Solar battery charger

Discussion in 'OnBoard Electronics & Controls' started by Vulkyn, May 28, 2017.

  1. Vulkyn
    Joined: Jun 2010
    Posts: 568
    Likes: 45, Points: 28, Legacy Rep: 654
    Location: Egypt

    Vulkyn Senior Member

    Ok so question for electronics guru :D

    Got my hands on an old cell charger, thinking myself smart i get the voltmeter (which i have no idea how to use btw) try to set it up for DC and measure the output.
    It's 43 degrees in the sun today, so got a reading of -18.97 volts (i think i switched something :S shouldn't be negative) and current was 1 (i think so took pictures so help me please :D)

    So my questions:

    1- Would this trickle charge be able to help charge my battery? Or is it enough to just keep battery from losing charge.
    2- Would i just plug it in the v12 socket and it will go back to battery or do i need a direct connection to battery? (get a socket and attach directly to terminals)
    3- Would be safe if I leave the batteries for extended time to have the solar panel connected (not on the boat of course)
    4- Did i measure the current or is that me making a fool of myself yet again?
    5- I have a secondary battery which i wanted to have as backup and if the above idea works I can make a socket and just have the solar panel charge it directly and if need be i switch batteries knowing my backup will be have some charge in it (or am i day dreaming here?)

    Thanks for the help in advance folks :D
    IMG_6594.JPG IMG_6603.JPG IMG_6605.JPG IMG_6607.JPG
     
  2. ondarvr
    Joined: Dec 2005
    Posts: 1,411
    Likes: 45, Points: 48, Legacy Rep: 506
    Location: Monroe WA

    ondarvr Senior Member

    That charger would have a tough time charging your cell phone battery, it would do almost nothing on a full sized battery.
     
    Last edited: May 31, 2017
  3. Vulkyn
    Joined: Jun 2010
    Posts: 568
    Likes: 45, Points: 28, Legacy Rep: 654
    Location: Egypt

    Vulkyn Senior Member

    Thanks ondarvr, that would be because of weak amp output right ? if so and i would like to pursue the solar chargers what output would i need?
     
  4. CDK
    Joined: Aug 2007
    Posts: 3,293
    Likes: 139, Points: 63, Legacy Rep: 1819
    Location: Adriatic sea

    CDK retired engineer

    To maintain the charge level of your battery without electronics, the (amorphous) solar panel should be able to provide a short circuit current of approx. 1/40 of the battery capacity. That is a rule of thumb for Western Europe, in Egypt it should probably be 1/50.
    So for a 80Ah battery the solar charger should have a current of approx 2 A. The toy charger you present here can supply 20 mA, not quite enough.
    The picture showing a current of 1.00 is meaningless because you have the selector on 20 Amps but used the mA input terminal.
     
  5. gonzo
    Joined: Aug 2002
    Posts: 11,987
    Likes: 177, Points: 63, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    It may not charge a battery, but is probably enough to keep it from discharging.
     
  6. Vulkyn
    Joined: Jun 2010
    Posts: 568
    Likes: 45, Points: 28, Legacy Rep: 654
    Location: Egypt

    Vulkyn Senior Member

    Thanks :) i think i did something stupid and burned the current dial on the voltmeter .... everything else is reading fine but the current is giving zero on everything (i think i shorted it on the battery says 20 A max and i had it on current when i was checking volt) couldn't find a fuse inside it so meh ... (guess i need to learn some stuff the hard way...)

    If it can reduce battery charge loss then that would be perfect, i have a regular battery so in theory if I plug the charger in and leave it for 2-3 month would be better off then to leave it to discharge.
     
  7. ondarvr
    Joined: Dec 2005
    Posts: 1,411
    Likes: 45, Points: 48, Legacy Rep: 506
    Location: Monroe WA

    ondarvr Senior Member

    Your charger can supply 12mA at best, this would be when it was new (as they age they lose efficiency), at noon on a cloudless day and at the time of year when the sun is directly overhead, any other time it will supply less or nothing. You need about 2 amps to actually do any charging or maintaining.

    Will it do something...sort of.....will it be of any value....not really.
     
  8. Vulkyn
    Joined: Jun 2010
    Posts: 568
    Likes: 45, Points: 28, Legacy Rep: 654
    Location: Egypt

    Vulkyn Senior Member

    Well its worth looking at some sort of alternative solar charging solution to keep battery healthy. In Egypt we have plenty of sun all year round.

    Appreciate the feedback !
     
  9. ondarvr
    Joined: Dec 2005
    Posts: 1,411
    Likes: 45, Points: 48, Legacy Rep: 506
    Location: Monroe WA

    ondarvr Senior Member

    Just scale up until you can get enough amps to do the job, plus get a charge/voltage controller so you can charge at the correct voltage for the battery type. Solar can work great to keep a battery charged.
     
  10. BertKu
    Joined: May 2009
    Posts: 2,241
    Likes: 31, Points: 58, Legacy Rep: 223
    Location: South Africa Little Brak River

    BertKu Senior Member

    Hi Vulkyn, you probably have figured it already out that you blew the internal fuse. If not yet fixed, open the meter and replace the normal 10 Ampere fuse of the same kind. But be careful not to unscrew too many screws, otherwise you will probably battle to put all the parts back again. Bert
     
  11. Vulkyn
    Joined: Jun 2010
    Posts: 568
    Likes: 45, Points: 28, Legacy Rep: 654
    Location: Egypt

    Vulkyn Senior Member

    I did it seems my voltemeter has 2 amp settings, fused for 10A and unfused for 20A (i think it was plugged as unfused). The fuse seems fine as all the other readings are working except amp.
    Will probably need another voltemer to see if i burned something on it lol
     

  12. Vulkyn
    Joined: Jun 2010
    Posts: 568
    Likes: 45, Points: 28, Legacy Rep: 654
    Location: Egypt

    Vulkyn Senior Member

    So had an interesting meeting today regarding the solar panels with a specialized electronics store.
    They recommended a 20 cm panel that will produce around 1 Amp, fit it a batter controller for regulation and overcharge protection in a water proof cover. I can then attach a marine 12 V socket with aligator clamp on the assembly so I can remove it with me after boating.

    They will send data sheet for the equipment and i will take it from there :)
     
Loading...
Similar Threads
  1. CRAMAR
    Replies:
    6
    Views:
    961
  2. seanform
    Replies:
    1
    Views:
    4,400
  3. BertKu
    Replies:
    7
    Views:
    181
  4. L'eau.Life
    Replies:
    43
    Views:
    2,515
  5. markstrimaran
    Replies:
    9
    Views:
    1,262
  6. ashwinnaique
    Replies:
    75
    Views:
    4,854
  7. whitepointer23
    Replies:
    11
    Views:
    874
  8. philSweet
    Replies:
    0
    Views:
    597
  9. brian eiland
    Replies:
    1
    Views:
    899
  10. SeriolaDumerili
    Replies:
    31
    Views:
    2,894
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.