: Oct 2010
Posts: 2,163
Blog Entries: 1
I think the concept is to have the batteries make up the additional power need to start the AC and to have the generator recharge the batteries when the AC is not drawing the full load from the generator? So it is not perpetual motion, but instead power management and storage. Sorta like a hybrid car.
There are generators that have built in capacitors that supply some starting power. I suspect it is not as easy as just hooking up a big inverter to the AC and running a charger with the generator. I do not think I have seen an inverter that will start a AC. Both the cost and power losses would seem prohibitive that way. Phasing would seem to be a big problem if the inverter and AC were rigged in parallel. But they do get the 2 genies phased somehow so maybe it is possible.
If I want to run my AC boondocking I will just add the second Honda. $1000, works fine, no problems, plus additional power while the AC is running. I can see the desire to only carry one generator with a short trailer and possibly small TV. Or sell the Honda and buy a bigger generator. Maybe mount it on the trailer tongue. Of course the cheapest solution is to use campsites with power during hot weather. We are finding more forest service sites with electric than ever. So I have not added the additional generator for the AC.
You might spend some time looking at the generator and inverter sales sites to see if there is anything out there addressing this issue.
__________________
Bill M. is offline   Reply With Quote
Old 04-18-2014, 08:25 AM   #8
Well Preserved

 
1993 21' Sovereign
Colfax , North Carolina
Join Date: Jun 2003
Posts: 20,190
By the time you accumulate enough peripheral "stuff" to make this work, you will either have enough 120 volt items to charge the batteries to run the inverter to operate the air conditioner you will need a 50 amp circuit, or you will have enough cash invested you might as well just go buy a second generator. So, to make it work, you would need enough electrically operating items that you would need a bigger generator to do it, in which case you could simply get the generator and forget the complex, Rube Goldberg solution.
__________________
Meddle not in the affairs of dragons, for you are crunchy, and taste good with ketchup.
Terry
overlander63 is offline   Reply With Quote
Old 04-18-2014, 09:14 AM   #9
3 Rivet Member
 
2007 27' Safari FB SE
Spokane , Washington
Join Date: Apr 2014
Posts: 123
Honda and Yamaha both have nice generators, from my research you need either 2x2000watt gens tied together or upgrade to a single 3000 watt model, both options set you back around 2200.00. I have been looking for a long time and decided to buy the champion 3100 watt inverter/generator. It's specs are identical to the honda 3000 handi, had it delivered on Tuesday and only cost me 659.00 from overstock. I love it, it's quite, has 1 30 amp plug 2x15 amp and a dc battery plug. It's the best option for the money and you could charge your batteries directly while running them at the same time but your drawing too much and not restoring enough so over time you batteries will be dead.
__________________
shaggy1970AS is offline   Reply With Quote
Old 04-18-2014, 09:31 AM   #10
3 Rivet Member
 
jkcru's Avatar
 
2010 28' Flying Cloud
Escondido , California
Join Date: Feb 2007
Posts: 195
I saw an inverter charger that could assist the generator at either Anchor Marine or West marine, not inexpensive, in excess of $1K
__________________
jkcru is offline   Reply With Quote
Old 04-18-2014, 09:46 AM   #11
4 Rivet Member
 
Silver Hawk's Avatar
 
1975 31' Sovereign
Palomar Mountain , California
Join Date: Feb 2013
Posts: 353
Keep in mind that inverters are at best only 90% efficient. The cheep ones are way less I'm told.
__________________
Silver Hawk is offline   Reply With Quote
Old 04-18-2014, 09:54 AM   #12
3 Rivet Member
 
2007 27' Safari FB SE
Spokane , Washington
Join Date: Apr 2014
Posts: 123
The efficiency rating are posted and the Champion is right inline with Honda 3000 Handi at 95%. I wish I could post link of videos but the forum does not allow me yet since I am a newbie and not a trusted member. There is a youtube video of a review that is 12 minutes long and shows the champion and made me make up my mind, also at supergen website there is a sound proof tent that you can buy for it that will drop the DB by 8 so making it the quietest generator out there. I am going to build my own sound proof box for those days I have a person camped right next to me.
__________________
shaggy1970AS is offline   Reply With Quote
Old 04-18-2014, 12:12 PM   #13
2 Rivet Member
 
2014 22' FB Sport
Mill Valley , California
Join Date: Mar 2014
Posts: 26
Wow.
Thank you to everyone who responded so quickly and with so much thoughtful information.

You are right that my considerations are driven primarily by weight and the expectation that the A/C will in fact be seldom used. I already have the Honda 2000 and 220 Ah of AGM batteries. I will want a good inverter anyway for silent running below 1 kW consumption in the evening or morning when generator noise would be inconsiderate to others. So the real cost appears to be the dedicated charger to run off the generator. A good quality charger will mind its manners and not fry the batteries, but I am concerned about the inherent inneficiency of the system.

Andrew
__________________
awiegel is offline   Reply With Quote
Old 04-18-2014, 01:27 PM   #14
Rivet Master
 
1974 Argosy 20
2014 20' Flying Cloud
Kooskia , Idaho
Join Date: Jul 2009
Posts: 4,591
Sync of generators is an interesting topic. Conventional small generators (not the inverter type) are virtually impossible to sync but the inverter ones sync readily and automatically. When you look inside a Honda inverter generator you will see that the parallel connection wires are simply two wires directly connected to the 120 volt outlet. They do not go into the inverter someplace special, they just go to the outlet. So, when two Honda's are connected together, with the parallel connection, all the synchronization is done by the inverters talking to each other through the power output.

Others have noted this automatic sync function of the inverters and there is one You Tube Video where a guy hooked up his sine wave inverter to a battery, and then to his Honda, and the inverter in the Honda adjusted itself to follow the battery inverter. So, he was able to get more power from the two together and then start an AC unit.

It all seems impossible, but the inverters in the generators apparently can be completely happy with any other sine wave power system, running in parallel. I would love to try it with my Honda inverter generator, but don't have the guts to do it. But again it has been done by others. I had a link to the You Tube video but have lost it, but I am sure that those of you who are good at You Tube searching can locate the video I saw.

I believe, but do not know for sure, that you can even sync (parallel) different brands of generators which have parallel ports, such as Honda's and Yamaha's. It seems to be a well kept secret, but if it doesn't work the smoke may be pretty expensive. I wish I had some old beater inverter generators to try it out.

No guts, no glory, right?
__________________

__________________
idroba is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Generator and inverter??? Streamside Electrical - Systems, Generators, Batteries & Solar 3 08-28-2011 09:16 AM
12v and 110 - Wired together? KellySLC Electrical - Systems, Generators, Batteries & Solar 13 11-09-2010 09:49 PM
And Now to put it back together. 59toaster Cabinets, Counter Tops & Furnishings 50 10-23-2005 07:56 AM
Airstream And Dealer Working Together DreamStream 2005 and newer - Bambi all models 9 04-08-2005 07:43 AM


Virginia Campgrounds

Reviews provided by




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 09:24 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.

Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.