Battery Dead?

KaomRuns
KaomRuns Member Posts: 16
in Battery/Electrical & Solar

trying to make heads and tails of my battery situation. Below are 3 Victron screenshots. While the solar is on I appear to be fine. When off my battery voltage I able. The trailer has been plugged in to 30amp for 3 days with the battery disconnect switch turned into the on position. Any insight is appreciated. Nothing was on inside the camper for these readings.

IMG_9654.jpeg IMG_9652.jpeg IMG_9651.jpeg

Battery - group 24 lead acid interstate

Victron - Mppt 75/15
wFCo- WF-8735-AD

Trailer - 2023 320 S boondock

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Comments

  • TourDeForth
    TourDeForth Member Posts: 132

    Has the battery gone below 10.8 volts? My battery behaved like you described. Something was causing a drain at night and then charged up with the solar panel during the day. So my battery cycled below minimum voltage many times, resulting in a battery that couldn’t hold a charge and had a high internal resistance. I put it on a battery tester which it failed.

    You can measure the internal resistance with a volt meter, it shouldn’t be higher than 4 to 7 mega ohms based on your battery type and CCA, you can get the internal resistance limit from the manufacturer. Or you can take the battery to an auto parts store that does free battery testing.

    2023 T@B 320s Boondock, 2013 Toyota Tacoma TRD 4x4 2016 Toyota Tundra 1794 4x4
    John, Northern California
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  • pthomas745
    pthomas745 Administrator, Moderator Posts: 4,575

    A lead acid battery will "always" read "higher than actual voltage" when being charged. The "14.21V" showing on the screen while plugged in is simply showing the voltage going in to the battery. Or, "higher than actual".

    When you try to take a reading with the battery in use, with no charging, even with just the battery switch on: you will get a reading "lower than actual".

    Your reading with the "Battery switch off and "no charging" is the proper way to monitor a lead acid battery: the battery is in a "rested" state, and even after a few minutes all the electrons in the battery settle down to give you a reasonably accurate battery voltage for a lead acid battery.

    The 11.27 volts "rested" would tend to show this battery did not take any of the charge you have tried to send it for a few days. If this battery is 3-4 years old, (which isn't too old) it may be close to failing. Generally, if the number of times a lead acid battery is allowed to drop below 12V happens too often, it can "sulfate" and be unable to hold a charge.

    So, your own driveway test shows something is not good on this battery, so taking it to a parts store or running through the test Tourdefort explains, would be a good idea. At the very least: it may be time for a battery upgrade.

    PS: edit: 3-4 years is "not bad" for a service life of a lead acid battery. A really well cared for battery that lasts 5-6 years is considered pretty good.

    2017 Outback
    Towed by 2014 Touareg TDi
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  • Grumpy_G
    Grumpy_G Member Posts: 743

    At the bottom the OP stated the battery is a group 24 Interstate battery. These are bottom barrel batteries and looking at the voltage after 3 days of charging tells me it likely has a failed cell. Very common, I have three failed Interstate batteries sitting in my shop waiting to be used as cores. One of them was bought new, put on a trickle charger for later use and was unusable by the time "later" came around.

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  • KaomRuns
    KaomRuns Member Posts: 16
    edited June 19
    https://tab-rv.vanillacommunity.com/discussion/comment/221986#Comment_221986

    thank you. Confirms what I had thought which is the battery is at the least compromised. I am going to move to a LifePo battery at this point and be done with Lead Acid. If I understand correctly I can swap out without needing to make any changes. Controller will only charge up to 80% but the solar and battery charger in storage will top off. Am I limited to a certain amp size though? I’ld like to get a 200 or 314 ah Lifepoint to replace the current one but not sure if there is a limit. My assumption is there is not as long as the physical size fits and voltage is the same?

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  • KaomRuns
    KaomRuns Member Posts: 16

    I should say thank you all for the feedback. I really appreciate the responses and direction on it.

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  • KaomRuns
    KaomRuns Member Posts: 16
    https://tab-rv.vanillacommunity.com/discussion/comment/221987#Comment_221987

    This is what I suspect happened to mine. It has been on a trickle charge while in storage. It's 2 years old and my 2nd Interstate battery to die on me. Perhaps I am running them too low when boon docking? Either way, I am planning to move on from lead acid at this go 'round

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