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I am out of town, and forgot my charger so i want to use my friend's but i heard that it might damage my battery or his somehow.. It sounds kind of illogical but i heard it's true.. Thanks for your help
What kind of macbook does the friend have? Is the charger the same wattage rating as yours and does it have the same magsafe connector?
If so it should work.
If it's the same charger then there's no problem. But if your charger was the 85 watt model and his is a 60 or 45 watt model used with MacBooks or MacBook Air, then it's ill-advised. There are circumstances where your computer could damage his charger due to excessive current requirements.
E999 wrote:
I am out of town, and forgot my charger so i want to use my friend's but i heard that it might damage my battery or his somehow.. It sounds kind of illogical but i heard it's true.. Thanks for your help
No magsafe charger (if it's working properly) will cause damage, but if it is too small you may not be able to charge and use the computer at the same time, if it is too large it makes no difference at all.
All magsafe chargers use compatible connecters.
Exactly. You can use any magsafe safely.
The thing is that we both have macbook pros but he's afraid that if i use his charger it might affect somehow his battery life or something
Yes very illogical and untrue.
Even if it is a higher or lower watttage charger (AC power adapter) it will still work.
If a high wattage, 90 instead of 65, the MBP will only take what it needs. The AC power adapter does not PUSH out 90 watts. It has the capacity of SUPPLYING 90 watts. But will only supply what the device connected to it needs up to the 90 watt rating.
If it's a lower wattage AC power adapter then one of 2 things will happen.
1) you can use your MBP with the adapter connected and it will power the unit but not change the battery at the same time.
2) charge the battery when the MBP is powered off.
It won't. Ask him where he learned such nonsense.
E999 wrote:
The thing is that we both have macbook pros but he's afraid that if i use his charger it might affect somehow his battery life or something
He is completely wrong and I may add totally illogical.
I Second Kappy.
Not without some qualifications. The issue is when using a less-than 85 watt charger on a MBP that requires an 85 watt charger. The MBP can require as much as 85 watts under heavy CPU and/or GPU usage. Trying to pull 85 watts from a 60 or 65 watt charger used by most MacBooks or the 45 watt charger used by the MacBook Air can lead to potential problems of possible overheating or over-current issues in the charger itself.
One should avoid using lower rated chargers than required by the equipment. The reverse is, of course, not a problem.
Kappy wrote:
If it's the same charger then there's no problem. But if your charger was the 85 watt model and his is a 60 or 45 watt model used with MacBooks or MacBook Air, then it's ill-advised. There are circumstances where your computer could damage his charger due to excessive current requirements.
That's incorrect, assuming no defects all that will happen is slow charge rates and inability to charge and run, the charger is more than capable of supplying its maximum output continuously.
People are just confused by the fact that there are three different rated adapters. I'd assume that this is just a matter of energy conservation, but as previously stated, there is no danger of causing damage.
So just to let him be at ease, we both have macbook pros, if i use his charger and then he uses it back it WILL NOT affect negatively his battery in ANY way.. Right??
Kappy wrote:
Not without some qualifications. The issue is when using a less-than 85 watt charger on a MBP that requires an 85 watt charger. The MBP can require as much as 85 watts under heavy CPU and/or GPU usage. Trying to pull 85 watts from a 60 or 65 watt charger used by most MacBooks or the 45 watt charger used by the MacBook Air can lead to potential problems of possible overheating or over-current issues in the charger itself.
Nope, Ohms law has yet to be repealed, the current drawn by the load will increase until the supply maximum is reached, then it will stay at that level until full charge is achieved. The supply will deliver up to its maximum specified wattage and can do that without strain.
Don't bet your charger on that. It's quite possible to exceed the over-current protection of a power supply (assuming it has one) and cause heat damage or part failure. There are limits in which you can drain 85 watts of power from a device designed to supply only 60 watts.
Having designed, built, and used power supplies over my last 50 years I think I understand a little about their limitations.
Perfectly designed power supplies contain both over-voltage and over-current protection, but it's more important to provide over-voltage protection for computers than it is over-current, so the latte is often if not always omitted.
Using another macbook pro charger might damage my macbook pro battery??
