Voltage regulator for S1 dynamo
Posted: 14 May 2008, 21:32
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.
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.