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Battery charging from shore power

scaupscaup Member Posts: 82
in Battery/Electrical & Solar
T@B We have a 2015 T@B 320. We recently upgraded to 2 6v batteries installed by our local RV dealership, the same place we bought the T@B. The first time out the battery read 12.7v on the SeeLevel Indicator. After a few days of dry camping, no sun, it read 12.4v. Seemed OK.

A few weeks later we went dry camping again. We had plugged to T@B into shore power at home, wanting to get the batteries up to max capacity. While still plugged into shore power, the indicator read 13.6v. We unplugged shore power but did not read the indicator before we left. When we got to the site we checked and the reading was 11.7v. Seems like it didn't charge at all from shore power. We know the batteries are capable of being charged because we connected the Zamp solar panels and the reading got as high as 12.5v.
The Zamp was connected to the battery thru the factory provided port.

Reading some other threads we see there is a component in the T@B that takes the 120v ac and converts it to 12v dc for both charging the battery and providing 12v dc for the equipment in the T@B that runs off of dc power.

Questions- and please answer like I know nothing (which I probably don't)

Where is this component located?

Because the 12v dc equipment in the T@B worked, such as the lights and the radio/dvd player, can only the charging portion of the component go bad?

Is there a way to check the component to see if it has charging output?

If its not the component, what else could it be?

Thanks

Gene
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Comments

  • MarcelineMarceline Member Posts: 1,598
    Just to rule it out - do you have a battery switch on your T@B and if so was it turned in or off?
    San Francisco Bay Area
    2013 CS-S us@gi
    2015 Toyota Tacoma PreRunner Double Cab
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  • AnOldURAnOldUR Member Posts: 1,387
    Voltage readings are only accurate when the battery is in a rested state. In other words no charging or drawing power from the battery for a while before and during testing. The obvious question is, was your battery switch on while plugged into shore power?

    I'm not sure if your 2015 has this converter?

    Stockton, New Jersey
    2020 nuCamp T@B 320S * Jeep Wrangler

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  • scaupscaup Member Posts: 82
    Good question. Yes I do have a battery switch and I believe it was turned off ?????? but I'm not sure. I've always been unsure about switch position when charging or traveling.

    Thanks
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  • ScottGScottG Administrator Posts: 5,549
    edited July 2023
    scaup said:
    ...
    Reading some other threads we see there is a component in the T@B that takes the 120v ac and converts it to 12v dc for both charging the battery and providing 12v dc for the equipment in the T@B that runs off of dc power.
    ...
    Hi @scaup. The component you refer to is--appropriately--called the converter. Your assessment of its function is correct.
    Where is this component located?
    It's an integral part of the WFCO power center (where all the circuit breakers and fuses are located).
    Because the 12v dc equipment in the T@B worked, such as the lights and the radio/dvd player, can only the charging portion of the component go bad?

    Is there a way to check the component to see if it has charging output?

    If its not the component, what else could it be?
    I suppose it's possible for only the battery charging component to go bad, but I don't think I have ever heard of this actually happening.

    You can check the charging output by measuring the voltage at the battery terminals while you are connected to shore power. As with your internal measurements, you should be seeing at least 13.6V at the battery.

    If the battery is NOT showing charging voltage, there are three fuses to check. One will be a 30A fuse in small holder on the positive wire, near where the wire connects to the battery's positive terminal. The other two are in the power center's 12V fuse block: one is 30A fuse that should be in the next-to-lowest slot, the other is a 40A fuse just below it in the lowest spot. If any of these three fuses are blown, the battery is effectively disconnected from the trailer and will not charge from the converter.

    Lastly--just in the interest of covering all the bases--make sure your battery disconnect switch (if you have one--they were not standard equipment in 2015 but many owner's installed their own) is ON.

    Start with this and report back what you find! 
    2015 T@B S

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  • HoriganHorigan Member Posts: 673
    Battery switch needs to be on for shore power charging from the converter.
    Rich
    2019 T@b 400
    2013 Toyota Highlander 3.5L V6
    Bellingham WA
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  • scaupscaup Member Posts: 82
    AnOldUR- what I have looks exactly like your picture, including the color of the fuses.
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  • scaupscaup Member Posts: 82
    ScottG- I'm just glad my 2015 had the WFCO converter installed.

    I'll plug in, turn on and report back.

    Thanks all!
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  • Grumpy_GGrumpy_G Member Posts: 537
    The battery switch needs to be on for traveling as well for the emergency braking to work. Generally leave it on unless the trailer is stored. 

    Simple converter test: Read battery voltage with shore power disconnected and some lights or the radio on. Plug in shore power, voltage should increase.
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  • pthomas745pthomas745 Moderator Posts: 3,956
    Battery monitoring is an art.  When you were discussing the battery voltages you were reading, you mentioned the SeeLevel.  The problem with the SeeLevel is it cannot be a useful battery monitor if the battery is being charged or if the battery is being discharged.  In other words: if the battery switch is "on"...the SeeLevel is always showing you a "false capacity" reading.  I chased the SeeLevel and "my battery is always dead" problems for a year before I figured this out.
    You need a separate battery monitor for voltage that can be used with the battery switch off.  A multimeter is a perfect "starter" device that can deliver "rested" battery readings with the battery switch off, and no charging coming in.  Until you get stable battery readings, you will always be second guessing yourself.  A meter is easy to use.  You can even use your SAE port where you plug your panels in to take battery readings. Like this:

    Once you get your "rested" reading, then compare that voltage to a "State Of Charge" chart for Lead Acid/AGM batteries.


    2017 Outback
    Towed by 2014 Touareg TDi
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  • scaupscaup Member Posts: 82
    ptthomas745- Your multi meter shows a reading of 13.07v while your chart shows the battery is fully charged at 12.7v.  When I was plugged into shore power the SeeLevel was showing a reading of 13.6v. In my readings on-line there are readings into the 14s.

    What does a higher reading indicate?

    Thanks

    Great idea about plugging into the solar panel input connector.

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  • AnOldURAnOldUR Member Posts: 1,387
    edited July 2023
    scaup said:
    What does a higher reading indicate?
    Since @pthomas745 was referring to a rested battery, my guess is that he has lithium battery(s). =)
    Stockton, New Jersey
    2020 nuCamp T@B 320S * Jeep Wrangler

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  • pthomas745pthomas745 Moderator Posts: 3,956
    @scaup Sorry, I should have explained that better.  That is a battery being charged, or that had just come off the charger and was still settling down to the "rested" state.
    When your SeeLevel showed you a battery voltage of 13.6, that was the charging voltage. 
    2017 Outback
    Towed by 2014 Touareg TDi
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  • scaupscaup Member Posts: 82
    So the only way to really know the state of the battery is to disconnect the battery from everything (turn the selector switch to off) and check the battery with a multi meter.

    How long does it take for a battery to "settle down" before an accurate reading can be obtained?
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  • MickerlyMickerly Member Posts: 428
    The battery should be connected for towing as stated above. Your 7-pin plug should have a charge wire too. The battery will charge whole towing. Yes, 13.6v means the WFCO unit is working.
    2018 320CS-S
    "Just Enough"
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  • pthomas745pthomas745 Moderator Posts: 3,956
    @scaup if you are in a battery laboratory and you are doing "science", they say it takes many hours for a battery to be "rested."  But, they are going out several decimal places.  Most of the time with my lead acid battery, it has "rested" down to the first decimal within just a couple of minutes.  You can test this for yourself and see how it works.
    2017 Outback
    Towed by 2014 Touareg TDi
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  • ColoradoJonColoradoJon Member Posts: 415
    When I upgraded to two 6V batteries I also had trouble getting a full charge from the onboard WFCO converter.  The absorption voltage (13.6V) is just too low to push the amps into the battery after 80% charge.  I now charge using a good quality external smart charger.  At the camp site I use my Zamp portable which can push 14.7 volts during the absorption phase.  If there is sun, that is :)
    Jon & Angela | Florissant Colorado | 2017 Outback S
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  • scaupscaup Member Posts: 82
    After charging overnight the reading is 13.34v using a multi meter.

    Based on the chart above, the battery is charged 100% when the reading is 12.7v. What does a reading of 13.34v mean?

    Thanks
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  • pthomas745pthomas745 Moderator Posts: 3,956
    Still charging?  Solar or shore power plugged in?  If you noodle around the web, you can find "AGM" battery state of charge charts that would show "13V" as fully charged. 
    If your batteries are "resting" the most it would indicate is a fully charged battery, and maybe a multimeter that is just a bit off.

    2017 Outback
    Towed by 2014 Touareg TDi
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  • ScottGScottG Administrator Posts: 5,549
    12.7V is just a benchmark for reference. I've found that new batteries in good condition (including plain old lead acid batteries) tend to settle in a little higher than that. With age and use that settling in point will slowly decrease until the battery won't hold even 12.7V, so enjoy that fresh battery energy while you have it!  :-)
    2015 T@B S

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  • scaupscaup Member Posts: 82
    Based on all the comments I isolated the battery by unplugging shore power and switching the battery selector switch to off. I took the multi meter readings thru the Zamp input plug as pthomas745 recommended.

    Do two 6v batteries give a higher reading that a single 12v battery?

    Either way it looks good.

    Now if I could get my tv to charge the batteries........

    Thanks
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