|Topic Review (Newest First)|
|06-13-2019 11:44 AM|
|B24Spider||Oh, and please don't talk about smoke, holy or otherwise, when discussing the generator/regulator.|
|06-13-2019 11:40 AM|
|B24Spider||We never put the top up or side curtains on, so air conditioning is full blast, full time. Hot or cold...|
|06-13-2019 11:22 AM|
Originally Posted by B24Spider View Post
|06-13-2019 11:10 AM|
(osso- Thank you for the move.)
Thanks all, panic temporarily averted.
Actually, my primary consideration is originality; as the Spider is a preservation car, even the headlights are the original 45/40 watts. Like I said, dim bulbs. Plus, it's a nice, soft look, sort of like the car.
LED lights would be way too bright/harsh, and though I have some spare NOS tail-light lenses, they're way too full of pigment, they'd look out of place; it wears the originals that are moderately bleached, but not deformed or crazed. The swirls are great. And carl750 is right about heat; I'd be afraid LEDs are way too hot for old plastic.
Another consideration is electrical; the Marelli DN22 single field generator, also fit to the early Alfa 1900, puts out a whopping 200 watts. When you add up all the components that could be in use at the same time, such as a variety of lights, Mousebreath heater fan, wipers, etc., well, it gets real close to it's limits. If I changed all four corner lights to 21/5 I'd be adding 12 watts to the load, 6% of capacity. Doesn't sound like a lot, but when you're close to the edge...
I suppose if I get truly desperate I could try adding resistors, but I'd really like to avoid the mickey mouse. Digging through my shelves yesterday I was lucky enough to find a pair of NOS Aurelia B10 sedan front turn signals, of which one still had it's "3/20"W bulb! I may have used the other one already, years ago (I really don't remember, I thought they were empty). I should test it to see what it's really rated at (carl750, can you point me to/supply me with Osram's test info? Thank you.), and if I can, find some way to test it's luminosity before I put it in. At least then I'd know what I might someday be trying to match.
So, I'm good for the moment, but it's just a matter of time before another burns out, so I'm still looking. Just not quite as desperate...
|06-12-2019 03:39 PM|
|radamm||A person could do a Rube Goldberg and put a rheostat in the circuit.|
|06-12-2019 10:32 AM|
|carl750||I assume his interest is "heat". That is why I investigated bulb wattage. I don't want to melt unreplaceable lens.|
|06-12-2019 08:00 AM|
Originally Posted by carl750 View Post
If you want to achieve a certain light level, another approach would be to put resistors in series with the filaments. For example if you knew you had a 25.00 watt filament and wanted to reduce its power dissipation to 20.00 watts, my calculations show that putting a 1.44 Ω resistor in series would do the trick (assuming the circuit receives 12.00 volts).
But I don't know whether a modern bulb rated at 25 watts that was "throttled down" to 20 watts would produce the same luminosity as an old-time 20 watt bulb. A better bet might be to use a rheostat to experiment with the level of added resistance to produce the desired luminosity. Then find a fixed resistor with the corresponding value (which might be tough, as resistors in the 1.5 Ω range aren't so common).
|06-12-2019 06:56 AM|
|carl750||Unfortunately you cannot rely on what it says on the package. I recently tested Osram (Sylvania in USA) 7528 Long Life listed as 21/5 and 7528 (regular) listed as 25/5. When tested at the prescribed (Osram literature) 13.5 volts they both came out to be 26 watts.|
|06-11-2019 04:40 PM|
|ossodiseppia||I moved your post to an appropriate forum|
|06-11-2019 03:12 PM|
Looking for Dim Bulbs...
....to match the others on my 1955 Lancia.
I am looking for older two filament 12V brake/turn signal bulbs with 20/3 watts rating and "standard" BAY15d base.
Philips 12500 and Osram 7241 are the designations of the original bulbs, but later production uprated them to 21/5 watts. They don't play well with the 20/3 bulbs, and they're also noticeably brighter.
Maybe someone has a box of these gathering dust on a shelf. Or even a couple sitting around?