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  1. #1
    Rolling Along Rgpracer's Avatar
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    Adding a second battery to my 2020 230RL

    Ok, I've read a bunch, but want to to get opinions anyway:

    Battery and cca.....battery is a DURACELL SLI24MDC, (GP24) CCA 500, MCA @ 32° 615 ....I know to add a second battery to mirror the specs on the first battery, (brand name is probably irrelevant, although I will probably do same/same), is this enough battery to add another the same or should I go more?

    Never used a Duracell, like to have Interstate, but won't waste money if brand is irrelevant.

    6 gauge.....good to use?

    I will install an inverter in the future, but, don't know what brand of Inverter or how to figure what size inverter and a wire diagram....I am capable of doing the work, just need a schematic or diagram to follow. I have been googling a lot.

    Thanks all.
    Ray
    Msgt Ray (Ret) and Margie Parker
    2022 GD 303RLS w/Gen-Y gooseneck
    2020 Ram 2500 HD Cummins 6.7/3.73 gears

  2. #2
    Left The Driveway
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    So here is my set up and opinion. I have two Mighty Max Battery ML100-12 batteries. They are wired in parallel. I always recommend the same brand and model of batteries when adding. The gauge wire needs to be appropriate for the amps that the two batteries are capable of pushing out. 2ft of 6ga wire will handle about 80 amps. I use 2/0 wiring between my batteries with a 200amp inline fuse. Looks like the DURACELL SLI24MDC are 75ah at 20hr so 6ga wire would be OK. I always like to go up a gauge when working with battery cables to help with heat.

  3. #3
    Fireside Member
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    Before you go adding another battery, you should first plan out what your expected load after putting in an inverter is going to be.

    Even with two batteries like you described, using only a small 1000 watt inverter, you will only get max an hour's usage.
    It would be money well spent to calculate usage, get two appropriate sized batteries now and the inverter later.
    Otherwise when you get your inverter, you'll be be buying two more bigger batteries.
    Since you should only use 50% of the battery capacity, with two of the same batteries, you would only have 75Ah of battery.
    For inverter use, that's like going on a long hike with half a water bottle.

  4. #4
    Big Traveler boyscout's Avatar
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    Quote Originally Posted by Rgpracer View Post
    Ok, I've read a bunch, but want to to get opinions anyway:

    Battery and cca.....battery is a DURACELL SLI24MDC, (GP24) CCA 500, MCA @ 32° 615 ....I know to add a second battery to mirror the specs on the first battery, (brand name is probably irrelevant, although I will probably do same/same), is this enough battery to add another the same or should I go more?

    Never used a Duracell, like to have Interstate, but won't waste money if brand is irrelevant.

    6 gauge.....good to use?

    I will install an inverter in the future, but, don't know what brand of Inverter or how to figure what size inverter and a wire diagram....I am capable of doing the work, just need a schematic or diagram to follow. I have been googling a lot.

    Thanks all.
    Ray
    Master Sergeant I'll echo advice from @grandcamper2021: it's pretty important (to long battery life) that two or more batteries be identical to each other. Same mfg, same model and specs, very close to the same age and operating performance. Otherwise the batteries may be forever working at trying to balance small differences between themselves which uses up some of their life and can accelerate degradation of the batteries such that differences between them become greater and greater until a battery fails and both must be replaced.

    I don't know anything about the Duracell battery you're considering but that brand sure doesn't appear often in the two Grand Design forums I frequent.

    The 6 gauge wire used by Grand Design is - as you might expect - pretty much minimum for the task in a single-battery factory-configured trailer. It could be quite risky to use more of it since you may be drawing heavy loads from the batteries through your inverter.

    Many owners - including me - have turned the project of improving batteries into one that includes replacing the factory battery "disconnect" switch (that doesn't disconnect everything) and re-wiring 12V supply through a better switch with a better configuration. Generally 1ga or 2ga welding cable or battery cable is used. 4ga might be OK (if loads will be constrained) but I would not use 6ga. Since you plan heavier loads - the inverter could be a big one - then you should definitely go big or go home on the cable.

    As for connecting batteries together, have a look at this page:

    http://www.smartgauge.co.uk/batt_con.html

    Rather than just wiring your batteries one to the other consider using method #3 on that page.

    I'll skip out on the inverter part of your questions for now... maybe others will jump in, or you can search for existing threads, or post a new thread asking for inverter advice.

    Good luck with your choices.
    Mark - 2018 Solitude 310GK - 2017 F-350 diesel SRW short box - Pullrite Superglide hitch

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