I would dred changing batteries even if it was once a week. I have a case on and it's a pain to go through all of that. It seems everyone has their own way of dealing with the poor battery life here on the incredible.
Your battery gauge is lying to you (and it's not such a bad thing)
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The battery stats should always be "learning," so if you just use your device normally, they will respond to that. If you want, go ahead and wipe them, but I think the effect of wiping them has been overstated. Even if you wiped them after a fresh bump charge, future standard charges still wouldn't hit the same charge state that a bump does.
Possibly the best presented thread I have read. I agree 100% with everything in post one. Confirms all of my beliefs about batteries/fixes, backed up with nice hard data.
Quality work. Appreciated.
Sent from my GT-I9000 using XDA Premium App
Quality work. Appreciated.
Sent from my GT-I9000 using XDA Premium App
entirely depends on the car charger. In general no, but some are known to overcharge. This goes really for any aftermarket battery charger.
If you're charging via USB than you're safe.
thanks for this. really great information here that i wasn't fully aware of.
regarding chargers, i always figured usb was usb was usb considering it is a standard and all. it does seem that some chargers behave differently than others however. one wall charger i have disables my touch screen and my car charger seems to make my phone really hot. i'm guessing this has to do with different current ratings of the chargers or something. any advice with regard to this? do i only buy htc branded chargers (and when i move to another phone i have to get new stuff?). that doesn't seem right.
regarding chargers, i always figured usb was usb was usb considering it is a standard and all. it does seem that some chargers behave differently than others however. one wall charger i have disables my touch screen and my car charger seems to make my phone really hot. i'm guessing this has to do with different current ratings of the chargers or something. any advice with regard to this? do i only buy htc branded chargers (and when i move to another phone i have to get new stuff?). that doesn't seem right.
Pretty much, yes. Even when they claim similar ratings, different chargers put out different currents. Cheaper units will generally have lower quality control and have the potential to introduce more problems (like your experience of the touch screen becoming unresponsive).
I wish I had hard and fast advice, but I don't really. There's definitely a balance to be struck between the $40 brand-name chargers and the $2 generic ones. I am not well-researched enough on the subject, however, to offer a specific brand or model recommendation.
Once you find a good one though, you should be able to just stick with it; MicroUSB has become the industry standard.
The lady at the Motorola store said to me that car chargers are only for emergencies and that they dont have to be used like a wall charger. She said that she learned this at a Motorola seminar.
If you think about it, a car charger gets continous current instead of alternative current, so there must be a difference.
If you think about it, a car charger gets continous current instead of alternative current, so there must be a difference.
I don't understand why you'd ask the question if you believe that you already had the authoritative answer.
My opinion mirrors POQbum's advice: it depends entirely on the charger.
In any regard, this is a hotly debated topic on the net. A few seconds of Googling will turn up more arguing than you could read through in a lifetime. No use in dragging that debate into this thread.
That's why wall chargers are referred to as AC Adapters.
A properly designed wall charger converts 120V* AC to 5V DC
A properly designed car charger converts 12V DC to 5V DC
No matter what, your phone shouldn't just be hooking directly into a raw power line.
*Varies by country
Ok, so what is what you personally do? Do you often charge your phone in the car using a Motorola charger? Do you personally think it is safe and that there is no difference at all with a wall charger?
Thank you.
Thank you.
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425I realize that much of this is common knowledge on XDA. Still, every day I see people post about how their phone "loses" 10% as soon as it comes off the charger. I also have friends who can't understand why their battery drains so quickly. Trying to explain this to people without hard numbers is often met with doubt, so I figured that I'd actually plot it out with real data.
So it's not a piece that is optimized for this audience, but I hope that you find it interesting.
--------------------------------------------------
Your Smartphone is Lying to You
(and it's not such a bad thing)
Climbing out of bed, about to start your day, you unplug your new smartphone from its wall charger and quickly check your email. You've left it plugged in overnight, and the battery gauge shows 100%. After a quick shower, you remember that you forgot to send your client a file last night. You pick up your phone again, but the battery gauge now reads 90%. A 10% drop in 10 minutes? The phone must be defective, right?
A common complaint about today's smartphones is their short battery life compared to older cell phones. Years ago, if you accidentally left your charger at home, your phone could still make it through a weeklong vacation with life to spare (I did it more than once). With the newest phones on the market, you might be lucky enough to make it through a weekend.
And why should we expect anything else? Phones used to have a very short list of features: make and receive phone calls. Today we use them for email, web surfing, GPS navigation, photos, video, games, and a host of other tasks. They used to sport tiny displays, while we now have giant touch screens with bright and vibrant colors. All of these features come at a cost: large energy requirements.
Interestingly enough, improvements in battery management technology have compounded the average user's perception of this problem. Older phones were rather inelegant in their charging behavior; usually filling the battery to capacity and then switching to a trickle current to maintain the highest charge possible. This offered the highest usage time in the short-term, but was damaging the battery over the course of ownership. As explained at Battery University, "The time at which the battery stays at [maximum charge] should be as short as possible. Prolonged high voltage promotes corrosion, especially at elevated temperatures."[1]
This is why many new phones will "lose" up to 10% within a few minutes of coming off the charger. The reality is that the battery was only at 100% capacity for a brief moment, after which the battery management system allowed it to slowly dip down to around 90%. Leaving the phone plugged in overnight does not make a difference: the phone only uses the wall current to maintain a partial charge state.
To monitor this, I installed CurrentWidget on my HTC ADR6300 (Droid Incredible), an app that can log how much electric current is being drawn from the battery or received from the charger. Setting it to record log entries every 10 seconds, I have collected a few days worth of data. While many variables are involved (phone hardware, ROM, kernel, etc) and no two devices will perform exactly the same, the trends that I will describe are becoming more common in new phones. This is not just isolated to a single platform or a single manufacturer.
Chart 1 shows system reported battery levels over the course of one night, with the phone plugged in to a charger. Notice that as the battery level approaches 100%, the charging current gradually decreases. After a full charge is reached, wall current is cut completely, with the phone switching back to the battery for all of its power. It isn't until about two hours later that you can see the phone starts receiving wall current again, and even then it is only in brief bursts.
The steep drop in reported battery seen past the 6.5 hour mark shows the phone being unplugged. While the current draw does increase at this point (since the phone is being used), it still cannot account for the reported 6% depletion in 3 minutes. It should also be obvious that maintaining a 100% charge state is impossible given the long spans in which the phone is only operating on battery power.
Using the data from CurrentWidget, however, it is quite easy to project the actual battery state. Starting with the assumption that the first battery percentage reading is accurate, each subsequent point is calculated based on mA draw and time. Chart 2 includes this projection.
Now we can see that the 6% drop after unplugging is simply the battery gauge catching up with reality.
The phone manufacturers essentially have three choices:
1. Use older charging styles which actually maintain a full battery, thereby decreasing its eventual life
2. Use new charging methods and have an accurate battery gauge
3. Use new charging methods and have the inaccurate battery gauge
Option one has clearly fallen out of favor as it prematurely wears devices. Option two, while being honest, would most likely be met with many complaints. After all, how many people want to see their phone draining down to 90% while it is still plugged in? Option three therefore offers an odd compromise. Maybe phone companies think that users will be less likely to worry about a quick drop off the charger than they will worry about a "defective" charger that doesn't keep their phone at 100% while plugged in.
Bump It. Or Should You?
One technique that has gained popularity in the user community is "bump charging." To bump charge a device, turn it off completely, and plug it into a charger. Wait until the indicator light shows a full charge (on the ADR6300, for example, the charging LED changes from amber to green) but do not yet turn the device back on. Instead, disconnect and immediately reconnect the power cord. The device will now accept more charge before saying it is full. This disconnect/reconnect process can be repeated multiple times, each time squeezing just a little bit more into the battery. Does it work?
The following chart plots battery depletion after the device has received a hefty bump charge (6 cycles) and then turned on to use battery power. Note that the system does not show the battery dropping from 100% until well over an hour of unplugged use, at which point it starts to steadily decline. Again, however, it should be obvious that the battery gauge is not syncing up with reality. How could the rate of depletion be increasing over the first 5 hours while the rate of current draw is relatively steady? And why does the projected battery line separate from the reported levels, but then exactly mirror the later rises and falls?
The answer, of course, is that bump charging definitely works. Rather than anchoring our projected values to the first data point of 100%, what happens if we anchor against a later point in the plot?
Aligning the data suggests that a heavy bump charge increases initial capacity by approximately 15%. Note that the only other time that the lines separate in this graph was once again when the phone was put on the charger and topped up to 100%. Just as with the first set of graphs, the phone kept reporting 100% until it was unplugged, dropped rapidly, and again caught up with our projections.
So what does it all mean?
If you absolutely need the highest capacity on a device like this, you will need to bump charge. There are currently people experimenting with "fixes" for this, but I have yet to see one that works. Be warned, however, that repeated bump charging will wear your battery faster and begin to reduce its capacity. If you are a "power user" who will buy a new battery a few months from now anyway, this presumably isn't a concern. If you are an average consumer who uses a device for a few years, I would recommend that you stay away from bump charging. The bottom line is that you don't really "need" to do it unless you are actually depleting your battery to 0% on a regular basis.
If you are someone who can top off your phone on a regular basis, do it. Plug it in when you're at home. Plug it in when you're at your desk. As explained by Battery University, "Several partial discharges with frequent recharges are better for lithium-ion than one deep one. Recharging a partially charged lithium-ion does not cause harm because there is no memory."[2]
Beyond that, the best advice I can offer is to stop paying such close attention to your battery gauge and to just use your phone. Charge it whenever you can, and then stop obsessing over the exact numbers. If you really need more usage time, buy an extended-capacity battery and use it normally.3For example on my old HTC Imagio:
Currently reporting 36% battery capacity.
DMM on the battery shows 3.760v.
This is perfectly accurate! Let me explain why!
As with most mobile OS's, Windows Mobile 6.5.X warns 10% charge is left in the phone when the battery has 20% SOC left. They cut off at 0% when there is 10% left in the battery. THIS IS GOOD. This keeps your phone from typically being used inside the remaining 20% battery life that quickly kills most chemistry lithium cells.
Whatever the State of Charge (From now own SOC) reported by the os, add 10% to that figure. That's what the battery actually has.
Absolutely NOT TRUE for lion or lipo batteries. The largest four factors in the lifespan & performance of lithium batteries are:
1) Discharging BELOW 20%. This RAPIDLY deteriorates capacity of typical lithium cells. (Stop at 3.2v for lipo)
2) Overcharging, beyond 4.1v (liion) or 4.2v (lipo)
3) Charge state VS age of cell.
Lithium chemistries give the longest lifespan when used & stored at 50% state of charge. The lifespan of the cell is greatly reduced when stored at high, or low capacity. For lipo this would be 3.85v.
There's a reason why hobby people that use lipo's will charge them to 4.2v, while military application lipo's are only 3.92v (and for that mattery NASA's lipo's are only used in a 5-15% window around 50% state of charge!) It greatly extends the effective battery life over the long term!
4) Abusing the C rating of the cell. Either charging OR discharging faster than the battery is designed for.
Keep in mind many smartphones can draw 1amp from batteries that are NOT rated for current draws that high.
To the OP. While the cheap electronics used can & do have some accuracy problems. Everything is done on purpose for battery life issues. High drain electronic devices commonly use batteries that are not up to the C ratings of the devices they're used in. They also tend to be stored incorrectly over long periods of time before the devices are even sold! Plus, in-use the devices tend to be "road hard & put up wet" in nearly all cases.
Devices shy away from using full capacity both low & high for the sake of the long term.2Pretty nice to know why it drops from 100% so fast now .....THANKS!
Sent from my ADR6300 using XDA App2Great read, well thought out and explained.
The only thing I'll add is that while there isn't a "memory affect" on our batteries, it is still recommended to do a full charge/discharge (don't let it get to <5% though) about once every 3 months.2
Wow, I'm a little flattered. This is the first time I've heard of an employer blocking my site.
I don't have hard data for my older devices like I do for this phone, so my answers to this (and your following questions) are a mixture of anecdote, reading, and conjecture.
I don't think that the older devices were still getting full current after hitting 100% but rather some sort of trickle charge to keep them topped off. Battery chemistry itself will limit the charging current that can be applied as the battery approaches capacity.
Depending on the device and its management system, damage could come from too much charge being applied, or it could simply come from keeping the battery at the highest charge level possible for prolonged periods. That may sound like the same thing, but technically it's not.
Batteries are wear items, and even use under ideal conditions will eventually kill them. As shown on Battery University's page on prolonging lithium-based batteries, however, even minor decreases in the final charge level will greatly increase the number of cycles that a battery can endure (note figure 2)
I'm not 100% sure whether:
- Bump-charging is simply charging the battery to its physical capacity, which is greater than the capacity that our software thinks is appropriate;
- Bump-charging is actually applying a charge to the battery that is outside of the rated specs for the battery; or
- Some mix of 1 & 2
Also, since I can't use any logging tools while the phone is off, I'm not sure how the current behaves once the phone hits 'green' while off.
I therefore don't want to make a hard guess at the three options listed, as I don't want to spread false information. With that said, I think it is apparent through both testing and real-world use that bump-charging applies a charge that is higher than what is allowed when all of the phone's protections are "awake." Given that, we have to ask ourselves why the waking protections are stricter.
If you are inclined to believe that the manufacturer is setting limits that are too low, in an effort to prolong cycle life (or limit liability), then maybe bump-charging isn't too bad.
If you are inclined to believe that the manufacturer chose the charging limits for a good reason, and has the best interest of the consumer in mind, then bump-charging should be considered problematic.
I don't know if one of these is absolutely true over the other, but my life is easier without bump-charging, so I just avoid it. That's a personal choice though. I'm not trying to advance a position here as much as I'm trying to spread information and spark discussion.
Thanks to everyone for taking the time to read, and for your questions and comments.
