Solar Trickle Charger Question

marsofold
marsofold Solar Expert Posts: 45 ✭✭
in Off Grid Solar & Battery Systems #1
Want to get a small solar panel to keep my propane generator starting battery (Automotive Diehard Gold) charged. Want to avoid having to run the generator for an hour each month just to keep it charged. Can't charge it with an automotive charger because my beloved German Shepherd dog will definitely chew the power cord. On eBay I've seen small panels for doing that ranging anywhere from 1.5 watts up to 20 watts. Have a hard time believing that a 1-1/2 watt panel could keep it charged. Don't want a charge controller or more panel than necessary to do it. But I really really don't want the battery to die from undercharging sulfation. How many panel watts do I need to maintain it?
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Comments

  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #2
    Re: Solar Trickle Charger Question

    i believe that battery may be a sealed agm so a charge controller or some kind of voltage regulation would be necessary. if i'm wrong on that then there's no harm going higher in voltage on an fla type without regulation for up to about 10w or 15w or so with up to 5w-6w as a bit safer to help to not boil out the electrolyte. (fla has vent caps)
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  • CATraveler
    CATraveler Solar Expert Posts: 98 ✭✭✭✭
    #3
    Re: Solar Trickle Charger Question

    Bad doggie! :D I'd shield the power cord as I did every power cord for the cat.
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  • PNjunction
    PNjunction Solar Expert Posts: 762 ✭✭✭
    #4
    Re: Solar Trickle Charger Question

    Not sure if the Gold is agm. I believe the Advanced Gold is. Sure looks like an East-Penn Deka Intimidator series, but I can't confirm it.

    Upgrading to an AGM with lower self-discharge might help as long as your charging setup can meet the specs.

    Are there any parasitic loads - is that battery supplying power to solenoids, leds, control logic to that propane generator when it is not running? That would definitely call for a bit more analysis on the panel sizing.
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  • Surfpath
    Surfpath Solar Expert Posts: 468 ✭✭✭
    #5
    Re: Solar Trickle Charger Question
    CATraveler wrote: »
    Bad doggie! :D I'd shield the power cord as I did every power cord for the cat.

    If you do manage to isolate the battery from your pooch, I recommend a Battery Tender. I have the 800 (the waterproof version) currently maintaining a charge on a 12V 220amp hr Trojan - seems to work fine. It's also compatible with AGM's. Seems 2 b a bullet proof, small unit.
    -SP
    Outback Flexpower 1 (FM80, VFX3048E-230v, Mate, FlexNetDC) 2,730watts of "Grid-type" PV, 370 AmpHrs Trojan RE-B's, Honda 2000 watt genny, 100% off grid.
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  • Surfpath
    Surfpath Solar Expert Posts: 468 ✭✭✭
    #6
    Re: Solar Trickle Charger Question
    Surfpath wrote: »
    If you do manage to isolate the battery from your pooch, I recommend a Battery Tender. I have the 800 (the waterproof version) currently maintaining a charge on a 12V 220amp hr Trojan - seems to work fine. It's also compatible with AGM's. Seems 2 b a bullet proof, small unit.
    -SP

    I also use a 5 watt panel attached to my boat battery to keep it charged. I recently repaired it & it's working great (I have a wee Morningstar controller on it as well, but probably don't need it).
    Attachment not found.

    Beware though, even if you get a small panel there will be 'delicious' electrical wires involved.
    Outback Flexpower 1 (FM80, VFX3048E-230v, Mate, FlexNetDC) 2,730watts of "Grid-type" PV, 370 AmpHrs Trojan RE-B's, Honda 2000 watt genny, 100% off grid.
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #7
    Re: Solar Trickle Charger Question

    We commonly use 1.5 and 1.8 watt "battery maintainer" panels, one per battery to make up for battery self-discharge over winter, both on lawn tractor batteries and large D-8 size boat batteries with great success. No controllers are needed with such small panels, and come spring, everything is fully charged and ready to go. Of course any and all loads are removed from the battery during the time it's on the maintainer.
    Oh, and since we live in the snow-belt, and since these maintainers are only used in winter for the boat batteries, the little panel is mounted in the vertical position. This keeps snow off, yet still catches the low-on-the-horizon winter sun, as well as the reflected light off the snow covered ground.
    We also use them in Summer, tilted back down of course, to keep lawn tractor and 4 wheeler batteries charged and ready to go. Again, no CC require with such small panels, and they DO work.
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