Are Mobile Car Chargers Good for Phone Batteries?

Chris Levo is the President and Chief Editor of Nteract Solutions. He sent me the following email after watching my video about charging my iPhone on the go. It’s excellent information, so you should read it carefully.

I was watching your video about leaving your house with your iPhone, and needing to charge it if it runs out of juice. You mentioned a car charger being a very good idea and what should be done (retract, iGo, whatever you want to call it). Any charger that goes into the car is bad for the device battery. Why? Because the power is not regulated like in your home. In my line of work, I have seen many batteries die because people use their car chargers WAY too much. A car charger should be a LAST resort. I try to explain to customers that when they get home they obviously (well I guess 99.9% of the world) take out their wallet, keys, coins, or whatever is in their pocket before going to sleep. Make it a habit to charge your phone with your home charger.

The same goes for purchasing cheap home chargers just to save a buck. Many customers frown at $30 for a home charger because they lost theirs and say they will just go to the “flea” market and get one for $10. The ones for $10 are worse then the vehicle/12v charger port (not called a cigarette lighter in any vehicle anymore because the lighter portion does not come with the car unless you add the option. That is another answer to a question you had at the beginning of the video).

I’m tired, it’s late, but I just wanted to get this out and make you aware of the fact that using a car charger can kill the length of the battery by as much as 50% (if used more then the home charger). Just something to think about before you go plugging in your expensive device in your car charger or don’t feel like running upstairs or where ever it is in your home to plug in your device because you might be too tired. Take the extra 2 minutes and plug it into the home charger.

The moral of the story here is to be proactive when it comes to keeping your mobile device charged. Use the proper home charger. Trying to save a few bucks or some time now will end up costing you far more down the road.

39 thoughts on “Are Mobile Car Chargers Good for Phone Batteries?”

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  3. I have one of those power converters in my car. You plug it into the cigarette lighter and it converts the power to 110/115v. It has a regular 3 prong outlet in it and I just plug my regular charger into it. I use it for my cellphone, laptop, MP3 player, etc. You can buy them from most electronics stores for about $40-$100, depending on it’s size. Works like a charm for me and no dedicated car chargers needed.

  4. I have always believed that an inverter 12v/120v is a safer way to go since it allows the normal charger to do its best at what it does.

    One thing about 12v inverters is to be sure (if you can) that the output voltage falls not only within normal standards±, but that it is a sine wave of 50~60 Htz and not some “harmonic”.

    I had an unpleasant situation with one such harmonic inverter. This was back in 1988-ish. The inverter came from a support group for Osborne computers and worked wonderfully with them, so I tried it with a fairly new Sharp PC-7000 “lunchbox” computer. It worked for about 10 minutes then the Sharp gave forth this really nifty blueish-yellow smoke. I tried to shut it down, but realized that a B+ canister (rather large capacitor – oil-filled – had overheated and begun a smokey near-burn situation). I plugged the Sharp back into the wall and it worked like nothing had happened. When I reconnected to the battery system (Florida has so many ground-strike lightening storms, it’s imperative, … at least back then before UPS) it began smoking less and finally stopped.

    From then on, the system ran flawlessly until I traded it to the Clearwater Marine Science center for their older colour CRT 8088 system and a Wang 5-station they no longer needed. Last I heard, it was still running wonderfully.

    The point is that equipment back then was more tolerant of some things modern equipment might not survive. Such things as a harmonic power source may not be so usable today as back then.

    What I do not know – since I have no “Scope/ocilliscope” – is what brands give “pure” 50~60 Htz outputs. Anyone know? (Hint: I live in rural north-central Missouri, so Wal-Mart and Radio Shack are all I have locally. I can get to Columbia for Best Buy, Circuit City and Staples, but not frequently.

    What do you know?

  5. I had no idea that car chargers were bad for devices. It’s amazing how unaware of the dangers of things we do every day we are, and it’s really not our fault. Products should have proper warnings on the packaging. I’m a bit mad that they would allow something that could negatively effect you like this, without proper warning.

  6. Great advice considering I hang on a boat that has 2 12v sockets for charging up various appliances. I’ll keep it to a minimum now.

  7. Thanks for the heads up but what is the background data for the information quoted from Chris Levo? Is this just his opinion or based on some actual scientific facts?

  8. Thank you Chris. Very useful information. I’ve been looking for this information for a long time. Permission to copy paste this blog to mine.


  9. Chris, Sorry, I can’t agree with all you’ve said. I have over 30 years repairing and maintaining electronic equipment.

    1st. The car system is regulated, really well, but that being said, any good car charger will be regulated itself. Most batteries, in most modern phones, are charged with about 5 volts, the charger regulates the automotive ( nominal 12v really 14-14.5 volts) voltage down to the required 5 volts or so.
    Some chargers actually pluse the phone battery as well.

    2nd. Most phones have the charge control circuit built in, so the charge amount and rate is controled by the phone.( As long as the charger is somewhere near the correct voltage)
    And if the voltage is too high, the control circuit just turns off the charging.

    Bob Francis

  10. Chris,

    I’m an electrical engineer by profession, so I feel somewhat qualified to question the statements by Mr. Levo concerning the unsuitability of car chargers.

    There is nothing about car chargers that makes them inherently worse or better than home chargers. A poorly designed charger of any type is not good for battery health, but a properly designed charger manufactured by a reputable company is suitable in either location.

    Device life may be shortened in a vehicle environment by things like dirt, vibration, extreme temperatures, etc., but statements such as “Any charger that goes into the car is bad for the device battery.” and “Because the power is not regulated like in your home.” are not based in fact.

    Mr. Levo’s advice about not purchasing “cheap” chargers is sound, but his opinion about vehicle chargers is not.

  11. Do you have test data that backs this up? What about the car charger supplied by the phone manufacturer?

  12. If the voltage regulator is in the home charger as implied, then use a 12 v DC to 120 vAC converter in the car and plug the home charger into the converter..

  13. I never really thought about this. I’m going to have to take my car charger apart to confirm this. It only takes a small chip and a couple other cheap components to make a voltage regulator, I just assumed that these chargers would have that in them. Likewise the phone itself should have a voltage regulator in it. This is pretty standard technology.

  14. Perhaps you should poll someone with a some degree of technical knowledge. The closest this article comes to providing any basis for his warning is “the power is not regulated like in your home”. News Flash: the power in your home is not regulated. In the US the voltage range allowed is almost 40 volts and in practice exceeds that. Any “regulation” is done in the charger by a voltage regulator chip. Is he saying that _no_ vehicle chargers use such a chip? And that that is the difference between the “$10” and the “$30” chargers? Sensationalistic, unsupported, “Chicken Little” warnings like this provide no service at all beyond entertainment value. In fact, you do yourself a disservice by promoting it without validation.

  15. I’d like to hear more evidence why car chargers are bad. what does he mean “the power is not regulated”? of course it is! car batteries put out about 12.5 volts give or take some. is that “give or take” really so bad? if so, why?

  16. I use my home charger, but plug it into an inverter in my car…wouldn’t that be as good as home charging? Mr. Levo’s comment, “…because the power is not regulated like in your home ” would only apply if you were not using the home charger (which I assume is the regulator that he is referring to) but I do, just plugged into my high-end aftermarket inverter.

  17. This is false information. Most car charges use voltage regulators such as diodes or voltage regulator chips. I don’t know of any 12V cellular telephone. Most run on 3-5V. Also, when a cell phone charger manufacturer makes a charger they have to account for the fact that when the car is off the car provides 12VDC and when the car is running the car will provide as much as 15.5V in some cases.

    As an electronics tech, I see alot of false information which is written by those whom know just enough to be dangerous. Did you know that 50 years ago people actually put covers on their electrical sockets so that the power didn’t leak out?

  18. Exactly what is he basing his information on? Is it the simple fact he feels the power is unregulated? If so, he should see my APC UPS log file…. Ninety percent of the logged outages are due to low voltage levels and cycle drops, not actual power outages. Charging exclusively in your hoome is no guarentee, especially in central PA.

  19. What difference does it make if you replace your phone every two years? With my last phone, I used the car charger probably as much as the indoor one and the device is still OK.

    I disagree with the part about emptying my pockets before bed. I think most people empty their pockets when getting home then go to bed hours later. This is the best time to charge the phone. I’ve heard differing opinions over the years about possible over-charging, but if you plug it in when you get home, you can check to see when it’s at 100%. I’m not too comfortable leaving it plugged in for 8 hours while I’m asleep.

    Levo must be some kinda workaholic.

  20. I would think that charging the batteries often just to keep them full, triggers the “memory effect” which is common in any type of battery.

  21. Having used car chargers (and I mean the cheap ones from convenience stores) almost exclusively for the past 10 years I have to say this guy doesn’t know Jack!

  22. I have to agree with those poo pooing the idea that car chargers are bad. Were did you get this from? did you just make it up on the spot? What a load of rubbish, it’s funny because I was just looking @ my car charger yesterday, cuz I am going into running stuff in car @ the moment in a big way(that’;s another story), the one I use is a Nokia branded one for my Nokia phone and it actually came in the package when I got the phone. It says on it 5v, so as the car is 12v it is obviously regulated. My work is 30 mins away from were I stay so the phone gets 60 mins a day on the car charger, it has never even been attached to the mains charger I couldn’t even tell you what it looks like, my phone (N95 gr8 phone BTW) is ~18 mnths old and work perfectly.

  23. Certain car phone chargers whether they were bought through oem providers or aftermarket, did not regulate voltage, and therefore shortened the life of the cell battery.
    Whether this was by design (to sell more batteries) or just shortsightedness, is immaterial. Most newer cell phones come with just a car charger, which makes one wonder why cell phone providers find it more convenient to supply just a car charger. My personal phone charger broke after 4 months, as I change cars often. I now have both a car charger, and purchased the appropriate home charger as a backup and have had no problems with either, although I suspect the home charger will last considerably longer.

  24. Well, the most safe to charge cell phone by it original charger. No others. Why we have to bring our cell phone to car and charge it with car charger? Make it easy, don’t make it difficult.

  25. Yeah.This is a very convenient and safe way to charge your mobile by your mobile charger.I think to charge mobile by a car charger will not be as safe as mobile charger.

  26. i use a home charger on an AC converter in my truck, it stays plugged in all day long, i cant say if the life of the battery has been reduced or not, but the phone is fairly new yet, and any timing of the battery life would probably require days as the phone would need to be switched to airplane mode to disable data and cellphone signal and the phone would need to stay stationary and in a dark box in order to not trigger any sensors which would throw off the timing of the battery life, all of which i just don’t have the patience to do… and i wont, since this is your claim that car chargers are bad for the battery life, therefore, YOU should do it for the rest of us. acquire a new phone, and time the battery after charging it in your home, switch airplane mode on and time how long it’ll last (in airplane mode with the screen off, it’ll probably last weeks, so good luck) then use the phone on a regular basis, charge it in car only, then time it again in 6 months, and just to be sure, you gotta do that again with a new phone in 6 months, same timing again in airplane mode, then charge in home exclusively for 6 months and time in airplane mode again. it’s your claim, so go ahead in back it up, then we might be able to take you more seriously. see you in about a year!

  27. I tried experiment with my car charger (Belkin) on my Samsung S3 the other day. 3 things I did: 1, charged the phone when the car engine was on, i.e. when the car generator kicked in; 2, Charged the phone when the engine is off, but the car battery is activated; and 3, plugged the charger and phone in and started the car. Each time I measured the voltages. The voltage for 1 – average 12.88v; 2 – average 12.06v; and 3 – when the engine started the voltage was 13.09v and tapered to 12.8-12.9v. If the car charger is not regulated to stabilise the voltage, my fear was that the phone battery would be affected, especially when the phone was plugged in before the start of the engine. This is just my deduction. Any comment?

  28. With all the electronics in cars these days, seems to me that voltage regulation is pretty important.

  29. What you don’t realise here is that your phone doesn’t charge off 12v.. no phone made in the last 10 years near as damnit charges on anything but about 5v, the car chargers (and home chargers for that matter..) have a transformer to bring it down to that, in the process some filtering happens and regulating, the actual output voltage is fairly stable, along with that the phone’s charging circuit manages a lot of it to ensure all is well. Unless you chop the USB cable in half and connect it straight up to the car battery, chances are you’re fine. I’ve never had an issue with phone chargers in cars, except I have older cars with different size sockets and the charger keeps falling out..

  30. I’m a truck driver. I ONLY charge using car chargers on my android devices, usually using a modified kernel that allows faster charging. Each of my devices has lasted 2 years plus EXCEPT my iPhone 3GS back in the day. It lasted 1 year. So, 50% less battery life? Sorry, but that theory doesn’t hold up to my real life usage (my phone is charging via cart charger a good 5 hours a day or more).

  31. Not sure the person wrote this article had any knowledge about electronic.
    Nothing wrong to use car cigarette adapter to charge your phone. All adapters should regulate output voltage as long input 12v within 12+/-3v. A good adapter should run cool when charging phone. The quality of adapter depends how much regulation and quality of internal assembly.
    Cheap one, when you open to see inside, it has poor soldering and PCb. Actual it could damage your phone if the adapter is malfunction.

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