820 Battery life on cold days & in general.

These are really odd battery observations. I'd say my last 5 gravel rides since the 10.0 update are all 2:00 to 3:00 hours and I don't dip below 75%. All 5 rides were at night w/ brightness at ~50% and I'm always following a saved course with GPS only selected. My 820 uses cadence sensor data and drives BT audio to my phone and controls a varia light. Not sure if it matters, but I fast scroll through 5 pages with 2 parameters on each page. Due to work and darkness, I haven't able to get out for longer than 3 hours since the update. The weather has been anywhere from 40F to 65F.

Ok... So based on recommendation above, I did a total device reset today. After my 3 hour ride, I had about 43% batter left. Much better than yesterday, but still not enough to get me through a ride of more than 80 miles, I don't think. Still unacceptable. Battery save "on" for the entire ride. Sensors connected were my 4iiii's power meter, my Garmin speed/distance, the Varia, and a Ticker HRM. No navigation.

Using battery save mode is a PITA if you're trying to monitor you effort using a PM. I can see using it if you are doing some really long ride (over 8 hours) or when the battery is low, but if you have to turn it on just to get through a 3 hour ride, well, it defeats the purpose of having the head unit, doesn't it?

I backed up my files, too, as recommended, but they did not restore, so lost all that info, too.

Sigh...

I bought the 820 when it first came out and could navigate centuries without any battery issues. But this season, I couldn't quite get four hours before having to go to battery save mode. I figured the battery was toast, but after seeing this thread I thought I'd check.

I charged the battery to 100%, removed it (it was at 4.20V), and put a 100mA load on it until it dropped to 2.95V, just about
7 hours later. The battery is marked 700mAh, and I got about 688mAh in my test, so I think the battery is fine. When I put it back in the Edge the next morning, it read 5%. A little overnight "recovery" probably plus a minute of charge while I got the battery display to come up could have inflated this number, so I think I got a reasonable measure of full capacity.

I'm guessing either the power drain on the Garmin has gone up significantly, or the battery state of charge is not being correctly displayed. Unfortunately, I don't keep track of when I apply firmware upgrades, but I did get a power meter in May and would have done one then if available. It was in June I first noticed the poor battery life.

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.

It's funny that I mentioned this last week. Now that DST is in full-effect I can clearly see one major problem that's definitely affecting battery life with latest FW (ver. 10).

With my settings mentioned above, and when the Edge auto-pauses when I come to a stop, the backlight stays on forever until I touch the screen again, even after I start rolling again.

Hi All

My Edge 820 is about 2 years old. The battery, if I am lucky, lasts max 5 hours when it is not too cold.
I have an HRT and the Vector 3 connected.

What puzzles me, is when I start riding with 100% (fully charged), that often the battery drops within the first 10 to 15 min to below 80%.

I don’t use the Garmin for Navigation, only for recording my ride!

I had a ride of 4:37h and started with fully charged battery. Without the saving mode coming up at below 10%, the ride couldn’t have been fully recorded with the 820. This is just not good enough.

I'm still getting poor battery life out of my 820, but recently I noticed something interesting.
On a four hour ride, my battery dropped from 100% to 10% in around 2-1/2 hrs.
It then went into battery save mode, and rapidly dropped to 2%.
But the 820 didn't run out of power for the rest of the ride.
So I suspect that yes, battery life is poor with 820's after ~1 year of use, but that the internal battery life gauge is wrong, and that there is more left than is indicated.

Guys, I have read the whole thread and tried almost everything. Basically these are the results I get:

Firmware 10 Phone on/ BT-WiFi on/ 0% brightness/Glonass/Radar on/Power on 5:40
Firmware 10 Phone OFF/BT-WiFi OFF/0% brigthness/Glonass/Radar on/Power on 6:24
Firmware 8.4 Phone on/ BT-WiFi on/ 0% brightness/Glonass/Radar on/Power on 5:26

I have not used Navigation in any of the above.

My Edge is 14 month old. I just now reinstalling firmware 10. I may try the new test version. The life of the batter is low for long rides. When I do a long ride am in battery saving mode and using the computer barely, no radar, of course this is far from ideal mainly when you use power value when you ride. For Power I use PowerPod, I have also a Garmin Vector 3 but most of the time I do not use it. If I use Cycling Dynamics battery is drained faster and I can can use powerstroke as replacement for Cycling Dynamics (but.. is off line and not exactly the same)

I wonder if the problem I have can be resolved replacing the battery.
-=terry=-

I am still using the refurb 820 replacement I received back in May, and it was fine all summer and fall. It has firmware version 10.0. Two weeks ago I did my first ride in weather I considered cold. It was just under 51 miles, 3 hours 10 minutes with two stops which were about 20 minutes. I was following a course, the screen was at 30% brightness, back light timeout set for 15 seconds, gps & glonass, had the varia radar, speed, cadence, HR, and the remote. This is the same setup I usually use. I started with 100% battery and ended with 14%, when normally I end with between 40-50%. This had me concerned that I was experiencing the same battery issue again. This past weekend, I tried setting the brightness to 0% and everything else was the same. At the end of the 42 mile ride (which included a ridiculous 40 minutes for another rider to fix a flat) I had just over 50% battery.

My only conclusion is the the cold weather adversely affects the back light sensor, Could this be the case?

Hi,
Did anyone try with the External battery pack from Garmin? Will the cable fit between the 820 and the external battery?

Lars.Tore, You might want to post your question on https://forums.garmin.com/forum/into-sports/cycling/edge-820-aa/1348395-recommendations-for-an-external-battery-pack-while-riding. Maybe someone who reads that thread has an answer.