Author Topic: 6v to 12v Step-up convertor for headlamp?  (Read 2827 times)

Online Greybeard

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6v to 12v Step-up convertor for headlamp?
« on: 25.08. 2015 14:50 »
I'm thinking about getting one of these: http://goo.gl/Ub2OzT

I could hide this in my headlamp shell or cowling and use a 12v headlamp bulb. I already have a really good 6v LED rear lamp arrangement and a bright 6v pilot/running light instead of a standard bulb. What I need is a better headlamp beam.

I've read an older post about these where it was stated there would be isolation problems. My thinking is that the headlamp supply, (going out to the dip switch) would only be connected to this unit and there is no reason why this converter should not share the earth with the machine earth for return on the headlamp bulb holder.

Would the power requirements for the converter be too much for the BSA 6v system; looks like it outputs 10 amps. I've sent a message to the seller asking about input power.

Wotjerfink?

Offline Johnny J

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Re: 6v to 12v Step-up convertor for headlamp?
« Reply #1 on: 25.08. 2015 16:03 »
If you have negative earth on your bike it should propably be ok since I belive the converter has a common minus, even thou there are 2 black cables.
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Online Triton Thrasher

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Re: 6v to 12v Step-up convertor for headlamp?
« Reply #2 on: 25.08. 2015 17:50 »
It will waste at least 15% of the power going to the headlight. It claims 85% efficiency.

You'll still have 6V characteristic losses in the charging and battery circuitry.


Online Greybeard

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Re: 6v to 12v Step-up convertor for headlamp?
« Reply #3 on: 25.08. 2015 18:00 »
It will waste at least 15% of the power going to the headlight. It claims 85% efficiency.

You'll still have 6V characteristic losses in the charging and battery circuitry.

Sorry TT; what does that mean in practice?

Online Triton Thrasher

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Re: 6v to 12v Step-up convertor for headlamp?
« Reply #4 on: 25.08. 2015 18:11 »
I think your charging system may struggle.

And- a 12V headlight needs 14 volts to be fully bright.

Offline Johnny J

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Re: 6v to 12v Step-up convertor for headlamp?
« Reply #5 on: 25.08. 2015 20:49 »
A LED lamp is a solution, only draws like 20W with the same (or better) light output than a filament one.
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Re: 6v to 12v Step-up convertor for headlamp?
« Reply #6 on: 25.08. 2015 21:05 »
This is from Paul Goffs site:

http://www.norbsa02.freeuk.com/goffyWhyNotLEDs.htm

I bought one of his 6v 35/35W Quartz Halogen bulbs. I'm not really impressed.

Offline sparx

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Re: 6v to 12v Step-up convertor for headlamp?
« Reply #7 on: 27.08. 2015 03:20 »
Maybe worth pointing out there is actually no such thing as a "6v" or "12v" L.E.D.
  The vast majority of LEDs work at about 2 or 3 volts. The critical thing is that the current through the LED is controlled to within very close tolerances, so a "driver" circuit is incorporated which makes sure the current draw through the LED or LED array is constant irrespective of the voltage supplied.
  If you fit a 6v to 12v inverter to run a 12v LED on 6v you may find that all you are doing is making the driver circuit in the LED work harder, so it makes more sense to ask the LED supplier what the operating voltage range of the LED is, and fitting a "12v" LED that will work ok at 6v.
 
  To answer another question, if an inverter doubles the voltage the input current is twice the output current plus any losses from the inverter. A typical 12v headlamp LED bulb draws about half an amp, so using one with an inverter means the inverter will draw slightly more than one amp. I could do the maths and be more precise but it's 3 in the morning, I've finished my fag and coffee, I'm going to bed.
   
Dave
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Offline Gavin

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Re: 6v to 12v Step-up convertor for headlamp?
« Reply #8 on: 27.08. 2015 14:45 »
Hi Graybeard, I Bought an  LED "globe" from these guys: http://www.dynamoregulatorconversions.com/online-shop-for-led-bulbs-and-light-boards-etc.php
and am very pleased with it. Low and High beam are very good. This is on my 12v -ve earth bike.

I am not aware of a 6v +ve earth LED that has low and high beam.

Hope I don't glow in the dark after drawing some counter responses.

Offline sparx

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Re: 6v to 12v Step-up convertor for headlamp?
« Reply #9 on: 27.08. 2015 15:17 »

I am not aware of a 6v +ve earth LED that has low and high beam.

These people seem to have it covered:-
http://www.dynamoregulatorconversions.com/led-headlamp-bulbs-shop.php
Dave
Peterborough (UK)

Offline cyclobutch

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Re: 6v to 12v Step-up convertor for headlamp?
« Reply #10 on: 27.08. 2015 15:35 »
This is from Paul Goffs site:

http://www.norbsa02.freeuk.com/goffyWhyNotLEDs.htm

I bought one of his 6v 35/35W Quartz Halogen bulbs. I'm not really impressed.

I have one of those bulbs in mine. I'd redone the wiring paying special attention to all of the connections and I'd have to say that mine is really quite impressively bright. So much so that I never bothered to wire in the relays that I'd bought for the occasion. Downside, as I've reported some time previously, is that the bulb doesn't work well with the Wipac lens/reflector. I either have the dip down on the front guard or high beam diverting planes in off of Stansted.

I was quite excited by this thread though. It had me thinking of hot grips and a sat nav hot shoe. I'd like those but I really am stuck on running my 6V dynamo (it's a lurve thing). I suspect from other comments here the numbers really aren't going to stack up for my application. Maybe I could just warm my digits on the device itself, I'm presuming that the missing 15% will be heat.
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Offline a101960

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Re: 6v to 12v Step-up convertor for headlamp?
« Reply #11 on: 27.08. 2015 15:44 »
Yep, that's what I have fitted nice and bright. Excellent piece of kit. The ammeter is now ornamental I never see the pointer move anymore. The lamp is available in -ve or +ve and operate between 14v and 6v (see details below).

"Our new "Double Dipper" range of direct replacement bulbs replace standard twin filament headlamp bulbs and have minimal current consumption and a white light enabling you to see and be seen.

 0.26 amp and 0.52 amp low/high beam @ 12v

(0.21 amp and 0.42 amp @ 14v)

0.52amp and 1.04a low/high @ 6v

(0.44 amp and 0.88a @ 7v) .

A crisp, white light with an excellent beam pattern that will change your night time driving experience.

No filaments to blow and no fragile glass envelopes.

 Multi voltage - Each bulb will work on both 6v and 12v systems (one bulb suits both voltages)

Negative and positive earth availabe"
John

Offline Topdad

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Re: 6v to 12v Step-up convertor for headlamp?
« Reply #12 on: 27.08. 2015 15:54 »
Sorry John, I'm missing something or just thicker today than normal. Did you use the inverter as per Graybeards initial post or the paul goff bulb, Bob.
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Offline a101960

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Re: 6v to 12v Step-up convertor for headlamp?
« Reply #13 on: 27.08. 2015 16:48 »
Quote
Sorry John, I'm missing something or just thicker today than normal. Did you use the inverter as per Graybeards initial post or the paul goff bulb, Bob.
Bob, neither of those options mate, I got my lamp from the source mentioned by Gavin
Quote
I Bought an  LED "globe" from these guys: http://www.dynamoregulatorconversions.com/online-shop-for-led-bulbs-and-light-boards-etc.php
and am very pleased with it. Low and High beam are very good. This is on my 12v -ve earth bike.
By the way the voltage converter is not an inverter. An invertor converts DCv to ACv. Personally I am uncertain why anyone would want to stick to 6v It is simple, easy, and cheap to convert to 12v and get better and more efficient lighting. Like Gavin, my bike is also 12v -ve. I can think of no disadvantages. Modern 12v batteries are compact (although actually I use X2 Cyclon 6v batteries in series to give me 12v). 12v means less current draw than 6v and therefore things like the dip switch contacts have an easier life, and for the purist there is no visible evidence that anything has been modified.
John

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Re: 6v to 12v Step-up convertor for headlamp?
« Reply #14 on: 27.08. 2015 18:00 »
I think your charging system may struggle.

And- a 12V headlight needs 14 volts to be fully bright.

Those points apply to the 12V headlight bulb you were proposing. 

Is it an LED now?