Reply
 
Thread Tools Search this Thread Display Modes
 
Old 09-17-2008, 02:49 PM   #15
Rivet Master
 
richinny's Avatar
 
2011 34' Classic
Westchester Cty.NY , / Miami FL
Join Date: Jul 2007
Posts: 3,122
the start load of the ac is much higher that the wattage listed. i think someone (lewster?) posted some numbers. low voltage is a very bad thing for your ac.
__________________

__________________
Ricky
2012 F150 Super Crew 5-1/2' bed Ecoboost 4x4 3.73 elec. lock diff. Propride hitch
give life. kidney & pancreas transplant 9/9/06
Ingrid-my unofficial '"World's Oldest Streamer" 1909-2008 R.I.P.
richinny is offline   Reply With Quote
Old 09-17-2008, 02:54 PM   #16
Rivet Master
 
richinny's Avatar
 
2011 34' Classic
Westchester Cty.NY , / Miami FL
Join Date: Jul 2007
Posts: 3,122
what some do, and what one should do, sometimes conflict.

here is the post from inland andy:
http://www.airforums.com/forums/show...61&postcount=2

note that is is for a 13.5 btu ac.
__________________

__________________
Ricky
2012 F150 Super Crew 5-1/2' bed Ecoboost 4x4 3.73 elec. lock diff. Propride hitch
give life. kidney & pancreas transplant 9/9/06
Ingrid-my unofficial '"World's Oldest Streamer" 1909-2008 R.I.P.
richinny is offline   Reply With Quote
Old 09-17-2008, 03:00 PM   #17
Rivet Master
 
utee94's Avatar
 
1963 26' Overlander
Austin , Texas
Join Date: Feb 2008
Posts: 2,636
Thanks for the input guys.

But then I cannot help but wonder why the A/C manufacturers don't list these additional requirements on their spec sheets?

For those who don't know, I'm an electrical engineer, though of the microprocessor variety. Still, we're forced to spec everything. Max rating should include startup and/or inrush current, and obviously power consumption would be based on that current multiplied by your actual voltage.

Also, at the "Rated" power consumption spec on the generator unit, I would not expect any voltage sag. I would expect to see some voltage sag when you are running near Max spec, but at Rated power the genny should be able to supply the full load specified at the voltage specified.

So, are people in the field actually seeing voltage sag on their gensets even when operating at the Rated spec, which is well below the Max spec?
utee94 is offline   Reply With Quote
Old 09-17-2008, 03:04 PM   #18
Rivet Master
 
utee94's Avatar
 
1963 26' Overlander
Austin , Texas
Join Date: Feb 2008
Posts: 2,636
Quote:
Originally Posted by richinny View Post
what some do, and what one should do, sometimes conflict.

here is the post from inland andy:
http://www.airforums.com/forums/show...61&postcount=2

note that is is for a 13.5 btu ac.
With all due respect to Andy, on that particular post, I believe he misunderstood the OP. The OP was asking about an inverter-style generator, rather than an inverter. I would certainly never consider running an RV A/C unit from a standard inverter using standard deep cycle batteries.

Also, the spec sheets only show about a 5% difference between the 13.5K BTU and 15K BTU models for max power and max current, so I suppose we could roughly estimate the same 5% difference for startup current/power...
utee94 is offline   Reply With Quote
Old 09-17-2008, 03:14 PM   #19
Rivet Master
 
richinny's Avatar
 
2011 34' Classic
Westchester Cty.NY , / Miami FL
Join Date: Jul 2007
Posts: 3,122
Quote:
Originally Posted by utee94 View Post
With all due respect to Andy, on that particular post, I believe he misunderstood the OP. The OP was asking about an inverter-style generator, rather than an inverter. I would certainly never consider running an RV A/C unit from a standard inverter using standard deep cycle batteries.
Also, the spec sheets only show about a 5% difference between the 13.5K BTU and 15K BTU models for max power and max current, so I suppose we could roughly estimate the same 5% difference for startup current/power...
you're right it wasn't the post i remembered but it had some useful info.

as for the surge rating on the ac units....that would be nice.
as for a surge rating on generators, i've seen them.

i'll wait for lew now :-) since he fixes them!
__________________
Ricky
2012 F150 Super Crew 5-1/2' bed Ecoboost 4x4 3.73 elec. lock diff. Propride hitch
give life. kidney & pancreas transplant 9/9/06
Ingrid-my unofficial '"World's Oldest Streamer" 1909-2008 R.I.P.
richinny is offline   Reply With Quote
Old 09-17-2008, 03:19 PM   #20
Rivet Master
 
utee94's Avatar
 
1963 26' Overlander
Austin , Texas
Join Date: Feb 2008
Posts: 2,636
Quote:
Originally Posted by richinny View Post
you're right it wasn't the post i remembered but it had some useful info.

as for the surge rating on the ac units....that would be nice.
as for a surge rating on generators, i've seen them.

i'll wait for lew now :-) since he fixes them!
Thanks for your input, of course. And this is precisely why I asked the question about empirical data.

If I can't believe what's on the spec sheets, well, I have absolutely no other basis for analysis.
utee94 is offline   Reply With Quote
Old 09-17-2008, 03:28 PM   #21
Rivet Master
 
richinny's Avatar
 
2011 34' Classic
Westchester Cty.NY , / Miami FL
Join Date: Jul 2007
Posts: 3,122
ok, this post might give a trail tomore data.

http://www.airforums.com/forums/show...7&postcount=11
__________________
Ricky
2012 F150 Super Crew 5-1/2' bed Ecoboost 4x4 3.73 elec. lock diff. Propride hitch
give life. kidney & pancreas transplant 9/9/06
Ingrid-my unofficial '"World's Oldest Streamer" 1909-2008 R.I.P.
richinny is offline   Reply With Quote
Old 09-17-2008, 03:35 PM   #22
Certifiable
 
mistral blue's Avatar
 
. , .
Join Date: Nov 2006
Posts: 4,460
FWIW, I took delivery of a gently used Honda 3000 w/wheels last year for about $1G total. New low profile 15K Dometic AC this year. Big frig. No microwave. No electric coffee maker. No TV. No hair dryers. No furnace. No solar. Plenty of lights. Stereo runs constantly. Laptop. iPhone. AGMs.

The issues I have are the weight, the size and the fuel. I wish it was lighter, smaller and could run off of propane. But for the price I paid, I am VERY happy with this unit.

Hope this helps.
__________________
"IT'S A MAGICAL WORLD, HOBBES, OL' BUDDY... LET'S GO EXPLORING!" ~ CALVIN
mistral blue is offline   Reply With Quote
Old 09-17-2008, 03:38 PM   #23
Rivet Master
 
TinLoaf's Avatar
 
2006 25' Safari SS SE
Trenton , Illinois
Join Date: Feb 2007
Posts: 794
Images: 22
I can only speak for myself here. My 13,500 btu DuoTherm Penguin heat pump takes 12.4 amps for the compressor and 3.5 amps for the fan motor totalling 15.9 amps of the 16.7 amps that the Yamaha 2400 is rated for. That leaves less than 1 amp of overhead which quickly disappears with elevation.

I assumed that a 15,000 btu unit would use more power, but the 15k Penguin heat pump takes 12.0 for the compressor and 3.3 for the fan totalling 15.3 amps - that's less than the 13,500 btu unit.

I think the key here is the surge at startup. It takes a lot of amps to get that compressor started and the Yamaha 2400 does the trick for me.
__________________
Steve
TinLoaf is offline   Reply With Quote
Old 09-17-2008, 04:02 PM   #24
Rivet Master
 
richinny's Avatar
 
2011 34' Classic
Westchester Cty.NY , / Miami FL
Join Date: Jul 2007
Posts: 3,122
http://www.cumminsonan.com/www/pdf/rv/f-1362.pdf
note the comments next to the microwave on page 2!

http://www.powermate.com/generators/...ide_update.pdf

Honda Power Equipment - GENERATOR WATTAGE CALCULATOR

Generator Sizing Chart - Yamaha Motor Corporation, USA

How to Select a Generator for an RV - Wattage estimator
__________________
Ricky
2012 F150 Super Crew 5-1/2' bed Ecoboost 4x4 3.73 elec. lock diff. Propride hitch
give life. kidney & pancreas transplant 9/9/06
Ingrid-my unofficial '"World's Oldest Streamer" 1909-2008 R.I.P.
richinny is offline   Reply With Quote
Old 09-17-2008, 04:13 PM   #25
Rivet Master
 
mustang's Avatar
 
1986 31' Sovereign
Kent , Ohio
Join Date: May 2006
Posts: 803
I found some info from 2 different A/C Installation manuels. I am not much on electricity so maybe this will shed some light on things.

It says the heat strip uses 12.7 amps or 1530 watts at 120 volts. This is on all units a BTU rateings

It says the 7100 and 11000 BTU units use 2.5 KW for A/C

It says 13500 to 15000 units use 3.5 KW for A/C

You would add the watts for heatstrip it looks like.

I am not sure of KW to convertion so feel free to give input I guess.

If I was better with my computer I would scan this page however, If it came with mine then we should all have the same Info.

It also says 12 AWG copper up to 24 ft and a 20 amp timedelay fuse or HACR Circuit Breaker

Fine print mentions High alltitude power loss and poor maint ect for generator.
Have at it guys
__________________
mustang is offline   Reply With Quote
Old 09-17-2008, 04:18 PM   #26
Rivet Master
 
mustang's Avatar
 
1986 31' Sovereign
Kent , Ohio
Join Date: May 2006
Posts: 803
Those are some good links Richinny

I wonder how to convert KW to watts??
__________________
mustang is offline   Reply With Quote
Old 09-17-2008, 04:25 PM   #27
Rivet Master
 
TinLoaf's Avatar
 
2006 25' Safari SS SE
Trenton , Illinois
Join Date: Feb 2007
Posts: 794
Images: 22
1 kilowatt (KW) = 1,000 watts.

I think your manual is suggesting that you need 3,500 watts to cover the surge to get the compressor started. That's a bit on the high side. Once running it takes much less.
__________________
Steve
TinLoaf is offline   Reply With Quote
Old 09-17-2008, 04:31 PM   #28
Rivet Master
 
mustang's Avatar
 
1986 31' Sovereign
Kent , Ohio
Join Date: May 2006
Posts: 803
It seems to be a bit off from the generator companies say is required. I will try to scan this and post it. I have the same info from my old penguin unit as my new Duo Therm. I fried my penguin at a state park from low power. That is what the R/V dealer said.

I was lucky he had a used one that was to small for a trailer and had to upgrade so he gave me a deal on this 13500 unit
__________________

__________________
mustang 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 Size for 13,500BTU Coleman Mach 3??? dscluchfc Generators & Solar Power 26 07-28-2010 07:07 PM
Hello ..what size generator should I use? ole81 Member Introductions 22 07-14-2007 11:49 PM
generator size and taking delivery altamont 2007 Safari SE 23 04-28-2007 09:24 PM
Generator size? cookeville34 Generators & Solar Power 27 03-25-2007 07:26 PM
help! what size generator?? tjj's63 Our Community 5 08-20-2003 08:33 PM


Virginia Campgrounds

Reviews provided by




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 02:56 AM.


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.