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Mobile Phone Chargers

I’ve heard that it’s not a good idea to connect a mobile phone to the cigarette lighter while starting the vehicle. Is this true?

I’ve never heard this before. But I suppose the extra current draw could compete with the starter motor, and cause it not to crank, esp if the battery was on the fritz anyway. The other possible reason might be that the cranking could cause electrical spikes which might possibly damage the cell phone. But I doubt that would be the case. I think if the car cranks ok while charging, don’t worry about it until such time that it doesn’t.

I’ve heard that the starting of the car damages the phone. Is this plausible?

The way I heard it (from electrical/electronic/automobile gurus), the problem is voltage spikes from the starter motor on the 12V supply. It is plausible that the spikes could damage the charger or the phone, but I’m not sure how plausible it is that there are spikes – would they not damage the rest of the car’s electronics? The battery is supposed to damp any spikes.

Nonetheless, my own practice is to unplug the charger when starting the car. But I hardly ever use the charger, so it’s no burden on me to unplug it.

I doubt it does any damage - it is high frequency high voltage pulses that could potentially kill sensitive electronics. The regulators they use inside those chargers give very good noise isolation.

If starting a car could do damage to electronics, we’d have blown ECMs all over the place. They very likely use very similar fairly robust regulators. We don’t.

As far as current draw is concerned, it is peanuts when compared to even lighting a dome light, let alone a starter motor.
Don’t worry about it.

Consider this claim entirely bogus. Millions of car owners leave a host of gadgets permanently plugged into the 12v receptacle – GPS, cellphones, laptops, etc. They stop and start the car numerous times throughout the day. We have no reports at all of damage to any accessory. That’s negative proof, but it should be good enough.

I figured it was a not really true.

When you turn the key to the start position, voltage is cutoff to all other circuits, including the 12v receptacle. when the engine starts and the key is returned to the run position, 12v is reapplied to all the other circuits, including the 12v receptacle. The misconception is that when the voltage is re-applied, there is a surge. There is no more surge to anything plugged into the receptacle when the voltage is reapplied than there is when something is first plugged into that receptacle.