Page 1 of 3 123 LastLast
Results 1 to 20 of 57

Thread: How to select a good 12volt solar panel?

  1. #1
    Premium Member
    ol' boy's Avatar
    Join Date
    Jan 2008
    Posts
    16,503
    Thanks
    7,497
    Thanked 9,122 Times in 4,650 Posts
    Rep Power
    3842
    Reputation
    157512

    Default How to select a good 12volt solar panel?

    So many camping style panels on the market, most people look at Max Current output, but what about Max voltage output?
    Apart from production quality and silicon quality, my question surrounds Max Panel Voltage

    As MPPT controllers have such a wide range of input voltage, is a higher max voltage beneficial when selecting a camping panel?
    I know we all look at Amp output, but i see some panels quote 18v Max and another might be 22.5volt Max
    The new breed of Projector IDC DC-DC (MPPT) chargers have increased Solar Input voltage from 23v Max to 29v Max.
    These are all for 12volt systems

    Or is it better to start with a voltage closer to what you need so the MPPT doesn't have to do so much work converting it to a useable voltage for charging?

    I ask this, as Kogan have an affordable range of panels

    The current output seems great, but the voltage seems low compared to others

    I have always liked the idea of a higher panel voltage, as that would allow better voltdrop on the connecting lead that is run out from your vehicle, which might be 5 or 10M long.
    Of course this means the MPPT charger is mounted next to your battery, not on the panel.
    If u want to go on an expedition get a Land Rover, if u want to come home from an expedition get a Landcruiser!



Look Here ->
  • #2
    Crazy Diamond
    Tiny's Avatar
    Join Date
    Dec 2010
    Location
    Tasmania
    Age
    59
    Posts
    5,881
    Thanks
    9,753
    Thanked 4,599 Times in 2,351 Posts
    Rep Power
    1748
    Reputation
    72317

    Default

    I use the dollar per watt formula for value.
    Then match the voltage to the equipment I already have or am purchasing.
    Cheers, Tiny
    "You can lead a person to knowledge, but you can't make them think? If you're not part of the solution, you're part of the problem.
    The information is out there; you just have to let it in."

  • #3
    Senior Member
    Uncle Fester's Avatar
    Join Date
    Jan 2008
    Location
    Commonly found in a pantry or the bottom of a fridge, searching for grains, fermented or distilled
    Posts
    4,642
    Thanks
    1,399
    Thanked 2,695 Times in 1,598 Posts
    Rep Power
    1243
    Reputation
    47398

    Default

    There is very little difference in the voltage.
    Either you have so called 12V panels that have their maximum power point around 18V while 24V panels have it around 36V.
    The so called max. voltage you quoted is irrelevant. This is the open circuit voltage and is usually 21-22V.
    You need to know the MPP voltage: voltage under maximum delivered power.
    A good quality MPPT controller will always get the optimum out of them and it doesn't really matter if it gets 17 or 19V input.
    It only needs to output around 14V for bulk charge.
    What matters is the sunlight the panels get and you will always find that the panels will provide significantly less than specified in practical use.

    I don't believe in spending big bucks for 5% extra power on 'high quality' panels.
    Truth is that panels get better AND CHEAPER almost from year to year.
    What if find is that newer panels have improved performance under cloud but I did not notice a higher open circuit voltage lately. They all seem to be 21-22V.

    What you mentioned about having the charge regulator on the panels and not with the battery is a big NO for me. Remove it from the panels and find a way to connect it as close to the battery as possible. I have the regulator built inside the battery box.
    However if it is just for camping I wouldn't bother if it is only few meters of cable.
    Last edited by Uncle Fester; 09-05-19 at 08:41 PM.
    This era of thoughtless consumption must end so we can encourage a world of creative geniuses rather than consumer idiots.


  • The Following User Says Thank You to Uncle Fester For This Useful Post:

    tristen (10-05-19)

  • #4
    Premium Member
    ol' boy's Avatar
    Join Date
    Jan 2008
    Posts
    16,503
    Thanks
    7,497
    Thanked 9,122 Times in 4,650 Posts
    Rep Power
    3842
    Reputation
    157512

    Default

    Quote Originally Posted by nomeat View Post

    What you mentioned about having the charge regulator on the panels and not with the battery is a big NO for me. Remove it from the panels and find a way to connect it as close to the battery as possible. I have the regulator built inside the battery box.
    However if it is just for camping I wouldn't bother if it is only few meters of cable.

    Did i mention that?
    If u want to go on an expedition get a Land Rover, if u want to come home from an expedition get a Landcruiser!

  • #5
    Senior Member
    Uncle Fester's Avatar
    Join Date
    Jan 2008
    Location
    Commonly found in a pantry or the bottom of a fridge, searching for grains, fermented or distilled
    Posts
    4,642
    Thanks
    1,399
    Thanked 2,695 Times in 1,598 Posts
    Rep Power
    1243
    Reputation
    47398

    Default

    .
    Last edited by Uncle Fester; 09-05-19 at 09:10 PM.
    This era of thoughtless consumption must end so we can encourage a world of creative geniuses rather than consumer idiots.


  • #6
    Senior Member

    Join Date
    Jun 2008
    Location
    Melbourne, NE.
    Age
    51
    Posts
    2,513
    Thanks
    348
    Thanked 516 Times in 355 Posts
    Rep Power
    361
    Reputation
    7118

    Default

    I use a 120w folding panel from Rich Solar, first thing i did was remove the regulator from the back of the panels and mounted it in the battery box of my camper trailer.
    Reg is just a cheap PWM but it works well with my meager power needs and in good sunlight keeps my 145AH battery charged enough to run a 50ltr waeco, stereo and led lights.

  • #7
    Premium Member
    ol' boy's Avatar
    Join Date
    Jan 2008
    Posts
    16,503
    Thanks
    7,497
    Thanked 9,122 Times in 4,650 Posts
    Rep Power
    3842
    Reputation
    157512

    Default

    I think its common knowledge to mount your solar charge controller or DC-DC as close to your Deep Cycle battery as possible

    I'm just interested in the vastly different Max Voltage Specs from panel to panel
    Can that be beneficial?
    Is it an indication of better silicone being used?

    As so many DC-DC chargers have recently upgraded their voltage range for solar panels
    If u want to go on an expedition get a Land Rover, if u want to come home from an expedition get a Landcruiser!

  • #8
    Senior Member

    Join Date
    May 2018
    Posts
    636
    Thanks
    154
    Thanked 666 Times in 302 Posts
    Rep Power
    293
    Reputation
    12894

    Default

    The max Voltage is related to the number of cells in the panel and the way they are wired in series/ parallel. Probably has to do with the actual layout on the panel as well for production purposes ( cheap) .

    Output wise it probably makes little difference in reality. Charge controllers have minimal start up values so a panel with a higher voltage could boot the controller up sooner and finish later in the day. That said, the Voltage is irrelevant as it is converted by the controller to what is needed and even if the panel was hooked to some loads direct, still makes little difference.
    Higher voltage will be pulled down to the required voltage at certain amps. Panels of the same rating in watts with lower voltage will just do higher amps. 6 of one, half a dozen of the other.

    I was playing today with one of my arrays powering a water heater element. The power coming from the array was 298V and there is about 3.2 KW of panels on that string.
    The heater element was 3.6Kw@ 240V. When I hooked the panels up the volts fell to just over 200. I have run strings that totalled over 350V to 240V resistive loads and as long as the total WATTAGE from the panels is not greater than the wattage of the load, the beaut thing about panels is they just pull down to a lower voltage and balance out. You won't blow a resistive load whatever voltage you feed it from panels as long as the wattage is not higher than the draw of the load. The panels just self level if you like and also panels virtually never give full output especially if they are a few years old.

    These camping panels seem like one hell of a rip off to me. I buy used 250W panels for $20 ea. These camping panels for $250 are a rip off in my book.
    It's also pretty well known that most of them from the Chinese sellers are over rated as hell like most other Chinese things especially on fleabay and the like. The Chinese just have no honour or moral standards and are dishonest as hell with most things they make. If something says 300W, I reckon you'd be lucky for it to make 225w under perfect conditions.
    They seem to think big numbers sell better and often ratings are just pure and utter fantasy and have no relationship to reality.

    If I were going to take a panel camping it would be a full size house hold one. Loads cheaper and probably more reliable as well. Many of these camping panels are thin film which means they are stuffed in virtually no time compared to the traditional types.

  • #9
    Junior Member Johnno's Avatar
    Join Date
    Jan 2008
    Posts
    87
    Thanks
    6
    Thanked 7 Times in 5 Posts
    Rep Power
    147
    Reputation
    151

    Default

    My 12v 200w panel (off ebay) has been charging a 100ah battery for a few years now..(mppt charger located next to batt)
    It's wired to run 8 x 15w led lights under my verandah and shed light. That's the only load I have connected to it so it should last many more years.

  • #10
    Senior Member

    Join Date
    Jun 2008
    Location
    Melbourne, NE.
    Age
    51
    Posts
    2,513
    Thanks
    348
    Thanked 516 Times in 355 Posts
    Rep Power
    361
    Reputation
    7118

    Default

    Bargain right here.


  • The Following User Says Thank You to loanrangiel For This Useful Post:

    ol' boy (16-05-19)

  • #11
    Premium Member
    ol' boy's Avatar
    Join Date
    Jan 2008
    Posts
    16,503
    Thanks
    7,497
    Thanked 9,122 Times in 4,650 Posts
    Rep Power
    3842
    Reputation
    157512

    Default

    Quote Originally Posted by loanrangiel View Post
    Bargain right here.

    Agreed, that is a great price for Bunnings and a Foldable

    Especially when you look at this:



    Might get Anaconda to price match
    Last edited by ol' boy; 17-05-19 at 12:03 AM.
    If u want to go on an expedition get a Land Rover, if u want to come home from an expedition get a Landcruiser!

  • The Following User Says Thank You to ol' boy For This Useful Post:

    loanrangiel (17-05-19)

  • #12
    Premium Member
    ol' boy's Avatar
    Join Date
    Jan 2008
    Posts
    16,503
    Thanks
    7,497
    Thanked 9,122 Times in 4,650 Posts
    Rep Power
    3842
    Reputation
    157512

    Default

    Quote Originally Posted by loanrangiel View Post
    Bargain right here.

    Thank you loanrangiel...

    4 purchased this morning.
    Deleted item at Bunnings, still top dollar at Anaconda...

    Very compact and lightweight
    Comes with a stand and tough canvas bag

    Last edited by ol' boy; 17-05-19 at 05:46 PM.
    If u want to go on an expedition get a Land Rover, if u want to come home from an expedition get a Landcruiser!

  • #13
    Senior Member

    Join Date
    Jun 2008
    Location
    Melbourne, NE.
    Age
    51
    Posts
    2,513
    Thanks
    348
    Thanked 516 Times in 355 Posts
    Rep Power
    361
    Reputation
    7118

    Default

    I should get another but i have a folding panel as well.

  • #14
    Crazy Diamond
    Tiny's Avatar
    Join Date
    Dec 2010
    Location
    Tasmania
    Age
    59
    Posts
    5,881
    Thanks
    9,753
    Thanked 4,599 Times in 2,351 Posts
    Rep Power
    1748
    Reputation
    72317

    Default

    Quote Originally Posted by oceanboy View Post

    4 purchased this morning.

    4! How many do you need?
    Cheers, Tiny
    "You can lead a person to knowledge, but you can't make them think? If you're not part of the solution, you're part of the problem.
    The information is out there; you just have to let it in."

  • #15
    Senior Member
    Thala Dan's Avatar
    Join Date
    Jul 2012
    Posts
    1,268
    Thanks
    793
    Thanked 1,398 Times in 626 Posts
    Rep Power
    669
    Reputation
    27047

    Default

    Quote Originally Posted by Tiny View Post
    4! How many do you need?
    When it comes to a bargain (particularly for camping or fishing) what's "need" got to do with it?

  • #16
    Premium Member
    ol' boy's Avatar
    Join Date
    Jan 2008
    Posts
    16,503
    Thanks
    7,497
    Thanked 9,122 Times in 4,650 Posts
    Rep Power
    3842
    Reputation
    157512

    Default

    I'm only having 2 of them Tiny.... The others are all for friends.
    They are low on voltage output compared to Kings *
    And the PWM controller is a toy. The cable size is also pathetic
    The positive is i just fitted 4 Solar panels (well blankets in my car) and it didn't even take up the space of a small esky

    *

    I'll give one a test tomorrow

    I like the idea of a solid 250Watt panel roof rack mounted or a Bi-Folding 200Watt panel, but the size and weight are a issue for storage and packing
    They are more stable when set up at camp though, and they probably cool better.

    Oh well, these are convenient. I'll see what they produce tomorrow
    Last edited by ol' boy; 17-05-19 at 08:33 PM.
    If u want to go on an expedition get a Land Rover, if u want to come home from an expedition get a Landcruiser!

  • #17
    Premium Member
    hoe's Avatar
    Join Date
    Jan 2008
    Location
    -30.7719955,121.495211
    Age
    55
    Posts
    5,426
    Thanks
    221
    Thanked 3,437 Times in 1,496 Posts
    Rep Power
    1268
    Reputation
    47348

    Default

    My local bunning didn't have any....

    Sent from my VOG-L09 using Tapatalk



    Finally got FTTN, 710m line length....

  • #18
    Premium Member
    ol' boy's Avatar
    Join Date
    Jan 2008
    Posts
    16,503
    Thanks
    7,497
    Thanked 9,122 Times in 4,650 Posts
    Rep Power
    3842
    Reputation
    157512

    Default

    Quote Originally Posted by hoe View Post
    My local bunning didn't have any....

    Sent from my VOG-L09 using Tapatalk
    I had to ring around a few different Bunnings
    The first told me which stores had them and how many
    But then ringing each store directly returned different results again.

    Turns out they are a "Deleted" item
    So they will not be re ordering them in, thus i found mine not even on a shelf, but in a random trolly with other camping products

    I think they are probably no better than any Chinese eBay version for similar price
    They got me over the line because they were so light and packed up so small, could keep one under your car seat

    From my searching, looks like that whole range has been rebranded "Roman"



    This might explain why they are a deleted stock item in Bunnings.
    Last edited by ol' boy; 17-05-19 at 08:45 PM.
    If u want to go on an expedition get a Land Rover, if u want to come home from an expedition get a Landcruiser!

  • #19
    Premium Member
    hoe's Avatar
    Join Date
    Jan 2008
    Location
    -30.7719955,121.495211
    Age
    55
    Posts
    5,426
    Thanks
    221
    Thanked 3,437 Times in 1,496 Posts
    Rep Power
    1268
    Reputation
    47348

    Default

    Next one is 600km away.....

    Might go down in the morning and see if I can find one....

    Sent from my VOG-L09 using Tapatalk



    Finally got FTTN, 710m line length....

  • #20
    Senior Member

    Join Date
    Jun 2008
    Location
    Melbourne, NE.
    Age
    51
    Posts
    2,513
    Thanks
    348
    Thanked 516 Times in 355 Posts
    Rep Power
    361
    Reputation
    7118

    Default

    Quote Originally Posted by oceanboy View Post
    I'm only having 2 of them Tiny.... The others are all for friends.
    They are low on voltage output compared to Kings *
    And the PWM controller is a toy. The cable size is also pathetic
    The positive is i just fitted 4 Solar panels (well blankets in my car) and it didn't even take up the space of a small esky

    *

    I'll give one a test tomorrow

    I like the idea of a solid 250Watt panel roof rack mounted or a Bi-Folding 200Watt panel, but the size and weight are a issue for storage and packing
    They are more stable when set up at camp though, and they probably cool better.

    Oh well, these are convenient. I'll see what they produce tomorrow
    They really only need to put out about 14v as the reg with reduce that to 13.7, amps is where the moneys at.

    Sent from my K10000 using Tapatalk

  • Page 1 of 3 123 LastLast

    Bookmarks

    Posting Permissions

    • You may not post new threads
    • You may not post replies
    • You may not post attachments
    • You may not edit your posts
    •