The mid-2012 13" MBP (A1278) uses the original MagSafe charger, not MagSafe 2. There is a simple physical adapter from 1 to 2, but AFAIK not the reverse.
You can buy a MagSafe2 to USB-C cable and then use any suitable USB-C power supply to charge an old MagSafe2 MBP. I bought two a while ago and have not had any issues with them charging older MBPs with newer chargers. I have no experience with such a solution for the original Magsafe, but I have seen offers like these.
According to MacTracker, a 13" Mid-2012 MacBook Pro uses a MagSafe power connector.
For the Mid-2012 releases, the MagSafe 2 connector is only used for the 15" Retina display model. You don’t want this one - the connector won’t fit.
Apple still sells MagSafe power adapters. They sell a 45W and an 85W version. Both for the same price ($79). Get the 85W version - the computer probably came with a 60W adapter, so you definitely don’t want anything smaller, and it never hurts to have a bit of extra headroom.
There are definitely third-party sellers, but I wouldn’t trust them. I’ve seen too many tear-down videos comparing an Apple power adapter against third-party knock-offs. The third party ones just don’t seem safe to me.
I did see some listings on Amazon claiming to be genuine Apple 60W adapters for a somewhat lower price ($65-70). If you actually get a genuine Apple part, that might be a good deal. But there’s so much counterfeit Apple parts sold that I wouldn’t trust the listing.
The MagSafe 2 power adapters are not compatible with this model MacBook Pro. The connectors will not fit.
I agree with @Shamino that you should avoid purchasing third-party adapters.
FWIW, the last time I needed adapters for my mid-2012 MBPs, I bought “Open-box” MagSafe 1 adapters from a major US retailer at much less than the price of sealed, unopened adapters. I was completely satisfied, the adapters were in “good as new” condition. My bet is that these adapters almost certainly were purchased and immediately returned by people who needed v2 MagSafe adapters, not v1 adapters. I realize that you probably are in Asia, but perhaps you can find similar offers through a trusted local retailer.
Personally, I would buy a USB-C to MagSafe cable/adaptor as @Simon suggested. Inexpensive and she can use it with any reliable/reputable USB-C power adaptor (including Apple’s current ones). Buying an Apple MagSafe power adaptor is spending a lot of money on something that is of limited use. Much better to spend the money on a good USB-C power adaptor if she doesn’t already have one and use a cable adaptor to fit the MagSafe port.
I agree that would be the best, most versatile solution, but I’ve tried a few different USB-C to MagSafe 1 adapters, and I haven’t been satisfied with them.
They usually work, but the ones that I have tried all had “form and fit” issues that also make me wonder about their internal quality. For example, various ones I’ve tried were significantly larger than expected, blocked other ports, wobbled when attached, or detached much more easily than a true Apple adapter.
If anyone has firsthand experience with a good USB-to-MagSafe1 adapter, I’d love to hear some recommendations.
Regarding wattage: If the original included power supply was rated at 60w, you can use one that matches or exceeds that wattage. So the 85w is fine as it will push what the 2012 laptop needs with room to spare, so to speak.
In a pinch you can use a lower wattage power supply, but ONLY to charge while the device is sleeping or turned off. It will also take longer to charge. Be very careful doing this, however. If your device wakes up or otherwise draws power at a normal usage rate, it will cause problems. Overheating and/or damage to components may result.
I have seen a 45w power supply from a 2015 MacBook Air used with a MacBook Pro in desperation, but it strained under active use and could not keep up… like watching someone paddle in a canoe near a waterfall.
Apple does overcharge ($) for their parts, but as others have stated, many 3rd party adapters and parts are just really not built well and may fail in very unfortunate ways.
But Apple seems to have some pretty robust current limiting circuitry/firmware. If you use an underpowered Apple PS, it will work, but if the computer needs more power than the supply can provide, you will see the battery drain (slower than normal, but it will drain).
The power brick may get hot, but it shouldn’t get to the point of causing damage.
Totally agree with David C. It is not worth risking a cheap 3rd party adapter to save a few $$.
I agree overall with you about Apple having better quality, but just to be safe, I would never leave anything unattended when charging with an under-powered adapter.
Apple may tend to use better parts, but they also have a number of cases on record where their part choices or engineering were not up to the task (ie. iMac G5 under-spec power capacitors bursting, or MacBook Pro 2016-2019 batteries erupting through the keyboard). While stories of laptops catching apartments (or planes) on fire are extremely rare and may have other causalities, one never knows when a lithium battery may fail due to a bad batch or age.
To be clear, a 60W adapter works fine with the 13" MBP. It’s what the 13" MBP shipped with. An 85W adapter adds the flexibility to charge 15" models well, which is great, but it is significantly bulkier than the 60W charger, which may be an issue for some travelers.
The 85W adapter is bigger than the 60W adapter (and much bigger than the 45W adapter), but I don’t think it matters that much - my laptop bag has plenty of room for it.
I use an 85W adapter with my 2011 MacBook Air (which came with a 45W adapter). Mostly because when I needed an extra adapter, years ago, they were all the same price, so I decided to get the big one, just in case I’d need it in the future. (And the Apple retail stores only stocked the 85W units on their shelves. Probably because they were compatible with every laptop sold at the time.)
In addition to being able to charge larger laptops, it also seems to run cooler than the 45W adapter. Which also doesn’t surprise me.
I should have been precise about my comments pertaining to the 45W / 60W adapters. It was in regard to the full size (15") MacBook Pros with discreet graphics chips in addition to the built-in Intel graphics that require much more power.