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Trickle Chargers

What’s a recommended trickle charger for a T@B 320 in garage storage over the winter?

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    VictoriaPVictoriaP Member Posts: 1,492
    I use NOCO Genius chargers to keep both my car and Tab batteries topped off as needed. As smart chargers, they can be left plugged in indefinitely without causing problems.
    2019 320s BD Lite, white with blue (“Haven”)
    2015 Subaru Outback 3.6r (unsafe 200lb tongue weight limit until 2020 models)
    2020 Subaru Outback XT
    Pacific NW
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    LauingerLauinger Member Posts: 30
    What amp amount does your Noco Genius provide? Is 2 enough?
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    Sharon_is_SAMSharon_is_SAM Administrator Posts: 9,489
    What what battery do you have?
    Sharon / 2017 T@B CSS / 2015 Toyota Sienna Minivan / Westlake, Ohio
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    VictoriaPVictoriaP Member Posts: 1,492
    As @Sharon_is_SAM noted, you should choose your charger size based on your battery size and type. The NOCO site has details. That said, I would never pick a small charger for an RV battery. If I were buying today, I’d buy a Genius 10. That would allow for full charging of my AGM battery from totally dead in a mostly reasonable number of hours if necessary, will trickle charge when a full charge isn’t needed, and will be adequate for handling the lithium I eventually plan to buy.
    2019 320s BD Lite, white with blue (“Haven”)
    2015 Subaru Outback 3.6r (unsafe 200lb tongue weight limit until 2020 models)
    2020 Subaru Outback XT
    Pacific NW
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    pthomas745pthomas745 Moderator Posts: 3,642
    And, a fully charged battery, with the battery switch off, will hold a charge for months.  No trickle chargers are really required. 
    PS:  love my Noco 3500!
    2017 Outback
    Towed by 2014 Touareg TDi
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    LauingerLauinger Member Posts: 30
    I have a 550 CCA deep cycle Interstate. Not AGM.
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    Denny16Denny16 Member Posts: 5,445
    Than a small storage type charger should work just fine.
    cheers
    2018 TaB400 Custom Boondock,  Jeep Gladiator truck, Northern California Coast.
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    Sharon_is_SAMSharon_is_SAM Administrator Posts: 9,489
    @Lauinger - do you know the 20 hr rating?  
    Sharon / 2017 T@B CSS / 2015 Toyota Sienna Minivan / Westlake, Ohio
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    deucedeuce Member Posts: 47
    edited September 2020
    I am recharging a new Marine/RV That was totally drawn down a day ago with a Duracell Ultra 7.5 Amp plugged into my generator.  

    I can’t believe how slowly the recharge is going.
    Does charging work better off a 120 Volt shore station or household current?

    What does @Sharon_is_SAM think?



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    Denny16Denny16 Member Posts: 5,445
    edited September 2020
    Household AC and a RV shore power plug are the same thing, 120VAC, the RV shore power has a higher amp rating, but the 15 or 20 amp home plug is more than enough for this small charger.  You are using a 7 amp charger to recharge 75-150 amp battery, it is going to take several days.  You might want to take the battery to a garage, for a bulk quick charge to get it part way back up to 50% then use your small charger.
    cheers
    2018 TaB400 Custom Boondock,  Jeep Gladiator truck, Northern California Coast.
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    VictoriaPVictoriaP Member Posts: 1,492
    deuce said:
    I am recharging a new Marine/RV That was totally drawn down a day ago with a Duracell Ultra 7.5 Amp plugged into my generator.  

    I can’t believe how slowly the recharge is going.
    Does charging work better off a 120 Volt shore station or household current?

    What does @Sharon_is_SAM



    As Denny noted, you need a much bigger charger if you want faster charging. There’s no difference between power supplied by your generator and power supplied by household current, so changing that variable isn’t going to speed up the task. At a bare minimum, fully charging an RV battery from totally drained is an overnight process (often longer), which is one reason you don’t want to let a battery drain completely. You’ll want to have that battery checked for damage anyway, so Denny’s suggestion of taking it to a garage is a wise one.
    2019 320s BD Lite, white with blue (“Haven”)
    2015 Subaru Outback 3.6r (unsafe 200lb tongue weight limit until 2020 models)
    2020 Subaru Outback XT
    Pacific NW
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    deucedeuce Member Posts: 47
    thanks @Denny16 and @VictoriaP.

    follow-up

    I am now infer that it is important not to use “too much” battery before putting it on the 7.5 Amp charger.

    Is the 7 1/2 amp charger then nearly worthless if, as Denny says, recharging could take several days?

    to what level of charge on the cabin gauge (that also shows freshwater, gray water, and black water) can the battery be drawn down to before it is advisable to put it on the 7 1/2 amp trickle charger?
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    VictoriaPVictoriaP Member Posts: 1,492
    edited September 2020
    @deuce It’s not “nearly worthless”, but like most tools, you need to use it correctly. 

    In general, unless you’re running lithium batteries, you do not want to ever go below 50% state of charge except in a true emergency. Again, that’s partly because it’s a pain to get back to 100%, and in part because you will eventually damage your battery going lower, especially if you do it more than once. 

    Basically, I treat my RV battery like I do my phone, if there’s power available and I’m below 75%, I recharge. If you are boondocking with a generator, you’re limited to whatever generator hours are allowed by the campsite, and also limited by how much gas you have on hand. If you are conservative with your battery use, you may be able to get away with topping off for a few hours a day. Is there a reason you are using a charger rather than simply using the 30 amp cable and a 30 to 15 amp adapter with your generator?

    Ideally? Most boondockers upgrade their batteries, use factory or portable solar panels, and rely on generators for backup rather than as a primary source of recharging. No one wants to carry enough gas to run a genny for days on end.
    2019 320s BD Lite, white with blue (“Haven”)
    2015 Subaru Outback 3.6r (unsafe 200lb tongue weight limit until 2020 models)
    2020 Subaru Outback XT
    Pacific NW
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    DalehelmanDalehelman Member Posts: 2,410
    Our 2015 has the original 12 volt battery that came with the trailer. Plus another 12 volt battery wired in Parallel. With a a 4 position isolator switch. When we are home which is most of the time except a couple of months in the winter. We are plugged into shore power 24-7. The charger converter has maintained our batteries just fine over the last 5 years. No other charging device’s have been needed, and the batteries remain in the trailer year round. I do check the water level periodically, but add water only once or twice a year.
    1. Hash  T@B Fun
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    Sharon_is_SAMSharon_is_SAM Administrator Posts: 9,489
    @deuce - all good advice here.  Do you have the KIB or See Level monitor?  The KIB has Fair, Medium, Good, Full as I recall none of which is a very good indicator.  Someone measured voltage and the readings tend to paint a better picture than reality.  If you have the SeeLevel, you at least get a voltage reading, but if you are measuring anything other than a tested battery, it will also be inaccurate.  If you don’t have the SeeLevel, buy a 12v plug in monitor like this and plug it in.  Turn off everything you can in the TaB, turn off your battery switch and rest your battery for a half hour, then, turn the battery switch back on and quickly check your voltage.  It will give you a decent estimate and according to this chart you want to not discharge your battery below 12 v.  Sorry if your battery is damaged.  You are now part of the club!  It’s a right of passage to kill your first battery.



    Sharon / 2017 T@B CSS / 2015 Toyota Sienna Minivan / Westlake, Ohio
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    deucedeuce Member Posts: 47
    Every new tab owner should be required to have this chart pasted by the battery gauge in the cabin
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    Sharon_is_SAMSharon_is_SAM Administrator Posts: 9,489
    Sorry @deuce.  The whole battery, electrical piece of an RV is a steep learning curve.  If you were considering upgrading your battery system, a good monitor is a good investment.
    Sharon / 2017 T@B CSS / 2015 Toyota Sienna Minivan / Westlake, Ohio
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    pthomas745pthomas745 Moderator Posts: 3,642
    edited September 2020
    Another way to use the simple plug in meters is to attach cable 12v plug at one end directly to the battery.  Dangle the plug outside the box.  You could turn off the battery switch.  Wait for the "resting" period, plug in the monitor, and take an accurate reading of a rested battery.   I've played with a simple plug in monitor recently, and compared it to my multimeter, and the differences in the two are very small.  Imagine how many batteries this could save!  Attach it once, get a great way to monitor.
    This is a very nice Noco cable, with fuse and cover for the plug.  There are many examples of these. 

    There are also SAE to 12v plug adapters.  With the correctly wired cable (the red positive wire should be "inside the plastic" on the plug) this would be even easier than the cable attached to the battery.  Don't even have to open the propane box.  This one appears to be wired correctly, according to one of the close up photos.

    2017 Outback
    Towed by 2014 Touareg TDi
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    Sharon_is_SAMSharon_is_SAM Administrator Posts: 9,489
    Good idea @pthomas745.  Better than running back inside!
    Sharon / 2017 T@B CSS / 2015 Toyota Sienna Minivan / Westlake, Ohio
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