Calibrate HTC EVO 4G Battery - EVO Tips & Tricks

Get the most of out of your HTC EVO 4G battery.  Calibrate and increase its performance!

As a followup to my earlier post on "how to save juice", I offer two tricks for ultimately increasing battery life.

First trick, a one-time only calibration:

This is a one-time only procedure.

1. Turn the EVO on and charge it for 8 hours.
2. Unplug it and turn it off.
3. Plug it back in and charge for 1 hour.
4. Unplug it and turn it on.
5. Wait 2 minutes and turn it off.
6. Plug it back in and charge for 1 hour.

There is circuitry in the phone (any phone) that controls charging.  The goal of this one time calibration is to help make sure the circuit ultimately understands the "full" point for the battery.  Many people have found that their EVO's ultimately show as "full" when they are really not.  If you're phone is showing juice drain immediately after it's unplugged, you probably are suffering from this issue.  Calibration like this will help, though it can be time-consuming.

Second trick, repeatedly filling the battery to increase the full point.

This can be done repeatedly and it has been proven to work very well:

• With the phone in the on position - Fully charge the battery (until the led turns green at the top.)
• Once the LED turns green, unplug the charger until the led goes off.  (this normally takes 5-10 secs after unplugging the charger from the phone)
• After the led goes off, immediately plug the charger back in.
• When the LED turns green, power off the phone. (this shouldn't take too long for LED to turn green))

Green LED = Finished Charging, Full

Now...with the phone fully powered off:

1. Unplug the charger.
2. Wait until LED goes off.
3. Plug charger back in until the LED turns green. When it turns green, unplug the charger again repeat the cycle.  In other words, unplug charger, wait for led to go off, plug charger back in, wait for led to turn green.  
4. Repeat steps 1-3, oh say, 10 or more times. This may take anywhere from 30 seconds to 30 mins per cycle. (from when led green, unplug charger, wait for led off, plug charger back in, wait for led to go green again.) Typically only about 1 minute though.

Orange LED = Charging

Couple words on what the second trick is doing (this works for most any phone, really):

We are basically doing the opposite of a complete drain and recharge, which was common with old batteries (NiCad).  We are continually "adding juice" by fooling the circuit.  Notice that steps have you charge (orange LED) until full (Green LED).  Then we unplug, and recharge (orange LED).  The goal is not to empty the battery and recharge like ni-cads (those have memory, these don't). These are lithiums, so we need to do the opposite..We are trying to fill up the battery, i.e. make the "full point" more full than it is now.  Think of it like like cheating in capacity.  Since it's a "trickle charge" you don't really have to worry about overload - that's what the circuity is there for in the first place.  We just want to fool the circuitry a bit. 

This method seems to work pretty well, and you can easily notice that

• You fill up the phone battery by charging it until the LED is green
• When you unplug, and the LED light goes off
• If you immediately plug the phone back in, the LED is ORANGE.  Why? 
• Because the battery can take more juice - hence the 1 minute or longer cycle times
• Each time you do this and it takes time to go from Orange to Green, you're doing good

You can find both of these types of tricks on mobile phone forums such as HoFo and XDA.  I have found good success with both tricks on many phones, including my HTC EVO 4G (and an iPhone 3GS).  I find the second trick is very effective and fixes the problem of losing battery immediately after unplugging.