How to check your Apple Watch battery for self-discharge.

How to check your Apple Watch battery for self-discharge.

Some battery drain problems have been identified in the forum as batteries with suspected electrical self-discharge, often caused by distortion of the internal lithium deposits during charging ('dendrites') even though the battery health maximum capacity is still way above 80%.

A good battery will only drain a few percent in 3 months whilst powered off.

To check this is very simple:

• Charge the Watch up to 100% (or as high as it will go) and leave on charge a little longer, then remove the charging puck.
• Then power off the Watch completely. ie Hold the side button in until you see the small off button top right of the screen. Tap it then confirm with the slider. After a moment briefly tap the crown to make sure nothing happens so you know it really is off. OS9 and later may show a small digital time display even when it's off.
• Leave the Watch off for 8 hours or so, overnight if that is the most convenient.
• At the end of the test period put the Watch on your wrist, power up the Watch after this period (hold in the side button to turn it on), put in your passcode, and see what percentage shows in Settings, Battery. It should only have only dropped to 98% at worst.
• If much more than that has gone then an internal electrical self-discharge is suspected and it should be taken or sent in for a new battery. See: Apple Watch Service & Repair - Apple Support. Include a copy of this tip and screenprint your battery graph after the test. The Apple Support App may not initiate a repair for batteries with Health over 80% so in that case contact Apple Support 
• After a couple of hours you can also check the battery usage graphic.

REMEMBER the Watch must be POWERED OFF and OFF CHARGE to do the test.

My good battery kept all its charge over 4 hours here

7:36

Then at 11:40 after 4 hours powered off

Here is a simulation of a "leaky" battery graph

Having a leaky battery is like blaming the engine for poor fuel economy when in fact you have a hole in the fuel tank.

Check yours!