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  1. #11
    Join Date
    May 2001
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    Default Re: Power Supply Problems - Help please

    The output seems a little low but not ridiculously so. I think Solar panels are rated at an output of about 16V, so the very best an 85W panel will give is about 5A - and that would be with the panel angled directly towards the sun at midday. Mount the panel flat and you could halve that even in the Canaries

    If possible try connecting each panel in turn individually through the controller and see what output (in Amps) that gives. You should also record and tell us what voltage you were seeing at the battery when you were getting 3A current.

  2. #12
    William_H is offline Registered User
    Location : West Australia
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    Default Re: Power Supply Problems - Help please

    I would suggest that perhaps one or both the batteries are the source of the problem. Do check first that each solar panel is giving similar current as already suggested. One may have bad connection.

    You should disconnect one battery and charge it as best you can then load it to several amps while monitoring volts to check for capacity. Do the same with the other battery.
    You should be able to discharge something like 50% of the Amp Hour rating of the battery at near 12 volts. olewill

  3. #13
    pappaecho is offline Registered User
    Location : S. Hampshire
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    Default Re: Power Supply Problems - Help please

    I had a similar problem on an otherwise faiult free solar/battery installation.
    After much huffing and puffing I found a perfect looking three pin so called marine quality plug and socket has 20 volts one side from the panel array and 3 volts when coming out the socket. Tried cleaning both plug and socket, without avail and replaced with another make.
    Def: Yachting - a way of spending the kids inheritance

  4. #14
    Join Date
    Feb 2003
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    341

    Default Re: Power Supply Problems - Help please

    Hi All,

    Thanksfor suggestions.
    I did remake all junctions as well as possible. The attachment to the solar panel is with a spring hiolding the wires in place which I was suspicious of. I fiddled about and remade some connections with screw choc boxes and got better results.

    Does anybody know whether a small shadow on part of one panel would have the effect of reducing the amperage by say 65%?

    I think that I was getting perhaps 7 amps. Even though I am in Canaries, it is getting late in the year. Perhaps that and a small shadow are the reason.

    I was getting almost 3 Amps from one today but the other had a shadow from one source or other all afternoon. I will have to try getting out of bed tomorrow morning and test then.

    I am fairly certain that I am not leaking power.

    Brendan
    [B]"The Boat Whisperer"[ /B]
    www.BrendanChandlerYachtDelivery.co.uk

  5. #15
    alan is offline Registered User
    Location : Nettuno, Italy
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    Default Re: Power Supply Problems - Help please

    Short answer to your question: "YES" . Also the time of the year and the time of the day will be very influential.
    As I said in my earlier mail, just a shadow from the mast of the boat next door knocked my current down from 2.1 amps to 0.45 amps. On my panel it seems to depend which part of the panel is in shadow as to how bad the effect is.

    Alan.
    Alan Cloke

  6. #16
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    May 2001
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    Default Re: Power Supply Problems - Help please

    From what I recall some panels do suffer a very large reduction in output if there is a shadow across it - I have an idea that amorphous silicion panels suffer more in that respect than poly/mono crystaline panels.

    3Amps from a single panel is pretty much what I would expect.

  7. #17
    Billjratt's Avatar
    Billjratt is offline Registered User
    Location : Firth of Clyde
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    Default Re: Power Supply Problems - Help please

    Theoretically the max amps should be about 14 at noon with unbstructed sun - that means no shadows from masts or even ropes depending on the angle. If you cast a shadow across the panels you get a different reading than going along them. Are they clear? Can you measure at the cells under load? If they're dragged down to battery voltage (plus 0.6v or so for the controller) then they should be trying to push amps into the battery bank. Are any of the connections getting warm? If so they are costing power. Maybe only one of your arrays is working, try each sparately.
    Left hand down a bit.

  8. #18
    alan is offline Registered User
    Location : Nettuno, Italy
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    Default Re: Power Supply Problems - Help please

    Sorry Billjrat, not trying to be picky, but max current will be :

    85W times 2, divided by 20 volts (not 12) = 8.5A.

    Don't want Brendan trying to find amps that are not there!!

    Alan.
    Alan Cloke

  9. #19
    Billjratt's Avatar
    Billjratt is offline Registered User
    Location : Firth of Clyde
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    Default Re: Power Supply Problems - Help please

    If you get 20 volts across the battery you've got real trouble!!
    Although the open-circuit voltage is that high, it falls to the battery voltage when connected. If you want to be really picky it should max-out at about 14.8v for wetcells so split the difference, but it ain't pumping amps by that time - the batteries are almost full. It only pumps amps while the batteries are low, so the 12volt reading is valid.
    Left hand down a bit.

  10. #20
    alan is offline Registered User
    Location : Nettuno, Italy
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    Default Re: Power Supply Problems - Help please

    In your post you said:

    "Theoretically the max amps should be about 14 at noon with unbstructed sun "


    I guess you meant volts; in that case I agree with you.

    Alan.
    Alan Cloke

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