I am using Micromax Canvas Nitro A310; recently, I bought a new USB cable and it seems its not doing the job as required.

My phone is not getting charged as it was before. Either it takes too long or the battery indicator not change to even 1% after being plugged on for 2-3 hours.

I am using Ampere app to check current and voltages with different USB cables and found that the one which I bought recently is showing very low current observations (230-250mA).

Need to know what are the normal ratings.

  • 1
    That's nothing specific to Android, but generic to the LiIo batteries. Charging devices usually reach from 500 mA (USB) to 2A (wallet plug). 250 mA is definitely too low.
    – Izzy
    Commented Jan 8, 2016 at 13:07

3 Answers 3


Firstly one needs to understand C-rate or charge rate. Quoting from the linked article

C-rate is a measure that governs at what current a battery is charged and discharged. At 1C, a battery rated 1,000mAh charges at a current of 1,000mAh. In an ideal world the battery would be fully charged in 60 minutes. At 1C, the same battery discharges at 1,000mA.

  1. Li-Ion or Li-PO (both have same charge/discharge characteristics) -typically charged between 0.5 C to 0.8 C, more often closer to 0.8 C (as a thumb rule, depends on a lot of other factors like charging algorithm,"quick charging" ,OEM specific charging protection methods etc)
  2. Next, one has to account for charging efficiency which is typically 90% for Li-Ion chargers, so effective charging rate would be about 0.7C (=90% of 0.8 C)
  3. Your device battery is 2500mAh as per information on net, so the charging rate in mA =0.7*2500= 1750 or less = 900 mA ( =90% of 0.5C* 2500) if your charger is charging at 0.5C (Edit OP has confirmed in comments that his charger is 1A rated, so the charging rate appears to be 0.5 C)
  4. This is the current your app should show using standard 2A,5V wall charger (rare to find lesser rated chargers these days)
  5. USB charging is much slower as USB 3.0 give only 900 mA and USB 2.0 gives 500mA (refer linked Wikipedia)
  6. Current drawn for charging is NOT uniform. Li-Ion batteries go through three stages of charging of battery charging Figure 1 of Charging Li-Ion batteries- Constant Current, Saturation Charge (current decreases), Ready (almost zero current). If you plot current drawn using your app while charging a battery from 10% or lower to 100%, you would observe this. So this had to be borne in mind while measuring. As a typical example of this graph plotted on charging my phone see this


So much for theory, coming to your question:

  1. Need to know what are the normal ratings Explanation above should have made it clear that there is no normal or standard rating being dependent on C-rate, battery capacity, charging efficiency, charging algorithm, source of charging and in which stage of charging it was measured
  2. It is not clear from your question whether the readings are obtained while charging from a wall charger (definitely very bad if that is the case ) or from USB charging from laptop (bad)
  3. USB cable purchased seems to be a suspect. While buying USB cables go in for shorter and thicker USB cables (they offer less resistance to current) compared to longer and thinner cables as normally available (offer more resistance to current and hence slower charging). You can always test the current using your app before buying. Alternatively Google for 24/28 awg micro USB cable and purchase that. I would suggest latter option, though more expensive but lasts across many phones you may own over a period of time (A robust Blackberry cable purchased ten years ago is still doing good)
  4. To estimate charging time required considering all the factors enumerated, use the Battery Charge Time Calculator
  • On my charger, its mentioned that its output is 5V - 1A. Do I need to change my charger itself..? (The charger came along with the box when I purchased this phone)
    – Ali_Waris
    Commented Jan 8, 2016 at 15:11
  • So how can I verify whether the USB cable which I bought recently is faulty or there is some problem with my battery?
    – Ali_Waris
    Commented Jan 9, 2016 at 2:56
  • This issue arised after flashing a custom rom. I guess I lost my battery calibration. Tried several full 0-100% battery charging cycles. But, somehow, it still seems to be charging at an extremely slow rate.
    – Ali_Waris
    Commented Jan 9, 2016 at 4:12

First of all, I would like to thank everyone who helped me understanding what can be the problem exactly; I am posting it as an answer because this is what solved my issue.

The problem was neither with the charger nor with the USB cable. The real culprit was an extension cord which was offering very high resistance probably.

Since my socket is at a certain height, i was using an extension cord to extend my USB. I observed readings from both ends, keeping extension cord and then removing it. I found huge difference in the current ratings. It came as 230 mA and 770mA respectively.

Now, I am using a home made mobile holder while charging and removed the extension completely from the circuit. Everything seems to be working as expected.

Hope this helps someone else who is encountering same issues using extension cables.


The voltage and current rating of your battery won't be the problem. It will be the quality and rating of the cable you are using.

Different qualities of cable will handle different amounts of current and this is what will allow your battery to charge at different rates (assuming a suitable charger is used).

The fastest type of cable would be a USB 3.0 compatible one as these are designed to handle much larger currents by default. At this time a standard Android device is likely to require at least a USB 3.0 compatible cable so that it can handle enough current to charge your device at a reasonable rate. You also want to buy a reasonable quality one and not just any old cheap variety.

Based on the battery your device is shipped with (Li-Ion 2500 mAh battery), you want a cable that is capable of handling at least 2.0A (2000mA) - the more the better as the device will draw what it needs and certainly no more than your charger can supply.

The other thing to check is that your battery is not "dying" and not holding charge.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .