Author Topic: Confused about the ballast resister and starting voltage.  (Read 3280 times)

Paul99

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  • United Kingdom, England, Hampshire UK
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  • 230 SL White. 1966.
Confused about the ballast resister and starting voltage.
« on: February 11, 2015, 17:46:29 »
I have upgrades to the red Bosch coil and 1.8 ballast resister. Car seems to run fine now.  But, in the technical manual it talks about a bypass on starting to provide additional volts.   I can't see how this happens as I don't have an additional wire from the coil end of the ballast resistor to the coil from either the starter motor or a relay.  So how can the ballast resister be bypassed on start up ? 

Confused!

Naj ✝︎

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Re: Confused about the ballast resister and starting voltage.
« Reply #1 on: February 11, 2015, 20:23:26 »
Hi, Paul,

The later higher HP starters have a hot terminal on the starter solenoid that can be used to bypass the ballast resistor.
The 230 SL original starter does not have tis extra terminal.
If you want to bypass the resistor, you have to add a relay wired to the coil side of the ballast resistor so that it gets the full 12V when cranking.
If your car starts OK now, maybe you don't need it?

Naj
68 280SL