P45T to H4 adapters - do they work?

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P45T to H4 adapters - do they work?

Postby Paul Dawson » Wed Nov 01, 2017 5:53 pm

Further to my request for assistance with a lighting switch in the wanted column (thanks Dave & Fred) I then discover my headlights are the old P45T fitting with ancient incandescent filament bulbs installed.

There are adapters available which enable you to use a H4 bulb in a P45T headlamp but I've read that they don't work very well. Has anyone any experience of them please?

For the time being I've bought a couple of halogen P45T bulbs which are the same 40/45W rating as the original bulbs but I hope will be a bit brighter.
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Re: P45T to H4 adapters - do they work?

Postby Fred Dukes » Sun Nov 19, 2017 5:59 pm

H4 are rated at 55/60W so it may be the problem is with the wiring as the increase in current may fry the wiring - you need to put in extra wiring from the 12v supply controlled by the original switch control via a relay - does the conversion kit you have looked at include that?
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Re: P45T to H4 adapters - do they work?

Postby Paul Dawson » Fri Dec 01, 2017 12:07 pm

To update on this - I found some P46T halogens (at Halfords no less!) rated at 55/60W. Having been told that the wiring will handle that no problem I fitted them and the difference is amazing. Much better lights.
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Re: P45T to H4 adapters - do they work?

Postby VampireTigger » Wed Aug 15, 2018 11:46 pm

I found the same bulbs at Halfords and put them in, I have since swapped to LED as they are brighter and have a lower draw which is more wiring loom friendly.

Image

Image

https://www.classiccarleds.co.uk/collections/headlight-led-bulbs/products/led-headlights-p45t-fully-integrated-with-colour-options-hi-lo-beam-conversion are the ones fitted, they have been inspected and approved by an MOT tester who then wanted to buy some for his Golf
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Re: P45T to H4 adapters - do they work?

Postby pbottomley » Mon Nov 12, 2018 8:12 pm

how did you refit the rubber boots on the back of the headlights? pics please
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Re: P45T to H4 adapters - do they work?

Postby VampireTigger » Thu Nov 15, 2018 12:29 pm

pbottomley wrote:how did you refit the rubber boots on the back of the headlights? pics please


Short version, I didn't. The bulb design is longer on the back and has a heat sink which if I tried to stretch the rubber over it it would probably melt. I'll take some pics when I'm in Dorset this weekend as the cars are hibernating there.
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Re: P45T to H4 adapters - do they work?

Postby VampireTigger » Thu Nov 29, 2018 9:20 am

Image

The rear of the headlamp with the H4 adapter and the LED bulb from https://www.classiccarleds.co.uk/ installed. The cable ends in the same style connection you'd find on the back of a standard bulb, so it just plugs on.
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