12V car cig lighter adapters - safe?

My family have a fair number of electrical devices ranging from mobile phones to electronic games to fridges, all of which lend themselves to being able to be powered or charged on the road by a 12V cigarette lighter adapter.

My question is, how safe are these adapters in terms of risking possible damage to the device in question? I read about 'surges' in power from the car; if so, is it down to circuitry built in to the device in question to protect itself from that? Or should such protection be built into the actual adapter?

Is it risky to buy a 'cheapo' aftermarket adapter in place of the device manufacturer - might that be a more dangerous proposition than buying an 'original' item? If so, how can you tell what's safe, other than by spending as much cash as possible? Can an existing adapter be tested for this?

Thanks David

Reply to
Lobster
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I've never had any problem with damage to delicate equipment like phones or satnav. Its a wise precaution to connect the ciggy plug before connecting the equipment just incase the power goes on and off a few times as you plug it in, but I've never had any problem.

Varies. Some adaptor leads have a regulator inside to bring voltage down to what the equipment needs and this will give protection, but from what? Alternator going overvolts will be sunk into the battery, so impossible to go above the battery terminal voltage.

I'm not concerned, but as you obviously are, then it would seem best to use the branded manufacturers lead, but I wouldn't bother myself as never had any problem. Just connect the ciggy plug first to prevent any problem with the power going on and off rapidly while the equipment is connected.

Graham

Reply to
Graham

Thanks for the response. I'm not so much "concerned" as ignorant! and seeking advice as to whether it's an issue or not. I've certainly used quite a few adaptors myself for different deviced without problems, and other than *possibly* a camping fridge which expired under warranty under dubious circumstances. I've recently bought a notebook computer which would be by far the most expensive device to charge from the car; hence the current interest.

David

Reply to
Lobster

Its certainly an issue, car electrics are very hostile in terms of transients, and lots of appliances just dont survive them. FWIW if the car is switched off the nasty transients dont happen, but thats a less than reliable way to avoid the problem.

Consider the cost of incorporating protection into an adaptor, and what youre paying for one. I'd be cautious before running anything not bulletproof on car 12v, as for a laptop noooooo. If the appliance in question comes with a car connector then its usually designed to tolerate car supplies, but if not its a risky strategy.

If you want to run masses of appliances from the car, a small SLA with a 2 way switch would solve the problem - the switch enables it to connect to either car electrics or appliance, but never both. 12v SLAs tolerate lower charge voltage than car batteries, so a series diode would be wanted.

Nicads could also be used in pricniple, but there are then more complex charging issues to deal with.

NT

Reply to
meow2222

i think the biggest danger with 12volt devices is of fire, if a wire is too thin it can get hot and burn plastic - it happened to me with my car second battery charger- i had a fuse on one battery but not on the second- whooops

Reply to
George (dicegeorge)

Its certainly an issue, car electrics are very hostile in terms of transients, and lots of appliances just dont survive them. FWIW if the car is switched off the nasty transients dont happen, but thats a less than reliable way to avoid the problem.

Consider the cost of incorporating protection into an adaptor, and what youre paying for one. I'd be cautious before running anything not bulletproof on car 12v, as for a laptop noooooo. If the appliance in question comes with a car connector then its usually designed to tolerate car supplies, but if not its a risky strategy.

If you want to run masses of appliances from the car, a small SLA with a 2 way switch would solve the problem - the switch enables it to connect to either car electrics or appliance, but never both. 12v SLAs tolerate lower charge voltage than car batteries, so a series diode would be wanted.

Nicads could also be used in pricniple, but there are then more complex charging issues to deal with.

Total Bollocks.

As I'm not in a very good mood, I'll call it like Conor.

All complex equipment like a laptop has a very complex power supply. Providing you have the 12v to laptop power supply provided by the laptop manfacturer, it will be absolutely fine. My old Dell ran happily off the car for years and that was with an after market 12 volt to laptop supply.

Graham

Reply to
Graham

I've yet to destroy anything that plugs into a cigarette socket with them

Most car batteries need aloer charge voltage than SLAs.

Reply to
Duncan Wood
[...]

Unless the battery terminal to cable connection is poor, of course!

;-)

Chris

Reply to
Chris Whelan

You'll have plenty of other things to worry about if that's happened :-)

Reply to
Duncan Wood

That is why there should always be a fuse as close to the battery as possible. Close to battery so there is only the smallest length of wire unprotected from a short should the insulation chaff and touch the body. Its surprising how often long lengths are left completely unprotected or naively fused at the far end. By all means fuse at lower amperage at the far end, but there must always be a fuse at the battery end to blow if a short to the body along the cable run. These days cars have a fusible link next to the battery terminal, but this is designed to stop wiring catching fire and a very high current rating, so not to be relied on for protection. Pick up power after the fuse box or if for some reason its needed to connect directly to the battery, say because its a very powerful piece of equipment like an inverter or ridiculously powerful car audio system, then put a fuse within an inch or two of the battery.

Graham

Reply to
Graham

Then no 'spikes' because the engine won't start. Unless you jump start it, of course. Which seems a bit extreme just to use your mobile.

Reply to
Dave Plowman (News)

LOL!

Chris

Reply to
Chris Whelan

:-)

Chris

Reply to
Chris Whelan

Utter and total bullshite.

Reply to
Grimly Curmudgeon

AFAIK The main source of surge/spike is when the starter motor stops turning - all those amps used to create the magnetic field have to go somewhere fast... On light aircraft, the rule is all avionics OFF until the engine has started. I neglected to turn off one item once and was rewarded with a fascinating display of random numbers/symbols (luckily no permanent damage) Just checked my car - the radio and cigar lighter power is disconnected from the supply while the engine is being started. I think you would probably be ok but if in doubt, just pull the plug out until engine running - this assumes you don't have any unusual heavy electrical items connected e.g. motors, large solenoids etc.

Geo

Reply to
Geo

But would that apply if, for example, you were trying to restart the engine in flight?

Reply to
Rod

Yes - the only supply required from the battery is the starter motor - ignition is from two independent magnetos (2 plugs per cylinder).

Geo

Reply to
Geo

I meant, would it be OK to turn off all avionics while struggling to get the engine running again. I imagine that would include altimeter, radio, etc.?

I know nothing about aircraft but am thinking that the systems will be broadly similar to cars - when the engine is not running, all ancillary equipment will run off battery?

Reply to
Rod

Yes - I am talking small (say 4 seat) aircraft in good weather. The aircraft will fly with basic instruments without battery power. Altimeter, airspeed and compass. Generally only two flight instruments are battery powered (in common Cessnas/Pipers) the direction indicator gyro and the turn/slip indicator. The other (avionics)stuff is mostly for flying when you can't see anything out of the window.

That is correct - in the event of alternator failure (for example) all unecessary stuff is switched off to conserve battery power for a couple of radio calls before landing at the nearest airfield.

Geo

Reply to
Geo

Across the switch contacts unless you've wired it oddly.

That's to maximise the available current though :-)

Reply to
Duncan Wood

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