Garmin forerunner 945 sudden battery life decrease.

I have exactly the same problem. Three years ownership, perfect function and days of charge then two days ago, sudden drop to go from 100% to 0 in an hour. Factory reset, full software update, unpair phone did not resolve it.

I have the same issue with my Garmin FR 945 which I've had for 4 years.

The batery is decreasing by 40% in two hours. I also test to do factory reset, update software, connect to Garmin Express, remove it from the phone but nothing works.

I am trying to contact Garmin but I do not have any answer to my problem.

If anyone could help us ...

Reply (in French) from garmin : 

Already tested and it doesnt work.

Cher Client,

 Afin de réinitialiser votre montre, merci de suivre cette petite manipulation :

 Si le problème persiste, nous pouvons vous proposer un échange standard de la montre complète. Si vous êtes d'accord, merci de répondre à cet e-mail afin de vous envoyer la procédure SAV.

Merci d’avoir contacté GARMIN France. Nous restons à votre disposition pour de plus amples renseignements et vous remercions pour l’intérêt que vous portez à nos produits.

Sincères salutations,

Garmin France SAS

i had the same problem, i was using a third party watch face with lots of data fields, it wasn't a problem with the battery to start with but all of a sudden it was draining the battery fast. try using a different watch face.. the less data fields the better esp ones that update frequently like seconds, steps, heart rate.... i still have heart rate but not the other two. i've only got 4 data fields on a standard garmin watch face now... but if you've been exercising a lot with your watch the battery health will be declining after this amount of time, remember the 945 was released nearly 6 years ago, the watch could have been sitting around for a long time before you bought it batteries decline with age as well as with use... i have more than one watch and had another one i was exercising with so mine has not been drained as much as it could have been... my watch is in airplane mode until i want to synch it after exercise... wifi or bluetooth can cause issues the chips can become faulty and they just broadcast constantly... letting your battery drain completely wears the battery out faster it shouldnt get below 20% and stopping charging before it gets to 90% reduces battery wear

Hello,

I have the same problem. To my mind this issue is due to the latest FW 13.70.

I use to pay attention to the battery, never above 80-90%, never less than 20. No smartphone notifications, no wifi, bluetooth only used to Sync with GCM. All sensors deactivated when not used. Assist turned off.

I was on FW 13.40. After it has been impossible to sync anylonger with GCM (tried different app versions, different phone, hard reset the watch) I upgraded to 13.70. Hard reset done, as I know now almost for sure that an old FW is most of the time messing up with the new one.

Standard watch face.

After update, battery 78%, went for a run with HRM connected. Battery loss was 4% for a hour.

Later on I did a home trainer session Ant connected and HRM connected.

Battery loss more than 40% in 1h30. Unbelivable. Never happenend before in  the exact same conditions.

The only watch which never failed me is not reliable any longer.

I'd like to revert to 13.40, but can not find it. I don't know what to do. The warranty ended last november.

I bought a 945 last week, made 1st charge on monday and it was depleted by thursdaym 5 days! My forerunner 55 used to last 9-10 days tracking activities everyday. is this normal?