Author Topic: H4 headlight  (Read 5020 times)

Offline Lobo

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Re: H4 headlight straining 15A fuse?
« Reply #15 on: August 12, 2020, 11:17:30 PM »
Rob... recently discussed in the 400F area under, Stanley Light Bulb.

As a general comment on a 55/60W headlamp, there seems to be a focus on fuse size, little has been said on battery charging .... which too will be adversely affected.

Given the age of our bikes, and the endless topics on corrosion, gremlin connections, corrosion, decrepit fuse holders, corrosion, bodged looms etc my gut feeling is that sticking bigger fuses in is not the way to solve electrical problems. Unless of course, your loom and components are new / verified tickety-boo.

A 55W lamp will indeed be brighter than a 45W bulb, but given there are LED offerings out there quoting 18W with the equivalent illumination of an 80W Halogen.... why wouldn’t you if needing to ride at night? Then add in the reliability of LED factor...

In the Stanley Light Bulb post, K2-K2 offered this... take a look at the numbers / specs - very impressive.

https://www.classiccarleds.co.uk/products/latest-led-headlights-p45t

EDIT - sorry Trig...our posts crossed and I’ve only just seen yours. Doh!
« Last Edit: August 13, 2020, 12:28:59 AM by Lobo »

Offline JezzaPeach

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Re: H4 headlight straining 15A fuse?
« Reply #16 on: August 12, 2020, 11:28:07 PM »
All helpful stuff 👍
1972 CB500/4 K1 Gold
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from 1975-78. Garnet Brown.

Offline deltarider

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Re: H4 headlight straining 15A fuse?
« Reply #17 on: August 13, 2020, 07:13:42 AM »
Then add in the reliability of LED factor...
Maybe you can explain, I see quite some cars that have only one side lit (DRL). I would not expect to much reliability of Chinese products. I myself will not buy any product from China, be it for more than one reason... The tabulation of ampères in reply #5 is all too simple and may lead to confusion. Riding we'll see a higher voltage than the theoretical 12V, which implies less current drawn. The 15A main fuse has proved to be quite capable of dealing with the 55/60 Watts H4 on mine for the last 40 years...
Furthermore there's more needed to have a good vision (beam pattern) than just replacing an incandescent bulb by a LED. Leds need their own, special projectors.
Here's a question, I have not solved yet. Due to a lame PA switch, I sometimes had both filaments in the H4 on. On entering a tunnel, I would detect this by the lit blue idiot light. I've fixed the PA switch some years ago. But te question remains: why did it not blow the 15A fuse?

Offline Bryanj

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Re: H4 headlight straining 15A fuse?
« Reply #18 on: August 13, 2020, 07:24:50 AM »
Delta you may think you are not buying from China but a lot of the big firms you buy from do

Offline sye

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Re: H4 headlight straining 15A fuse?
« Reply #19 on: August 13, 2020, 08:29:30 AM »
Then add in the reliability of LED factor...
Maybe you can explain, I see quite some cars that have only one side lit (DRL). I would not expect to much reliability of Chinese products. I myself will not buy any product from China, be it for more than one reason... The tabulation of ampères in reply #5 is all too simple and may lead to confusion. Riding we'll see a higher voltage than the theoretical 12V, which implies less current drawn. The 15A main fuse has proved to be quite capable of dealing with the 55/60 Watts H4 on mine for the last 40 years...
Furthermore there's more needed to have a good vision (beam pattern) than just replacing an incandescent bulb by a LED. Leds need their own, special projectors.
Here's a question, I have not solved yet. Due to a lame PA switch, I sometimes had both filaments in the H4 on. On entering a tunnel, I would detect this by the lit blue idiot light. I've fixed the PA switch some years ago. But te question remains: why did it not blow the 15A fuse?

55 + 60 = 115W. 115W @ 12v = 9.5A. 115w @ 14v = 8.2A.

Offline JezzaPeach

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Re: H4 headlight straining 15A fuse?
« Reply #20 on: August 13, 2020, 08:55:07 AM »
sye’s formula, which I forgot due to daydreaming of Hondas in my school physics lessons, maybe helps answer other posts on condenser etc problems with a weak battery combined with poor coils/plugs/caps.
1972 CB500/4 K1 Gold
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from 1975-78. Garnet Brown.

Offline deltarider

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Re: H4 headlight straining 15A fuse?
« Reply #21 on: August 13, 2020, 11:27:44 AM »
55 + 60 = 115W. 115W @ 12v = 9.5A. 115w @ 14v = 8.2A.
I know. I hinted at that myself in reply #17, but how is it, the fuse didn't blow, giving all the other oh, so demanding consumers, many are happy to sum up, whenever they feel the urge to buy just another  thingie? In other words: I don't see Jeremy's problem.

Offline JezzaPeach

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Re: H4 headlight straining 15A fuse?
« Reply #22 on: August 13, 2020, 11:44:13 AM »
Yes mine isn’t a problem, just concerned reading it in the other post. So maybe when it’s a problem for someone it’s due to other bad connections or parts.
1972 CB500/4 K1 Gold
Wanted: my 500/4 UGP96M
from 1975-78. Garnet Brown.

Offline Lobo

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Re: H4 headlight straining 15A fuse?
« Reply #23 on: August 13, 2020, 01:40:25 PM »
Some interesting points raised, and before I go on I’ll declare I’m no official sparky...

(1) Reliability of Chinese products. Agreed, but 2 issues, the first of which Bryan promptly answered, and secondly, when put into perspective of a conventional bulb... well, I’d reckon the Chinese LED would win through.
Point of manufacture aside, these LEDs appear to have a very broad voltage range (10-30v DC) which further assists in making ‘em bullet proof in respect of 50yo agricultural voltage regulators!

(2) my tabulation of post #5 is indeed simple, I declared it ball park and was aimed at giving a basic feel of it all. I don’t however agree with the amps decreasing in relation to the voltage increasing...if this were the case the lumens would remain constant as you revved the bike from idle to 5000rpm. They don’t; we all know the headlamp brightens with increased voltage through experience...
(the resistance of a light bulb is fixed, so if you increase the Voltage, then using Ohms law I=V/R then the current (I) must increase too. Yea, I know.... ZZZzzzzz)

(3) Appreciate the point about beam pattern. However, the quality manufacturers seem to be at pains pointing out their products mimic the make up dimensions of the equivalent Halogen... and given stringent Western automotive standards you’d kinda think they’d be keen to get it right? (I honestly don’t know, but am happy to take a punt here)

(4) your own bike deltarider / 40yrs etc, there are differing circuit options / specs across the bikes and I wouldn’t know what yours is. Assuming though a UK spec the  numbers are not outside of the fuse rating. (unless adding in indicators, brake lights etc when your fuse might be working hard and managing to keep its head above water when additional loads are temporarily On.

(5) your ‘dual’ dipped + full beam; yep I’m surprised you got away without blowing a fuse, though if NO other loads on (brake light etc) you might just get away with it.
Oh hang on... you did!

Horses for courses etc, personally it seems to me that (1) battery charging is being overlooked, and (2) a more elegant fix is available than the Jeremy Clarkson approach of.. “MORE POWER!!!” 😂

Offline sye

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Re: H4 headlight straining 15A fuse?
« Reply #24 on: August 13, 2020, 02:56:01 PM »
Amperage drops as voltage increases.
120w @ 12v = 10.0a
120w @ 120v = 1.0a
120w @ 240v = 0.5a

Offline deltarider

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Re: H4 headlight straining 15A fuse?
« Reply #25 on: August 13, 2020, 07:59:16 PM »
Ok, here's my take. In my house practically all lights are LED and, although as for ambiance, nothing beats halogen, I'm happy with the results. LED in the workshop is a nightmare. Light is everywhere, reflecting from all parts, making it very difficult to work.
 Now to the bike itself. As far as headlight, I'm always open for innovation, but I prefer to wait for a product by Philips or Osram, that will come as a unit and will be a direct replacement for reflector and bulb combined and then only after I've seen independent tests. Under tests I do NOT count reviews by consumers which are possibly biased by the expenditure they had to do. So far I have not seen LED headlight performances that could convince me. The brightness that some see as a quality, to me is an annoyance and I wonder if I could live with the reflecting light, seen my experience in the workshop.
As for brake- and indicator lights, I really don't see the gain. Energy saved isn't really that much and you'll have to accept the miss of the glow on glow off effect which incandescent bulbs offer. The latter category is also better noticed at an angle. As for longevity, my brake/taillight was replaced only once and two of the four indicator bulbs are still the same the bike had, when it left the assembly line. Not a bad result for 44 years. Conventional bulbs are dead cheap and widely approved. Fitting LEDS for indicators IMO is too much a hassle. You need another relay and diodes. Why people do it? No idea. Maybe they like to tinker.

Offline Rob62

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Re: H4 headlight straining 15A fuse?
« Reply #26 on: August 13, 2020, 08:15:45 PM »
Some interesting links there trigger and lobo. I will certainly give the led bulbs a try.. The reason i said “they’re expensive” is because i have tried cheap led’s before (although not that type) in the car i used about 6 bulbs in the rear lighting, 3 of them failed within a day so i took them out and wrote the idea off...but at the time i did notice that branded equivalents were much more expensive. I will try the bulbs in triggers link..on the CB and RD250 which is especially poor with a std bulb.. cheers.

Offline Lobo

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Re: H4 headlight straining 15A fuse?
« Reply #27 on: August 13, 2020, 10:52:02 PM »
Sye... whilst power divided by volts indeed gives amps it’s not the full story when resistance is then bought into the equation. Your post fails to explain why lamps brighten as you increase the voltage - which you’ll know from 1st hand experience. The current (A) actually increases as you increase the voltage through the filament...the power rating of a lamp will be only be valid at the stated voltage .
Anyways, please don’t take my word on it, but rather google the explanation.

Yea, Deltarider, horses for courses. I’m gonna take a punt on the LED headlamp bulb, and will report back in due course. They annoyingly come in pairs... so if fail early I’ll have a spare 😂.

Trig... you say you’ve got LED replacement ‘globes’.... how are they performing?
« Last Edit: August 14, 2020, 12:54:16 AM by Lobo »

Offline sye

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Re: H4 headlight straining 15A fuse?
« Reply #28 on: August 14, 2020, 08:25:29 AM »
Sye... whilst power divided by volts indeed gives amps it’s not the full story when resistance is then bought into the equation. Your post fails to explain why lamps brighten as you increase the voltage - which you’ll know from 1st hand experience. The current (A) actually increases as you increase the voltage through the filament...the power rating of a lamp will be only be valid at the stated voltage .
Anyways, please don’t take my word on it, but rather google the explanation.

Yea, Deltarider, horses for courses. I’m gonna take a punt on the LED headlamp bulb, and will report back in due course. They annoyingly come in pairs... so if fail early I’ll have a spare 😂.

Trig... you say you’ve got LED replacement ‘globes’.... how are they performing?

You are right of course, the power output does indeed increase with revs, sometimes to 14v. The headlamp filament is a crude affair that glows white hot by the heat created by the current passing through it. The higher the voltage, the brighter the lamp. If the voltage gets too high the lamp will blow. LED is deffinately the way to go.

Offline Trigger

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Re: H4 headlight straining 15A fuse?
« Reply #29 on: August 14, 2020, 08:50:43 AM »
Sye... whilst power divided by volts indeed gives amps it’s not the full story when resistance is then bought into the equation. Your post fails to explain why lamps brighten as you increase the voltage - which you’ll know from 1st hand experience. The current (A) actually increases as you increase the voltage through the filament...the power rating of a lamp will be only be valid at the stated voltage .
Anyways, please don’t take my word on it, but rather google the explanation.

Yea, Deltarider, horses for courses. I’m gonna take a punt on the LED headlamp bulb, and will report back in due course. They annoyingly come in pairs... so if fail early I’ll have a spare 😂.

Trig... you say you’ve got LED replacement ‘globes’.... how are they performing?


I have had the cob type fitted to a 750 and a 550 for about a year or so and the 750 is just over a couple of thousand miles, since fitted with no problems. They are white light and not the yellow light you get from basic H4's.
I bought a trade pack of them and they worked out around £3 per bulb. I am no expert when it comes to electrics and can't understand why some of them have a cooling fan (which will not fit in the headlight bowl) and the cob type don't.



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