batesrt
ohio
New Member
Joined: 01/21/2009
View Profile
 Offline
|
Hi I'm pretty new to RV'ing so sorry if this has been asked a million times.....
We bought a used 20' travel trailer, and are mainly boondocking it at races. It's always insanely hot in the summers, so the main thing I'd like to run is a little 1 amp box fan (since AC is not an option). I am just using a little power inverter to plug the box fan in to.
I bought a brand new deep cycle marine/rv battery (Everstart MAXX from Walmart), charged it up several days (using the supplied RV electrical cord from my house). Tried out the box fan and one little light bulb to see how long they lasted...... 8 hours and the battery is totally dead! The fan is only listed as 1 amp, so shouldn't that last for several days at a time?
So went back to Walmart and swapped the battery for the largest one they had (MAXX 125 amp hr deep cycle). Charged it all up, and again with the fan and one little light on it lasted less than 16hrs !
If I have a battery that is 125 amp hours, and I'm running say just a 1 amp fan......shouldn't that fan last in theory nearly 125hrs ???
Any help on this subject would be great thanks!
|
donn0128
Pronounced Ore-gun
Senior Member
Joined: 04/21/2005
View Profile
Offline
|
One battery will not last very long. If you are going to be boon docking you really need at least two batteries. Preferably golf cart 6 VDC deep cycles. What you may be getting from Wallyworld is a combination battery and they will not work for long. In reality a single battery running a fan for 16 hours is pretty good. once you add up all the parasitic draw plus the fan if you get 8 hours on a single battery,you will be lucky.
Donn,Lorri,Max (The Rescued Lab)
Resident Know It All 
|
Chakara
New Mexico
Full Member
Joined: 07/17/2011
View Profile
Offline
|
I hope my math is right here, but 12V 1amp is much less than 1amp @ 120V.
Watts=Volts * Amps
So:
120V@1A = 120W
120W / 12V = 10A
Not counting loss from the inverter, your 1A fan pulls 10A from the batteries.
Is that right guys?
-Chak
- 2005 Dodge 2500 5.9 standard
- 2010 Starcraft Autumn Ridge 246RKS 28'
Link to my Blog with Techie stuff like LED's and Boondocking
|
Son of Norway
Denver, Colorado
Senior Member
Joined: 10/12/2011
View Profile
Good Sam RV Club Member
Offline
|
Chakara stated your problem exactly. Try using a couple of DC fans.
Miles
Miles and Darcey
1989 Holiday Rambler Crown Imperial
Denver, CO
|
batesrt
ohio
New Member
Joined: 01/21/2009
View Profile
Offline
|
Son of Norway wrote:Chakara stated your problem exactly. Try using a couple of DC fans.
Miles
So basically the power inverter is the issue causing it to drain way more than I thought?
Maybe a dumb question but do the DC fans just connect directly wired to the battery?
|
|
|
batesrt
ohio
New Member
Joined: 01/21/2009
View Profile
Offline
|
.....also any idea how many amps my little roof vent ceiling fan would use?
|
Chakara
New Mexico
Full Member
Joined: 07/17/2011
View Profile
Offline
|
Your fan probably draws 1-4 amps. I found a chart At this RV Solar site that you could use for rough guessing on the draw of stuff.
Many RV's have cigarette lighter type outlets that you could use to run a DC fan. That should be MUCH nicer on your battery. Otherwise you may need to tap into the electrical system to install one. They are very handy for things like this as well as charging gadgets like cell phones.
Hope this helps!
-Chak
|
Huntindog
phoenix arizona USA
Senior Member
Joined: 04/08/2002
View Profile
|
Fans pull a lot of juice. For example, most find that the heater fan is by far the biggest draw on the battery. Figure one night of heat per battery for most people.
The inverter is not the big problem. But you are looking at a 1 amp rated fan that is 110 volts. Convert that draw to 12 volts and it is no longer 1 amp.
A 12 volt fan that moves the same amount of air will not be any more efficient other that the tiny amount of power lost in the inverter.
Figure around 10% on average for that.
For what you are trying to do, a small cheap generator will probably work better. You can get 900-1000 watt generators for less tha 100.00 on sale. That will run just about any fan, with power to spare.
Huntindog
2010 Palomino Sabre 30BHDS
TWO bathrooms...No waiting!
MICHELIN XPS RIBS LRE
2011 Silverado Big Dually 3500 4x4 CC D/A
EQUALIZER Hitch
100% BOONDOCKING
Check out Rusty and her pups at www.bluecollarbrittanys.com
|
Chakara
New Mexico
Full Member
Joined: 07/17/2011
View Profile
Offline
|
Oh yeah, I was just thinking about this and remembered that I installed a MaxxAir TurboMax fan. On low speed it pulls 1.4A and moves a LOT of air. High speed is 4A and I bet changes the air out in the trailer in a few minutes. I love it and it was easy to install....
Check them out here.
Plus you get fresh air when its raining - and stay nice a dry.
(I have no affiliation, just a love of the product - there are other brands that are likely just a good)
-Chak
|
skipnchar
Topeka or somewhere else
Senior Member
Joined: 12/17/2003
View Profile
|
Tell you ANOTHER little fact about the Everstart....it will die for good after very few of those deep discharges. Never found one that would last over a year when used in the trailer. Marine/RV batteries are basically starting batteries (boats need starting batteries) and they don't stand up well to deep discharges.
Good luck / Skip
2011 F-150 HD Ecoboost 3.5 V6. 2550 payload, 17,100 GCVWR -
2004 F-150 HD (Traded after 80,000 towing miles)
2007 Rockwood 8314SS 34' travel trailer
US Govt survey shows three out of four people make up 75% of the total population
|
|
|
