Lotus Elan and Lotus Elan Plus 2 Forums

Ok, so I'll admit that this is probably the most minor problem one could have with an Elan, but I'd still like to solve it.

I am looking for a replacement bulb for the parking brake warning light. It's the same one used for the brake warning light. It is small, with a brass base that has a ridge on one side of it and it fits into the socket which has a recess to accomodate the ridge.

Before anyone suggests that I check with the "usual suspects" please verify that the vendor you recommend actually has this bulb. Thank you.

Frank Howard wrote:Before anyone suggests that I check with the "usual suspects" please verify that the vendor you recommend actually has this bulb. Thank you.

Would you like them bought for you AS WELL ??

Frank,

I replaced all my bulbs (with the exception of headlights) over the winter with LEDs. Source - UltraLeds <http> they have everything you will need.

The only 'fiddle' was the indicators that rely on the filament bulb level of resistance to work properly in older cars such as Elans. The LEDs have very low resistance and therefore, will not work without adding some resistors to each bulb feed wire ? on reflection I should have stuck to filaments, but bloody-mindedness took-over, so I had to make them work.

I still have the old park brake filament bulb ? I can send it to you if you wish.


Brian Clarke
(1972 Sprint)

http://www.britishwiring.com has (obviously) British Wiring and bulbs.

I'm also experimenting with installing 5W halogen instrument lights in the smaller instruments and 10W in the Speedo and Tach (Rev counter ). I'm kind of nervous about the potential heat produced, but I also like to see my instruments at night; I've also upgraded to 14ga wiring, and am going to put an in-line fuse ahead of the switch. I assume that's prudent. The stock screw-in-type metal bulb-holders for the Smiths instruments are no longer available. The replacements are plastic and accept pin-mounted bulbs only.

I got the screw-in hologens from the Little British Car Company, but they're VERY expensive... about $13 each. I'll let you know the results of my noble experiment.

Gary
'71 Elan Sprint
Miami, Florida

Gary,
I'm interested in your comments on heat output from lights. I've always assumed that if two bulbs consume 5W, the bulb with the higher light output puts out less heat simply because all the energy ends up as heat or light.

Having said that, the Halogen bulb may well run at a much higher temperature.

Does this make sense, 'A' level physics was nearly 40 years ago?!?

Mike

Mike,
A better way to think of light output vs. heat is to also consider energy consumed and light generated. Watts are a measure of work produced - in essense, light output. A 5-watt halogen will consume less energy than a 5-watt incandescent bulb, but both produce 5 watts of light, and the halogen will produce as much or more heat.
Looking at it another way, a halogen will produce more light for the same current draw (amperage) - say the work of a 7-watt incandescent bulb - but it will get hotter, while consuming the same amount of energy. Halogen gas burns HOT. Light output, amperage consumed, and heat are all interdependent, but not identical between the two bulb types.
It's also useful to also consider the light temperature. A halogen light produces a higher temperature (Kelvin) than an incandescent bulb given the same wattage, which often makes them seem brighter. This same effect occurs with white LEDs - the light temperature is higher (it's a whiter/bluer color) than an incandescent, but uses less energy).
If a halogen bulb is being sold to replace an incandescent, you would want to be very sure that it consumes less current (is lower amperage) than the incandescent it replaces, or you risk melting wires, bulb holders, gauges, etc. Much better idea to use LEDs with resistors if you must change.
Good luck,
Greg
71 Elan S4
All of the above is from personal experience, quality-checked by an electronics engineer (Dad).

If you have an interest in LEDs for cars, have a nose round this site...

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

Some good thoughts especially the radially mounted LEDs to illuminate the whole lens. Expensive, but I have had them in the stop/tail lights for the last 3 or 4 years with no failures. I haven't changed the instrument lights yet, but its only a matter of time (including for my modern).

Jeremy

Greg,
I'd always thought that the 5W was the input power not the light output. If it's not the input power, how do you choose the right fuse?

Regards
Mike

Greg,
I'd always thought that the 5W was the input power not the light output. If it's not the input power, how do you choose the right fuse?

Regards
Mike

Mike,
Sorry for the late reply - too busy with work away from home...
You choose a fuse to protect the wire based on current draw. You select the conductor in the same way. You can obtain tables online that show correct sizing of conductors based on current draw at various lengths.
I too was confused about the wattage thing, until my engineer father explained it to me, AFTER making me read his fundamental theories of electronics book - cripes!
Bulbs are rated in wattage primarily because that is a relative measure of their brightness in relation to current draw.
Does this help?
Cheers,
Greg