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Garmin 820 Sporadic Battery Life

I have seen many complaints about the battery life on the 820, but my concern is that the battery life on my 820 is very inconsistent. It is never as good as advertised, but I assume the 11 hour life is with the screen off, no sensors, and gps off while riding indoors. This is not how I use my devices.

I rode 60 miles while using navigation with the screen in the sleep mode, or as I call it the "asleep at the wheel mode" because it often forgets to notify me that I am supposed to turn. I would like to be able to see my speed, cadence, and elapsed time, but I have to chose between navigation or seeing the screen in order to get a full ride out of the 820. This ride was about 5:15 long and I finished with my battery at 60%. I was impressed with the battery life, but don't trust this device enough to attempt a ride this long with the screen on.

One week later (last weekend) I rode the same route in the opposite direction. 2.5 hours into the ride I get a message stating that my battery is low. It was at 100% when I started. This is not the first time that I have had such short battery life. Also during this ride I was getting the turn in 0.1 mile prompt about 100 yards before a turn. After each turn the prompt would remain on the screen for miles. The only way to get the screen to go to sleep was to stop, remove my glove, and touch the prompt to dismiss it.

Are other users having sporadic battery life like this? Has anyone else seen this problem with messages not going away? Is there a comparable edge device with better battery life that will allow me to ride with my screen on?

FYI: software is 10.0.0. I bought this unit shortly after it was released, so I have had it for a couple of years.
  • ......Also during this ride I was getting the turn in 0.1 mile prompt about 100 yards before a turn. After each turn the prompt would remain on the screen for miles. The only way to get the screen to go to sleep was to stop, remove my glove, and touch the prompt to dismiss it.

    ....


    If you change screen sensitivity settings to high, you don't need to remove your glove for the prompt to be dismissed.

    For battery life I can not comment yet as have only been on couple of rides. From my limited experience, with heart rate, cadence, phone, live track active and varia radar connected but no turn by turn navigation, after about 7 hours of ride I had 35% left. Back-light set to 40%, back-light off after 15sec, 6gb of maps were removed and replaced with Cy open map, about 30mb. Removal of maps improved considerably the performance of the device.

  • In the earlier firmware versions of my Edge 1000 it would sometimes get sluggish and eat battery on the occasional ride. I concluded that sluggish meant "processor is busy doing something it shouldn't'". I therefore learnt to reboot and performance and battery life would be back to normal. Problem was solved in a later FW version.
  • FWIW: Most all of these discussions assume that the battery level indication is correct. In my (limited) experience, it often isn't, and despite low battery indications, the battery will last for significantly more time than the level indication would suggest.

    My admittedly meager understanding of this is that the slope of the discharge voltage/load curve of the batteries are very shallow until they reach depletion and small changes in the curve over time will have a large effect on the charge level estimation. I'm not sure about the 820, but in some other LI powered devices, the level estimation is adaptive and you can train it by allowing the device to run until it shuts off. Near shut off, the discharge curve is much steeper and the circuitry should ensure cutoff occurs before the battery might be damaged.
  • If you change screen sensitivity settings to high, you don't need to remove your glove for the prompt to be dismissed.

    For battery life I can not comment yet as have only been on couple of rides. From my limited experience, with heart rate, cadence, phone, live track active and varia radar connected but no turn by turn navigation, after about 7 hours of ride I had 35% left. Back-light set to 40%, back-light off after 15sec, 6gb of maps were removed and replaced with Cy open map, about 30mb. Removal of maps improved considerably the performance of the device.



    Thanks. I will try changing the sensitivity in cold weather. In hot weather I prefer keeping it at medium sensitivity so that the screen is not triggered when sweat drops or rain hit the screen.

    The real issue I was trying to point out was that I had to dismiss the turn prompts. This has never happened in the past. It was only giving me the first prompt at .1 mile and the prompt would not show for turning in 500 feet. Sometimes I would be well past the turn and I would stop and dismiss the prompt and then 30 seconds later it say something stupid like turn in 13ft even though I had already made the turn.
  • FWIW: Most all of these discussions assume that the battery level indication is correct. In my (limited) experience, it often isn't, and despite low battery indications, the battery will last for significantly more time than the level indication would suggest.

    My admittedly meager understanding of this is that the slope of the discharge voltage/load curve of the batteries are very shallow until they reach depletion and small changes in the curve over time will have a large effect on the charge level estimation. I'm not sure about the 820, but in some other LI powered devices, the level estimation is adaptive and you can train it by allowing the device to run until it shuts off. Near shut off, the discharge curve is much steeper and the circuitry should ensure cutoff occurs before the battery might be damaged.


    I have had to train a previous Garmin device that would shut down minutes after starting a run. The battery indicator on that device become more accurate after being re-trained. That was also a very different situation. That device was consistently bad until it was retrained and then it was fine.

    The 820 is very inconsistent and I never know how long the battery will last. 2.5 hours is way short of the advertised 11 hours. I understand that the more functionality that I use the shorter my battery will last, but a 75% reduction in battery life while using functionality that I find necessary during most rides is unacceptable. I own many Garmin devices and I consider the 935 to be on the other end of the spectrum. It has amazing battery life and has never let me down. I expect the 820 to meet the same standards as the 935.
  • I give no excuses for the Garmin 820's shortcomings (screen halo, short battery life). To be ready in case of low battery, I carry a light-weight portable charger in my jersey pocket. I can easily add 20% or more charge to my 820 when stopping at a rest break. Recently, one of our club riders showed up at the start and commented that his Garmin 520 (not 820) was at 1% battery level. I handed him my Tzumi PocketJuice Solo 4000 mAh charger. He plugged it in to his 520, and put both together in his jersey pocket while his ride was still running. An hour later when we stopped at one of our normal stops, his 520 battery was 100%. He did not miss any of his ride data as his 520 recorded while charging. He only missed seeing his data while his 520 was in his pocket. He was so happy he said he was going straight to Best Buy to get one after the ride. He could have given it to me even earlier if we had reached a stopping point. Unfortunately, my out-front mount will not allow me to run "connected" to a portable charger since Garmins the size of the 820 have their micro USB ports masked by a mount like mine. I think the Garmin 1000 and 1030 would allow access to their ports in my mount, but might not need charging unless one started a long ride with less than a full charge on one of them. This idea is not original with me. I read it in another thread in the Garmin forum several months ago. I got my PocketJuice for $5 on Black Friday at BBuy. The price has gone up a little since then. Of course, there are other portable chargers to consider. I keep mine in a ziplock bag in my jersey pocket to shield against moisture. It's light enough I don't notice it there.
  • Thanks for the suggestion. Carrying a charger seems like a band-aid for a problem that should not exist, but that may be my best option on long rides. Carrying my 820 in my Jersey pocket may not be a big deal considering that I have to keep it in power save mode with the screen off to get thru a ride. If I did not need navigation I would just switch to using my Forerunner.
  • Unfortunately, my out-front mount will not allow me to run "connected" to a portable charger since Garmins the size of the 820 have their micro USB ports masked by a mount like mine.


    I am using the Garmin out-front mount that came with my 820, which does not block the USB port. Due to the 820's faulty battery life, I regularly have to charge from a Jackery Mini USB battery while riding, with the 820 mounted normally. There's no need to ride with the unit stuffed in a pocket while charging.
  • I have an integrated handlebar on my Canyon Ultimate SLX, which has a different out front mount than the Garmin OF mount. However, after closer inspection, I was able to unscrew the insert in my OF mount and move it back to the next set of holes. That gave me enough clearance to plug in a cord to my 820 when mounted. I don't like the rubber port cover on the 820 getting distorted and I will not run it connected in wet weather. I plan to mount the battery with Velcro on top of the flat area where a stem would be on a conventional bar/stem combo and use a short micro USB cord to the 820. Then I can pull the battery from my jersey pocket and run the 820 with external power when needed (very long rides or in case I start with less than a full charge.
  • Another benefit of carrying an external battery is so you can also charge your mobile phone on a long ride. Running Garmin Connect while riding will drain your mobile phone battery faster than normal. I always run Garmin Connect with Live Track on so my wife can see where I am on the road. I posted a couple of photos of my setup on another thread where others have also shared info about using external batteries: https://forums.garmin.com/forum/into-sports/cycling/edge-820-aa/1348395-recommendations-for-an-external-battery-pack-while-riding