I'm trying to find something that is quite simple and sensible in my head, but apparently no one makes.

I'm looking for a USB (preferably dual) car charger that has a power switch on it.

The reason is because I currently use a car charger, and it requires me to remember to unplug it every time I leave the car. I use the damn thing every time I'm IN the car, so there has to be a better idea. Unfortunately, my Ford Taurus doesn't turn off the ports when the car is off (no, not even after 10 minutes of accessory power), so without doing some wiring that would assuredly end with me burning the car down, I'm stuck finding a USB charger with a gorram switch.

Apparently these don't exist.

Anyone have any ideas of any, or maybe another solution to my problem?

You could add a power switch to the outlet. Or just correct the wiring. It'd be pretty easy, and you'd get to learn a little bit about how to take your car apart. http://www.amazon.com/Heavy-Duty-Toggle-Switch-SPST/dp/B0002ZPBRA/ref=pd_sbs_auto_1


Of course, adding a switch means you still have to remember to use it. I'd just fix the wiring.

Disconnect it from the device?

If you are forgetting to unplug the charger when you get out of the car... why would you be any better at remembering to use a power switch?

The charger still draws power. I don't want the charger draining my battery in there just by burning some stupid LED and some circuitry. (Especially if I leave it connected to my bluetooth adapter, which I don't intend to remove from the car often)



I don't forget often, it's just annoying as hell to unplug it every time, especially since it's under the dash on the passenger side. It's also probably not all that good for the charger nor the plug itself to constantly do that.

So don't leave your car parked for a week.

So don't leave it connected to your bluetooth adapter.

So get an extension cord.

The idea of convenience is lost to you? Stop being a tool.

So pull the fuse.

Yeah, gotta go with Jon'C on this one... Assuming you're driving the car daily (or hell, even leaving it parked for the weekend) you're not going to drain your battery to any significant degree by having a LED light on on a charger.

Install a relay to feed your 12v accessory plug and activate the relay from an ignition/accessory controlled source.

No, CM, your car's battery is huge. Your starter motor draws over 300 amps every time you turn on the car. The charger will be in a low power standby, using only a little power for the LED. You could literally leave it running for years before it became an issue.

Edit: A quick calculation says 5 years before you drain an average small car battery. Even if you had it plugged in and charging your phone, you're looking at an order of months before it's a problem (and that's assuming a constant drain, which wouldn't be the case once the phone is charged). And every time you turn on your car the alternator is recharging the battery.

According to my math (detailed below), if the charger was attached and at full load (1 amp) my car's battery would completely drain in ~54 hours or less, depending on the condition. I have no idea what sort of load the charger draws without anything attached, so I won't even dare speculate there, but even 10ma would be more like months, not years.

Math:

My car's battery has 130 reserve capacity minutes, which from my understanding is how long the battery can supply 25 amps. Assuming this is linear (I know, crappy assumption), 1 amp of power draw is 54.16 hours.

If the charger really does use only mere single milliamps of power when not attached to a device, I'm not too concerned. But I don't have any numbers on that, and I suspect it varies wildly on each individual charger.

Full disclosure: I'm obviously not an electrical engineer and I know even less about cars, so feel free to point out where I'm wrong. That's just my conclusion.

Unplugging would work just as well as a power switch. I would imagine you're just as likely to forget to turn it off as you are to forget to shut it off.

But that would never happen, because charging at 1 amp, your phone would be completely charged in just a few hours. At that point the battery circuitry will no longer be drawing at 1 amp. At that point it'll be drawing roughly equivalent to the amount of power consumed by the device being in standby. Also, your car's battery is 12v, the amp hour rating is for draw of 12v and 1 amp every hour. You're actually using less power with a charger because your phone uses 5v, so there's a DC->DC power conversion to get it down to 5v, so it's not as costly (the loss of the conversion is probably 10% at most, DC->DC conversion is very efficient, I would expect more like 5%).


A typical superbright LED draws about 20 mA, a regular indicator LED draws about 1-5 (depending on how bright it is). The rest of the circuitry is probably canned ICs that have ultra low power modes built in (these are super common and cheap these days) which are probably drawing on the order of microamps.

I understand your concern but I do not believe this is a practical concern. I've been using a charger in my car for years and never had a problem. And these days I drive maybe once a week.

If you are that concerned, try to find one without an LED. The LED is actually going to be the largest draw of power for such a device. You might also look at anything advertised as specifically being low power, some might even advertise power draw.

Even it did have a stupidly bright led on there that was drawing 10ma, unless you plan to park your car for months straight, the alternator is going to recharge the battery back to capacity every time you use it. I think the self discharge rate of the battery is going to dominate here, unless there is some subtle chemistry issue that I'm not aware of.

I don't know the math but from personal experience, I leave a car charger or a DC-> AC converter plugged in to my car at all times. Before deployment, I drove every weekday, and never had any issues with the converter (which I'm assuming draws more power than the car charger) or the car charger. Nor did I have any problems on the weekends where I didn't go anywhere and left the car sitting from about 1330 Friday afternoon until 0600 Monday morning. Additionally, now that I'm on deployment, I know my wife drives even less than I did, and I have no reason to believe that she would have unplugged those accessories, so it's likely one of those things is still plugged in and NOT causing her any trouble.

Like everyone's pretty much said, if a little 12 V DC -> USB adapter is going to kill your battery, you probably need a new battery anyway. The draw is so miniscule that it really shouldn't register, and your alternator is going to top your battery off every time you drive for more than a few minutes.

And have you tried both 12V outlets to be sure they both remain powered? In a lot of cars, one outlet stays on always, and the other is tied to the ignition so it cuts off when the car is off.

Yeah, I have. It's stupid. I'd prefer if that were the case.

http://www.walmart.com/ip/Pyle-PL12V5SW-Plug-In-Car-1-To-5-Cigarette-Lighter-Multiplier/17242494 Is the closest to anything you're looking for.

Its okay mb, you probably just missed my post because your belly covered it up.

That and I already answered it

http://www.walmart.com/catalog/product.do?product_id=16792389&findingMethod=rr This has USB. I use it because I only have the one outlet in my car. Works nice. I shut off when I'm out. Its perfect for me.

My car's the same way (I think... haven't sat there longer than a minute to see if the ports power forever), but I just don't worry about it because I have to take advantage of the regenerative braking somehow, right?

Anyway, try this: http://www.amazon.com/Charger-Single-iPhone-SY-IPO20010-White/dp/B002G1YP5M

or try using the search term 'automatic shut-off'.