ElectroClassic EV
Classic Cars Reborn into the Electric Future

Incandescent to LED

As you might suspect, designing an electric car includes eliminating every little possible drain on the batteries.  A good place to start is replacing all of the light bulbs, top to bottom.  The entire car will run low wattage LEDs (except for the headlights), and will save valuable electrons – especially when night driving.  Above, you can see the taillight LED bulbs installed, including the smaller side marker light.   They were all purchased online at Autolumination, where an exhaustive catalog of replacement LEDs cross-references most every bulb you can imagine.  Not counting the headlights, there are seven distinct types of stock bulbs in the ’74 914, as follows:

1156 – single circuit bayonet (parking)

1157 – dual circuit bayonet (turn signal and brakes)

Ba9 – single contact bayonet (side markers, license plate, trunk light)

Ba7 – single contact midget flange (dash gauge illumination)

#74 – T5mm wedge base (dash indicator lights)

211-2 – capsule-type (39mm or 1-1/2″ dome light)

194 (168, 2825) – wedge base (front Euro style running lights)

Philips 12227  – single contact bayonet “wings” (35W tungsten fog light bulb)

Using the nomenclature above will point you to all the correct LED replacements, except for the vintage fog light bulbs, for which even stock replacements were difficult to find.  As a result, I’m replacing the fog lights altogether with a set of Pilot PL-193 driving lights, which closely match the stock originals.  Since they use a halogen H3 style bulb, they provide a guaranteed LED replacement option. Although they won’t be as bright as either the original fog lights or headlights, they have amber lenses and will serve nicely as pilot lights. Finally, the standard Sylvania H6024 headlamps were replaced with H4 halogen housings, allowing an easy conversion to HID bulbs (see Electric Eyes), which put out less heat, more visible light, and use half the energy.


Pictured above is the “Euro” style turn signal kit installed in the stock light bucket.  This was purchased online from CAMP 914.  While the US version of the 914 had only one dual filament bulb under a solid amber lens, the European model had a separate running light under a classy two-colored lens.  Installing the kit was really easy, and just required pressing the white insert into place and tapping into the positive electrical lead from the side marker light.  Since I shaved my side markers, I’ll just use the original lead itself.  You can see above that the upper dual filament bulb has been replaced with an LED.  I’ll swap in C194 LEDs for the additional lower mini wedge bulb when they arrive in the mail.


Lastly, the various gauge and instrumentation lamps in the dash can also easily be replaced with LEDs.  The blue masking tape you see above is my simple scheme for labeling the wires for reassembly.  Originally, I examined just one dash bulb and mistakenly assumed that all the bulbs were the Ba7 midget flange bayonet style, and then promptly ordered ten.  In the above picture, the Ba7 is the round-headed LED hanging at the lower right.  Once they arrived and I attempted to install them, I found the Ba7 accounted for only a few of the dash bulbs, and most of them were actually the #74 mini-wedge variety.  Those are the cylindrical flat-headed LEDs pictured above.  Back to the interwebs!  No worries – I always enjoy getting those clean little white boxes in the mail from AutoLumination.


6 Responses to “Incandescent to LED”

  1. What a bright idea! Go Brems Go!

  2. Would you mind posting a youtube video of your LED lights in action? Thank you for the great information!

    • I recently purchased a Wagan EA2045 SelfCharge Auto Jumper In-Car Jumpstarter, so I have portable 12v juice I can use to test my rewiring and make sure everything is working properly before I install the motor/controller/batteries. The unit puts out 5 amps, which should be plenty to briefly operate any of the lights and accessories for diagnostic purposes. Once it arrives, I’ll post a video of the lights in operation. Here’s a link to the unit.

  3. If you put an LED in the alternator indicator socket, your alternator wouldn’t charge your battery.

    • Interesting to note, although of course my conversion project won’t be using an alternator. The batteries will be refilled by a charger and battery management system when the car is plugged in at night.

      Is there a reason the lower wattage/current of the LED indicator would cause the alternator to discharge the battery?

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: