Flat battery in new unit?

I received a new replacement F5X Plus a few days ago, due to a screen issue in my original unit.

What I found curious was that the battery had no charge out-of-the-box, and the unit wouldn't power up. It revived after charging for about 20mins, and has booted up as oer usual.

My concern is that I've heard that Li-Ion batteries should be stored at about half charge, and that leaving a battery flat for too long will damage the cell, and shorten battery life.

Does anyone have experience with this? What should I look our for? Shorter time to full discharge? Or random shutdowns at odd %? (Eg. Watch dies at 20% battery)

Thanks!

0 Dr Phil over 6 years ago

Seems to be a thing recently. Fully charge it, then leave it on charge for an hour or two past the 100%.

When you use it, compare the use you get with that in the specs. I'd suggest you just use it straight out of the box for a week or so to ensure that any issues are due to the device and not anything you might have added....just in case.

0 jylong over 6 years ago

Hey, could I clarify if this 'being a thing lately' means that there are a number of units shipping with flat batteries without ill effects, or which then exhibit problems? I couldn't really fins anything recent with my rudimentary Google-fu.

Have been monitoring the background usage in Activity Tracker/Watch mode, and it does seem to have a higher background draw than my previous unit on the same config. No idea if this is because of increased consumption, or lower capacity (since usage is displayed in %, not mAh)

Have flagged it with Garmin Aus, who have admitted that the flat battery wasn't intentional. They've paved the way for a return if thr battery does play up in thr near future.

0 tmk2 over 6 years ago

Hey, could I clarify if this 'being a thing lately' means that there are a number of units shipping with flat batteries without ill effects, or which then exhibit problems?

A couple of weeks ago I received a Forerunner 35 with a completely depleted battery, but after 2 or 3 charging cycles the battery life is as specified.

0 jylong over 6 years ago

Thanks for that feedback. I tried asking Garmin if there were any 'standardised tests' that I could run, to see if the batterry was up to code, but they were frustrating to try and get a straight answer from.

I do wonder if cell degredation may effect the number of recharge cycles as well, and whether I'll see more charge degredation over time?

0 Dr Phil over 6 years ago

could I clarify if this 'being a thing lately' means that there are a number of units shipping with flat batteries without ill effects,

There have been a number of comments in the 5Splus/5plus thread about receiving units with flat batteries. Too early to say if there any ongoing issues. I haven't seen anything out of the ordinary.

0 jylong over 6 years ago

Did some experimenting, and thought I'd share just for interest. I actually ran the GPS until the battery was almost flat (just below 3%) to see if it would give me the supposed '33 hours' of GPS and OHR. Long story short, it did. This included walking indoors and outdoors, as well as a stint on a commercial flight.

The other interesting thing was relating to the 'flat battery' and voltage levels. From the 'service menu' screen, a 100% battery is 4.3v. The battery at 3% was about 3.6v, which is well above the 'danger' level for Li-Ion discharge. I powered down the watch at 3% battery, to access the service menu, and discovered that at that % battery, the unit won't boot up (just gives empty battery image). It did boot up once I plugged it in, though.

Long story short, it looks like a 5x Plus with a battery 'flat' enough that it won't boot up may still have some small charge, and the battery protection circuit seems to kick in at a very safe voltage.