I am having trouble understanding Watts and voltage. I have a led bulb that projects reasonably well from my 5.75” housing. My system is a CDI with 75watt lighting coil. I want to know what happens if I feed the led headlight from the battery. Or why can’t I do that. My battery is 12 volt 5Ah/20hr. Can I not Just use The light voltage to keep the battery charged? My led is 18w on high beam. The rest of the bike already runs off batt. Sorry I just don’t see the issues with this
Adding a LED to an aftermarket large housing.
- Thread starter Deoodles
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Kirrbby is right. It's available current output from the alternator, minus total current draw (entire system) equals amount of current left to charge the battery. IF the remainder is a positive number, that's how many watts are available to charge the battery. (As long as that's at least 5-8W, you should be okay, although values below 10-15W are going to mean very slow charging capability, with 12v.) If the number is a negative value, the battery will discharge...and the rate of discharge can be calculated. The basic formula: volts x amps = watts...a manipulation of Ohm's law...analagous to horsepower = torque x rpm/5252. With some basic algebra, any missing value can be calculated.
LEDs don't like AC, so battery feed is ideal...as long as you can supply enough DC charging voltage to keep the battery from discharging. How's that 75W alternator outputting that power? If it's the full 75w, you could power an H4...or later 65W automotive version. If it's 100% available as DC, then your biggest concern would be a regulator that controls output well enough to prevent the battery from being cooked. OTOH, if it's a typical half-wave system...with a split/"balanced" output...then AT MOST, 50% of alternator output is fed to a diode, leaving less than half of that as DC voltage. That'd be somewhere around 15-18W, max. It could be a 5-pole radial array stator...in which case the coil arrays would be split 3/2, with the smaller, 2-coil array feeding the charging circuit, unless you swap the feeds (white for yellow). The thing to remember is that a diode, with a half-wave system, not only transforms half of the AC waveform into waste heat...it's not very efficient, so you'll get less than 50% of the AC input as DC output.
FYI, I ran everything off of battery power (5.0ah/12v) for 15 years...knowing that the system ran at a partial loss. With a 35W incandescent HL bulb, 1157 array LED TL rated at 1W/5W, that left the system with -18W, while the HL was powered. That's 1.5a @ 12v... 1.5 x 3 = 4.5, thus I estimated 2-3 hours of usable HL power, before the 12v/5.0ah battery was completely discharged. I've since gone to an 18W/24W LED headlight...and a full-wave DC system, with an estimated 70W (a conservative estimate) available output. I probably could have gotten by (just) with the old system, leaving one 3-coil array unused and it would have been a big improvement. An 18W LED can be impressively bright. However, there are sound reasons why running a partial-loss electrical system can be a bad idea. I've a horrible tendency to leave the HL "ON" and that's very easily overlooked on a sunny afternoon. Having enough electrical output to power everything and charge a drained battery can be more than just convenient...especially if you're riding back home around sunset.
LEDs don't like AC, so battery feed is ideal...as long as you can supply enough DC charging voltage to keep the battery from discharging. How's that 75W alternator outputting that power? If it's the full 75w, you could power an H4...or later 65W automotive version. If it's 100% available as DC, then your biggest concern would be a regulator that controls output well enough to prevent the battery from being cooked. OTOH, if it's a typical half-wave system...with a split/"balanced" output...then AT MOST, 50% of alternator output is fed to a diode, leaving less than half of that as DC voltage. That'd be somewhere around 15-18W, max. It could be a 5-pole radial array stator...in which case the coil arrays would be split 3/2, with the smaller, 2-coil array feeding the charging circuit, unless you swap the feeds (white for yellow). The thing to remember is that a diode, with a half-wave system, not only transforms half of the AC waveform into waste heat...it's not very efficient, so you'll get less than 50% of the AC input as DC output.
FYI, I ran everything off of battery power (5.0ah/12v) for 15 years...knowing that the system ran at a partial loss. With a 35W incandescent HL bulb, 1157 array LED TL rated at 1W/5W, that left the system with -18W, while the HL was powered. That's 1.5a @ 12v... 1.5 x 3 = 4.5, thus I estimated 2-3 hours of usable HL power, before the 12v/5.0ah battery was completely discharged. I've since gone to an 18W/24W LED headlight...and a full-wave DC system, with an estimated 70W (a conservative estimate) available output. I probably could have gotten by (just) with the old system, leaving one 3-coil array unused and it would have been a big improvement. An 18W LED can be impressively bright. However, there are sound reasons why running a partial-loss electrical system can be a bad idea. I've a horrible tendency to leave the HL "ON" and that's very easily overlooked on a sunny afternoon. Having enough electrical output to power everything and charge a drained battery can be more than just convenient...especially if you're riding back home around sunset.
Looks like I have a little more to ask. Yes it is a 5 pole array. It seems that it may be closer to 90 watts. As I am never inside my box on electrical systems I’m going to ask for some step by step. What is my next move. Clearly I can run wire to feed the headlight but from where. And, what’s tests do I perform and from where. This is my stator and aftermarket wiring system.
The yellow lead of your system is T'd with the HL circuit feed & reg/rec unit...same as every Honda since the Z50 K0. But...the Lifan schematic shows no stator ground and that's confusing, to me, at present, because your system otherwise appears to have the same circuitry as any other half-wave (grounded stator) system.
What I'm seeing in the dratv schematic indicates a floating ground stator. I don't see how it's possible to run a 3-coil array to power the HL and a 2-coil array to a diode...without a ground. If the five coils are wired in-series, there's an additional problem, even with a floating ground...it's an odd number of coils. So, assuming that each coil is wound in reverse rotation, relative to its neighbors...there's an uneven number between the two winding rotations. To use a full-wave, bridge diode rectifier, there has to be an equal "push-pull" to feed each side of the diode bridge...and get DC output.
I'm guessing that the schematic shown, is not completely correct. One thing you can check for yourself...continuity between the yellow stator output and ground, that can be done for the white lead, also. Unplug the stator from the harness first. Continuity, to ground, means you have a grounded stator. A floating-ground stator will have continuity between the outputs only.
Now...I hope this makes sense.
What I'm seeing in the dratv schematic indicates a floating ground stator. I don't see how it's possible to run a 3-coil array to power the HL and a 2-coil array to a diode...without a ground. If the five coils are wired in-series, there's an additional problem, even with a floating ground...it's an odd number of coils. So, assuming that each coil is wound in reverse rotation, relative to its neighbors...there's an uneven number between the two winding rotations. To use a full-wave, bridge diode rectifier, there has to be an equal "push-pull" to feed each side of the diode bridge...and get DC output.
I'm guessing that the schematic shown, is not completely correct. One thing you can check for yourself...continuity between the yellow stator output and ground, that can be done for the white lead, also. Unplug the stator from the harness first. Continuity, to ground, means you have a grounded stator. A floating-ground stator will have continuity between the outputs only.
Now...I hope this makes sense.
Not really understanding why the ground is important, to me feeding the yellow switch side of the left handle switch from pos on the battery will feed dc to the led. What to do with the yellow that fed the switch isn’t anything I thought about. I was hoping total dc draw would be low enough to not be concerned. My water system skills help me read a schematic but don’t really help with an electrical schematic
Almost worked. I have to locate a keyed batt source. The light is nice and bright. I don’t know what state my charge will be in when I run the bike. How do I test that? I’m not going to pick up on full wave, floating ground, or any other concepts that easily. I don’t know how a regulator works or how some is turned into dc and some ac. Not my area. What I do understand is I may have an unused ac lead. Can I add that to my batt somehow to add charging capacity
Clearly I don’t have enough battery to pull this off. My blinkers flash the headlight. They could be swapped for led. I don’t know my charge rate but I could easily enough go out after dark and try to kill the battery. I thought since signal bulbs are 17w that the led would work it still may. I may swap signals to led and try again
An electronic relay will cure the flash rate problem, regardless of load, making any combination of bulbs & LEDs possible. The battery should be able to provide way more current than the alternator and that my work to power short-term/intermittent high-current loads.
As for explaining grounded and floating ground coils, it's not complicated as it might seem. Any coil is just a length of wire wrapped around a core (armature). That wire has two ends. If one is run to ground, it's a grounded coil. If both ends are free (not grounded) then you have a floating ground...each lead can be used to feed one input of a full-wave bridge diode rectifier, the rectifier/regulator unit, itself, is grounded; that's how a full wave system is configured. With a stator that has a radial array, the coils are wound, in-series, each one in the opposite direction. That creates the same effect as a large, single, coil (as with the 6v stators). That's about you need to understand to navigate your way through one of these electrical systems...and enough time to work your way through it all.
As for explaining grounded and floating ground coils, it's not complicated as it might seem. Any coil is just a length of wire wrapped around a core (armature). That wire has two ends. If one is run to ground, it's a grounded coil. If both ends are free (not grounded) then you have a floating ground...each lead can be used to feed one input of a full-wave bridge diode rectifier, the rectifier/regulator unit, itself, is grounded; that's how a full wave system is configured. With a stator that has a radial array, the coils are wound, in-series, each one in the opposite direction. That creates the same effect as a large, single, coil (as with the 6v stators). That's about you need to understand to navigate your way through one of these electrical systems...and enough time to work your way through it all.
Battery voltage 12.7v.
Turn on lights voltage is 12.2v
Run motor at 4K battery voltage is 12.5v
disconnected daytime running bulbs 8w each
Battery v 12.5 (lower than before from testing)
battery with lights on motor off 12.2
Battery with motor running no running lights but headlight and taillight on 13.1v at 4K
Led running/signal bulbs may be the cure. BUT.... what happens to the system with yellow wire at headlight disconnected. I don’t want to cause damage
white to ground continuity
Yellow to ground continuity
White to yellow no continuity
Now I understand my setup is grounded and full wave isn’t possible
thanks.
Turn on lights voltage is 12.2v
Run motor at 4K battery voltage is 12.5v
disconnected daytime running bulbs 8w each
Battery v 12.5 (lower than before from testing)
battery with lights on motor off 12.2
Battery with motor running no running lights but headlight and taillight on 13.1v at 4K
Led running/signal bulbs may be the cure. BUT.... what happens to the system with yellow wire at headlight disconnected. I don’t want to cause damage
white to ground continuity
Yellow to ground continuity
White to yellow no continuity
Now I understand my setup is grounded and full wave isn’t possible
thanks.
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Based on those results, I'd say that you have two, discrete, coil arrays...one consisting of 3 coils, the other consisting of two. Leaving one unconnected won't hurt anything, there's no electrical load. I would, however, try using the 3-coil array for the higher current output.
BTW, I spent a lot of frustrating hours, over a span of years, trying to realize a full wave electrical system. I had a stator modified, which means lifting the grounds and wiring all six coils in series, with the winding rotation correctly oriented. It works...beautifully. Unfortunately, the wiring mods were done so well that my aging eyes haven't been good enough, yet, to figure out exactly what has been altered. There's always rewinding, from scratch, but I'd rather not do that to a brand-new, OEM Honda stator. The coils were epoxied from the factory, bulletproof stuff. This is why I'd use a CRF 50/70 stator, for a 49cc-based build. They had 5 bare armature posts; only the CT70 version had lighting coils.
It is possible to run two separate diodes, in a half-wave system...one for each coil array. The Achilles heel of half wave is voltage regulation. That said, I somehow managed to get a dozen years from one SLA battery, running an OEM 12V Honda half-wave reg/rec and only using one 3-coil array.
BTW, I spent a lot of frustrating hours, over a span of years, trying to realize a full wave electrical system. I had a stator modified, which means lifting the grounds and wiring all six coils in series, with the winding rotation correctly oriented. It works...beautifully. Unfortunately, the wiring mods were done so well that my aging eyes haven't been good enough, yet, to figure out exactly what has been altered. There's always rewinding, from scratch, but I'd rather not do that to a brand-new, OEM Honda stator. The coils were epoxied from the factory, bulletproof stuff. This is why I'd use a CRF 50/70 stator, for a 49cc-based build. They had 5 bare armature posts; only the CT70 version had lighting coils.
It is possible to run two separate diodes, in a half-wave system...one for each coil array. The Achilles heel of half wave is voltage regulation. That said, I somehow managed to get a dozen years from one SLA battery, running an OEM 12V Honda half-wave reg/rec and only using one 3-coil array.
Thanks.
So I can switch white and yellow at the voltage reg looking for the better coil set?
Also. The 13.1 is enough to keep the battery charged?
I found some 2w led bulbs for the signals
One last question. What happens if I use both white and yellow at the regulator or why not?
So I can switch white and yellow at the voltage reg looking for the better coil set?
Also. The 13.1 is enough to keep the battery charged?
I found some 2w led bulbs for the signals
One last question. What happens if I use both white and yellow at the regulator or why not?
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kirrbby
Well-Known Member
On the reg/rec...
I think one of the outputs...yellow I think...is regulated AC power. It's regulated, but not rectified.
The other output...white wire..? is rectified to DC, but it's not regulated. Some power is lost in the process of rectifying to DC, some is used by lighting, excess charges the battery, battery is the buffer that soaks up voltage spikes.
On the DC side, feeding it too much power could cook the battery.
A partIng thought. Why not isolate the signal system and use the un used ac lead to power them. They are the biggest drain on the system and not in use often. It would allow me to keep the dc system charged and eliminate the headlight flash when the signals are used. It seems like the perfect use of available power solution for the limited system. Any thoughts before I attempt? Comments?
I think you'll be fine with just a little testing & a minor tweak, or two. Only thing that surprises me is how your turn signals seem to be draining the entire system; there's either a bad connection (possibly an oxidized contact) somewhere in the system, oversize (in terms of wattage) bulbs, or a weak battery. Seriously, I've run old-school turn signals, using a 12v 5.0ah SLA battery and never had the HL pulsate like this, even with the engine not running. It's a bit of a head-scratcher.
I'd go for LED signal bulbs and an electronic flasher relay. That's rock-solid reliability, long service life and no more wild spikes in current draw...everything powered from the battery. The last electronic flasher relay I sourced was a $35 item.
Just as mph turns a speedometer into a surprisingly reliable "poor man's dynamometer", a voltmeter can be used to test system electrical output/load balance. As long as acceptable voltage levels are sustained, under maximum load, you know (accurately enough) that you're not running a partial-loss charging system, or cooking the battery (from over-voltage).
A seriously "teachable moment" occurred the first time I restored a non-battery-equipped Z50. Just going 5W "too heavy" with the HL bulb resulted in dull orange light output. Hard to believe that Honda made these "balanced" electrical systems work as well as they did...by matching current draw this closely ("balancing") to alternator output. IMO, that's a plate-spinning/high-wire balancing act...one little change and the whole act fails. I ended up sourcing a number of bulbs, of the same nominal wattages, before finding a combo that delivered acceptable light output without popping filaments.
Using your 90W figure, there should be (nominally) 18W per coil (18 x 5 = 90). That gives you a choice of a 36W array or a 54W array...18W or 27W DC (less current losses due to diode inefficiency), using a simple diode rectifier. One of those should come very close to OEM-style "balance", with your lighting/charging setup...probably neither will cook a battery anytime soon.
Parting thought...voltage regulation is where a full-wave bridge diode reg/rec unit truly shines. You get 95%, or better, alternator output as clean DC, any excess voltage gets dumped to ground and peak system voltage can be adjusted to within 0.1V via trimpot.
I'd go for LED signal bulbs and an electronic flasher relay. That's rock-solid reliability, long service life and no more wild spikes in current draw...everything powered from the battery. The last electronic flasher relay I sourced was a $35 item.
Just as mph turns a speedometer into a surprisingly reliable "poor man's dynamometer", a voltmeter can be used to test system electrical output/load balance. As long as acceptable voltage levels are sustained, under maximum load, you know (accurately enough) that you're not running a partial-loss charging system, or cooking the battery (from over-voltage).
A seriously "teachable moment" occurred the first time I restored a non-battery-equipped Z50. Just going 5W "too heavy" with the HL bulb resulted in dull orange light output. Hard to believe that Honda made these "balanced" electrical systems work as well as they did...by matching current draw this closely ("balancing") to alternator output. IMO, that's a plate-spinning/high-wire balancing act...one little change and the whole act fails. I ended up sourcing a number of bulbs, of the same nominal wattages, before finding a combo that delivered acceptable light output without popping filaments.
Using your 90W figure, there should be (nominally) 18W per coil (18 x 5 = 90). That gives you a choice of a 36W array or a 54W array...18W or 27W DC (less current losses due to diode inefficiency), using a simple diode rectifier. One of those should come very close to OEM-style "balance", with your lighting/charging setup...probably neither will cook a battery anytime soon.
Parting thought...voltage regulation is where a full-wave bridge diode reg/rec unit truly shines. You get 95%, or better, alternator output as clean DC, any excess voltage gets dumped to ground and peak system voltage can be adjusted to within 0.1V via trimpot.
Can I use that on the ac line? Signals pull 32 watts. 8 per bulb plus the 2 running lights up front. I jumped yellow ac input from the regulator to the black at the flasher. All works properly without visible drain anywhere including the led headlight and still 13.1v dc at the battery. This exercise was very helpful. I have great lighting no drain and an awesome LED headlight. Very happy
I'm pretty well over my head when it comes to understanding, let lone calculating, the effects of transient load spikes...such as turn signals. By-the-numbers, your turn signals should be drawing no more than 17-18W, as only two bulbs are being activated at any given time and only for a fraction of a second. That 5.0ah battery should be capable of delivering up to 60W for an hour before being totally discharged. And peak current delivery can easily exceed 10 amps, as evidenced by short circuits resulting in nothing more than popped 10a fuses. Your turn signals pull less than 2 amps. Doing a little bit of mental math, peak draw of your entire system should be somewhere close to 4 amps.
As much as I prefer knowing what a system is doing, over edumacated guesses, (i.e. the "why") there does come a time when the most practical solution is to figure what works and just enjoy the fruits of your labor. The bottom line is that "whatever works, works" whether we know the why or how behind it. In this case, if the lighting and battery life are acceptable, you've succeeded.
As much as I prefer knowing what a system is doing, over edumacated guesses, (i.e. the "why") there does come a time when the most practical solution is to figure what works and just enjoy the fruits of your labor. The bottom line is that "whatever works, works" whether we know the why or how behind it. In this case, if the lighting and battery life are acceptable, you've succeeded.