• Device Charging USB-C, PD, PPS Wattage

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    Here’s a question that has so many answers that there isn’t a consensus that I can find. Some people even try to apply ohm’s law which really doesn’t make much sense. I’m curious what the group thinks here.

    Q. Let’s say I have a older device that typically would charge with a USB type charger, 5 volts @ 2 amps or 10 watts.  Can I safely plug the same device into a charger that has a maximum delivery of 30 watts? These are typically USB-C type chargers with PD or PPS technology.

    The reason I ask this question is because I thought that a device would only draw the necessary current and therefore wattage and not exceed what it needs.


    Viewing 6 reply threads
    • #2470913

      You cannot force more current (i.e. Amps) into a device it needs to operate so using a charger/power adapter that provides more Amps than a device uses will not cause problems.

      What can and does cause problems is using a charger/power adapter that provides the incorrect voltage (i.e. a 12 VDC charger/power adapter for a 5 VDC device or vice versa.)

      Plugging a device that uses 5 VDC into a charger/power adapter that provides 12 VDC will quickly destroy the device (i.e. the internal electrical components aren’t designed for 12 VDC and will quickly burn out and possibly even cause a short.)

      Plugging a device that uses 12 VDC into a charger/power adapter that only provides 5 VDC “typically” won’t cause any harm to either the device or charger/power adapter but it also won’t charge the device.

      Note: it is “possible” for a 5 VDC charger/power adapter used with a 12 VDC device to overheat and fail if it’s plugged in for an “extended period” as it tries to provide 12 VDC to the device.

      So the rule is, your charger/power adapter’s voltage must always match the device’s voltage but it can either match or exceed the device’s Amps.

      1 user thanked author for this post.
    • #2470972

      Thanks “alejr”.  You pretty much confirmed what I thought.  It’s always good to get feedback from you.

      But, I still wonder about PPS, QuickCharge, etc. delivery.  Here (from my understanding) are chargers that can communicate with the device and “adjust” the delivery.  So, what happens if you try charging an older device?  Does the charging protocol fall back to a safe delivery of power?

      If you were to call Anker or RavPower….or other companies, they say no to using a charger that is rated over the input on your “older” device.  Curious, I even called Samsung who said the same thing…..”you can only use the charger that is equivalent to the one that came with the device”.  In this case a tablet that came with a 8 watt maximum (5V@1.55A) and non-PD, non PPS.  They said: “Otherwise you’ll likely overheat the battery and possibly damage it”.

      To further complicate things in the USB protocol, manufacturers have decided to “market” their chargers with things like:

      iSmart, QuickCharge (Qualcomm), Boost!Charge (Belkin) FastCharge…etc.

      Add to that, inconsistency in labeling the cables (Thunderbolt, Superspeed, USB4).  Finally, confuse everyone with the non-existent labeling of data rate on cables.

      At least the EU got fed up with the different USB charging ports and will fix that next year.



    • #2470998

      alejr is correct.

      Volts supplied must be equal
      Amps / current supplied can be equal or above.

      cheers, Paul

    • #2471047

      BTW, Power in this discussion means Watts which is Amps × Volts.

      The reason manufacturers always tell you to only use their charger/power adapter is that “legally protects them” if someone tries to sue them because their product got damaged using a “non-approved” charger/power adapter.

      But, I still wonder about PPS, QuickCharge, etc. delivery. Here (from my understanding) are chargers that can communicate with the device and “adjust” the delivery. So, what happens if you try charging an older device? Does the charging protocol fall back to a safe delivery of power?

      As I stated previously, you cannot force more current (i.e. Amps) into a device than it needs.

      So chargers/power adapters and devices don’t need to “communicate” with each other because there’s no need to “adjust” the power delivery.

      A device will only pull as much power from the charger/power adapter as it needs and not a single milliamp more (regardless of how much extra power the charger/power adapter may be capable of providing.)

      The only chargers/power adapters that I’m aware of that actually do communication with the device they’re plugged into are from Dell and it’s sole purpose is to ensure you can only use the correct “Dell approved” charger/power adapter with their device (you’ll get a WARNING: The AC adapter type cannot be determined. error if you boot using a non-approved charger/power adapter.)

      iSmart, QuickCharge (Qualcomm), Boost!Charge (Belkin) FastCharge…etc.

      You’d need to look each one up to determine its particular specs, but each of those refers to a different “type” of charging and its applicability is determined by whether the device it’s plugged into accepts that type of charging not whether the charger/power adapter can provide it.

        i.e. my Moto e6 uses an Adaptive Fast Charger which can recharge it in 4 hrs or less but the same charger also recharges my Ozark Trail camping lantern only it takes 8-12 hrs because the lantern doesn’t support Adaptive Fast Charging.

    • #2471097


      QC (Qualcomm) and Adaptive (Samsung).  Quick Charge is supported by devices such as mobile phones which runs on Qualcomm SoCs, and by some chargers; both device and charger must support QC, otherwise QC charging is not attained.

      PD.  USB Power Delivery is much more powerful, supporting up to 240W of power.   It’s also safer, as gadgets and chargers communicate with each other over the USB cable to confirm the optimal charging power level. This handshaking approach supports voltage steps at 5V, 9V, 15V, 20V, and beyond for power outputs ranging from 0.5W to 240W.

      PPS.  The new USB Power Delivery Programmable Power Supply (USB PD PPS) standard supports configurable voltages too, enabling more optimal charging. If two devices fail to communicate a suitable power rule, USB Power Delivery will default to the next power option supported by the relevant USB protocol, such as USB-C 1.5A.


      iSmart (RavPower).  iSmart charging tech can adjust the charge current and charge time accordingly to the battery specifications, which can help extend battery life. It also supports 2.4A output.  iSmart Chargers correct charging irregularities caused by older ports and cables.


      USB-C cables (E-Mark, Wattage, Data) .  Not all are equal.

      E-Mark is short for Electronically Marked and is actually a protocol controller. This will include the power supply, power receiving, and power transmitting capabilities of the product (cable, source, and sink), and the corresponding protocol and transmission requirements, which generally require PD (power-delivery) or PPS (Programmable Power Supply) devices. E-Marker cables are divided into different types; some can carry out 100W of power transmission, while others can only transfer 60W for charging and some can achieve the highest 10Gbps data-transmission speed, while some only can support USB 2.0, which is twenty times slower at 480Mbps. In most cases, charging-based USB-C cables are USB2.0.

      More here: https://www.totalphase.com/blog/2020/10/what-is-e-marker-how-does-it-work/

    • #2471133

      Add to the above

      PPS. Programmable Power Supply

      Programmable Power Supply (PPS) is a standard that refers to the advanced charging technology for USB-C devices. It can modify voltage and current in real-time by feeding maximum power based on a device’s charging status.

      The USB Implementers Forum (USB-IF), a nonprofit group that supports the marketing and promotion of the Universal Serial Bus (USB), added PPS Fast Charging to the USB PD 3.0 standard in 2017. This allows data to be exchanged every 10 seconds, making a dynamic adjustment to the output voltage and current based on the condition of the receiving device’s specifications.

      Differences between PPS, PD, and QC

      PPS’ main advantage over other standards is its capability to lower conversion loss during charging. This means that less heat is generated, which lengthens the device battery’s lifespan.


      PIQ or Power IQ.  (Anker)

      PIQ(abbreviation for Power IQ) 1.0, PIQ 2.0, PIQ 3.0, PIQ 4.0 are Anker’s proprietary fast-charging technology, which Intelligently identifies your device to deliver the fastest possible charge.

      • Power IQ 1.0: Supports 5V/2.4A max
      • Power IQ 2.0: Compatible with QC 3.0 + Power IQ 1.0
      • Power IQ 3.0: Compatible with QC 3.0 + PD 3.0 + Power IQ 1.0
      • Power IQ 4.0: Compatible with QC 3.0 + PD 3.0 + Power IQ 1.0 + Dynamic Power Distribution (automatically detects and adjusts the voltage output of connected devices and shortens the overall charging time)

      Summary:  The device defines which fast charging technology it supports. There is Power Delivery(the official standard) and Qualcomm Quickcharge (that was the unofficial standard until Google said they will be enforcing the official Power Delivery). Compaines that manufacturer chargers have their own proprietary technologies, like Anker which has products for Quick Charge and PD.  There are also device (Phones, Tablets, Notebooks and Laptops) vendor specific technologies.


    • #2471203

      A USB-C charger that adheres to the PD (power delivery) standard will not deliver any more voltage than the device requests. You can plug a phone (charged at 5v) into a laptop USB-C charger that supplies well above that voltage (perhaps 20v) to a laptop and it will still only provide 5v for the phone. The charger will only provide greater voltage when it has been requested by the device itself. Unless this negotiation has taken place, the voltage will not rise above the nominal 5v (which is what you would get from the simplest chargers that only provide 5v and don’t entertain any requests for more voltage).

      I use my 60w and 45w USB-C chargers for my phone all the time (and I have been for over a year). Works just fine, and saves the trouble of trying to have separate USB-C chargers for laptop and phone.


      Dell XPS 13/9310, i5-1135G7/16GB, Kubuntu 22.04, OpenSUSE Tumbleweed
      XPG Xenia 15, i7-9750H/16GB & GTX1660ti, Kubuntu 22.04, OpenSUSE Tumbleweed

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