How interchangable are A/C adapters?

I just bought a new Sony laptop last week (F series). The included A/C adapter has an output of 19.5 volts (model # VGP-AC19V54). I have an older Sony laptop that is seldom used anymore. It's A/C adapter (model # VGP-AC19V27) also has an output of 19.5 volts and its plug is the same size as my new one. Can I safely use my older A/C adapter with my new laptop? (I'd like to keep one at the office so I won't have to lug it back and forth). Is there anything other than plug size and voltage output that I need to be concerned about?

Thanks.

 

I have the VGP-AC19V26 power adapter powering an old Vaio VGN-Z530 with a P9600 and 8 Gigs RAM upgrades, originally they were P8400 with 3 Gigs of RAM. This is a fairly small power adapter, look at the size of it.

It seems you stepped down to a small power adapter than the original one designed to run your laptop, so I'd say it's not safe to run it. Recharging your battery and running your laptop on something intensive at the same time might be a little bit to much to take for your power adapter. It wasn't designed to output that much. Find the right power adapter for your laptop.

I believe the F series have the i7 inside and a pretty powerful dedicated graphics inside so I'd say you need to upgrade the power adapter.

 

You also need to look at how much wattage/amps the adapters can put out, and you need to find something that either matches the original, or exceeds it by some amount. I can't use any adapters unless they can go up to 120w+ for my notebook, even if the voltages match. (I've tried 90w and 65w ad adapters and neither works). I don't even think anything less than 120 will even charge the battery...

 

Like Blaze said, the voltages have to match, as do the tips. And then the "second" adapter needs to provide the same or more power (wattage) than the original. If those conditions are all met, you're fine. Unless it's Dell and they have their stupid power-brick authentication mechanism.

 

Ummm its not just voltages that have to be matched, but also, much of the battery charging/control circuitry is in the power brick itself, at least on the Dell units. If the chip doesn't match what is compatible with the system, it won't work. Universal adapters are rarely a good idea.

 

That's why I said Dell was an exception. It's not for a valid technical reason, as the charging is the same and smart chargers exist without Dell's chip. It's because Dell wanted to cut out the universal and aftermarket adapters, pure and simple. Other manufacturers haven't become quite as customer-hostile as Dell yet.

 

Ummm, I disagree here. The charging circuitry, as hot as it runs, tends to have a higher failure rate. By embedding much of the circuitry in the power brick (easily replaced), instead of the laptop itself, Dell improves reliability and eases replacement. Much easier to ship a new power brick out than do a whole motherboard swap just because the charger circuit dies.

eBay is full of knock-off/after-market adapters for cheap, so I don't see your complaint of Dell trying to cut out aftermarket adapters being well founded. Anybody can call up Analog Devices, National, or whomever builds the chip Dell uses and order them for inclusion in their own aftermarket/"knock-off" supplies if they so choose. Its not a proprietary Dell-only part with like a digital encryption front-end or anything like that.

 

Charging circuitry? That's usually embedded in the battery, not in the charger or the computer. All the chargers do is supply a voltage within tolerances at a given wattage. I've looked into this stuff.

I have a "knock-off/after-market" adapter for my Envy that works fine. It charges the battery, nothing gets too hot, and it just works. Even more interesting is that the same adapter will run the Dell I have perfectly fine, the Dell just refuses to charge the battery when it's plugged in. Again, there is NO VALID REASON for that. It's purely lock-in, requiring you to buy Dell branded adapters and batteries.

Here, read it from someone that works with that stuff for a living: https://nctritech.wordpress.com/201...-ac-adapterschargers-hardware-vendor-lock-in/

 

I know I have seen high power laptops come with say a 100w adapter and find out later on it was not enough power for the unit so they release an improved 120w power adapter.

The wattage is the combination of voltage and amperage.

So its pretty safe to say if the new power brick matches the voltage and has more amps your OK, the laptop will only consume the amount of amps it needs to function and not use the rest. However if there is lack of amps needed then it will not work properly.

Here are the important things to know:

These are inverters they are converting AC to DC. DC power has polarity so you must make sure the new adapter has the proper polarity. If you need an easy way to visualize what I mean, just think about putting batteries in a device backwards.

Tip size is obviously important so that it fits, but not a big problem for me if I find the proper adapter with the wrong tip size. I will just use the tip from the old broken adapter and splice it on myself (make sure you get the polarity right)

Voltage - Most devices handle a small deviation of voltage but you want to go ahead and make sure this matches.

Amps - The device will use the amount of Amps it needs so if you have extra its ok (and even good) but if you have less than what you need the device may malfunction or even get damaged.

Catch 22 about amps, some cheaper power supplies if they are not outputting a certain % of there total power output will actually deviate and send more voltage. So dont use some 200w china power supply to replace your 100w authentic power supply even if the voltage matches.

wattage - is just amps x volts so if your focusing on matching amps & volts separately (as you should be) this is just an extra figure. However often they do not give you amps & voltage but say will give 120w 12volt so you have to use simple math and say 120/12 = 10amps

 

And in the power brick itself. I mean, otherwise the 3rd wire wouldn't be required. Replacing the power brick and the battery gives you an entirely new power subsystem on a Dell laptop, which is quite a good feature reliability-wise since these are some of the most likely to fail (other than fans) on these machines.

I've never seen the problems referred to, and use tons of knock-off stuff on the Dell (Latitudes). Might have been an issue when the Chinese builders were trying to cheap out on the chips, but they've since learned their lessons. In my experience, the only issue with Chinese Dell knock-off batteries is that the cells are generally inferior, but thats what you get for paying $40 instead of $200 for a battery.

The rest of it seems like rather unprofessional blabber, especially the broad generalizations that his tech made.

 

Maybe not as hostile, but they're certainly not completely product open either. Just how many parts on your computer can be changed intra manufacturer...the HD?

And this isn't just a laptop/computer thing, virtually the entire electronics industry has that "proprietary" thinking cap on when they design a product. Just think of Apple products from cell phones all the way to their computer's proprietary ports. Now there's just no reason for greed like that. Anyway, I stray from the topic.

 

I've happily powered my Dell Latitude (battery charging and all) using a Kensington PSU so it's not a total lock-in. Dell uses the centre pin on the PSU plug to communicate the PSU power rating between the computer and a chip in the PSU. If the computer can't read the power rating or it is not enough then two things usually happen: (i) The battery charging is disabled while the computer is running and (ii) the CPU is locked to minimum speed.

Given that genuine Dell PSUs are available on ebay for similar prices to unbranded PSUs then it's not an attempted to force customers to use expensive PSUs. Sony, on the other hand, might be up to that track.

John