I should buy a pure sine wave inverter for my smartphone?

Does anyone buy such a car power inverter to charging smartphone in car?

Not necessary. Just buy any charger approved by your phone’s manufacturer and you will be fine. :sunglasses:


An inverter won’t help charge a phone in any situation. Phones need DC (direct current) power to charge. The adapters that come with your phone (or at least used to) take your utility power, such as 120 volts AC (alternating current) in the US, and convert it to DC. Most every phone these days uses a USB charger, which operates at 5 volts DC.

Inverters take DC power, and change it to AC power. If you plug your phone’s charger into a receptacle on an inverter, the charger will just convert the AC power back to DC power. Car chargers (AKA “cigarette lighter adapters”) take the 12 volts DC in your vehicle, and change it to 5 volts DC for your phone.

Any time you change electricity between AC & DC, or between voltages, you will experience some power losses as a result of inefficiencies. This lost power is dissipated as heat. So taking the car’s DC power, inverting it to AC power, then converting it back to DC power again can be very inefficient. Just using a quality car charger will only change the voltage of the DC power once, so there is less loss from inefficiency.

My suggestion is to save your money; don’t buy an inverter to charge your phone. Purchase a quality car charger, or use your vehicle’s built-in USB ports on many newer cars. Many of the cheap, made in China chargers (like you see next to the cash register at a gas station) are pretty inefficient and don’t work well. But many that have a major brand name on them will work pretty well. And most anything of a decent quality will still be less than $20-25 US, so they are not extremely expensive.

And at the end of the day, as long as your charger is capable of outputting at least as many amps as your phone requires at a steady 5 volts DC, it won’t really know the difference. Your phone will just charge.

(Yes, I know this is relatively simplified, and there may be other technical reasons for an inverter in very specific use cases, but I was targeting this information to the average person’s phone usage.)

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Agreed. Your phone needs DC. Your car has DC, but wrong voltage. You don’t want to convert to AC then back to DC. It’s a lot of expensive hardware for nothing. All you need is a proper voltage converter for your phone. Make sure you get the right one. Many are simple USB 12V to 5V, but other exist for 12V to QC3 for quickcharge3, or 12V to PD for Power Delivery.

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Sorry to be pedantic, but to convert 12v DC to 5v DC, these days you have to convert the 12v to AC, then step down to 5v AC, the rectify the 5v AC to 5v DC. All done at high frequency for efficient conversion. All DC-DC converters work this way, gone are the days of linear converters…

One of the most common types, the buck converter, uses a MOSFET to chop the higher voltage down to the specified voltage. It never converts to AC.

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Nice try! But chopped DC is still a current that alternates between two states, thus not DC. Like I said, I was being pedantic…

LOL. Nope… From Cambridge Dictionary (below), the defining aspect of AC is that the current must change its direction. Chopping the voltage never changes the current direction, only its amplitude. It’s always going in the same direction. :crazy_face:



There I was thinking the original post was going to be marked for deletion !

You just never know on this forum

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Agreed! Best case, the OP just joined the wrong community/forum to ask this question. Worst case, the OP is just trying sell the product linked in the first post (i.e. SPAM!)

In either case, this thread should not exist in the ST Community. :stuck_out_tongue_winking_eye:

I did wonder if the first post was just Clickbait, but I decided it didn’t really matter since it’s a very straightforward question with a really simple answer. (“No.“ :wink:)

And it does have potential relevance since if The answer were Yes then that might impact Geopresence on the phone. But since the answer is no, there’s no HA impact.

So I thought it a potentially valid question for the forum. It’s just that the answer doesn’t help with any existing Geopresence problems.

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