Forum Discussion

maria_bettina's avatar
maria_bettina
Explorer
Jul 22, 2022

Renogy 20A MPPT Controller- electrical/amp question

I've been watching the display on the solar controller for a few days now. Our TC is parked at home, not on shore power but is sitting outside with the 3@100 watt solar panels charging the 200Ah deep cycle battery. The only electrical appliance that should be drawing current is the Renogy unit itself. The elec fridge is unplugged, nothing else plugged in, no electronic devices being charged.

At about 1:00 p.m. today I noticed that the display showed that about 0.5A are being drawn...but for what?

The Renogy unit itself uses <100mA (so 0.1A?) as I recall (for lights/display), so I am worried there is a short somewhere.

What can be causing that high usage and is it something to worry about? Does a battery need that much juice during the float stage?

PS It's in the upper 90's here, so maybe that's an issue?
Truck Campers
  • Lwiddis's avatar
    Lwiddis
    Explorer II
    Jul 23, 2022
    “This battery is less than 2 years old.”

    While a wet battery does self discharge, if your two year old battery has been properly maintained, it is more than likely not the problem. Even pop ups, that you can zip up almost as tight as a hard sided trailer, have co2 and smoke detectors.
  • StirCrazy's avatar
    StirCrazy
    Moderator
    Jul 25, 2022
    maria_bettina wrote:
    StirCrazy wrote:
    your propane detector and any circuit boards in the camper will be drawing power. 1/2 a amp isnt much, but it is why a lot of people used to kill there batteries over the winter when the manufactures started putting parisidic load items into the rv's

    Steve


    Lwiddis wrote:
    Half an amp isn’t high use IMO. Smoke detector, co2 detector, entertainment center, TV booster etc.



    Only thing drawing power is the Renogy unit. No circuit boards, no detectors. We have a pop-up TC bare bones.


    so propane detector? I though all the stuff needed one of them now.
  • maria_bettina's avatar
    maria_bettina
    Explorer
    Jul 31, 2022
    StirCrazy wrote:
    maria_bettina wrote:
    StirCrazy wrote:
    your propane detector and any circuit boards in the camper will be drawing power. 1/2 a amp isnt much, but it is why a lot of people used to kill there batteries over the winter when the manufactures started putting parisidic load items into the rv's

    Steve


    Lwiddis wrote:
    Half an amp isn’t high use IMO. Smoke detector, co2 detector, entertainment center, TV booster etc.



    Only thing drawing power is the Renogy unit. No circuit boards, no detectors. We have a pop-up TC bare bones.


    so propane detector? I though all the stuff needed one of them now.


    No LP detector. There was a battery-operated one but we do not have LP in the camper so it's disconnected.... But it was double-A battery operated anyway, so...
  • time2roll's avatar
    time2roll
    Nomad
    Jul 31, 2022
    At these low draws a hand held voltmeter should have a 2amp setting to measure amps. Stop the solar and remove a battery cable and put the meter in series to measure the current being drawn out of the battery. Possibly it will read zero. Or maybe 100 mA. Post the results.
  • maria_bettina's avatar
    maria_bettina
    Explorer
    Aug 10, 2022
    time2roll wrote:
    At these low draws a hand held voltmeter should have a 2amp setting to measure amps. Stop the solar and remove a battery cable and put the meter in series to measure the current being drawn out of the battery. Possibly it will read zero. Or maybe 100 mA. Post the results.


    Awesome reply! Very helpful. We are going to remove the battery and check that. We will also do what you suggested prior to removing the battery :B I will report back, but my hubby's knee is acting up so it might be a few days+++ before he can kneel without pain in the TC, and get that battery out of the camper. Getting old sucks. :D
  • 3_tons's avatar
    3_tons
    Explorer III
    Aug 10, 2022
    Not necessarily saying your reading is wrong, but when dealing with smallish current amounts (or voltage differentials), digital meters are NOT the repositories of infinitesimal accuracy that their digital readouts might imply…It’s been my ’more often than not’ experience that, readings below whole numbers should not be viewed with absolute credibility (often rounded)…It’s at these smaller measurement levels why some dedicated VOM meters cost hundreds ($$) while less costly generics are fine for general use…

    3 tons
  • maria_bettina's avatar
    maria_bettina
    Explorer
    Aug 10, 2022
    3 tons wrote:
    Not necessarily saying your reading is wrong, but when dealing with smallish current amounts (or voltage differentials), digital meters are NOT the repositories of infinitesimal accuracy that their digital readouts might imply…It’s been my ’more often than not’ experience that, readings below whole numbers should not be viewed with absolute credibility (often rounded)…It’s at these smaller measurement levels why some dedicated VOM meters cost hundreds ($$) while less costly generics are fine for general use…

    3 tons


    Yea, that's was where our thinking was headed. That the battery is likely fine, but the controller readings aren't as accurate as I would like or thought they'd be.

    We'll see! Still have to check things with a volt meter, but the "good" news is my hubby's knee is just a product of old age and nothing can fix it. So we wait til the inflammation subsides, then get back to figuring out this battery stuff and how accurate the Renogy controller display is.

    Thanks for the reply!
  • StirCrazy's avatar
    StirCrazy
    Moderator
    Aug 11, 2022
    maria_bettina wrote:
    3 tons wrote:
    Not necessarily saying your reading is wrong, but when dealing with smallish current amounts (or voltage differentials), digital meters are NOT the repositories of infinitesimal accuracy that their digital readouts might imply…It’s been my ’more often than not’ experience that, readings below whole numbers should not be viewed with absolute credibility (often rounded)…It’s at these smaller measurement levels why some dedicated VOM meters cost hundreds ($$) while less costly generics are fine for general use…

    3 tons


    Yea, that's was where our thinking was headed. That the battery is likely fine, but the controller readings aren't as accurate as I would like or thought they'd be.

    We'll see! Still have to check things with a volt meter, but the "good" news is my hubby's knee is just a product of old age and nothing can fix it. So we wait til the inflammation subsides, then get back to figuring out this battery stuff and how accurate the Renogy controller display is.

    Thanks for the reply!


    I'll check the reading on my renogy controler vs, my inline shunt. might take a few days though as I am working right now.

    Steve
  • pianotuna's avatar
    pianotuna
    Nomad III
    Aug 11, 2022
    Maria,

    Assuming lead acid "wet" batteries, how long since they were equalized?

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