Space heater when boondocking question

Curious if we can run a 400watt space heater for 1/2 hour on our batteries and then expect the solar to recharge?
Am I asking to much of the batteries, or the solar system?

(Tab 400)

Comments

  • pthomas745pthomas745 Moderator Posts: 3,961
    edited February 2020
    First question: How big is your battery?
    And:  How big is your inverter?

    400 watts divided by 12 volts equals 33 amp hours.
    For a half hour, it would use 15 amp hours of your battery capacity.
    IF your inverter can handle that many watts.
    AND..the inverter must be wired directly to the battery.
    2017 Outback
    Towed by 2014 Touareg TDi
  • treefrogtreefrog Member Posts: 95
    @pthomas745 Thanks for answering I am beyond clueless when it comes to electrical matters. We have a new 400 with dual batteries and a 1200w inverter. Not sure about battery size. I can pull the cover to check if I need to.

  • webers3webers3 Member Posts: 415
    Curious, why would you want to use the space heater while boondocking instead of propane?
    2017 T@B 320S   2019 Jeep Cherokee - Southern Connecticut
  • pthomas745pthomas745 Moderator Posts: 3,961
    I know that seeing the batteries is hard work...so it can wait!  But it is something good to know.
    Your inverter is "hard wired" to your battery, and at 1200 watts, it "should" handle the 400 watt load of the heater.
    I'm going with your dual batteries being "about" 200 amp hours.  You can usually use 50 percent of those amp hours to extend your battery life,  which gives you 100 amp hours to play with.
    So, those 15 amp hours for that little space heater will be 15 percent of your "usable" battery capacity. 
    Everything is a trade off when using battery power, and only you can decide if the 15 amps is worth it.  Your solar panels (you also should know how many watts of solar you have) will take a little extra time (an extra hour?) to recharge your batteries.  Also, keep in mind the rest of the trailer's battery use:  what fridge do you have?  Are you going to run the fan or watch TV?  The trailer has a number of "parasitic" drains that use up about 4 amps a day all by themselves.
    All those things have to be added up when you try to figure out how long it will take the solar panels to recharge.  As long as the sun is out, of course!
    It can be done, it just has to be thought out a bit.

    2017 Outback
    Towed by 2014 Touareg TDi
  • treefrogtreefrog Member Posts: 95
    edited February 2020
    @webers3 We are headed out to 30-40 degree nights and with the Alde off it gets down to 45 degrees inside. That is perfect for sleeping for me.  I don't sleep well with the Alde on, I can hear it and the heat makes me uncomfortable. It takes a long time for the Alde to heat the trailer from a cold start (I have not used the Alde "sleep mode" yet, I will try on this trip). We enjoy using the Alde and will use it this trip, just wanted to get a quick burst of heat.

    @pthomas745 Thanks for your help. I just wanted to know if I was asking to much from the system. I will start with a 15 minute cycle on the heater and see how the batteries recover. We will be in the desert so plenty of sun.
  • ChanWChanW Member Posts: 3,161
    edited February 2020
    @treefrog sounds like fun. 

    Desert ... sun (hope!)... Sounds like you'll have plenty to recharge with! Especially from early in the day.

    We've been known to roll over in the morning and press the Alde 'On' switch, and stay under the covers until things warm up a bit. 

    Of course that's a benefit of the smaller Tab, it's quicker to warm up!
    Chan  -  near Buffalo NY
    2014 S Maxx
    2011 Tacoma 4cyl ... edit: 2022 Tacoma 6cyl - oh yeah! 

     A_Little_T@b'll_Do_Ya
  • jkjennjkjenn Member Posts: 6,394
    treefrog said:
    @webers3 We are headed out to 30-40 degree nights and with the Alde off it gets down to 45 degrees inside. That is perfect for sleeping for me.  I don't sleep well with the Alde on, I can hear it and the heat makes me uncomfortable. It takes a long time for the Alde to heat the trailer from a cold start (I have not used the Alde "sleep mode" yet, I will try on this trip). We enjoy using the Alde and will use it this trip, just wanted to get a quick burst of heat.

    @pthomas745 Thanks for your help. I just wanted to know if I was asking to much from the system. I will start with a 15 minute cycle on the heater and see how the batteries recover. We will be in the desert so plenty of sun.
    I camped in sold weather after driving all day. I found d folding the bed down flat soed thi gs up, significantly.

    2021 T@b 320 Boondock "Mattie Ross" | 2021 T@b Nights: 239 | Total nights in a T@b 455 | 2022 Jeep Grand Cherokee L Overland | T@b owner since 2014

  • Tundra57Tundra57 Member Posts: 640
    I use a small propane heater. It has the small screw in propane tanks. I sit it on the dinette table or on the kitchen work surface long enough to boost up the heating while the Alde is ramping up. Then I shut it off. I leave the roof vent open with fan on min and a window hardly cracked. Do not leave unattended or overnight!!!
    This is true of any heater that is not part of the camper.
    Electric heat can start a fire as easily as propane heaters. My dog and I have camped in January in PA it was around 28 degrees and we were toasty. At night I set the temp down to 65. In my 2019 Tab the Alde is under my head and I never heard it at all. Is it the pump whine you hear or the burner? If set correctly the pump should be silent.
    If you are boondocking away from everyone and need to charge the batteries beyond solar why not get a 2000 W quiet generator and run during the day to recharge?
    While driving your TV can help with the recharge.
    But it seems a poor use of your precious energy to use it for electric heat when propane is available.
    Also if you are hitting sustained sub 32 temps watch your cold water tank or piping doesn't freeze. It can push off a pipe or burst a pipe or the tank probably hidden behind a wall.
    Also if you don't use antifreeze the toilet or drain can freeze even the black and grey tanks/dump valves.
    Just my thoughts.

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