indicator bulb question

[agentpineapple]

my friend has a set of aftermarket indicators, they use a 12v G18.5 BA15S bulb (non led), if I was to replace them with these led bulbs, would I need a different indicator relay?
what throws me, is it uses a bayonet fitment, even tho the bulb is now led...
http://www.ebay.co.uk/itm/BA15S-12V-24V ... qLYsWtM4Vg

[bertye]

How would the bulb fit if it did not have the same fitment. Led or filament make no difference to were it is being fitted into. If it has a bayonet fitment, then the bulb has to. Most indicator units need the total wattage of the bulbs to go on and off, which LED's will not give, so the they either stay on or stay off. This is not to say that it would not work on the VTR, as I have not tried. I am sure that some one on here has.

[sirch345]

As Bert points out, they will be fine with the bayonet fitting.

In my experience I say you will need a different indicator relay for the LED's, or flaff about soldering in resistors,

Chris.

[agentpineapple]

not sure I made myself clear, the bulbs that are already in the indi's, are fairly standard bayonet bulbs, but the type i'm thinking of fitting, are led bulbs that still retain the bayonet fitting, I've not seen them before, and was wondering, that if I fit them, will I need to change the indicator relay?

cheers chris

[sirch345]

not sure I made myself clear, the bulbs that are already in the indi's, are fairly standard bayonet bulbs, but the type i'm thinking of fitting, are led bulbs that still retain the bayonet fitting, I've not seen them before, and was wondering, that if I fit them, will I need to change the indicator relay?

cheers chris

I say you will need to change the relay Marty, as I said above
I think you'll find LED's with a bayonet fitting have been around for a while.

One thing I would check is the dimensions of the existing bulbs against the LED's before buying them,

Chris.

[hallie]

The relay will need to be changed. Have tried it before

[tony.mon]

It's not the fitting that is the problem.

You can get Leds that fit almost any fitting, but the load that the lamp creates is the thing that affects the relay.
The relay works by heating a bimeyal strip, which then breaks the contact. It the cools, allowing the contact to be remade.
The load on the bimetal strip affects how quickly it can heat up, and if there's less load the strip is allowed to have more power, so heats up quicker.
So because filament lamps eat more current than leds, the bimetal strip gets less current to heat them up.
This means the cycle of heating and cooling is slower.

Doesn't matter what the fitment is, the load from a led will always make a std relay flash quicker.