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Post by djm16 on May 22, 2020 9:44:10 GMT
Quite apart from damaging the electronic ignition unit, the battery will be damaged if charged at 16-17 V. Modern batteries cannot be re-filled, and 17V will boil away the electrolyte.
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Post by enigmas on May 22, 2020 11:33:33 GMT
I've just fitted an Powerspark kit to my 1968 A-series saloon. After a bit of fettling to get it to fit inside the early distributor, it started up first time. However I measured the voltage at the coil and it was showing 16-17v . I need to bring that down to around 14v otherwise the module in the kit will fry. Any suggestions how I can do this? The car originally had a ballast resistor fitted but this was removed and has since been running a Lucas 12v sports coil to the standard points system. Thanks all.
Have the charging system checked and corrected to see why the voltage output is so high. When that's done you can wire in a ceramic ballast resistor (I have no idea what is available in the UK) to drop the voltage to the coil and module incrementally. I have several in a stash ranging from .4 ohms - 1.8 ohms. Here's an example You can buy these either new or visit a motor wreckers with a multimeter and collect several from older cars for a few dollars. 1.5 ohm ballast resistor. * Also refer to my comment in the following post. roverp5.proboards.com/thread/11404/parts-help-needed?page=1&scrollTo=93585
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revoxy
Rover Rookie
Posts: 30
Location: Linz, Austria
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Post by revoxy on May 22, 2020 16:58:06 GMT
I've just fitted an Powerspark kit to my 1968 A-series saloon. After a bit of fettling to get it to fit inside the early distributor, it started up first time. However I measured the voltage at the coil and it was showing 16-17v . I need to bring that down to around 14v otherwise the module in the kit will fry. Any suggestions how I can do this? The car originally had a ballast resistor fitted but this was removed and has since been running a Lucas 12v sports coil to the standard points system. Thanks all.
Have the charging system checked and corrected to see why the voltage output is so high. When that's done you can wire in a ceramic ballast resistor (I have no idea what is available in the UK) to drop the voltage to the coil and module incrementally. I have several in a stash ranging from .4 ohms - 1.8 ohms. Here's an example You can buy these either new or visit a motor wreckers with a multimeter and collect several from older cars for a few dollars. 1.5 ohm ballast resistor. * Also refer to my comment in the following post. roverp5.proboards.com/thread/11404/parts-help-needed?page=1&scrollTo=93585Thanks. A ballast resistor was originally fitted to the car and is still in place although now bypassed. I’ll have a go at reconnecting it.
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Post by djm16 on May 22, 2020 23:59:32 GMT
I fear that a ballast resistor may not protect the electronic unit. All it will do is cause the supply voltage to the unit to oscillate between 17V (when no current is drawn) down to 12-ish when current is drawn.
Rather the overcharging needs fixing at source or the electronic ignition will not be the only thing to blow. A list includes all light bulbs, tachometer, radio.
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Post by enigmas on May 23, 2020 3:16:07 GMT
I fear that a ballast resistor may not protect the electronic unit. All it will do is cause the supply voltage to the unit to oscillate between 17V (when no current is drawn) down to 12-ish when current is drawn. Rather the overcharging needs fixing at source or the electronic ignition will not be the only thing to blow. A list includes all light bulbs, tachometer, radio. That's exactly what I said David. Fix the overcharging issue first...then tweek the voltage to the correct level with the appropriate resistors. It's worked for me for the past 30 years or so! "Have the charging system checked and corrected to see why the voltage output is so high. When that's done you can wire in a ceramic ballast resistor (I have no idea what is available in the UK) to drop the voltage to the coil and module incrementally."
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