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Thu Jun 01, 2023 1:05 pm

Guys, I read all the posts on this and did not see a resolution.

superbright LEDs does not make a Ba7s bulb that is not polarity sensitive. I just called them..

So what are you guys doing for LEDs for the oil, generator and turn signal bulb.

Thanks

Thu Jun 01, 2023 2:08 pm

I think the bottom 3 bulbs are generally left incandescent. An LED doesn't draw enough current to reliably start an alternator. LED bulbs are also sensitive to reverse voltage greater than 5 volts.

Thu Jun 01, 2023 4:45 pm

auto-hub.com has them all including for the alternator light. Fit in the stock holders and work great! At least they have in my bug for at least five years!

Thu Jun 01, 2023 4:47 pm

If you can get an LED for that application (except for the alternator, as noted), I'd use it. A dim flickering oil light might not get noticed, but the fast switching, voltage tolerance, and brightness of an LED gets your attention FAST.

Thu Jun 01, 2023 5:17 pm

I just did this on mine a few weeks ago. I had some single SMD LED T5 bulbs in different colors, it was easy to just remove the LED chip from the T5 base and solder it into a stock lamp holder with the negative lead in the center and positive on the shell. Sorry I don’t have photos, it seemed kind of hack-ish at the time,
:lol:
Something like this, only I wouldn’t use a white LED since it will wash out the gel colors.
https://www.ebay.com/itm/121821344205?mkcid=16&...media=COPY

Thu Jun 01, 2023 8:12 pm

HarrysRatBug wrote: auto-hub.com has them all including for the alternator light. Fit in the stock holders and work great! At least they have in my bug for at least five years!

Thank you. Are they still in business. Their web page in unsecured (no certificate)

I read another post they are not responding to orders.

Fri Jun 02, 2023 7:00 am

EVfun wrote: An LED doesn't draw enough current to reliably start an alternator.

You need an alternator exciter module to make the alternator charge.
An alternator exciter creates the needed current draw for the alternator to charge when using an LED.
https://www.thesamba.com/vw/forum/viewtopic.php?t=...mp;start=0

Also https://bluewireautomotive.com/products/alternator...nal-module

Regards.

Fri Jun 02, 2023 7:25 am

Use the old bulbs. they work fine. I see no reason to extend effort into making these led.
Yeah, stop lights I under stand, even tail lights, but dash lights?

Fri Jun 02, 2023 7:53 am

Ovally wrote: EVfun wrote: An LED doesn't draw enough current to reliably start an alternator.

You need an alternator exciter module to make the alternator charge.
An alternator exciter creates the needed current draw for the alternator to charge when using an LED.
https://www.thesamba.com/vw/forum/viewtopic.php?t=...mp;start=0

Also https://bluewireautomotive.com/products/alternator...nal-module

Thank you. I have a generator

Regards.

Fri Jun 02, 2023 4:46 pm

I have been reading the forums for hours and I have not seen a post that comes out and says what the solution is. I think the solution is ordering bulb holders with two posts to correct the polarity issue. Which two prong posts bulb holders. Who sells them that fit.

Is there another two pronged bulb holder that will accept spade type bulbs.

:)

Fri Jun 02, 2023 5:33 pm

DesertG wrote: I have been reading the forums for hours and I have not seen a post that comes out and says what the solution is. I think the solution is ordering bulb holders with two posts to correct the polarity issue. Which two prong posts bulb holders. Who sells them that fit.
https://www.wolfsburgwest.com/cart/DetailsList.cfm?ID=113957397

Fri Jun 02, 2023 6:25 pm

If you want to run an LED on the exciter wire usually people put a regular bulb somewhere else in the system and that regular bulb still turns the alternator on while the LED is in place on the gauge. On mine I run all LED except for the exciter wire and it never bothered me because the alternator light is only on for a few seconds at start up anyways

Fri Jun 02, 2023 8:36 pm

I just soldered up a different style, 3-LED board assy into a stock lamp holder today to see if I liked it better than the single chip bulb. It’s about the same brightness/intensity as the single chip and quite a bit more difficult to solder in place! https://www.ebay.com/itm/314572825140?mkcid=16&...media=COPY This is the ebay link I bought my LEDs from, no affiliation.

It doesn’t take long to make them and I have 20 each red, green, and blue for just a few bucks. This one was blue, and they actually fit the illuminated switches, so I put a red one in my emergency flasher knob.

Fri Jun 02, 2023 8:42 pm

scrivyscriv wrote: I just soldered up a different style, 3-LED board assy into a stock lamp holder today to see if I liked it better than the single chip bulb. It’s about the same brightness/intensity as the single chip and quite a bit more difficult to solder in place! https://www.ebay.com/itm/314572825140?mkcid=16&...media=COPY This is the ebay link I bought my LEDs from, no affiliation.

It doesn’t take long to make them and I have 20 each red, green, and blue for just a few bucks. This one was blue, and they actually fit the illuminated switches, so I put a red one in my emergency flasher knob.

Thank you Sir. I can't tell my the photos. Are those bulbs non polarity sensitive. How did you get the positive lead on the bulb to make contact

Fri Jun 02, 2023 9:14 pm

This specific bulb is the blue high beams lamp, with standard polarity/negative outer shell. For reverse polarity oil pressure, I used a red LED board and just soldered it on with the positive lead to the outer shell of the bulb holder, and the negative lead to the center contact. Easy peasy!

I’m not 100% sure how the non-polar LED lamps work - all of mine have a polarity.

Fri Jun 02, 2023 11:27 pm

DesertG wrote: superbright LEDs does not make a Ba7s bulb that is not polarity sensitive. I just called them..

So what are you guys doing for LEDs for the oil, generator and turn signal bulb.
It's good that you understand that the three (3) bottom indicator lamps work off reverse polarity with a shared 12v+ coming into the bottom terminal and individual switched grounds down the blue wires. But it is not as simple as that for the turn signal indicator lamp and the GEN lamp. These two bulbs may turn ON when the polarity is reversed.

For the speedometer turn signal indicator, current flows from the fuse box towards the corner lamps when the turn signals are working and the ignition switch is ON. But when you use the E-Flashers while the ignition switch is OFF the current flows in the opposite direction making the speedometer indicator lamp a 5th corner lamp. A polarity sensitive LED bulb will not flow current in both cases.
For the turn signal indicator lamp you have an option... install a motorcycle LED turn signal diode kit like this:
https://www.amazon.com/BikeMaster-Turn-Signal-Diode-HO002001/dp/B01DYS3A56/
Like Beetles, many motorcycles only have a single indicator lamp. You will need to use one of those bulb holders with 2 prongs. Ground one prong and wire the other prong to the diode kit. The 2 wires coming off the diode run to the L and R side turn signal circuits to make the turn indicator lamp a single 3rd turn signal for each side. The diode kit prevents one side circuit from powering the other side lamps. Now the indicator lamp will always flash in sync with the corner lamps and will work for both turn signals and E-Flashers.

That you are running a generator vs. an alternator makes it easier to get your generator charging. Unlike alternators, generators do not depend on a charge coming from the GEN lamp to get the charging system going.
But once the engine is running and the charging system is working the GEN lamp serves as an indicator that there is something wrong with the charging system. When the charging system is under-charging the GEN lamp turns ON when positive current starts to flow from the fuse box towards the VR. If your GEN lamp turns ON before you start the engine it will also light up when this happens.
But when the charging system is over-charging current flows from the VR towards the fuse box. The same polarity sensitive LED that worked before the engine started will NOT flow current in the opposite direction to warn you of over voltage coming from the generator.
The above diode solution doesn't work here because once the engine is running there is always positive current coming from both the fuse box and the VR. One/both would keep the indicator lamp ON all the time. You really need a small LED bulb that will allow current to flow in both directions. I've not seen one yet. Here you probably need to keep the stock incandescent lamp or sacrifice one of the functions of the GEN lamp.

Sun Jun 04, 2023 10:28 am

Nice thread, THANK YOU for the links .

Mon Mar 17, 2025 12:54 pm

It's good that you understand that the three (3) bottom indicator lamps work off reverse polarity with a shared 12v+ coming into the bottom terminal and individual switched grounds down the blue wires. But it is not as simple as that for the turn signal indicator lamp and the GEN lamp. These two bulbs may turn ON when the polarity is reversed.

For the speedometer turn signal indicator, current flows from the fuse box towards the corner lamps when the turn signals are working and the ignition switch is ON. But when you use the E-Flashers while the ignition switch is OFF the current flows in the opposite direction making the speedometer indicator lamp a 5th corner lamp. A polarity sensitive LED bulb will not flow current in both cases.
For the turn signal indicator lamp you have an option... install a motorcycle LED turn signal diode kit like this:
https://www.amazon.com/BikeMaster-Turn-Signal-Diode-HO002001/dp/B01DYS3A56/
Like Beetles, many motorcycles only have a single indicator lamp. You will need to use one of those bulb holders with 2 prongs. Ground one prong and wire the other prong to the diode kit. The 2 wires coming off the diode run to the L and R side turn signal circuits to make the turn indicator lamp a single 3rd turn signal for each side. The diode kit prevents one side circuit from powering the other side lamps. Now the indicator lamp will always flash in sync with the corner lamps and will work for both turn signals and E-Flashers.

That you are running a generator vs. an alternator makes it easier to get your generator charging. Unlike alternators, generators do not depend on a charge coming from the GEN lamp to get the charging system going.
But once the engine is running and the charging system is working the GEN lamp serves as an indicator that there is something wrong with the charging system. When the charging system is under-charging the GEN lamp turns ON when positive current starts to flow from the fuse box towards the VR. If your GEN lamp turns ON before you start the engine it will also light up when this happens.

But when the charging system is over-charging current flows from the VR towards the fuse box. The same polarity sensitive LED that worked before the engine started will NOT flow current in the opposite direction to warn you of over voltage coming from the generator.

I know this tread is old, but thought this might help. You can actually buy non-polarity LED BA7 bulbs that will work in original sockets. I got some on Amazon: https://www.amazon.com/dp/B0CQK2SX85?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_1&th=1
Of course you'll have to use it with an LED flasher if you don't use resistors to activiate the stock flasher.

Mon Mar 17, 2025 1:02 pm

THANK YOU SO VERY MUCH ! .

I will remember this, right now I am converting my 1971 BMW R75/5 Motocycle to LED's, it has a wimpy 13 ampere (!) alternator that barely keeps the battery charged .

Mon Mar 17, 2025 2:31 pm

Thank you. So if I get non polarity bulbs and have an electronic flasher, do I need to make any other mods to get oil, gen and turn signal on LED bulbs? :)