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12V Solar Battery Charger

Discussion in 'Gen 4 Prius Care, Maintenance and Troubleshooting' started by Harters, Apr 28, 2020.

  1. sam spade 2

    sam spade 2 Senior Member

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    He posted the specs. back in message #4.
    It says that the max. current output is .55 amps.
    That is about 6.6 watts, MAXIMUM, with a duty cycle of about 50% given the night time off hours.

    There would have to be some really unusual conditions for that to cause any problem.
     
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  2. Harters

    Harters Active Member

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    Thanks Sam, so it looks like it's not needed then, just call me paranoid... or worse :LOL:
     
  3. davecook89t

    davecook89t Senior Member

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    I like to call it "erring on the side of caution". I accept Sam's judgement that a charge controller is not necessary. Mine is sitting on a shelf unused.
     
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  4. davecook89t

    davecook89t Senior Member

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    That looks very similar to another one I have attached to some 100 W solar panels that I use with my camping trailer. It is definitely necessary to use a charge controller for that much power going into a 12V system and I find the USB ports useful for charging my phone and other small 12V DC electronics. If you want to experiment with using solar power for things similar to what I am, it would be necessary to have something like that and would probably work fine, although I have no experience with that particular model.
     
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  5. Harters

    Harters Active Member

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    I must say looking into this more has whetted my appetite for solar and now wish I purchased a more powerful panel and controller to experiment some more. For now I will use what I have purchased confident that I am not going to overcharge my battery and maybe look at getting a more beefy solar set up later in the year now that I have a bit more knowledge and undestanding.

    Should have consulted here before buying :rolleyes:
     
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  6. jerrymildred

    jerrymildred Senior Member

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    I looked at the specs on Amazon before I saw that you'd quoted them.

    First, if connecting it to your battery pulls the 18V output down to just 12V under load, it's gonna struggle to get your battery charged since fully charged is well over 12V.

    Second, it says the charging current is "Output current: 400mAh-550mAh(Max.)" That's NOT a measure of current. Remove the "h" and it becomes current, and it's a really really low current. On a bright sunny day. On a rainy day? Probably not going to do much. I would not get it especially at that price. If it was $15-20, I might roll the dice.
     
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  7. Harters

    Harters Active Member

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    Unfortunately I have already purchased it, but the main thing is that I know I am not going to overcharge my battery which was my main concern.

    Thank you.
     
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  8. jerrymildred

    jerrymildred Senior Member

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    I looked at a couple others online and didn't find any that had very much power. I'm very curious how well this works, so please give us a review after you've had a chance to use it for a while. The main thing is if it'll stay ahead of the drain the car puts on the battery over a stretch of cloudy days. I'm not sure which part of the UK is home to you, but I got to spend a few weeks in Yorkshire (LOVE THAT PLACE!) and remember having some clouds now and then. LOL!
     
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  9. Harters

    Harters Active Member

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    Think I need to get myself a battery meter of sorts so I can see how much its putting into the battery, all I have is a device that shows whether the charge is OK, Low, med, high etc.

    I am on the South Coast so a long way from Yorkshire, a place I have never been to :LOL:

    I would happily swap for Tampa any day (y)
     
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  10. kithmo

    kithmo Couch Potato

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  11. jerrymildred

    jerrymildred Senior Member

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    Ahhhhh! The Yorkshire ambience ... even at 12,000 meters. :LOL:
     
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  12. Harters

    Harters Active Member

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    As a quick update, I ordered a multi-meter which has just arrived . I have checked my battery and it is reading exactly 12 volts so it looks as though the panel is giving just enough to maintain the voltage.

    Not knowing what my initial voltage was when I first started using it, now I have a meter I can monitor it and see if it gets any higher.

    If the voltage is maintained I will be happy that its doing what I wanted. This is with the panel attached to the inside of the glass on the side garage door. I would obviously get more charge if I had it outside in full sun all day, but for now I will carry on as I am.
     
  13. davecook89t

    davecook89t Senior Member

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    12.0 Volts is significantly discharged. I would think you would want to maintain it at 12.5 V or better. My advice would be to buy a smart charger similar to the one @Mendel Leisk referenced in #12 (although I see a 2 Amp version that costs quite a bit less and would still probably do the job). After using the charger to get the voltage up to something like 12.7 V, see if your solar panel can maintain that. Also, to get a true measure of the voltage you would need to disconnect the solar panel for a few hours before using your multi-meter. If the solar panel is charging the battery at all, there will be a surface charge on the battery that should be allowed to dissipate before measuring the voltage.
     
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  14. Harters

    Harters Active Member

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    The panel has been off all night as I hadn't connected it this morning as I knew the meter was today so I should be getting an accurate reading.

    I will see how things go and if its not doing what I hope then I will go down the smart charger route.
     
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  15. sam spade 2

    sam spade 2 Senior Member

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    About 50%.
    And may indicate that your battery is either defective OR is not being charged properly when the car is running.
     
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  16. Harters

    Harters Active Member

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    Went out and started the car this morning without any problem after sitting unused for just over two weeks.

    The voltage on battery in ready mode was 14.42 volts

    The ICE didn't come on as it was 13 oC in the garage so I blipped the throttle to start warm up and the voltage dropped to 14.38 volts and quickly went back up to 14.42 volts after warm up finished.

    As it was in the garage the headlamps were on and in the UK we do not have an off position, so I turned them to sidelights, but the meter didn't move.

    I checked the charge a couple of hours later and the battery is sitting at 12.4 volts so I am happy with that. I have just put the solar panel back on and have put it outside so now I have some measurements to go on I can monitor how things go.
     
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  17. jerrymildred

    jerrymildred Senior Member

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    What was the voltage before you started the car?

    As it should be. That's the output of the DC/DC converter to the battery when the car sees that the battery needs charging. As the battery nears 100%, that output voltage will reduce to protect the battery from over charging.

    Without checking the voltage before starting, you can't tell how well the solar panel worked, but it's clear that the 12V was not 100% charged when you started the car or the READY state voltage would have dropped to about 13.1 or thereabouts within a very few minutes.
     
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  18. Harters

    Harters Active Member

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    I checked the battery cold this morning (solar panel was disconnect last night) and the voltage as 11.94 volts so had dropped a bit since I checked it last.

    Now I understand things a bit more I can monitor how things go and whilst the weather is dry I am putting the solar panel outside so it gets a bit more oomph than it would behind the double glazed window.

    It does look as though the solar panel is hardly doing anything, but now I have some figures I can monitor things more.

    I have earmarked a the item below which seems to be what everyone recommends

     
    #38 Harters, May 5, 2020
    Last edited: May 5, 2020
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  19. sam spade 2

    sam spade 2 Senior Member

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    You should NOT be happy with that.

    12.4 is a bit more than 50 % discharged......and it is unlikely that your solar trickle charger will EVER be able to put back a full charge.
    You just don't seem to grasp the importance of tenths of a volt when measuring a battery.

    And the voltage readings you saw above 14 is NOT the "battery" voltage.......but the charging voltage.
     
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  20. sam spade 2

    sam spade 2 Senior Member

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    That is not a "bit", it is a LOT.
    11.94 is about 80% discharged and often qualifies as DEAD.
    It's pretty obvious to me that you need a new battery........and that no charger will extend it's life much.
     
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