I am currently using a charger that outputs 15 V @ 4.0 A. I would like to know if I can use a charger that shows these output details in the back:

[email protected] / [email protected] / [email protected] / [email protected]

From my understanding, all these outputs (20 V, 15 V, 9 V, and 5 V) are available and the charger will match the device's voltage requirement (15 V) (please correct me if I am wrong).

I also read that as long as the voltage is the same, it is safe for the charger to output a lower amperage and it does not pose a risk to the device to receive 3.0 A instead of 4.0 A.

Can anyone confirm how this works and if I am taking a risk charging a device that accepts only 15 V @ 4.0 A with an output option of 15 V @ 3.0 A?

  • \$\begingroup\$ Yes you probably are taking a risk. This sounds like a laptop. At this point I cannot answer your question, what is this charger connected to, what was the original charger's rating. Can you post links to technical information on each of the devices. \$\endgroup\$
    – Gil
    Mar 16, 2022 at 3:54
  • \$\begingroup\$ @Gil This charger is in fact connected to a laptop more specifically the Surface book 1 (with GPU) from Microsoft. as stated on their website, the charger model is 1706 with the specs stated above. What technical information are you referring to? There isn't much technical information available for the laptop other then the provided information of the charger specs. \$\endgroup\$
    – Yossi Levy
    Mar 16, 2022 at 4:06
  • 1
    \$\begingroup\$ It's not a charger. It's a power supply. Standard rules for power supplies apply. If your laptop needs 4A at 15V, the 3A at 15V supply can't provide it. But you never said what the laptop needs so we can't tell you if the replacement adapter matches the current the laptop needs. \$\endgroup\$
    – Justme
    Mar 16, 2022 at 5:24
  • \$\begingroup\$ @Justme I understand, the laptop is the Microsoft Surface book 1 and there seems to be no documentation to determine what it needs. If anyone can direct me to the correct location I'll gladly look but from my research I wasn't able to find any details in regards to what the device needs \$\endgroup\$
    – Yossi Levy
    Mar 16, 2022 at 13:45
  • \$\begingroup\$ Manufacturer has a web page with power supply and charging requirements for your model. Go look your exact model there. \$\endgroup\$
    – Justme
    Mar 16, 2022 at 21:59

1 Answer 1


To answer the question directly, it depends, but I'll say "no" for a conservative answer. If the original charger that came with your Surface book 1 is rated at 15V@4A, you should not use that replacement charger. If the charger that you are using uses USB-C, then you'll have USB PD enabled (look at the picture & follow the link provided below), then yes, the charger will match the device's voltage requirement, but you won't be providing enough current to safely (or at least, as timely) charge your laptop. Generally, the current on your charger should be equal to or larger than the original one.

Here's some additional information on USB PD:

TI USB PD Profile

The second bullet point states the above. If you are curious, this is the webinar that talked about this.

  • \$\begingroup\$ that makes sense thanks for the response, If I find a charger that has USB PD enabled (USB C charger) at 15v with 4.0A or higher, then is it safe to say that I should be safe to use to charge the device? \$\endgroup\$
    – Yossi Levy
    Mar 16, 2022 at 4:47
  • \$\begingroup\$ @YossiLevy It seems that I assumed it has a USB-C port like some other Surfaces do, but looking it up, that is not true. In that case, I wouldn't use it. All USB-C cables can do USB PD, but you need a USB-C port. Therefore, I wouldn't advise getting a USB-C to USB 3.0 adapters and charging that way. I also took a look at the Surface Charger 1706 and it seems that it has a special connector to fit Surface laptops specifically. I'd advise looking for a cheaper alternative/knock-off on Amazon or Best Buy or Walmart. That can be a risk, but it will be cheaper than an official charger. \$\endgroup\$
    – Nick S.
    Mar 16, 2022 at 5:09
  • \$\begingroup\$ that makes sense thanks for your response! \$\endgroup\$
    – Yossi Levy
    Mar 17, 2022 at 0:22

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