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Solar Panel on Top Box?

Discussion in 'Equipment' started by Snarky, Apr 24, 2013.

  1. Snarky

    Snarky Vodka Infused.

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    I was bored and was looking for things to experiment with...

    I wanted to put a 10w panel on my bike. For several reasons:
    1. To use as a trickle charger, because my commute is short (really short), and I don't feel the bike gets adequate recharging after the starting process.

    2. Although the bike has good power output and a decent sized battery, I wouldn't want to run it to power a communications or entertainment device while camping or whatever. It's hot outside... So I wanted it disconnectable

    3. I've only seen a few bikes with top case panels before, and I wanted to experiment with it.

    The panel I ordered is 13" x ~12", with a 10 watt output ~12 volts nominal. Since watts = volts x amps, it should output ~.8 amps, which reviews say it does nicely. I believe the GSA has a ~12Ah battery, which I believe means it should deliver about 12 amps at 12 volts for 1 hour, although chemical and physical limitations make this impossible I think.

    You divide 12 Ah by .8 amps, which equals ~15 hours. So I think if it were theoretically possible to completely drain and recharge this battery, which it isn't, it would take about 2 days of sun light to do so. My math could be wrong... However, I think for real world use and minor drain on a battery that spends most of it's time 95% full, 10 watts of solar power is plenty....

    My ultrabook drains about 30w of power at 12v, so it would theoretically take ~3 hours of panel charge for 1 hour of usage. But I think for the iphone 1 hour of sun should get you at least as much charge. Of course a lot of this stuff is math and not practical other than to get an idea of things. The real world will vary.

    Anyways... stuff:

    10W Ramsond Monocrystalline PV Solar module, it's ~13" x 12" and I bought it because of it's size compared to the top of my pelican 1500 top case. It has an aluminum frame and an impact resistant glass.
    [​IMG]

    Pelican 1500.
    [​IMG]

    Ramsond 8 Amp Solar Charge Controller Regulator.
    [​IMG]

    A few battery tender connections.
    [​IMG]

    I also have a small 4.6Ah 12v lithium battery pack laying around, which I threw in there.

    Here was the plan before I started...
    [​IMG]

    Here's the panel mounted to the box...
    [​IMG]

    Rubber grommets for a little shock resistance.
    [​IMG]

    Charge Controller.
    [​IMG]

    Wires and battery that need to be tidied.
    [​IMG]

    Output cable.
    [​IMG]

    Off bike.
    [​IMG]

    On bike.
    [​IMG]

    [​IMG]

    Charging.
    [​IMG]

    Connection to bike.
    [​IMG]

    [​IMG]

    Case opened.
    [​IMG]

    Obviously I'm missing something: multimeter readings! My Craftsman multimeter is dead, even after a battery change, I need to take another look at it and see if I can resurrect it. I don't trust my wiring of black and black wires without a multimeter, so the power unit is remaining disconnected from the bike until I make sure. Might have to buy a new meter...

    Manufacturer specified this panel to withstand ~44kg of weight. I don't plan on loading it that heavy, but I should still be able to strap things onto the panel when I need to, such as my water bag. This panel was also rated for 145 mph winds, and a few other things that are probably bullshit. But it does have a 25 year warranty on power output, but something equally implausible. Whatever, it was only 40$... Although all my holes were tight for the bolts and wires, I still need to dab a bit of sealant on them, I also want to get a little velcrow wire keeper to hold the power box's cable closer to the bike. I also need to clean up the interior wiring with some zip ties.
    #1
  2. * SHAG *

    * SHAG * Unstable

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    Now I understand your Avatar. I have a headache after reading that! :1drink :lol3

    Just don't forget to put new batteries in your flashlight before your next trip :freaky
    #2
    08StangGT_CS likes this.
  3. lhendrik

    lhendrik Putins Puppet

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    That is very cool and practical. I want to do this too.
    #3
  4. worwig

    worwig Long timer

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    Don't forget that the 10 watt figure that they give is with the panel alligned nearly perfectly. So figure a good percentage less due to misalignment. I would use 50% just to make sure I have enough factored in.

    Also, do you need any protection on that lithium pack? If you run it too low, it is destroyed.
    If you are paralleling the Lithium battery and the bikes main battery, you may pop the fuse constantly when you start the bike. One way around that would be to put a headlight bulb, or such, in series with the fuse.
    #4
  5. Grinnin

    Grinnin Forever N00b Supporter

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    Sweet!

    Your reasons for adding solar panel actually make sense and your installation looks good. (I've read posts asking about solar panels on a bike when they don't make so much sense, such as power for camping.)

    Your post mentioned a couple of measurements and doubt or questions about them.

    A 12Ah motorcycle battery is probably measured at the 10 hour rate, i.e. 1.2A for 10 hours. Using 12A will discharge it in far less than an hour. You'll get less than 12Ah out of it if you discharge it faster than the rate they used to measure capacity.

    The 10W panel is similarly rated in not-quite-realistic conditions (although you come far closer where you are than we do up here in Maine).

    You also mentioned that the panel is 12V, but some 12V panels are 14V or so and many are 16V to allow for longer wires (and more voltage drop) to a battery.

    Now I have a question: Do you intend to disconnect the lithium battery when you connect to the MC battery? Would the lithium battery be protected from the bike's charging system if you just rode away instead of disconnecting? (I.e. do you have blocking diodes in the circuit?)

    Thanks for showing it!
    #5
  6. genka

    genka SUV hater

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    Interesting project! Keep in mind that the load capacity refers to a static load, bumps on the road and uneven distribution of weight may overload the panel. I would also install an inexpensive voltmeter to keep an eye on the battery.
    #6
  7. Snarky

    Snarky Vodka Infused.

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    Yeah, it's 'ideal' wattage with everything perfect. It will never reach it, but will probably still be pretty close in El Paso tho...

    I would like to get a volt meter for it to monitor it's usage. I'm not too concerned about it tho. It was rubbish as a main battery, so it was just laying around waiting for a use
    #7
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  8. Snarky

    Snarky Vodka Infused.

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    Thanks for the info. I don't envision any problems with the lithium connected all the time if needed. It shouldn't need protection, as it used to be the bike's main battery and has protective electronics to keep it from being on fire, it's pretty stout outside of cold weather. The bike should be able to handle the charging of both batteries. I hope tomorrow to get some multimeter readings off the lithium, the charging system, and the solar panel. The solar panel is supposidly rated conservatively, many people report it's putting out at least 10w in normal conditions, so we'll see.
    #8
  9. Pib

    Pib Adventurer

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    #9
  10. Friction275

    Friction275 Been here awhile

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    Nicely done, I like your style. Boredom breeds the best invention. I built a similar system for camping power and emergency power for small devices.

    I used 2x30w 12v (18v actual) panels run in parallel through a charge controller to 2 12v 12ah batteries, also in parallel. the charge controller feeds a single 12v lighter port with up to 5amps and automatically cuts off power to the port if the battery gets to low so the batteries cannot be damaged through normal use. I did wired it so I could bypassed the charge controller and feed the 12v port on the front of the case directly from the batteries if I am ever more concerned about having more power then I am about damaging the batteries.

    [​IMG]

    [​IMG]

    These links have good info on charging of SLA batteries and answer some of the questions above.
    http://www.powerstream.com/SLA.htm

    http://www.surplusbattery.com/batteryimg/10_facts_about_agm_batteries.html
    #10
  11. Snarky

    Snarky Vodka Infused.

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    Nice set up, I'm jealous. I think I need to get, not necessarily a different charge controller, but certainly some kind of power cut off device that cuts power from the panel's battery at a certain point. I'll browse amazon a bit later.



    So anyways, I finally got my damned multimeter to work today... The old multimeter batteries were toast, leaking like crazy. So I replaced those yesterday, but it still didn't work. Popped it open today and cleaned the battery contacts, still no worky.
    [​IMG]

    Then I looked at the fuse... nothing inside, the element has vanished....
    [​IMG]

    I don't keep mini glass fuses around, so I rigged up a temporary jumper with a tiny wire and a little solder. It's a cheap meter anyways, and I'm not reading high voltages, I'll replace the fuse later on.
    [​IMG]

    It's got some life finally!
    [​IMG]

    Anyways, next I measured the battery's charge, putting out a nice ~14 volts.
    [​IMG]

    Next I measured between the controller and the panel, in the area that is taped to the lid.
    [​IMG]

    From inside a dark room, through blinds, on a cloudy day, I'm getting about ~5 volts or ~.10 amps. Which should be good enough to charge an iphone. That was with the battery disconnected. Reading from after the charge controller without a battery yields 0 volts, because the charge controller turns off power.
    [​IMG]
    [​IMG]
    [​IMG]

    Not only is the charge controller supposed to prevent power drain with no light, but the panel is supposed to have a diode too.

    I'll get some more outdoor readings, probably tomorrow when it stops being a cloudy dust stormy day in El Paso
    #11
  12. Snarky

    Snarky Vodka Infused.

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    I was searching for my sealant goop today. I still haven't found it. Instead I found the Fuzeblock off my Versys and an old 12v switch. I figured the fuzeblock would allow me to isolate things with fuses and allow me to turn on/off certain accessories with the switch if needed. I need to find a few fuses.

    I so far I have the battery connect to the main power, the solar panel on one circuit, the input/output from the bike on another, and a 12 outlet on another.

    I put the switch between the battery and the 12v trigger on the fuzeblock. I would like to find some kind of device to put between the battery and fuse block that shuts off the accessories with a draw at a certain threshold. I'll look more into that.

    [​IMG]
    #12
  13. Friction275

    Friction275 Been here awhile

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    I think you can use any charge controller equipped with a low voltage disconnect to do what you want to do. The power through the controllers 12v terminals is usually limited to ~5 amps or less but if you need more than that you can use that as the switching/trigger lead on a relay between your battery and the accessories.

    Most basic 12v automotive relays can handle up to about 30amps so with an LDV equipped charge controller and an external relay you could have all the power going into the power block regulated by the charge controller with or without the solar panel even being hooked up. If you ran a second lead to the trigger wire on the relay, through a switch, from the battery itself that would function as a manual override for the charge controller.

    I found all my stuff on amazon and they have several cheap LDV charge controllers available. The only differences are in the logic within the systems. Different companies use different voltages for the voltage cut off and recconect limits and the "best" settings are highly debatable and subjective based on the battery chemistry being used.
    #13
  14. Friction275

    Friction275 Been here awhile

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    "I'm getting about ~5 volts or ~.10 amps. Which should be good enough to charge an iphone."

    By spec, an IPhone 4/5 requires a full amp to charge. I've pulled it off with slightly less but even a spec USB port at .5 amps can't handle it. The phones will usually show that they are plugged in but not charging. The older iPhones could charge from .5 amps and slightly less but I'm confident that at .1, even if increased when you cut the voltage to 5.5v for USB, will not be enought to charge an iPhone.
    #14
  15. swimmer

    swimmer armchair asshole

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    How will you reconcile your urges, on a hot day, to park in the shade?
    #15
  16. Yossarian™

    Yossarian™ Deputy Cultural Attaché

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    FWIW, you can find VW solar panel chargers on eBay and the like. VW uses them when shipping vehicles, to keep the batteries charged so they are fine when the dealerships take delivery. These units contain all the necessary circuitry to charge a 12v battery.

    Anyone starting this from scratch could do worse than to cannibalize one such unit.
    #16
  17. swimmer

    swimmer armchair asshole

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    Only about 3W though.
    #17
  18. Snarky

    Snarky Vodka Infused.

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    I have an iPhone 4s, I charge it from the computer all the time with other devices on the same port it takes longer, but it always charges. That was that the worst case senario though, inside a building, cloudy day, obstructed light. I checked the output today, it was at 14.5 volts or so from the panel to the controller, didn't check the amps though. I rode about 200 miles today from Tularosa and back, I checked the controller when I stopped, it said they battery was fully charged, which was encouraging. I didn't check voltage at that point though.

    Easy, there isn't any in El Paso. Trees are rare, covered parking is a luxury, parking is almost always away from buildings. It's sad :(

    Yeah, I heard about these, they are supposed to be available for pretty cheap. But this panel was only about 40$, and it seems pretty decent.
    #18
  19. 9Realms

    9Realms Drawn in by the complex plot

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    All great accomplishments.

    You are part way to a solar-lectric bike. :evil


    I do think there is some merit to the solar stuff, I do indeed.
    #19
  20. Snarky

    Snarky Vodka Infused.

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    The other day I installed LEDs under the cabinets in the kitchen for some extra in the prep area. I had a couple of feet of strands left over, so I wanted to add them to my box and get some use out of it's battery power.
    [​IMG]

    They we're all one piece from trimming, so I have to solder the strips together. They are 12 with resistors and everything built in. Unfortunately without an extra controller, I can only do solid colors. I decided to ground the RGB altogether giving it white output. Here they are off.
    [​IMG]

    Here they are on. They are wired to the previously added fuzeblock on the switched trigger. They'll only come on with the switch flipped on. It would like to possibly add a microswitch to flip them on when the box is open. And possibly stay off if theres plenty of ambient light. But one thing at a time. I would also like to add a controller to be able to dim the bright bastards.
    [​IMG]

    I also had some red wheel tape lying around. I was going to use it to redo the tap on my wheels, because it's a bit screwed up. Instead I added two strips of it to the solar panel for some extra visibility. Though, after my new pannier decals, it was entirely unnecessary. .

    Here it is with no light.
    <a href="https://snarky.smugmug.com/Other/solarbike/29083939_ZjD4Qw#!i=2480615395&k=c2QRzBJ&lb=1&s=A" title=""><img src="https://snarky.smugmug.com/Other/solarbike/i-c2QRzBJ/0/L/smugshot_6329387-L.jpg" title="" alt=""></a>

    Here it is with a flash. The old white reflective tape on the top box is brighter than the new tape on the panel.
    <a href="https://snarky.smugmug.com/Other/solarbike/29083939_ZjD4Qw#!i=2480615688&k=P9GZqWf&lb=1&s=A" title=""><img src="https://snarky.smugmug.com/Other/solarbike/i-P9GZqWf/0/L/smugshot_8570890-L.jpg" title="" alt=""></a>

    Here it is from the front. The panel on the back lights up well.
    <a href="https://snarky.smugmug.com/Other/solarbike/29083939_ZjD4Qw#!i=2480615902&k=b4jqS4b&lb=1&s=A" title=""><img src="https://snarky.smugmug.com/Other/solarbike/i-b4jqS4b/0/L/smugshot_4836430-L.jpg" title="" alt=""></a>

    Here's a color look from the front. The panel is bright, but still not as bright as the old white tape on the case. I might take a razor blade to the panel's tape and remove some sections to break it up, like the angled pieces on the panniers.
    [​IMG]
    #20