Cap lamp bulbs · AditNow Community

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wheldale
50.2% (Neutral)
Newbie Topic Starter

10 years ago

Has anyone replaced a halogen bulb in a Oldham cap lamp with a Maglite LED bulb? Just spotted this on Ebay
http://www.ebay.co.uk/itm/TTS-1-Watt-Cree-XP-G2-LED-Bulb-2-to-9v-upgrade-for-Maglite-torches-many-others-/281335978220?pt=UK_SportsLeisure_Camping_LightsLanternsTorches&hash=item4180ee58ec

Just wondered if this would work ok or would produce too much heat in the lamp??

Thanks all!

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rufenig
50.2% (Neutral)
Newbie

10 years ago

S.M.T. replaced 22 traditional bulbs in Speliotechnics lamps with LED replacements from him.

They have been VERY reliable and well worth the money.
:thumbup:

Roger L
50.2% (Neutral)
Newbie

10 years ago

Thanks for the info. Will try them out

Mine Lectures & Walks available for around Huddersfield

jagman
50.2% (Neutral)
Newbie

10 years ago

I'm fairly sure they won't work
If I remember rightly the polarity on an Oldham bulb is the opposite to the Maglite.

I think the case of the Oldham bulb is the live with the base being the negative.
I stand to be corrected however

Morlock
50.2% (Neutral)
Newbie

10 years ago

"jagman" wrote:
I'm fairly sure they won't work
If I remember rightly the polarity on an Oldham bulb is the opposite to the Maglite.

I think the case of the Oldham bulb is the live with the base being the negative.
I stand to be corrected however

IIRC I had that issue with the R2 led conversions and got round it by swapping the leads in the headpiece and possibly the same with the charger, I think!

Edit: I've now moved on to 18650 pack in Oldham case so Oldham set up is a bit vague.

royfellows
50.2% (Neutral)
Newbie

10 years ago

The Oldham is negative switching through the spring contacts so Jagman is correct, bulb case is +V and base is -V

It should however be a simple task to change over the terminals provided that through the headset charging is not required.

My avatar is a poor likeness.

Mr.C
50.2% (Neutral)
Newbie

10 years ago

"jagman" wrote:
I'm fairly sure they won't work
If I remember rightly the polarity on an Oldham bulb is the opposite to the Maglite.

I think the case of the Oldham bulb is the live with the base being the negative.
I stand to be corrected however

Dead right, you will have to reverse the head piece & charger polarity.
Hope you're keeping well Jagman!
Not seen you for ages.

We inhabit an island made of coal, surrounded by a sea full of fish. How can we go wrong.......

jagman
50.2% (Neutral)
Newbie

10 years ago

"Mr.C" wrote:

"jagman" wrote:
I'm fairly sure they won't work
If I remember rightly the polarity on an Oldham bulb is the opposite to the Maglite.

I think the case of the Oldham bulb is the live with the base being the negative.
I stand to be corrected however

Dead right, you will have to reverse the head piece & charger polarity.
Hope you're keeping well Jagman!
Not seen you for ages.

Not bad ta MrC
Don't do an awful lot other than work at the moment

You keeping well?

rufenig
50.2% (Neutral)
Newbie

10 years ago

When I did the SMT lamps I had to change-over the wires in the headshells.
This is ok because the batteries plug into the charger separatly.

wheldale
50.2% (Neutral)
Newbie Topic Starter

10 years ago

#10

On the link to the eBay page it says the bulb is "non polarity" so wiring should not be an issue, I'm no expert here so have I missed something regarding reversing wires etc?

Mr.C
50.2% (Neutral)
Newbie

10 years ago

#11

"wheldale" wrote:
On the link to the eBay page it says the bulb is "non polarity" so wiring should not be an issue, I'm no expert here so have I missed something regarding reversing wires etc?

I suppose it could have a bridge rectifier in the the lamp body, that would make it "non polarity" but you would loose 1.2V.
Shouldn't be an issue though with a single LED & 4.5V of battery to play with.

We inhabit an island made of coal, surrounded by a sea full of fish. How can we go wrong.......