motorbike trickle charger

Discussion in 'The Projects Forum' started by Upex, Jun 8, 2014.

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  1. Upex

    Thread Starter Member

    Nov 10, 2013
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    Hi all,

    Been thinking about this for a while and confused after reading lots of threads on here.

    I want to add a small solar panel or two the the back of my motorbike to trickle charge the battery when she's parked up at work.

    I assume this is possible, but unsure what I need to consider or use.

    I'm not after charging the battery as such, just maintaining it a little. Its a big old lump and if the battery not in decent charge, sometimes there isn't enought juice to turn her over. I can't use a charger in garage as have no power there, so thinking of adding a panel there to.

    I'm looking to add a small panel or two to my rear seat cowl and have them on a quick connect type attachment so can be used when out and about and then when back in garage, disconect and connect to a panel mounted on garage door, so effectively swapping the panels so gets trickled charged wherever she is.

    Is there a minimum panel needed for the cowl to make it worth it, or will any do?

    Would I need a charge controler or would a diode be enough to stop the cowl panel causing any discharge? Also, is there any concern with overcharging and having it plugged in whilst running the bike (ie whilst riding).

    Regards the garage door panel, would a 20w panel with controler be safe for leaving plugged in, ie same overcharge and discharge preventions.

    Sorry for all the A's, I don't understand solar and this is my first foray so any help would be great.

    Kind regards, Upex
     
  2. Dodgydave

    Distinguished Member

    Jun 22, 2012
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  3. wayneh

    Expert

    Sep 9, 2010
    12,094
    3,033
    If the panel is small enough, all you need is a blocking diode to prevent reverse current. With a small panel the current flow in full sun, into a charged battery, will be small enough that the battery can absorb it as a constant trickle. You want a panel that can produce at least about 18V in open circuit (no load).

    If the panel is capable of over-charging the battery, then you need a charge controller such as the current shunt in the first link from Dodgydave.

    If you have the battery and panel specs, folks around here can help you determine how they match up.
     
  4. Upex

    Thread Starter Member

    Nov 10, 2013
    67
    3
    Thanks for the replies folks.

    Dodgydave - not sure if I need linear charge etc as brand new to this and it all over my head. Was holding to literally buy the bits on plug together if possible, rather than building anything bespoke, unless that's the only way to achieve it etc.

    Wayneh - not clued up on battery and charge behavior etc, but the on bike panel will have to be small. Only the size of the back seat cowl, or two smaller ones, one on either side. Thinking 20-30cm long by 15-20cm wide tops.

    Would this size be any good to trickle charge?

    Battery is:

    Specification
    Voltage 12 Volts
    Capacity 14 Ah
    CCA 190 A
    Length 151 mm
    Width 88 mm
    Height 147 mm

    The clamp on 1.5w panels would be the type of thing I'm looking for, but want to build it in so can be there and still ridden and no one can walk by and nab it. That's why I've not got one off the shelf already. Guess I'm after the same thing, but a permanent fixture.

    Will this be possible? Ie could one of the normal ones be used if the engine is running, or can they only be used with engine off?

    Thanks for the help thus far folks.

    Upex
     
  5. DerStrom8

    Well-Known Member

    Feb 20, 2011
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    Not sure if this thread will remain open--vehicle modifications are not allowed to be discussed here due to safety and liability issues. This rule comes directly from the ToS.

    Not sure if the moderators will allow it, so just be warned that this thread may be closed.
     
  6. Upex

    Thread Starter Member

    Nov 10, 2013
    67
    3
    I guess my questions at this stage are:

    1) What size panel do I need to put on the garage door to trickle charge the battery when its parked in the garage.

    2) what type and size disconnect can be used to save me having to remove the seat to connect the garage or tail panel?

    3) what size cable do I need to use for the garage door panel to disconnect, and from batter to the other end of the connector (the perm cables to be left on the bike)?

    4) what ratings / power panel will be the minimum for the small tail panel?
    4) what cable is needed from the small tail panel and to the disconnect?
    5) how best to manage any charge for both small tail and larger garage door panels?
    6) will both these be safe to leave plugged in for a week or two if I don't use the bike?
    7) will the tail panel be ok to leave connected whilst riding?
    Thanks all, upex
     
  7. Upex

    Thread Starter Member

    Nov 10, 2013
    67
    3
    Derstorm8, ok, thanks for heads up. I hope that it doesnt get closed as its litterally how to maintain a better charge and the only mod the bike would be to cut a hole in my seat cowling, which I can take off anyway etc, so not interfering with safety etc.

    Not to mention that anyhelp to get it right will avoid me strapping a portable one to the tail with duct tape and bungies, which is a safety and liabilty issue, but will the angle I take if can not figure out how to use my own tail panels.

    Cheers though, Upex
     
  8. DerStrom8

    Well-Known Member

    Feb 20, 2011
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    No worries Upex, just wanted to let you know just in case :)

    Regards,
    Matt
     
  9. Upex

    Thread Starter Member

    Nov 10, 2013
    67
    3
    Much appreciated. Least ill not I'm not going loopy if can't find the thread LOL.

    Cheers, Upex
     
  10. wayneh

    Expert

    Sep 9, 2010
    12,094
    3,033
    Without doing the math, I think that's plenty. They sell dashboard panels no larger than that for cars. They plug into the accessory outlet, which must be always-on for the battery to charge without the ignition on.

    Sizing a panel to a battery is complicated. Too big and you need a charge controller to avoid harming the battery. Upside: Faster charging and the controller does a nice job. Too small, and the panel helps very little. Upside: There's no danger to the battery and the electronics are as simple as a single blocking diode.

    Some of the aspects to consider are how much solar exposure you have, how the panel will be used, the required amount of power needed and things like that. Basically, how much juice is needed while the bike is hooked up and the sun is out. Only you can answer those things. The faster you want to charge and the more often you'll need a charge on cloudy days, the larger the panel you need. If you're talking about a near-constant trickle just to keep the battery at 100%, then the panel can be quite small, maybe just 10cm square or so.
     
  11. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,535
    I referred this to the other mods, and the verdict is in.

    The owners of All About Circuits has elected not to host discussions of automotive electrical system modifications/enhancements due to safety concerns, the potential of legal ramifications and the possible circumvention of vehicle regulations at the state and federal level.

    This thread is against the AAC forum rules, Chapter 6, as seen here:

    This can be found in our Terms of Service (ToS)

    Automotive modifications of any kind are strictly forbidden. Therefore, this thread will be closed.

    Please try to understand the reasons behind this action, and feel free to browse and use the forums.

    You might find answers to your questions in one of these forums:

    http://forum.allaboutcircuits.com/showthread.php?t=54400

    Another good forum that shares many of the same membership is http://www.electro-tech-online.com/ . Good luck.
     
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