Good replacement LED Headlight bulb?

[davetherave]

Hi,

Please could someone recommend a good LED Headlight bulb?
I currently have a regular H4 fitting Bulb, It is very bright but my stock charging system isn't good enough to charge the battery with the lights on. I do intend to get a PMA from Hugh eventually but for now I'm just looking to pop in a LED as a bright daytime running light, to be seen rather than to see the road ahead.
Cheers,
Dave.

Ps. My headlight is allready full of wires so a 3000 lumen wiath a big heatsink is out the question.

 

[retiredgentleman]

Why not correct the root cause of the problem?

My suggestion:

1982 bike...................replace the two #1157 rear bulbs with a LED tail light.

If you are using a 55 watt head light, replace it with a 40 watt Halogen.

1977 engine..............If your bike has the old original rectifier, replace it with a modern
3 phase rectifier, that can be bought on E-bay.
Also, if your bike has the old original regulator, replace it with an automotive
NOS VR-115 regulator.

How old is your battery? No charging system can keep a dying battery charged up.

Are you sure your brushes are 0.4 " long or longer? The copper slip rings need to be cleaned as part of maintenance.

You should measure the rotor resistance from one slip ring to the other slip ring, to see if its in spec. 5 to 6 ohms is normal.

What is the battery voltage, when you rev the engine to 3000 to 3500 rpm?

 

[davetherave]

Hi retiredgentleman,

My tail light is 1 bulb with two elements, one is for tail and plate, other is brake, do you know if there is there one LED device to replace this type of bulb or would I have to get two seperate LEDs? Also brake light i think should be very bright, would LED be as bright as a regular bulb?

I am running a modern Rec/reg combo.
Battery age is unknown but my Optimate charger does a test phase after charging and reports back OK (green&orange) on a scale of good(green) thru Ok (orange) to crap(red) lights.

I cleaned up the outer slip ring as it was a bit dirty.

Getting 14.6V when I rev the engine but only 12v at idle, switching on the headlight the idle 12v starts dropping slowly.

I will grab a lower H4 bulb for now but,
In the future I would like to run a PMA, sparx cap combo with no battery so I would be after LEDs all round for lights and signals. but I swapped out my mech advance for pamco e-advance so I am not sure If I can stilll go down that route?


Best regards,
Dave.

 

[retiredgentleman]

Quote: "Getting 14.6V when I rev the engine but only 12v at idle, switching on the headlight the idle 12v starts dropping slowly."

The word "idle" does not mean much, if you don't specify the rpm. The stock alternator will put out around 13 volts with the engine at 1200 rpm. If your idle speed drops off to say 1100 rpm, then voltage will go down to 12 volts, which is quite normal.

The stock alternator does not charge the battery at idle, as there is no intention or need to do so. Roughly 90% to 95% of your riding has your rpm above idle speed, and that is where the battery is charged. You charge your battery as you drive down the road.

If you see 14.6 volts as you rev the engine, then you have an excellent charging system, so be happy

If you want to see more than 12 volts at idle, then raise your idle rpm to 1300 or 1400.

 

[weekendrider]

Dave to answer your original question, the Harley riders are really liking their LED headlights in 7 or 5 3/4".

 

[davetherave]

Quote: "Getting 14.6V when I rev the engine but only 12v at idle, switching on the headlight the idle 12v starts dropping slowly."

The word "idle" does not mean much, if you don't specify the rpm. The stock alternator will put out around 13 volts with the engine at 1200 rpm. If your idle speed drops off to say 1100 rpm, then voltage will go down to 12 volts, which is quite normal.

The stock alternator does not charge the battery at idle, as there is no intention or need to do so. Roughly 90% to 95% of your riding has your rpm above idle speed, and that is where the battery is charged. You charge your battery as you drive down the road.

If you see 14.6 volts as you rev the engine, then you have an excellent charging system, so be happy

If you want to see more than 12 volts at idle, then raise your idle rpm to 1300 or 1400.

thing is, I don't have a rev counter only a speedo.
When I say idle I mean just ticking over at minimum revs my estimate based on my ears is around 1200rpm

 

[retiredgentleman]

thing is, I don't have a rev counter only a speedo.
When I say idle I mean just ticking over at minimum revs my estimate based on my ears is around 1200rpm

Yes, I was thinking you probably did not have a tachometer. You may only be idling at 1100 rpm or lower, which means the alternator is not generating more than 12 volts.

Something to keep in mind, is that the alternator and the battery are wired in parallel, which means either can supply the needed current to the bike's loads. If the rpm is below 1200, and the alternator output drops below 12.5 volts, the battery should start to supply current and the voltage will remain at around 12.5 volts. Since you see your voltage drop down below 12 volts, that is an indication that your battery cannot supply the needed current. The only way to know for sure is to have the battery load tested. If your bike had a starter motor, it would show a weak battery by being very difficult to start or fail to start completely.

LED's are good when using the stock alternator, because the alternator current is controllable, however if you plan to buy a PMA, then incadescent bulbs may be a better choice, as the PMA current (heat) has to go someplace, so its better if the heat is consumed in the bike's loads.

Edit: I'm going to take a guess, that perhaps you are using a battery that is smaller than the stock size of 14 amp/hr. If it is smaller, and if it is an older battery that is losing its capacity, and your rpm is much below 1200, then you would expect the voltage to drop off to less than 12 volts.

 

[davetherave]

Good guess, yes its 7 or 8Ah I think, Squeezed in between the lowered seat rails.
Maybe it's time to start thinking about a replacement.