recharging mobile from cigarette lighter

tir21

hi - how many times could one do this for a smart phone without flattening the battery

thanks

Retrogamer

It depends on lots of things.

One would need to know the ambient discharge rate of the battery when the vehicle is left sitting.
The capicity of both the car and phone battery.

forgotmyname

Without killing the car battery?

How efficient is the charger? What voltage and capacity is the phone battery? What capacity is the car battery. Is the car battery fully charged?

You may get 10 recharges, You may get more.

How much of an issue will it be to get into the car and find the battery flat?

ariba10

With most cigaret lighter sockets in a car, the ignition must be on for them to be live.

That might have more effect on battery life than the phone.

Richard53

One way of looking at it is the capacity of the two batteries. A phone battery is typically in the 1500mAh range, and a car battery 70Ah. That means the car battery has greater capacity by a factor of about 47.

A phone charger has a typical charge rate of 1000 mA, so a car battery could in theory sustain that level of charge for 70 hours, or nearly 3 days. But the phone would be charged after about 90 minutes, so unless you want to charge several phones one after the other, it's not an issue.

I am not an expert, and I know there are a lot of other factors involved, but what that says to me is that charging a phone battery from a car in normal circumstances isn't going to have any significant effect on the donor battery.

I have left a phone on charge in my car overnight and it made no difference whatever to starting the car the next day, and I wouldn't even consider it a problem.

ETA: the 12V socket in the front of my car is permanent live, so no need to keep the ignition on. I wouldn't leave the ignition on overnight if the socket was wired the other way.

F1F93

You can buy 12v sockets with built in voltage-meters so you can tell how much charge the battery has. Mine cost about a tenner, and it's got 4 sockets. You can get them a lot cheaper than this if you don't need all 4 sockets.

These will show how much charge there is so you don't let it run too flat.

tir21

Thanks everyone

Im going camping for a week so will have no other way of charging phone other than car

So might need about 25 recharges

Richard53

For what it's worth, I go off camping on my motorbike (battery capacity 10Ah, or 1/7 of an average car) and I charge my phone from the 12V socket on the bike all the time. As long as the bike gets a run every couple of days, I don't notice any adverse effect.

Bantex_2

tir21 wrote: »

Thanks everyone

Im going camping for a week so will have no other way of charging phone other than car

So might need about 25 recharges

I would just buy a 10 quid throw away phone for the week. Most will carry a charge for weeks.

WTFH

Crazy idea, but how about switching off your phone, only use it in an absolute emergency, then it won't need recharging 3x a day, and you might get to enjoy. Bit more of your camping break with your friends.

tir21

WTFH wrote: »

Crazy idea, but how about switching off your phone, only use it in an absolute emergency, then it won't need recharging 3x a day, and you might get to enjoy. Bit more of your camping break with your friends.

Too late. Already addicted