Forum Discussion

Twistedlarch's avatar
Twistedlarch
Explorer
Apr 12, 2020

Amp hours

I'm trying to determine whether my current solar system is adequate or if I need to add more panels/batteries.

Currently I have 2 6 volt lead acid batteries.
I have 300 watts of panels
40 amp controller

I'm curious as to how many Amp hours my trailer uses.

Small 3 way fridge running on LP
CM detector
Stereo on standby mode
Water pump

I usually try to use battery powered lights at night.

The kids also watch a movie to unwind at night, the TV and DVD player run on a separate small battery hooked to an inverter. Small battery will be charged during the day from the panels.

We keep water use at a minimum.

I also have two dual USB charging ports.

Heat is set at 60. Night time outside temps can dip down into the high 30's in Spring and late Summer where we usually camp

Our usual camping area is at 4,500-5,000+ altitude with pretty intense sun in the afternoon.


Thanks
Brian
  • CA_Traveler's avatar
    CA_Traveler
    Explorer III
    Apr 12, 2020
    Furnace is your main draw. You can use a DVM to measure voltage (battery has to be completely at rest) hence look up SOC and then Ah used. There are inexpensive volt/amp measuring devices on up to better battery monitors.

    I use to just check voltage and based on prior experience with the rig I was an adequate "battery monitor".
  • Bigbird65's avatar
    Bigbird65
    Explorer
    Apr 12, 2020
    My suggestion would be to buy a digital DC current meter. Fully charge the batteries, clamp the meter over the positive lead and turn all the DC items you mentioned. Amazon has several to select from. Good investment.
  • jdc1's avatar
    jdc1
    Explorer II
    Apr 12, 2020
    The only killer usage is the heater motor. Use a "Mr Buddy" heater and you're fine. Change out all the light bulbs to LED's too (Amazon...least expensive)
  • Camper8251's avatar
    Camper8251
    Explorer
    Apr 12, 2020
    Nobody will be able to answer this for you. Way to many variables.
    Need a meter or something else..

    Kind of like saying what is may cars MPG without telling anyone want type of car what size motor etc etc
  • Lwiddis's avatar
    Lwiddis
    Explorer II
    Apr 12, 2020
    All this solar/battery math and surveying should have been done prior to you mounting any panels as you posted on March 27.
  • Lwiddis's avatar
    Lwiddis
    Explorer II
    Apr 12, 2020
    Separate batteries for lights and separate batteries for kids to watch TV. Trying to limit water pump use. What a PITA! Two six volt batteries doesn’t tell us their AH rating. 300 watts of solar can feed batteries with 300 AHs under “good” conditions. Do an energy survey. Determine your AH needs and multiply by 1.5. Buy batteries with double that storage capacity. Then you can determine how many solar watts are necessary and if your present controller is up to the task. Make sure your wiring is adequate to keep losses minimal.

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