Home » Public Forums » GMCnet » How long with my house battery run the air conditioner fan? (How do you determine battery capacity?)
| How long with my house battery run the air conditioner fan? [message #245770] |
Sun, 30 March 2014 11:37  |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
Karma: 15
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On the way back from Montgomery, we stayed in a couple sub standard campgrounds. The alternative would have been to stay at a WalMart etc and just run the air conditioner fan to circulate the air and provide white noise. We aren't interested in trying to sleep with the generator running. Given the weather, we needed no heat.
So the question is, if we turned off our 12V fridge over night, how long can we expect a strong 12V house battery to run various 'things'. Does the amp hour rating on the battery mean it will run a total of X amps for one hour? For instance, will an 850AH battery, fully charged, run 850amps for 1 hour, 425A for 2 hours, 212A for 4 hours, etc?
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
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| Re: [GMCnet] How long with my house battery run the air conditioner fan? [message #245772 is a reply to message #245770] |
Sun, 30 March 2014 12:41  |
Dave Mumert
Messages: 272
Registered: February 2004
Location: Olds, AB, Canada
Karma: 0
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Hi Kerry
Power Sonic has a document on their web site that shows:
AH capacity versus discharge rate
Life expectancy versus total discharge
AH capacity versus temperature
http://www.power-sonic.com/images/powersonic/technical/1277751263_20100627-TechManual-Lo.pdf
Basically the faster you discharge a battery the less capacity it has, most of the batteries we use would be rated at a 10 hour or
20 hour discharge rate.
Some battery manufacturers recommend a maximum discharge to a depth as low 50% (you can use 50% of rated capacity), some are 30%
(you can use 70% of rated capacity).
So your 850 AH battery is probably good for 85 amps for 10 hours (or 42.5 for 20 hours) you need to check the manufacturers site to
find out which.
You also need to limit the depth of discharge to the manufacturers recommended maximum (typically 30-50%) for maximum life.
So if you are conservative with your battery and want the best life you 850 AH battery is good for 42.5 amps for about 10 hours.
Rolls Battery http://rollsbattery.com/ has a good selection of high capacity batteries, their 880AH 2 volt batteries are 119 pounds
each, that is 714 pounds for 12 volts, not too bad if you are dumping the Onan.
Dave Mumert
'76 Eleganza II
Alberta, CA
> -----Original Message-----
> Subject: [GMCnet] How long with my house battery run the air conditioner fan?
>
> On the way back from Montgomery, we stayed in a couple sub standard campgrounds. The alternative would have been to stay at a
> WalMart etc and just run the air conditioner fan to circulate the air and provide white noise. We aren't interested in trying to
sleep
> with the generator running. Given the weather, we needed no heat.
>
> So the question is, if we turned off our 12V fridge over night, how long can we expect a strong 12V house battery to run various
> 'things'. Does the amp hour rating on the battery mean it will run a total of X amps for one hour? For instance, will an 850AH
battery,
> fully charged, run 850amps for 1 hour, 425A for 2 hours, 212A for 4 hours, etc?
> --
> Kerry Pinkerton
>
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| Re: How long with my house battery run the air conditioner fan? [message #245773 is a reply to message #245770] |
Sun, 30 March 2014 12:49 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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The simple answer to you question is "Yes" but.....
You never want to run you house batteries all the way down. Some places say not below 30%. Some say 40%. Also the amp hour number is for a new battery. As they age their capacity drops based on several factors. My dual golf cart batteries have never been totally discharged and I think they have been in there 8 years.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: How long with my house battery run the air conditioner fan? [message #245777 is a reply to message #245770] |
Sun, 30 March 2014 13:44 |
roy1
Messages: 2126
Registered: July 2004
Location: Minden nevada
Karma: 6
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Kerry if you just need some air circulation so you can get a little sleep get a battery powered box fan and put it in an open window by the bed. Walmart had such a fan I bought one there.it is 12" square and holds 8 D batteries which adds up to 12 volts. It can also be connected to an adaptor that plugs into a cigar lighter. It draws less then 1/2 an amp from the battery. I store mine in the foot locker by the bed and plug it into the cigar plug I wired from a reading light. The name of it is O2 cool and it was around $15 or so when I bought it a few years ago. I blow it mostly on Paula if she sleeps I can sleep easily.
Roy Keen
Minden,NV
76 X Glenbrook
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| Re: How long with my house battery run the air conditioner fan? [message #245781 is a reply to message #245770] |
Sun, 30 March 2014 15:21 |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
Karma: 15
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I mainly want the air handler ONLY just for the noise. A box fan wouldn't be loud enough to mask the parking lot noise. The wife is a light sleeper. I don't want to run the AC from battery. Obviously that is not really feasible without some MAJOR batteries and recharging capacity.
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
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| Re: [GMCnet] How long with my house battery run the air conditioner fan? [message #245783 is a reply to message #245781] |
Sun, 30 March 2014 15:41 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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If alls you need is the sound, try one of these:
http://www.amazon.com/s/?ie=UTF8&keywords=white+noise+machine&tag=googhydr-20&index=aps&hvadid=21605624647&hvpos=1t1&hvexid=&a mp;hvnetw=g&hvrand=16510945998695038630&hvpone=&hvptwo=&hvqmt=b&hvdev=c&ref=pd_sl_7szu81tlxs_b
--johnny
________________________________
From: Kerry Pinkerton <Pinkertonk@MCHSI.com>
To: gmclist@temp.gmcnet.org
Sent: Sunday, March 30, 2014 4:21 PM
Subject: Re: [GMCnet] How long with my house battery run the air conditioner fan?
I mainly want the air handler ONLY just for the noise. A box fan wouldn't be loud enough to mask the parking lot noise. The wife is a light sleeper. I don't want to run the AC from battery. Obviously that is not really feasible without some MAJOR batteries and recharging capacity.
--
Kerry Pinkerton
North Alabama, near Huntsville,
77 Eleganza II, "The Lady", 403CI, also a 76 Eleganza being re-bodied as an Art Deco car hauler
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Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: How long with my house battery run the air conditioner fan? [message #245789 is a reply to message #245770] |
Sun, 30 March 2014 16:23 |
A Hamilto
Messages: 4508
Registered: April 2011
Karma: 39
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| Kerry Pinkerton wrote on Sun, 30 March 2014 11:37 |
On the way back from Montgomery, we stayed in a couple sub standard campgrounds. The alternative would have been to stay at a WalMart etc and just run the air conditioner fan to circulate the air and provide white noise. We aren't interested in trying to sleep with the generator running. Given the weather, we needed no heat.
So the question is, if we turned off our 12V fridge over night, how long can we expect a strong 12V house battery to run various 'things'. Does the amp hour rating on the battery mean it will run a total of X amps for one hour? For instance, will an 850AH battery, fully charged, run 850amps for 1 hour, 425A for 2 hours, 212A for 4 hours, etc?
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To answer the question of the subject, probably not overnight.
You should be able to find a DC fan that will generate enough airflow and noise to do what you want, and will last all night on your house battery (think passenger car dash heater/AC fans). If you can't find one noisy enough, there are other ways to generate "white" noise at very low power draw.
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| Re: How long with my house battery run the air conditioner fan? [message #245797 is a reply to message #245789] |
Sun, 30 March 2014 18:15 |
Craig Lechowicz
Messages: 541
Registered: October 2006
Location: Waterford, MI
Karma: 0
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Kerry,
An 850 amp hour battery is a very large battery, and probably would run the fan only on the a/c unit for a couple of days. But, I suspect you may have a battery with 850 Cold cranking amps which is a different measurement. Cold cranking amps (CCA) are what starting (chassis batteries) are rated at, and give a measure of how powerful a battery is for a quick discharge at high load. Usually batteries with CCA rating are not "deep cycle" batteries that are better at lower loads over long periods of time. Amp hours are used for that measure, and usually aren't measured for starting batteries.
I did look up a group 27 (size class) Autozone "marine" or dual-purpose battery to try and relate the 2 measurements. It is listed as 800 Cold Cranking amps (CCA), and doesn't show amp hours. But, it did list a reserve capacity rating of 180 minutes. And, I did find a rule of thumb on google that said reserve capacity X 0.6 approximates amp hours, so that battery would have about 108 amp hours available.
The typical 2 golf cart batteries used for coach batteries are rated at about 225 amp hours, or about 2x the "dual purpose marine" 12v. battery above. And, at low loads, hours x amps probably applies for those ratings. (at high loads, the batteries are less efficient, so it doesn't.)
I'm not sure what the fan on low speed draws on the A/C units, but I'll guess that it is 1.5 amps at 120 volts. To allow for inverter in-efficiency, multiply by 10 and say it's 15 amps of load at a nominal 12 volts. And keeping in mind the 50% depth of discharge rules others have mentioned, it ought to be somewhere around 7 hours for the 2 golf cart batteries, or about 3-1/2 hours for the dual purpose marine battery. (Although dual-purpose marine batteries aren't really very good at deep cycle applications, so it probably won't do it very many times.)
My guess on the fan motor draw could be wildly inaccurate, one of those Kill-A-Watt plug in testers would be a good way to find the real number. The rest of the assumptions and math ought to be close, though.
Craig Lechowicz
'77 Kingsley, Waterford, MI
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| Re: How long with my house battery run the air conditioner fan? [message #245824 is a reply to message #245770] |
Sun, 30 March 2014 21:38 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
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| Kerry Pinkerton wrote on Sun, 30 March 2014 10:37 |
On the way back from Montgomery, we stayed in a couple sub standard campgrounds. The alternative would have been to stay at a WalMart etc and just run the air conditioner fan to circulate the air and provide white noise. We aren't interested in trying to sleep with the generator running. Given the weather, we needed no heat.
So the question is, if we turned off our 12V fridge over night, how long can we expect a strong 12V house battery to run various 'things'. Does the amp hour rating on the battery mean it will run a total of X amps for one hour? For instance, will an 850AH battery, fully charged, run 850amps for 1 hour, 425A for 2 hours, 212A for 4 hours, etc?
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One of the best ways to determine that is to monitor voltage. A fully charged battery rests at 12.6 V. You should not let the battery go below 12.2 V or you will dramatically reduce it's life.
Bob de Kruyff
78 Eleganza
Chandler, AZ
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| Re: How long with my house battery run the air conditioner fan? [message #245844 is a reply to message #245781] |
Mon, 31 March 2014 00:54 |
roy1
Messages: 2126
Registered: July 2004
Location: Minden nevada
Karma: 6
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Senior Member |
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| Kerry Pinkerton wrote on Sun, 30 March 2014 13:21 |
I mainly want the air handler ONLY just for the noise. A box fan wouldn't be loud enough to mask the parking lot noise. The wife is a light sleeper. I don't want to run the AC from battery. Obviously that is not really feasible without some MAJOR batteries and recharging capacity.
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Wearing hearing aids has some advantages a quiet nights sleep in a noisy environment. Even a smoke alarm wouldn't wake me up.
Roy Keen
Minden,NV
76 X Glenbrook
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| Re: [GMCnet] How long with my house battery run the air conditioner fan? [message #245873 is a reply to message #245819] |
Mon, 31 March 2014 11:32 |
Dave Mumert
Messages: 272
Registered: February 2004
Location: Olds, AB, Canada
Karma: 0
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Hi Mike
There is some debate over the weight of the Onan, a friend removed his complete with the slides and mount. He said the complete
unit was 500 pounds.
I would think the Onan plus the existing batteries would be over 600 pounds. I would guess if you were to dump the pod (and all the
junk in it) and replace it with a couple of 250 watt panels you would have very little weight difference.
Some people don't like parallel battery strings without a charge controller for each battery. The Rolls battery string is about the
same weight as the Odyssey PC-1800's but would be a series string. The 1380 AH Rolls is $403 Canadian at the local dealer, I
couldn't find prices for the Odyssey.
There are pros and cons for each setup. The Odyssey system would let you start with a single battery and add capacity as you needed
it. The Rolls series string would be simpler to charge but you need to buy the entire capacity up front even if you don't need it
right away. Both are AGM so you would only need to vent to control heat.
At my latitude we have less solar power available so charging a battery bank that large would require more panels than I have room
for, or at the very least a tilting mount.
Have fun with this and keep us informed, a number of people have discussed this in the past but I don't know who, if anyone, has
implemented a system this large.
Dave Mumert
'76 Eleganza II
Alberta, CA
> -----Original Message-----
> Subject: Re: [GMCnet] How long with my house battery run the air conditioner fan?
>
> You quote 850 ah for 714 lb, of 2 volt batteries in parallel to make a 12 volt unit and compared that to the Onan. My question
is...how
> much does that beast (thge Onan) weigh? I'm thinking of going solar with 2 140 watt panels and 5 Odyssey PC-1800's that weigh 660
> and have an amp hour rating of 190/20 hours EACH.
>
> I'm thinking if I do this I will be fat city for EMF...and if push come to shove I have the 140 amp alternator for emergency
recharge.
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