what to do during a blackout?

Discussion in 'Electrical' started by HeadSmess, Aug 18, 2014.

  1. HeadSmess

    HeadSmess Well-Known Member

    its cold. its wet. its nasty outside.

    so i pulled apart yet another magneto today :)

    and rewound with 800 odd turns of .25 wire, ending up with a coil that delivers approx 30 volts at idle. thats AC, with no load, mind you. dare say it drops a bit with load.

    then snuck on the main winding, but fell a bit short at 2800, reading back on the last time i did this, appears im about 700 short...oh well! yeah, well, it still only took an hour by hand. would have taken me longer to find my winding machine!

    it still started first kick, with a stock cdi and reading about 30 volts there, too. possibly a bit retarded now i guess...

    all for what?

    well, the 800 turns of heavy wire is for my freaking headlight! 18w 12v led monster of a thing, turns the night to day! and my sla battery died due to the vibration, rather awkward as it gets dark at night... ever tried navigating by the white line when there ISNT a white line to navigate by? and if someone pulls out in front of me...ouch. they always do, too!

    theres only about 250 turns normally, so i tripled and added some :)

    the verdict?

    wired up a reggy reccy from the local "dead pitbike pile", ie my shed, found my multimeter is now grumpy and wont give me a good reading BUT... (3v regardless on DC? maybe i should heed that battery indicator and replace it?)

    the headlight and the taillights are now motor powered :) bit of strobing at idle, but that quickly settles down with a touch of throttle.

    next...wire it up permanently and fit some capacitors instead of this 3 kg SLA paperweight :)

    time will tell how reliable it is i guess. 18w is a fair bit of current draw, and thats not factoring in the tails, at least another 5watts there... so im guessing 2 amps. meh. as long as my headlights blindingly bright, doesnt fry out, and well...im happy :)

    pics? what pics? whattya need pics for? maybe in a few days when reliability is thoroughly tested... for now, im keeping that lead counterweight in place, just in case... and carrying a spare magneto :jester:

    was unusual, unwinding this one. appears it was wound "sensibly" with that nasty solder join being what its assumed to be, a centre tap! must have been the one that would run lights previously before it fried out. cus none of the other ones with "white" wires have been able to!
    Fabian likes this.

  2. jaguar

    jaguar Well-Known Member

    so you have a single winding that runs both the CDI and lights?
    or two windings?
    I know from having mine rewound at a local shop that you can only go slightly thicker in wire (because of space limitations) and still remain close in the resistance reading. But anyway that only reflects on the combination of number of turns and wire gauge. If you can get away with using a thicker wire while keeping the stock number of windings then that is the way to go.
    Fabian likes this.
  3. HeadSmess

    HeadSmess Well-Known Member

    two windings.

    replaced the heavy winding with 800 turns of 0.2mm rather than the standard 250 of 0.4mm. as far as i can trust my multimeter, it was 30 volts@idle with no load. stick it on the dyno later on if it doesnt fry out, and get some definite voltage/load readings.

    as far as i can work out from here, 0.4 should take 2 amps. 0.2 is a quarter that! nothings fried yet though? so many other factors to consider, like duty cycle, etc. remember, its not drawing current constantly, unlike DC would. or even 0.717 of the time, with plain AC.


    still had plenty of space for the other 700 odd turns of 0.1 for the ignition, i just didnt check my notes first! im not about to unwind it again. or game to try a join. and as long as its running... doesnt seem to be too critical.

    its not delivering the full 18 watts required, plus some, (lights not getting to full brightness but definitely bright enough for night riding) but hey... yeah i need a new multimeter, why the %^^% is the 10 amp socket unfused? been bugging me since i got the thing(first thing i did, fry its amp socket!)... does everything but amps and frequency count. grrr.

    anyway, i can safely say that its next to impossible to pull 20 watts or so from a HT magneto without totally re-engineering the setup. multiple poles and new stator plates and all that silly stuff. maybe another couple of hundred turns before i say that 100% confidently? iunno. need to set a four jaw up on the winder so i can hold these nasty things anyway. seems like too much effort! hard enough winding on just a bobbin, chuck in the core and its plain frustrating...

    yeah, resistance is meaningless in this case, its the total number of turns that counts. resistance is just the ratio between thickness and length of wire.

    maybe if i used silver wire?

    Fabian likes this.
  4. Fabian

    Fabian Well-Known Member

    This is a productive and useful conversation.
    What could be achieved if the standard magnet were replaced with a short throw ultra high power neodymium magnet setup?
  5. HeadSmess

    HeadSmess Well-Known Member

    i dare say an increase in voltage...more lines of flux being cut by conductors. and currently (oooh, a pun!:p) i need more voltage for my load to get enough current(2 amps)

    mmm, i could make an alloy magnet with a neo or two stuffed into it. problem being they need to be a certain shape so they dont get flung out, but....hmmms. ill think about that one... nothing stopping me from, say...pockets in the alloy, with some steel pole pieces poking through.

    then the timing changes but i dare say its not too hard to find exactly where to cut the (new) keyway.

    making me want to pull the CRO outta the box. in time, in time. too much on my plate currently. an idea for the backburner, let it stew a bit longer.
    Fabian likes this.
  6. HeadSmess

    HeadSmess Well-Known Member

    need to start tinkering with the magneto on a pitbike... they can generate 12v at about 50 watts with just a single coil... couple of magnets in there is about the only difference. is see no real reason other than "thats the way theyre made" to have the magnet inside the stator... definitely a lot easier if its the magnets on the outside ;)
  7. HeadSmess

    HeadSmess Well-Known Member

    this is peculiar.

    today, my cdi failed...well, it still was producing a spark, but it wasnt starting. very weak and insipid, that spark was... ripped one off the other bike and well, fired straight up. so, therefore, the cdi has failed. the handwound magneto was fine :)

    but while i was fiddling, i decided to add the other 1000 turns to the magneto coil.

    still started just as easily, and the run to the PO to get the latest parcel was fine, but heres where it gets weird.

    got home and wired up the lights again. they didnt work! at first, i suspected the regulator/rectifier, as 15+ voltsAC was going in... but less than 5 was coming out.

    its taken some digging, but i finally found just a standard bridge rectifier.

    so. the engine starts, the lights come on almost instantly...and then the engine splutters, coughs, dies. something peculiar is going on here.

    cut the wire to the rectifier. engine runs perfectly again.

    only thing i can think of...there is a limited amount of flux travelling through that magneto. well DUH! :dunce: so, while i had less turns on the ignition side, there was enough surplus to maintain power through the lighting side. exactly how the white wire works as a killswitch. just overloads the poor lil thing. :(

    i also suspect the lowered voltage had something to do with the CDI failing. cant be sure of that one. just a sneaking suspicion. its a pretty old box though. i knew something was going to die today. i had that feeling in my guts, and that lil voice that i always ignore telling me to put the coil and homemade unit off the motor in the dyno on instead, for the last day or two. but ive had that feeling since i wound this thing, and ive really been using it hard the last week just to find out :) been through 20 litres of fuel this week :)

    so there really is only a few options left.

    the neo "rare earth" magnets in the magnet. increase the magnetic strength tenfold!

    a separate coil with its own core, but where to put it? there is space in there, but not much :( if i could get something mounted inside the cover, with the poles at right angles to the existing magnetos poles, so im not trying to "steal" power from the ignition part... that was actually one of the first ideas i had before i stuffed around winding a new magneto!

    it currently seems the most logical too. grrr. i dont wanna do any machining yet! also means i can use any old magneto again.

    make a new magneto system entirely, as mentioned previously. two separate coils, four magnets in the rotor, and then...then one has to change to the same CDI used in just about every other engine...one with a trigger coil! theres that custom work again. not good.

    go back to the unreliable battery setup. i hate batteries. they go flat, leaving you in the middle of nowhere, unable to see or be seen... the whole reason ive been doing this! (though i do need a battery anyway, cus if i snap a chain or finally blow this thing up, but can ride home still...its dark!)

    hmmms. 3 watts is easy. 18+ is another matter entirely :( i refuse to downgrade these lights!

    ive even contemplated sticking a brushless motor in instead of the standard tensioner. but i have the feeling that it just wont spin fast enough to be worth it down there.

    oh well. time to start actually measuring and drawing something. cus i reckon i can get this to work still. i know i have about 10mm of depth between cover and magneto. plenty :)

    really was hoping i could ride to woolies tonight. i need some dinner... thats a 30km round trip that ive been doing nightly this last week :) tacked on top of what i normally have to do... lots :)

    i tend to get complacent... :jester:

    meh. have another coffee and off to bed :)
  8. Fabian

    Fabian Well-Known Member

    :clap: Now that's my kind of language !!!
  9. HeadSmess

    HeadSmess Well-Known Member

    i shall have to order some neo magnets in the near future and try it out.

    and a brushless motor with a low KV rating...

    this doesnt work...

    IMG0006A.jpg IMG0005A.jpg

    made a nice core piece, managed to squeeze 600 turns onto it, and all i get is about 7 volts. grrrr. cant get much better coupling than this had, and definitely cant get any more turns in there! i am not in the mood to make another one!

    may just be that i have a short, having used no insulation, but as it stands... no go.

    (edit...it WAS a shorted turn! back to the winding i guess...)

    oh well :)

    brushless motor as a generator...


    30kv...hmmms. rough maths... 4000 rpm, sprocket will be just under 1000rpm.

    stick a 10 tooth sprocket on brushless, it will spin at 1000 rpm.

    1000/30 = lots :) lets say 30 volts for 900 rpm.

    thats with no load. could actually work. i always liked the idea of the tensioner being a generator as well...
    Fabian likes this.
  10. Fabian

    Fabian Well-Known Member

    Now we are talking !!!

    My thoughts exactly, at least using the SickBikeParts shift kit, left hand side or right hand side chain tensioners as power take-off device.
  11. KCvale

    KCvale Motorized Bicycle Vendor

    Just remember that electric power is not free, it comes at the cost of gasoline engine power.
  12. Fabian

    Fabian Well-Known Member

    So long as i can get my hands on enough electric power (250 watts) to run my heated jacket, heated pants, heated boots and heated gloves, i'll be very happy.
    Last edited: Aug 30, 2014
  13. HeadSmess

    HeadSmess Well-Known Member

    my motorbike was hard pushed to get that! thats over 20 amps at 12 volts! (most are only rated for 120-150 watts) not to mention what it ended up doing to the wiring system(lots of charring and melting and 3 volt drops!)... eventually had to wire the regulator straight to the battery, with a relay on the headlights, powering the heaters directly from the battery only when the engine was running... those oxford heaters had a major drawback... they sent your battery flat if you forgot about them...

    mind you, i ended up with about twelve heaters on it :) removed the defective "brain" from the oxford system, just ran a blinker can for half-heat. ebay sells heater pads for about $5...

    side note...theres also a 200 watt personal refrigerator/cooler available :)

    at one stage i setup a funky system so i could heat AND cool at the flick of a switch :)

    then found the concept was already patented...just not for motorbikes. electric blankets rather. possibly the only type id ever contemplate using, as they DONT have electrizzity running through them.

    mmmm, free power....

    right. ordered said brushless motor, worth a go :)

    need to go get some glue so i can rewind this coil thingy i made...with insulation this time :) maybe skim the slots out another half mm or so... if it does work...it will need laminated core, as it really did get rather warm!

    ooh. i just had the thought...what about a peltier module attached to the head? i know mine are good for 80 watts... shame i scrapped the few heads i made.
  14. KCvale

    KCvale Motorized Bicycle Vendor

    Peltier module's are pretty cool, I looked at them a couple years back to generate power from wasted engine heat.

    I found rechargeable LI batteries to be far less expensive and more reliable.
  15. HeadSmess

    HeadSmess Well-Known Member

    got to agree with that. had several for a few years, never did much with them but i feel quite chuffed that i managed to get one to frost up in the middle of summer :) really good heatsinking.
    still, worth experimenting with one day. calls for making a new head with out fins, attach one of those big fat copper heatsinks from a dead PC...

    my only gripe with li batteries is the po's explode, and the other ones...ive gone back to nicd for my cordless drills?

    though that has been my fallback for the last week. 5000mah lipo with a cellchecker stuck on the balance plug, so i know when its getting too low... and a spare 1800 in the sack on back...

    which i sort of still have/had to do with the generator coil. what happens when something occurs and the motor aint running? yeah... one has to keep their ears open and hide in the bushes when danger lurks! i just dont want to be dependant on a wall wart for lights. extension leads are very restrictive on travelling range!
  16. KCvale

    KCvale Motorized Bicycle Vendor

    Lithium Ion based batteries are in everything from your cell phone and laptop/tablet to your watch and hearing aid.

    Why rob your gas engine of power when you can put 8800mA at 4.2V to power a 1200 lumen CREE LED for $20?


    I don't do much night riding but I love the strobe on lights like this for daytime riding, saved me more than once.
  17. Fabian

    Fabian Well-Known Member

    Even though it does not appear to include a wall charger, it's still a smoking hot price.
    Got to wonder about the quality of the battery cells and light for such a cheap listing.

    Having said that, electric power derived from the engine, never goes flat or needs recharging. So long as the engine is running, you have a bunch of electrons ready to do work; even being able to recharge an 8800mA battery pack.
  18. HeadSmess

    HeadSmess Well-Known Member

    tis rather neat...my gripe with batteries, the whole reason for endeavouring with this task...is that batteries DIE! at the least desirable moment!

    and when the moons not out, and theres 30km of darkness between me and home... kangaroos...wallabies... maniac car drivers with homicidal tendencies... bad roads, no lines, no lights...wtf am i out here for again? oh! cus its actually quite enjoyable when im not about to get run over!!

    i think i have to settle with fabians comment...

    "charging a ****mah battery"....

    i also tend to find every bike light ive purchased lasts about a week before the mount breaks... i like the o-ring type that that light has, but then the ring snaps... another "arrrgh" situation. even my $130 ($30 after a staff discount) headlight, i bought two of them...even theyre currently held together with zip ties! so much for "rugged mountaineering gear" :rolleyes:

    so far my 4wd 18w spotlight hasnt budged, with its 2mm thick, steel mounting bracket :)

    sorta wishing i had settled for 6 watts though, in hindsight... :(

    oh! and warm white leds, i find, are for more "rider friendly" in being able to see! maybe its just my eyes, but these blueish, cold white lights, i just cant see with them... sure, they light everything up, but i cant make out distances, unlike yellow lights.
  19. butre

    butre Well-Known Member

    I've got a tiny little motorcycle battery that's just running LEDs front and rear and the thing lasts ages. I've barely put a dent in the charge in the couple months I've had it
  20. HeadSmess

    HeadSmess Well-Known Member

    18 watts is 1.5 amps at 12volts... a 3ah motorbike/sla battery is useable for just under 2 hours. more like an hour before the voltage drops too far, for the battery's sake. when they work and dont just suddenly collapse, losing all charge completely!

    no. i am not getting weaker lights! these things are better than the HID i had on my moto! finally...i can SEEEE! seeee the light! praise the LED!

    lipo is currently appearing to be the best, and lightest option... at least i already have them on hand :)

    apparently the lights will take up to 35 volts, so i could just use 5s packs (my charger wont do 6...), but that requires a lil bit of expense for packs and a balancer. the current demand is reduced though :)

    still means i have to charge them. carry spares on long trips. yik :ack2: