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Gen 2. Adding leisure battery for camping

Discussion in 'Gen 2 Prius Accessories & Modifications' started by Anthone, Jun 3, 2024.

  1. Anthone

    Anthone New Member

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    Hello

    I have a large hybid leisure/start battery I was going to parallel with the 12v battery in the back. Fully charged to begin with and the link up to recharged after use depletion.

    I was thinking of using clamps to disconnect when being used. So the prius battery is never discharged by leisure use. Reconnect when driving away, to recharge for next time.

    But, I read the everything a newbie should know thread and it intimated that using the prius to charge a battery is doable but a black art. With a refusal to go into detail.

    So is my plan madly unwise?

    Assume I'm electrically competent and not going to reverse any polarities.

    Thanks
     
    #1 Anthone, Jun 3, 2024
  2. mr_guy_mann

    mr_guy_mann Senior Member

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    It depends on how much the new battery will draw during charging. The DC-DC converter can supply 14V at about 100A through the main fuse to power every low voltage device on the car. That includes charging the 12V battery. You don't want to exceed that maximum. And will you operate the car long enough to charge this new batterythrough expected operation?

    That and whatever you use to connect to the car should be incapable of reverse polarity connections. It's less about competency and more about complacency and brain farts.

    Posted via the PriusChat mobile app.
     
    #2 mr_guy_mann, Jun 3, 2024
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  3. T1 Terry

    T1 Terry Active Member

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    I fitted a 4 cell Winston 100Ah LYP battery in the space where the standard 12v battery lived WB-LYP100AHA(A) (winston-battery.ru) It's been there for ..... probably 5 yrs or more. I did add a cell equaliser MAZAVA HA02 Battery Equalizer Voltage Regulator Balancer for 4pcs Batteries Parallel Connected in Series for 48V Battery System, Solar Power System Extend Battery Life… : Amazon.com.au: Electronics but didn't pay anything like that for it.
    I run a winch from it to drag what ever onto the trailer when required, including my other Prius when a CV joint exploded, often run a 1000w inverter off it for low draw 240vac items and it will provide over night 12v LED lighting for the campsite when needed. Simply start the engine the next day and the battery recharges quickly, just leave the headlights etc off so you don't over stress the DC to DC charger.

    T1 Terry
     
    #3 T1 Terry, Jun 4, 2024
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  4. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    It's not unwise, and it's not a dark art. It's just that everyone who really needs this solved the problem RV-style, with a dual-battery isolator. So the solutions are all over the RV/marine and camping forums instead of the Prius forum.

    The isolator automates the actions I've quoted from your post, and it's reliable 1930s technology, extremely safe. You can run the leisure battery down twice a day forever and never worry about a no-READY.

    There have been a few good threads about isolator selection and installation on Priuschat, that might be worth a specific search.
     
    #4 Leadfoot J. McCoalroller, Jun 4, 2024
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  5. Anthone

    Anthone New Member

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    Complacency making me not put my glasses on once, only once, had me blow the top clean off a charging battery when the excessive arc ignited the hydrogen.

    Fortunately no other harm done and a very vividly memorable experience that haunts me whenever I have a battery clamp in my hand.

    So I do hear you with that.

    It does ward me from future repetition but I will look into the automatic dual battery set up as advised.
     
    #5 Anthone, Jun 5, 2024
  6. Anthone

    Anthone New Member

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    It doesn't draw much unless it's nearly completely empty. That's why it was no good for a solar panel array, never got very charged, and I got given it.
     
    #6 Anthone, Jun 5, 2024
  7. T1 Terry

    T1 Terry Active Member

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    If you really want to add a second battery, use a DC to DC charger to separate and isolate one battery from the other. It can be programmed to disconnect from the primary battery at voltage you can set, it will boost the charging voltage to the secondary battery to ensure it charges as fast as it can absorb it, yet limits the current draw from the primary battery, and won't start to charge the secondary battery until the primary battery reaches a voltage you can set.
    Victron make good products, avoid cheap ones, they over heat, so make sure they have a fan as part of the set up and current limiting if they get hot to allow them to cool.

    T1 Terry
     
    #7 T1 Terry, Jun 5, 2024
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