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  1. #1
    Fireside Member JohnJCES's Avatar
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    Idle 12 volt current draw

    Good day!

    I seem to be using these forums quite a bit with my new 2020 Reflection 230RL and I thank-you for any info and answers.

    I Searched The Forums (STFed) and read quite a bit about battery life, battery draw and the like but I would like to find out, somewhat accurately, what the 12 volt DC idle current draw is. Does anyone have a fairly accurate idea? I have tried to find out even from some of the equipment spec sheets. Get info on 120 VAC easily but can't seem to easily find the 12 volt current draw.

    When the fridge is turned off, DC power switch still on, lights off, nothing running, how many amps does this thing consume?

    I know there is draw from all the circuit boards even when 'Off', I.E. landing gear/leveling controller, slide controller, refrigerator board, water heater board, (maybe.. not certain here), Stereo when Off, and furnace when off. I think the thermostats draw 12 volts all the time as well. I have a VOM and it will go to 10 amps, and I may resort to that but maybe, someone has already done this. Hopefully it is only a few amps... but I have a feeling it may be well over 5 amperes.

    Anyway, I would sure like to figure it out!

    Thanks again!

    John

  2. #2
    Site Sponsor
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    Figuring will lead to errors and omissions. Minimum draw is not a common spec for equipment. Maximum draw is usually the concern.

    Getting a DC amp meter on the main battery lead will tell you far more, and more accurately.
    Rick

    2019 Reflection 150 273MK
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  3. #3
    Fireside Member JohnJCES's Avatar
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    Just for some initial testing, I did a "non-intrusive" test with a fairly good clamp on AC/DC Ammeter in DC mode. To judge accuracy, to some degree, some basic research showed that the LED lights draw about 5 watts each. At 12 volts, that's almost half an amp.. so a good "known" reference one or more LED lights on/off.

    With everything off and whatever is in an idle on state, (stereo, landing gear electronics, etc.), the trailer only drew about 1.1 amps! Unbelievable! I turned on a led light and it went up almost half an amp. And each LED light I turned on, of the 5 watt variety, added another half ampere. Turned the refrigerator on in gas mode. Amp and a half. Water pump with no water, (just running), 2 amps. Tank heater pads, 5.5 amps.

    This seems low to me so just wondering what others might think.

    Next, my VOM wired in between the battery and positive cable, since I believe the draw can be kept under 10 amps so as to not ruin my meter.

    John

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    Site Sponsor sande005's Avatar
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    Back a couple of years ago, when I owned SOB (some other brand), several people on that forum published the results from testing all the small stuff "idling", both with the main power off, and then on. Your results are in the range. An average grp 27 battery has about 66 amp hrs. Therefore, at 1.1 amp, the battery will be dead after about 2 1/2 days....
    It would be interesting to see what you get with the main power off (which as we all know doesn't actually turn everything off).
    2017 Imagine 2670MK
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  5. #5
    Setting Up Camp
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    Not sure what you mean by idling. I know that if I have everything turned off. The only things that should be draining power is refrigerator and O2 sensor, I think. The water heater my also have some draw if it’s on gas. I took my amp meter and measured from battery and it was pulling approximately 1.4 amps. On the grp 27 battery that really gives you 40 - 50 hours if you figure 50 percent of total battery capacity. Most grp 27 batteries range for 80 to 100 amp hours. Draining lead acid batteries past 50 percent will damage the battery. I destroyed my first battery after 3 times of totally draining it.
    2019 Reflections 315RLTS
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  6. #6
    Big Traveler boyscout's Avatar
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    Quote Originally Posted by JohnJCES View Post
    Just for some initial testing, I did a "non-intrusive" test with a fairly good clamp on AC/DC Ammeter in DC mode. To judge accuracy, to some degree, some basic research showed that the LED lights draw about 5 watts each. At 12 volts, that's almost half an amp.. so a good "known" reference one or more LED lights on/off. With everything off and whatever is in an idle on state, (stereo, landing gear electronics, etc.), the trailer only drew about 1.1 amps! Unbelievable! I turned on a led light and it went up almost half an amp. And each LED light I turned on, of the 5 watt variety, added another half ampere. Turned the refrigerator on in gas mode. Amp and a half. Water pump with no water, (just running), 2 amps. Tank heater pads, 5.5 amps. This seems low to me so just wondering what others might think. Next, my VOM wired in between the battery and positive cable, since I believe the draw can be kept under 10 amps so as to not ruin my meter. John
    I just went out to the 310GK sitting in my driveway. For complete disclosure, the junk factory radio is unplugged, so not part of the equation.

    With everything turned off but the main battery switch NOT turned off a good clamp meter reads 0.6 amps current draw. With the main battery switch turned off the current drops to 0.2 amps.

    While these values are well below yours (hard to believe that the radio draws so much) it doesn't make me as happy as it seems to make you. As @sande005 has pointed out, these loads are enough to draw the battery dead flat - well below its life-preserving ideal discharge level - in weeks. (I've experienced it on a careless dealer's lot.) To avoid it the battery should be completely disconnected.

    If your curiosity about this is because you're planning some kind of minimalist boondocking exercise, now you know what you can get away with. If like most of us you're thinking about what happens when the trailer sits for a while without external power, take your battery-disconnecting tools with you.
    Mark - 2018 Solitude 310GK - 2017 F-350 diesel SRW short box - Pullrite Superglide hitch

  7. #7
    Seasoned Camper Coheeba's Avatar
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    100w solar panel will take care of that.
    2019 GMC 2500 HD Denali
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  8. #8
    Fireside Member JohnJCES's Avatar
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    Thanks everyone for the replies! I seem to be on the ballpark on this stuff and my reasoning for knowing this is in fact for dry camping and being away from the trailer while it is away from all power. I was figuring, somehow, that this trailer might need on the order of 5+ amps of current while it was just sitting with the refrigerator running on propane. My second reason was to gain a baseline for a solar system to keep everything charged up plus an inverter.

    You all have been a big help!

    Thanks!

    John

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