Switched Power Electrical Question.

Discussion in 'The Garage' started by CDN Rick, Nov 3, 2019.

  1. CDN Rick

    CDN Rick Canoodia Eh?

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    My electrical knowledge is pretty basic so feel free to talk to me like an idiot. I'll appreciate the clarity and probably understand you better if you do know how to help.

    My girlfriend bought a 2008 Honda CRF150F and wants to run heated grips.
    I found a set of grips that require 35w, and I'm told the stator produces 60w. My understanding is that the system on the bike only charges it's own battery, and dumps the rest of the power through the Reg/Rec or Voltage Reg or whatever it's called.

    I want to wire them in so that they ONLY work when the motor is running, My intent was to wire them in with a standard "bosch" relay, but the bike does not have a switched running power wire anywhere on it I can find which runs 12v. It has no headlight, no taillight, it's carbureted, and E-start with no backup kicker. The key switch always has 12v running to it, and from it when it's switched on, but I'm worried she'll forget to turn the key off, run the battery low, and will have no way to restart the bike unless I'm with her to bump start it.

    I did find a wire coming from the stator that varies between ~1v and ~3v depending on rpm, but that won't hold open a Bosch relay.

    Is there a way to wire this that I'm missing?
    Is there a low voltage switching relay that I could use from that stator wire?
    Is there a controller of some sort I could put somewhere in line?
    I'm totally lost on this one.... I dislike electrickery......
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  2. Johann

    Johann Commuterous Tankslapperous

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    Might not be the answer you want to hear but with a stator output that low I wouldn´t want to be adding any accessories, let alone grips. If the output is quoted as 55W then that will be a maximum figure at x amount of revs (normally fairly high). At lower revs or doing slower speed trail work it is going to be less. If the absolute maximum margin you have is 20W when the stator is at max output you haven´t got anything spare at lower revs for the CDI/coil/charging the battery. The first thing to look at would be a stator with a higher output, Baja designs or similar? It depends on the design of your stator as well, some stators have dedicated outputs for the CDI, some are straight to the battery (via R/R) which then in turn powers the CDI (normally via ignition switch). Either way 55W doesn´t give you much to play with.

    With a higher output stator there would be a few options, some grips have an auto shutoff/minimum voltage shutoff if you did forget to turn them off (Oxford grips?) so you can wire them straight to the battery if you want to keep things really simple. A switched live by definition will be live when the ignition is on, to deactivate the relay and kill power to the grips from the battery needs the 12v switched power source to the 85 terminal on the relay to be turned off, which means turning the ignition off. If lights or ignition switch aren´t an option then look for the main fusebox and see what is live with the ignition on.

    As a rough guide a bike I had with an 80W(ish) OEM stator (KLX300), direct AC lighting and no battery could just about power a 35W front light, tailight and the ignition. I had to get the stator rewound just to be able to run a 55W halogen front bulb let alone grips (LEDs would have been another option). A lot of smaller trail trail bikes come as standard with very low output stators.
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  3. CDN Rick

    CDN Rick Canoodia Eh?

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    Interesting...

    Other people I've talked to are running 35w headlights on the same bike without any problem so I figured 35W grips would be fine. They are just wiring straight off the battery and running an inline toggle switch.
    There is no fuse box. It has one fuse on the entire bike, and it's for the e-start system.

    Edit: apparently it’s 60w
    #3
  4. Johann

    Johann Commuterous Tankslapperous

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    Sounds pretty marginal to me, I bet they are getting little to no charge into their batteries with the light on, probably need to start the bike with the light off then wait a while to get a bit of charge into the battery. If you can get it to work for you then great, I´d personally be looking at an upgraded stator, but my first choice option by far would be a pair of hippo hands or thicker winter gloves.
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  5. Granitic

    Granitic Backcountry rider

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    Possible but very marginal. It's a tiny battery designed only to start this little bike.

    Here's what I experienced when I tried to operate LED riding lights on a CRF230F, which is similar: "My RUN-D's pull 1.28 amps x 12.76 volts = 16 watts each. So two are 32 watts. These LEDs run down the battery. With the engine on, they drop the voltage by 0.5 volts. After awhile the battery goes to to 12.3 volts and then it won't crank. Bump starting can be impossible in sandy badlands, canyon bottoms, etc."

    I ended up installing a Trail Tech system which includes a new rec/reg with automatic timed shutoff. Lots of details and pics here:

    http://bit.ly/2KUzFjP

    It has worked great but this was a large and expensive project. Getting the gasket off the left case cover was brutal.

    Maybe look at other options first like excellent cold weather gloves with chemical hand warmers?
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  6. CDN Rick

    CDN Rick Canoodia Eh?

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    Can I ask what year your 230 was?
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  7. Granitic

    Granitic Backcountry rider

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    It's a 2008, as noted in my sig (if you can see it)
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  8. CDN Rick

    CDN Rick Canoodia Eh?

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    I can’t.

    I hardwired the grips to the battery. Battery voltage remains healthy with 5 min of runtime as long as I keep a little bit of throttle....

    Just looking for an answer. Is there a way to create a circuit that only works when the bike is running?
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  9. Johann

    Johann Commuterous Tankslapperous

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    There aren´t many options on a bike with no lights, there has to be 12v DC power between the ignition switch and the starter button with the ignition on. I would normally avoid any ignition wires if possible but not sure what other options there are. That will power the relay with the ignition on. That will still be live if the ignition is turned on regardless of the engine running or not. On a small Japanese bike the power in to the ignition switch is probably red, the power to the starter switch is probably black, the other wires will be for the killswitch but double check with a wiring diagram. Unless somebody else can think of another way of doing what you´re asking?

    Taking power from the stator before the regulator/rectifier isn´t an option, it will be unregulated/unrectified AC.
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  10. CDN Rick

    CDN Rick Canoodia Eh?

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    Understood. That’s what I was worried about.

    My other thought is to wire in a 12v buzzer of sorts to remind her to turn the key off. Is there a way to do this so that the buzzer only sounds when the bike is not running?
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  11. Yinzer Moto

    Yinzer Moto aka: trailer Rails Supporter

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    Do you have any 12v power tools? I have a lot of the M12 tools. I would stick 1 of these batteries behind the headlight. Carry a spare in the backpack. Run them at total loss. Charge them at home.


    https://www.amazon.com/Milwaukee-48...ocphy=9005948&hvtargid=pla-641961311164&psc=1

    DDEA426F-8094-48CB-A7D3-BA7CB3C2A238.jpeg
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  12. CDN Rick

    CDN Rick Canoodia Eh?

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    That’s not a bad plan actually. But I only have Ridgid 18v stuff. Excuse to buy new tools? :D

    Another thought I had is to run a tether cord like the trials guys wear but just use it to break the circuit for the grips. Then when she steps off the bike it would automatically kill the system. I know they come in NO and NC. I’d just have to figure out which one I need.
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  13. Al Tuna

    Al Tuna NSFW

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    Rechargeable heated gloves.
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  14. Yinzer Moto

    Yinzer Moto aka: trailer Rails Supporter

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    Bar mitts and 100% brisker gloves.

    7C2C9D2D-ADB4-44CE-9644-BBEC7CA3A30D.jpeg
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  15. CDN Rick

    CDN Rick Canoodia Eh?

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    I own those and run them on my enduro bike for ice racing and winter riding.

    0% chance they don’t freak her out... they freak me out when I get moving and think about how hard it’s gonna be crashing with my hands stuck in those. I’ve had one crash where I couldn’t get my hand out fast enough to break my fall and it still messes with my head.
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  16. Beezer

    Beezer Long timer Supporter

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    I think there is enough watts there if you manage the load properly.

    "a wire coming from the stator that varies between ~1v and ~3v depending on rpm"... guessing that is AC volts. your meter was set to read AC or DC? no matter, it can still be used as a trigger with the right goodies

    another thought is a timer circuit
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  17. CDN Rick

    CDN Rick Canoodia Eh?

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    Do you know what those goodies would be?
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  18. Beezer

    Beezer Long timer Supporter

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    at random off the net....

    [​IMG]

    that should say "transistor starts conduction FROM collector to emitter". what they show as "battery, 1.5v" would be your trigger circuit, rectified to DC (one diode and probably a capacitor to stabilize it). the 1K resistor they show might need to be a different value. the transistor is a NPN (turns on when base is Positive)

    2 ways to go from here: make all the power for the grips run through the Transistor. to do that, battery connects to the controller, and all the grounds from controller and grips go to the "collector" terminal, the transistor's emitter goes to ground. I have made several controllers for heated vests with a similar circuit using a 3055 trans (couple dollars)

    or: use a small transistor to power a relay coil.... the main battery plus connects to a standard relay. it goes to both the switched power terminal AND one side of the coil. the "ground" side of the relay's coil goes to collector terminal on the transistor, the emitter goes to ground. when the engine runs, the coil energizes and makes the connection to power the grips. something like a TIP29 transistor (probably overkill, but thats all I can think of off hand... stuff I've used)

    either way, you need a diode in the trigger wire to make it 1/2 wave DC, and a capacitor to smooth it out. the cap is wired in parallel with the diode. and then a resistor to limit current. the picture shows a 1K but that value might vary. I would start with a 1N4001 diode, 47mF cap 100v, and a 1k 1/2 watt resistor. have a couple other sizes like a 500 & 680 on hand.

    either way, its only a couple bucks worth of parts tops
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  19. CDN Rick

    CDN Rick Canoodia Eh?

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    I'm pretty confident I follow. Thanks so much for this.
    I'm gonna try work it out a little more in my head then start fabricobbling...
    I really need to up my electrical knowledge game anyways and this isn't a bad project to work on it a little.
    Thanks again!
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  20. Beezer

    Beezer Long timer Supporter

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    they are kool things... "transistor" is a contraction of two words.... transformer and resistor. the guys that invented it came up with that. they can be used as a switch to make an off/on connection like a switch, or as a variable resistor... "transforming" power by changing base current. that makes a proportional change in the C/E circuit
    #20
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