Voltage regulator for S1 dynamo

[Huib Geurink]

After suffering quite a few dynamo and (imitation) regulator failures I made another attempt today to find NOS of the original Bosch regulator.

I found someone nearby who stocks original Bosch 30 amp regulators for VW Beetle and Bus. Surprise. These turned out to be modern fully electronic original Bosch regulators for their 30 Amp dynamo of the sixties. I am flabbergasted. The guy told me he has been selling those for over 6 years in high quantity with zero failures. He dumped his complete stock of imitation ones when he had a few months experience with the new Bosch ones. I can imagine that as I have a pile of bad Cargo and Transpo units that I cannot jump over.

The thing works very nicely. It produces 14.0 volt. I would have preferred 14.2 volts but I am not complaining.

If a dynamo is not turning it can discharge the battery with a very high current. To prevent this the mechanical regulators have a relay that switches off when the reverse current exceeds 2 Amp. Sometimes the relay sticks. That will destroy the dynamo in a few minutes (and possibly the battery). Smells like someone burned his dynamo. The electronic regulator uses Schottky diodes which always work.

I assume from looking at the thing that the voltage is regulated not by switching the voltage on and off like on a switch mode power supply as the old mechanical regulator does but by modulating the field current. This should lengthen the life time of your dynamo.

The unit is made by Bosch Mexico. Be carefull when mounting. The outer cover serves as heatsink for the diodes. It carries the full voltage from the dynamo. I taped off the inner wing section below the regulator and the top of the bracket it is mounted on to prevent any short circuits. Do not tape the regulator it self.

If you have any doubts about your regulator, replace it today. I would do it yesterday even without doubts. Just to make sure my dynamo does not burn out.

The thing costs practically nothing. Should not be more than 50 euro.

[Stephan Protzen]

When I had generator (dynamo) trouble I went through this. I ordered a regulator but was sent the wrong one, for a S2. In frustration I went to my Alfa mechanic, He works on some Giulietta's (some had Bosch dynamo's) and asked him about voltage regulators. He laughed and told me to go to the local VW specialist.
I would have shared this information but I thought I was the last one to know!

[Geoff Goldberg]

OK - I'm sold. Will it work on older Lancias, with regulators and dynamos, like Aurelias? Mindyou, in the 11 years of driving Aurelias around, the failure has been in the dynamo, typically the brushes, and not the regulator, but any bit will help!

Geoff

[Huib Geurink]

Does the Aurelia have a 30 Amp dynamo?

[georges]

Hi, very interesting point
can you confirm the right Bosch reference number ? (to avoid any error when ordering)
I found this reference on a web site :

1973-1974 Volkswagen Beetle - Bosch Voltage Regulator

Our Price: $88.95Quantity: Part Number: W0133-1614043

This Product Fits the Following Vehicles:
1973-1974 Volkswagen Beetle
1973-1974: 4Cyl 1.6L Base
Thank and regards

[Huib Geurink]

Fortunately I have a spare one in the boot. Even if I have complete faith in the Bosch made electronic one I am not giving up on the policy of keeping a spare regulator in the boot. (And a spare dynamo, a set of brake pads and an original Marelli distributor plus blue Bosch coil. The latter two because I have an electronic ignition. These are the only spares I have on board on a well sorted S1 Fulvia.)

Anyway the Bosch number is 9 190 040 099 E
The 9 up front means the part is from Bosch Mexico.
Bosch dealers and even Bosch it self in Europe do not carry this part as an available item in their computers. Some computers list it as an 30 Amp regulator but no ordering info. You have to go to a well sorted VW specialist.

Talking about the electronic ignition. Yesterday I had a customer coming back into my workshop who wanted his old distributor reinstalled as he found the car (Fulvia S2 berlina) too fast and too dangerous. I installed the electronic distributor and black super coil last sunday. When he had arrived home he already called to say that the car had become very fast and his wife was also complaining about the dangerously fast acceleration. I like this.

[Geoff Goldberg]

I don't know. Its listed at 200 amps (does W=VA?).

[Neil Cundy]

Aurelia dynamos are 25A IIRC.

[Brian Long]

Yes, for DC power.

Cheers.