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Rickkrus
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# Posted: 8 Nov 2017 21:54
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I am running a 100 watt panel to a charge controller and then direct to the battery terminals. This worked for a while but now I only get power when the sun is shining. It says full charge but when there is no sun they have no power at all. What am I doing wrong?
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ICC
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# Posted: 8 Nov 2017 23:39
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It's not clear to me what you mean when you say "it" says full charge and then you say "they have no power at all".
Does that mean a volt meter indicates a full charge (by a high enough reading) or ? And by "no power" does that mean the battery does not supply enough power to make a light or a fan or something work?
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beachman
Member
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# Posted: 9 Nov 2017 06:53
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Sounds like the battery is cooked. I would test it. Power during the daylight might mean power from the panel only. Just a guess.
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SE Ohio
Member
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# Posted: 9 Nov 2017 09:52
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Charge controllers can vary by manufacturer- Some route the battery output through the charge controller. If your battery circuit or charge controller is is fused, check the fuse. Some controllers shut off battery drain if voltage falls to far. Charge controller manual might have debugging guide.
As mentioned above, a voltmeter or digital multi meter is handy test tool. The battery should be reading above 12 volts when charged, close to 13-14 when fully charged.
Also as above, more details would be helpful. Charge controller details, system sketch, etc.
Hope you resolve easily!
SE Ohio
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Rickkrus
Member
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# Posted: 9 Nov 2017 16:11
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I have a Rohrs Wanderer 30 amp charge controller. Solar panel run to that, then to dual batteries in a travel trailer. Positive hooked to one battery negative hooked to the other. I'm using the indicator inside the trailer. Second set of batteries this happened to. Full power when sun is shining. No power at night.
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ICC
Member
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# Posted: 9 Nov 2017 18:36
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Are the batteries the flooded type so you can check with a hydrometer? Check to see if the sp gr actually is what it should be if the batteries are actually fully charged. This is the best check.
Or if the batteries are sealed and if you don't have a multi meter to take a voltage reading at the battery go buy one. HF has them cheap and good enough for off grid solar. Any self respecting off grid solar user should have one.
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Mike 870
Member
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# Posted: 10 Nov 2017 19:08
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Second set of batteries? I’d look very suspiciously at your charge controller. More info you can give us the better we can help, a multimeter is going to be a must here. Also what kind of loads are you running during the day? Sounds like you are running your batteries to zero and eventually killing them. It will work like this for so many cycles then die. That would explain having power during the day but not at night.
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SE Ohio
Member
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# Posted: 11 Nov 2017 10:18
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Something basic, along with previously mentioned fuse check- Do you have a good connection between the controller and batteries? And between batteries? Are you using 2 6 volt batteries in series, or 12 volt-ers in parallel?
Are panels in full sun all day?
Unlikely but possible- Most panel/ controller setups use a diode to prevent current back flow when panel is in shade or dark. If that diode isn't there or working this could be your problem. Diodes are pretty robust but not infallible.
Have you a multimeter? Some tests:
1. Turn off/disconnect controller- Pull fuse if need be. Disconnect battery, careful not to short battery. Set multimeter on DC volts, check battery voltage using red positive meter lead to battery positive lead, black meter lead to negative. A well charged battery will be more than 13 volts. Less than 12 might be expected in this case?
2. Set meter to ohms scale. With fuse/fuses out of circuit, check fuse. You should read very low ohms, about the same reading as when you touch meter leads together. Large or infinite reading means blown fuse. Replace blown fuse with mfg suggested fuse size.
3 Still on ohms scale with battery disconnected, check for low ohms on the wires between the controller and battery connectors. Should be very small reading again, similar to fuse. If large or infinite reading, bad wire or connection.
4. Put everything back together (per your manual instructions). Set meter to DC high amps setting, may have to plug meter lead into different jack labeled "10 amps" or the like. This is important 'cause you will blow the meter fuse if not... This is the tricky part- The meter leads need to be completing the circuit between the controller plus battery terminal and the plus battery terminal. When the sun is shining directly on the panels you should get (100 watts / 12 volts ) 10 amps or so. Same test at night with no load (nothing plugged in, no lights being run) should be minimal current, just enough to feel the controller, milliamperes, I'm guessing? If you instead have a large current, eg a half amp or more, this could explain the battery charge loss.
Make sure you are intimate with the controller manual and multimeter manual before starting. I've read of some charge systems that can be damaged when there is full sun and no battery load! In this case you'd have to do some of this testing at night or with panel covered.
Others, feel free to chime in and clarify my instructions! Might be other simple tests?
Harbor Freight has a DMM under $10 that can get you through this process.
SE Ohio
PS I'm no pro, I play with old electronics as a hobby, no so much solar. We'll let others chime in and correct/improve... Use at your own risk!
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