12V Stamina?

Discussion in 'First Time & New Camper Owners' started by Brendan Michael Roche, May 18, 2019.

  1. Brendan Michael Roche

    Brendan Michael Roche New Member

    Messages:
    6
    Likes Received:
    1
    Joined:
    May 18, 2019
    we are brand new to the pop up world, and bought a brand new (cheap) 12V.

    We were soo excited to go camping that we went up early (last night) in Colorado (boondocking) and got snowed on a little. We thought we could limit the power (12V - lights etc) and run the furnace all night as we had extra Propane. The furnace gave out about 9:30 due to the power (12v) being near dead.

    Do we have to get a generator? I figured as the 12v would run the fan and the propane the heat that we would run out of gas long before battery, not the case.

    We cuddled together (w 10 month old) and were fine (just like tent camping) but we really like to figure out how to run furnace when needed for a multi night trip.

    Appreciate the responses from your cold (but happy) new pop up owners!

    Brendan
     
  2. gladecreekwy

    gladecreekwy Well-Known Member

    Messages:
    508
    Likes Received:
    482
    Joined:
    Sep 25, 2016
    When you say the furnace ran all night do you mean it cycled on and off or it ran continuously? We use sleeping bags and generally don’t run the furnace at all. Just fire it up in the morning to warm up. It gets pretty cold at night where we camp in the summer but the sleeping bags are fine for us. No water pump in our pup, just one light so we can go a week at least on our group 31 battery. Propane lasts a lot longer than battery.
     
  3. Brendan Michael Roche

    Brendan Michael Roche New Member

    Messages:
    6
    Likes Received:
    1
    Joined:
    May 18, 2019
    I figured we could set it to turn on for a few minutes (~15) an hour. It wasn’t running continuously but pretty frequently for a few hours before the battery drained.

    We typically would just use sleeping bags as well, but for the 10 month old we might have to get a sleeping bag and go that route and not rely on the furnace. Right now we have a sleep sack for him as we are still not giving him blankets, but almost out of that age.
     
  4. generok

    generok Well-Known Member

    Messages:
    2,376
    Likes Received:
    523
    Joined:
    Feb 7, 2013
    Location:
    Anchorage, AK
    Ok, in general, you should be able to get a couple of nights out of a battery if:

    It is in good condition
    It is fully charged
    It is is at LEAST a RV/Marine "deep cycle"
    You don't run a bunch of other stuff off of it (inverter especially)

    So, I have to ask a lot of questions. They are not accusations, just questions to better help:

    Did you charge your battery before going out with a battery charger you plug into a wall outlet at home?
    Is your battery an RV/Marine "deep cycle" battery, or a regular auto battery?
    What temperature do you expect to maintain in the PUP and where was it set the time above you described?
    How often was the fan running?
    Were you trying to run the fridge on 12V power too?

    On an average box store Group 24 RV/Marine battery (let's say about $85), you SHOULD be able to get two nights of setting the t-stat at about 60 if you only run it at night, and are VERY conservative with 12V power at all other times. This only applies if the battery is fully charged heading out.

    I base this on my experience with a single Group 24 battery. You can extend this easily by hooking up jumper cables to your PUP battery to your TV and letting the TV idle for about 20 min each morning. You likely don't need a genny... yet.

    Let us know a little more and we can help more too.
     
    kitphantom likes this.
  5. Brendan Michael Roche

    Brendan Michael Roche New Member

    Messages:
    6
    Likes Received:
    1
    Joined:
    May 18, 2019
    Not taking it as accusations, and we are new to this so no offense taken :)

    1. We did charge the battery prior to leaving
    2. Deep cycle battery: not positive but I believe it is
    3. Around 60 degrees
    4. We were running the fan probably too frequently (about 15 on 15 off maybe)
    5. I think that the fridge was on 12V as opposed to propane (which definitely helped w the depletion)

    Thank you all for your responses very helpful!

    Brendan
     
  6. kitphantom

    kitphantom Well-Known Member

    Messages:
    11,491
    Likes Received:
    705
    Joined:
    Dec 26, 2009
    Location:
    Albuquerque, NM
    The fridge on 12v will empty a battery very quickly
     
  7. Brendan Michael Roche

    Brendan Michael Roche New Member

    Messages:
    6
    Likes Received:
    1
    Joined:
    May 18, 2019
    Shoot, I bet that was the cause. Thanks for your help
     
    Blackripley likes this.
  8. generok

    generok Well-Known Member

    Messages:
    2,376
    Likes Received:
    523
    Joined:
    Feb 7, 2013
    Location:
    Anchorage, AK
    Yup. The fridge killed you. Run the fridge on propane. The 12V option on the fridge is meant for a "keep cool" while traveling IFF you have a 12V feed from the vehicle to the PUP (a whole other thread I avoided earlier). If you had the fridge on 12V mode, that's what did you in, not the furnace.

    Learning curve is steep, but it smooths out quickly.
     
    Sjm9911, kitphantom and gladecreekwy like this.
  9. Brendan Michael Roche

    Brendan Michael Roche New Member

    Messages:
    6
    Likes Received:
    1
    Joined:
    May 18, 2019
    Well thanks for your help! Rookie mistake.

    Cheers
     
  10. Dingit

    Dingit Well-Known Member

    Messages:
    716
    Likes Received:
    300
    Joined:
    Mar 8, 2017
    If you still find yourself running short on battery after switching to propane on the fridge, look into a small solar system. Ours isn't fixed so that we can move it to where ever the sun peeps through the trees.

    If you upgrade your thermostat (household ones work), you can program it and just generally get better performance from your heater. Once you can get that baby to stay in a sleeping bag, you can skip the nighttime furnace and the cuddling for warmth altogether. (So...in about 8 years, judging by mine :p .)
     
    Brendan Michael Roche likes this.
  11. bearman512

    bearman512 Well-Known Member

    Messages:
    1,192
    Likes Received:
    60
    Joined:
    Apr 17, 2010
    Location:
    Albuquerque NM
    "Shoot, I bet that was the cause. Thanks for your help"
    Yup rookie mistake, don't ask how I know this. [;)][LOL]
     
  12. WrkrBee

    WrkrBee Well-Known Member

    Messages:
    1,752
    Likes Received:
    636
    Joined:
    May 23, 2018
    Location:
    South Carolina
    IFF-???
    Another acronym I need to know for the "Acronym" page.
    Interstellar Free Fall
    Interstate Fast and Furious
    Instant Funky Feet
    Incognito From Felons
     
    Sjm9911 likes this.
  13. generok

    generok Well-Known Member

    Messages:
    2,376
    Likes Received:
    523
    Joined:
    Feb 7, 2013
    Location:
    Anchorage, AK
    Well, it's actually not an acronym, more of a mathematical shorthand... IFF is "if and only if"
     
    Eric Webber likes this.
  14. Anthony Hitchings

    Anthony Hitchings Active Member

    Messages:
    215
    Likes Received:
    74
    Joined:
    Mar 2, 2019
    Our Dometic frig draws around 10A on 12V mode. We have a Group 27 105 Amp-Hour battery. So if we ran just the firg - we would get 105/10=10 hours (less, actually). Frigs are terrible on 12V.
     
  15. davido

    davido Active Member

    Messages:
    862
    Likes Received:
    158
    Joined:
    Jul 17, 2014
    The furnace didn't deplete your battery, the 12v fridge did.

    My fridge consumes 180 watts. 180 watts at 115vac is 1.6 amps. But 180 watts at 12v is 15A. Your Group 24 deep cycle battery starts out with 85 amp hours. It is half discharged when you've consumed 42.5 amp-hours, and that's the lowest you SHOULD let it go, to prolong its useful lifespan. Battery-cut-out switches should kick in when you get below about 10.8v, which is about 20% capacity remaining. 20% of 85 AH is 17AH. So that means your electrical system will usually cut out to save the battery after you've consumed 68 amp-hours of capacity.

    68/15 = 4.53 hours. So with no other loads, your fridge could run you to cutoff point in four and a half hours.

    On the other hand, the furnace probably consumes about 2.5 amps while the blower is running. Lets say you wish to avoid dropping the battery below 50%. So you will stop at 42.5AH of draw-down. 42.5/2.5=17. You could run the blower full time for seventeen hours. In reality it probably runs about 1/2rd of the time, for half of the 24-hour day. So you're running it six hours total in a 24 hour period. At that rate you'll get 2.5 days use out of it if you have no other loads. If you add back in typical loads, you get two days out of a Group 24 battery if you run the furnace a lot.

    Only use the 12v setting on the fridge while you are plugged into your tow vehicle and the vehicle is running. Even then, only do so if your vehicle has a charge line running to the trailer hitch's electrical connector. The rest of the time (when you are not towing), you run it either on shore power (115vac) or propane (which will last you a long, long time).

    Don't worry about the fridge using up all your propane. If you only ran the fridge, it would last about three weeks on a 20 pound tank.

    Because my family likes to keep warm, and because we didn't want to be limited to either 2-nights of camping, or to running an generator, we installed a second battery. This gives us 4 to 5 nights between charges.
     
  16. joet

    joet Well-Known Member

    Messages:
    4,155
    Likes Received:
    721
    Joined:
    Mar 16, 2011
    Location:
    Elkins WV area
    Besides the fridge being a power hog. Incandescent lighting will be next. Switching to LED's will make a big difference
     
    Sjm9911 and BillyMc like this.
  17. BillyMc

    BillyMc Well-Known Member

    Messages:
    628
    Likes Received:
    255
    Joined:
    Mar 25, 2018
    Location:
    South Carolina
    Yep, and some are more efficient than others.
     
  18. jmkay1

    jmkay1 2004 Fleetwood/Coleman Utah

    Messages:
    4,323
    Likes Received:
    1,271
    Joined:
    Oct 10, 2013
    Location:
    Northern Virginia
    If you plan to boondock or camp without power a lot you may want to take an inventory of your power needs so you can determine if you need to upgrade your battery and buy a solar panel or generator. A group 24 deep cycle is ok to get started with, and for infrequent use, etc but a larger battery could provide more amp hours etc. The furnace also uses a lot of juice. So usually have to conserve power by using it only at night and at a lower temperature than you are used to or what some do only turn it on just before bed and first in the morning. I managed to make three nights in temps below 32 with one night very breezy on a group 24. Turned the furnace on just before bed and kept it at 50. Turned it off the second I was up and dressed. Lights are LED so less power consumed and used water pump sparringly. I've now upgraded to a group 27 battery, wanted a 29 but I wouldn't be able to lug it every trip. (I keep camper in storage and don't want it stolen). I also bought a cheap 100 watt solar panel but have yet to give it a try.
     
  19. roybraddy

    roybraddy Well-Known Member

    Messages:
    2,003
    Likes Received:
    640
    Joined:
    Mar 23, 2016
    Location:
    King George, Virginia
    It certainly takes a lot of planning and asking questions haha.. I too found out real quick like you - just can't show up and expect it all to work haha...

    I beefed up my batteries to make it through one day/night with all the things we want to have running and not to drop my batteries below 12.0VDC by 8Am the next morning. Then I fire up my 2KW Generator hooked up to the trailer and charge my batteries back up from their 50% charge state to their 90% charge state with a three hour run off the generator... This is during breakfast so this is when I get to my my grind and brew coffee for the day as well...

    When I get it back up to the 90% mark it is almost as good a full charge. Makes the next day/night run just fine for us... We only do 4-5 nights of this and head back for the home base. Then the first thing we do is a full 100% charge which takes around 12-14 hours for us... I got around 5-6 years out of the batteries by never letting them get below their 50% charge state...

    Roy Ken
    [​IMG]
     
    Brendan Michael Roche likes this.
  20. davido

    davido Active Member

    Messages:
    862
    Likes Received:
    158
    Joined:
    Jul 17, 2014
    This is a tactic that sailboat cruisers employ as well. It takes as much generator time to go from 50% to 80% as it takes to go from 80% to 90%, and as long as it takes to go from 50% to 90% is how long it will take to go from 90% to 100%. So sailors looking to conserve generator fuel on long passages will carry enough battery so that they can live in that 50-80% zone all the time, and only top off to 100% when back at shore power.
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.