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A Little Story

My phone claims it has a battery of 4000 mAh that lasts for 3 days. I got the phone, really psyched because of the battery. When I bought it it has 50% left on the battery. I did some texts and some first time testing on the phone, but no heavy usage. The phone lasted 19 hours before saying it was now low on battery (5%).

The next day, I charged it for six hours, turned on the 3G and used the Facebook app, Opera Mini, and Google Play for four hours before I removed the 3G. The battery read 29%. I was disappointed. Most of the people who bought this phone reported that it should last 10 hours with 3G on and heavy usage. Most people even say that with heavy usage their phone lasts 2 days, using the internet, apps that require it, and gaming with the phone.

Now I'm on the process of claiming the warranty and I called some service centers to determine where I will take it to. The first service center claimed that all Android phones last for only one day, the second one claimed that even if only a Messaging app is on, if I leave it open even if my screen is off the battery will be drained quickly. The third one basically told me to go to the Play Store and download a Task Killer. The last one I called told me to bring the phone to the service center so they could "observe it". That doesn't sound good to me.


My question is can technicians actually tell if the battery has the capacity it claims it has and if the battery is healthy? I want to go prepared to that service center if the observation they'll be doing will be to look at my "Battery" setting only and asking me what I've been doing only for them to say that's what been draining my battery.

Also can 3G drain a battery within 4 hours if a battery has 4000 mAh?

Note: My phone is a rebranded Innos D9, it's a Cloudfone Thrill 430x.

2 Answers 2


Multiple things with your issue:

  1. I would never trust a tech who recommends a Task-Killer for this problem. Disqualified 100%.
  2. Same for the one claiming all Android phones last for only one day. That's bogus. It always depends on usage. I have one lasting 7 days (well, no SIM card inserted, not WiFi activated -- it's rather used as a stand-by computing device for some apps -- but it's a phone, and it runs longer than 10h ;), and my "standard phone" ends up at ~75-80% after 14h usage.
  3. tech #2 and #4 sound more reasonable: any app (especially if "consuming push services") can be the cause for such a problem (see below), and monitoring battery usage is a generally good idea (that tech I would trust most from the ones you mentioned)
  4. Different kind of usage causes different battery drain.
  5. Sometimes processes go havoc and drain the battery quite fast. I had that "big surprise" multiple times already, last time yesterday: went down from ~80% to 5% and "emergency shutdown" within ~2h while in my pocket -- I only noticed that by the "beep" on shutdown. But this should not be a regular (daily) issue; I experienced this maybe 4-5 times in a year with my current device.
    • recommendation: Take a look at the battery statistics (usually found in Settings → About Phone) to determine which app(s) are causing the most battery drain. Maybe you've got some "bad egg" on your device, if this happens regularly.
    • second recommendation: Take a look at How to deal with (orphaned) WakeLocks? -- maybe that's what affects you. Again, this could be a mal-functioning app.
  6. battery only lasting for ~10h is nothing rare with heavy usage. Remember these are no longer "dumb-phones", but rather "pocket-computers which also can make phone calls".

Useful resources also include:

  • Whoa, quite a comprehensive answer! Might I just add that I don't know what your phone is but the battery seems impressive. This leads me to think my 4000mah phone really has a problem.
    – Audiophile
    Jan 4, 2013 at 0:02
  • Nah, the phone is no big deal (HTC Wildfire/Buzz). Thing is: just for fun, try one day without data services enabled (i.e. no WiFi, Bluetooth, mobile data, etc.) -- you will get big eyes. Then take out the SIM completely, and have another shock. Once you removed these "permanents", there's not so much left eating your battery. OTOH, my main device (Motorola Milestone²) ends up with ~75..80% as well (fixed to 2G, and kept all data eating apps well configured to not eat to often).
    – Izzy
    Jan 4, 2013 at 0:40
  • Could ram probably eat my battery too? I made a new question here android.stackexchange.com/questions/36828/0-ram-free-on-ics where I found out my ram usage was maxed out. Anyway, I think 3G's the one at fault on this. I used the Facebook app for a straight 4 hours without even turning the screen off. I was left with 29% when I disconnected the data.
    – Audiophile
    Jan 4, 2013 at 1:33
  • Nope. There's no such thing as "unused RAM" on Linux/Unix based systems. But the Facebook thingy: Yeah, 4h with screnn on on 3G, that's it. Check the battery-life tag for questions on battery saving/usage, I've made an answer somewhere detailing what components are especially "battery hungry" -- ah: here it is.
    – Izzy
    Jan 4, 2013 at 6:50
  • 1
    No. I said the combination of having the screen turned on permanently while heavy-using 3G have been the biggest contributors to that. Taking a look at the linked table, you see you only could top that by (additionally) recording a video ;) Values for your device will certainly look different, but making a raw estimation: just those two items ~ 8000mWh; @4V -> 2000mA = 50% (not accurate, just wildly calculated).
    – Izzy
    Jan 4, 2013 at 10:20

How far can we trust on the battery capacity that these manufacturers mention in their devices and in their product specification? This is one important question which we can't overlook during such debates. Also, the battery capacity is at its best during its first charge cycle and it actually drops with every successive cycle, though the rate of drop varies from type of battery to number of cycles and many other factors included.

So, the only true way to measure the current battery performance is to monitor how many amps being drawn during a particular operation/duration. Unless you are doing for a research purpose this kind of investigation doesn't pay off in any way.

BTW, if your 4000 mAH battery drains in 4 hours from full charge, the current handled is around 1 Amps and I think that is too much for these kind of electronics.

In your case, I would lay all my suspicion on the over optimistic battery rating of your manufacturer.

  • But people actually claim the battery claim is true, the majority of them anyway. In a group I'm in, all the members claim that the battery is what they say it is, excluding me and another person whose battery drains like crazy only second to mine. The first charge cycle means the first charging I did after I got the phone? That's the 4 hours in 3G. So you're basically saying that the technician couldn't possibly check if the battery has the capacity it says it has?
    – Audiophile
    Jan 3, 2013 at 7:50
  • First charge cycle - correct. With a Multimeter/Ammeter and with few wiring you can even trouble shoot. Take a bulb with a known wattage and connect it to your fully charged battery and see how long it sustains (and do the math). This can ascertain whether your battery is defective or not.
    – Narayanan
    Jan 3, 2013 at 7:58
  • Hey bud, if you're reading this then you'd know I chose the other answer. Lesson learned? Don't accept answers too eagerly. To make up for it, I made up my mind that my other question you've answered has been satisfied. Thanks for answering my questions! :)
    – Audiophile
    Jan 4, 2013 at 0:23
  • 3
    Reputations? It means nothing for me other than a number. So down voting, up voting, accepting or rejecting an answer are all not that attractive for me from reputation point of view, rather I am happy to see you've got better answer. :)
    – Narayanan
    Jan 4, 2013 at 4:24

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