820 Battery life on cold days & in general.

After having my unit replaced awith a refurbished one and having apllied the changes to settings as adviced the lifetime on a battery increased to 10h without using navigation and to 7-8h when following a route. That's still not 12h as mentioned in the manual but much better than on the previous unit. I'm sure there is still something to be done to the software to make things better. Lookign forward to the update.

I went for a 43.5 mile ride, which was just under 3 hours of riding and a 30 minute stop, and i had 64% at the end. (this was with firmware version 8.80 not 9.0 I )was not following a route, but had the varia radar, remote, speed and cadence sensors connected. A lot better. I had the screen at 20% brightness, and back light timeout 15 seconds, gps & glonass. Was the problem a bad batch, or will I have a similar problem in 18 months again?

New firmware does not fix this issue. Battery charge dropped at over 1%/mile on a 73 mile ride today. Also dropped from 100% to 40% while in sleep mode. I thought that I had powered it off, but it really went into sleep mode. When I powered it on (really just woke it up) it was at 40%.

I've had the same issue. The past month I am lucky if the unit stays fully charged for more than 3 hrs. Did a century this weekend with the battery saving mode on and when I finished the unit was at 3%. Contacted support today and they said there is no known issue with the software and to reset my device. If that doesn't work then I can pay +$100 to have it fixed since it is out of warranty.

I've got the same issue with my second 820 unit (a first has been replaced due to blue halo). Both had started losing battery capacity after 4-6 months of usage. The current 820 unit was refurbished and I think warranty had ended after a month so I'll check a possibility to replace a battery or a whole unit by something more reliable. Definitely not worth to pay $$ for next ugly 820...

I like the 820 and since I have a Virb Ultra 30 camera (which also has a horrible battery life) the integration of the two make for some great videos. But its getting to the point where I may need to find a non-Garmin replacement for my 820.

The batterylife of my 820 dropped to about 5 hours, with all settings in favour of minimum energy consumption (Bluetooth off, WiFi off, Glonass off, no navigation, screen off after 15sec, etc) only heart and speed/cadense sensors. It may well be a software error, but batterylife was never close to the 12-15 hours specified by Garmin. The unit is about 18 months old.
On my long rides of over 6 hours I use a batterypack, of course. The irony is that a software error causes the backlight to stay on permanently, inspite of the 15 sec off-setting, unnecessary draining my batterypack. Poor powermanagement by Garmin. Will this ever be solved by a new FW update? I doubt it.

I received a warranty replacement for my Edge 820 in May so it's relatively new. The screen brightness was set to Auto, the backlight timeout was 15 seconds and Glonass off. The Edge 820 was paired with Garmin RTL-510, Garmin speed sensor, Wahoo Ticker X HRM, and Quarq DFour Powermeter. The Edge 820 was fully charged when I started my ride this morning, with Strava Route navigating, 4 hours and 55 minutes later, battery life was down to 9%. It's bad.

Battery has been getting unusably bad with the latest update. On my last team ride, my battery dropped from 100% to 35% in the first 15 miles. I switched Garmin to power-save mode and was able to complete the 70 mile ride only dropping down to 25% on the rest of the ride. There's clearly something going on with the display settings.

I generally use auto-brightness and 15 second timeout. I'm starting to experiment with 0% brightness, but it's annoying not being able to see the display in the dark.

My battery life has been declining substantially. I've never gotten more than 6 hours, ever, which means I rarely complete a century without the device putting itself into "battery save" mode. In June, the device died entirely after 7.5 hours. Oh, and I don't DARE not charge after every ride. Even the shortest rides leave me with less than 50%.

I have done all Garmin's recommendations, but today was the worst. For the record, it was not colder than 50F (10C). I had a HRM (Ticker), a Speed/Distance sensor (Garmin), and a PM (4iiii's), and for the first time, a Varia. All ANT+ devices. I had backlight set for 15 secs, battery save enabled, No nav. Seriously... no nav. That's one of the reasons I have a GPS device, but I knew the route, so I turned it off. I wanted to see EXACTLY how long my battery would last.

Two hours, 53 minutes. Yep. Not even three hours. Totally unacceptable, and practically makes the device useless.

It's Saturday, but I will be calling Garmin this week.