Is there a technical reason why there aren't standard mobile phone chargers?

Nearly every single different brand of mobile phone that I’ve seen has had a different form of charger. Are there technical reasons why they might be different or is it just to annoy people?

Pretty much to annoy people.

Well, technically, various cell phones probably use slightly different voltages and different types of rechargeable battery (Li-Ion, NiMH, NiCad) require different charging schemes, but that said, it would be a fairly trivial task (from an engineering point of view) to standardize connectors and simply use one universal smart charger.

Economically, said charger might be somewhat more expensive than simply packaging the cheapest circuitry that will fit into a wall wart.

There’s just no standard. Same with mains PSUs for laptops (although they’re converging a bit) and indeed PSUs for almost anything else. I don’t think the manufacturers are doing it on purpose (at least not for the most part) - they know they’re going to give you a suitable charger with the phone, so it’s just not a big enough problem - in terms of their design considerations - that you can’t swap it out easily.

No there is no technical reason. I saw a press release from Motorola, LG and Samsung saying they were going to standardize on the mini usb connector (5V) for charging phones. I have not heard much since then. Moto seems to have been using this as a standard for a while.

It is so the guys making the phone and charger can charge you out the wazoo for the cost of a custom charger instead of competing for bottom dollar standard chargers.

I’ve not seen any LG or Samsung phones using that connection yet
However the JCB phone, Blackberrys, HTCs and one Nokia all use the same size port as the Motorola phones.

The trouble is we still have two different kinds of charger putting out slightly different power.

Still, a move in the right direction.

In the past the main reason to avoid this kind of cooperation is to prevent your competition getting rich supplying chargers for your phones. There is a huge market for bulk sales of chargers when people move phones from one country to another to get a better price. The so called “Grey Market”

There’s definitely no reason. In Korea all cellphones have the same connecter. A new cellphone doesn’t even come with the charger. If you need one, the person selling it will often just throw in one as “service” (free) or charge about $5 for it. So much more convenient than the crazy assortment of chargers we have here.

Maybe, but every cell phone I’ve ever had, from whatever the manufacturer, there was a generic charger readily available at my local big box discount store.

China has mandated the mini usb connector for all their phones manufactured after a certain date in the very near future.

There are several good economic reasons for it. See this article for some information on the work involved in supporting standards for interoperability. It’s mostly talking about software, but the basic points apply to hardware as well.

Basically, standardizing on a particular design adds restrictions to your design. Obviously, it restricts you to the form factor of the plug, but it might restrict you in other ways, as well. For example, let’s say that you have this great new plan to introduce a fast-charging device that draws more power. If you’ve standardized on a connection that can’t handle the load, there goes your new cool feature. Or maybe you manage to miniaturize some other components, and you want to have this slick, thin phone. But the plug has to go somewhere, and it ends up being an unsightly bulge on the side. Those are fairly minor cases, but they do matter.

An even worse case would be that there’s a bug in your phone hardware that will cause it to short out and start fires sometimes when connected to a certain version of the standard power connector. This could be a major disaster, requiring a recall of all the phones, potential lawsuits, etc. If you control the power adapter, you can just recall the bad adapters (much cheaper than recalling all the phones), issue new ones, and the problem’s solved. Furthermore, if you controlled the adapter from the beginning, you’ve probably been testing it thoroughly, so this is much less likely to happen.

Of course, there is something to gain from standardizing. It’s probably cheaper to buy a standard adapter than a custom one (even in the volumes that cellphone manufacturers are dealing with). Instead of redesigning the power system every time, the engineering work can be reused (Not without risk: this makes it much more important to get it right the first time).

Since “standard adapter” isn’t a feature driving sales, it takes a while before the economic benefits of standardization win out over the risk of additional constraints and loss of control.

As an electrical and computer engineer, I can tell you that the answer to your question is “no, there is no technical reason” for this. As above, there are economic reasons, and it’s not “to annoy you”, but there are no technical ones.

Actually a good tip to avoid having to buy replacement chargers is to check at the front desk of any hotel in which you’re staying while travelling. Most hotels have boxes full of left behind chargers from everything from phones to laptops to ipods. Most are never claimed and on the many occasions where I have left a charger at home, plane, or other hotel I have always been able to find a replacement this way.

iamthewalrus(:3=** has given a few very good technical reasons against standardization.

Design issues, differing charging systems, various battery voltages, load rating of the contacts, tolerance specs from the power supply, use of the charging socket for things other than charging… All these and more argue against complete standardization across all manufacturers’ mobile phones.

We aren’t talking about some IEC plug that we KNOW is going to supply a certain voltage. The myriad of power supply sockets were designed the way they are for a reason. Do we want some yokel plugging in his 5V@500mA max charger into a phone which requires 12V@1A nominal? That’s lawsuit city.


And I know that ISO or IEEE or someone could come up with some sort of “future proof” spec that would take into account the various configurations manufacturers may come up with, but, as was indicated above, that would limit innovation in ways that could make cell phones suck more than they had too.

Also, some phones and other devices require a “smart” charger which may include a EEPROM in the charger itself, or on the battery. These are used (sometimes) to increase safety and efficiency, and (sometimes) to “lock in” a certain charger or battery to the phone or device. This isn’t always a bad thing.

Bingo! engineer_comp_geek in one!

Absolutely right- why would Motorola want to make a phone that uses a charger that your old Nokia could use, if they can screw around with the connectors a bit, and then turn around and stick you for a charger when your current one breaks.

That’s simply not true. Witness all the 98¢ chargers on ebay. The real reason was stated above - there’s just no incentive for the manufacturers to settle on a standard, and they all feel like a standard would compromise their design in some way (usually mechanical).

Eh, I was mentioning that there are no technical reasons that they could not be standardized. As mentioned, there are economic reasons for why they are not standardized. Are those economic reasons technical? Sure, if you want to call it that. But at this point we’re arguing semantics, not engineering.

Again, all phone manufacturers could standardize on one adaptor, if they chose. The reason they don’t isn’t that they can’t.

If there was a standard charger, then engineering resources spent to design custom power supplies could instead be spent on engineering more or better phones, or costs could be reduced so that they would make more money from each phone.

As i see it there are two significant design parameters: the electric side of things: what voltages you supply at what tolerances and how much the charger interacts with your phone. then there is the physical interface aka the plug.

Lots of manufacturers can’t even settle on one plug for all of their models. Even if the two phones require the same voltage. Round here replacement chargers generally go for $30. There is a bit of profit to be made if you are forced to get one that is specific to your particular model.