Battery life cycles vs battery charge

[Dab-123]

There is no info on this site on what the battery *life* (not the charge) is for their devices. The Fitbit info page on this is also misleading because it talks about "battery life" when it means "battery charge." A battery life is how long it lasts before you throw it away. A battery charge is how long it lasts before you need to recharge.

The battery life is determined by the number of cycles and the cycle refers to how many complete charges and discharges a rechargeable battery can undergo before it will no longer hold a charge. Every battery has a benchmark number of cycles by the manufacturer.  If the cycles are 300 and you have the Fitbit settings that give you 6 days on a single charge, your battery should last 1,800 days (ie about 5 years) under ideal conditions.  If you have features that drain a battery and get only 3 days on a charge, your battery will only last about about 900 days (3 days x 300 cycles) ie 2.5 years.  If that's the case and since the warranty is only for 2 years, I might as well drain my battery with features I would really prefer (like Always On Display) and then have the battery replaced by a private contractor, even though it voids the warranty.

Fitbit would do its customers a service by stating this info, so that they maximize their enjoyment of the device. Having to flip my wrist to see the time--which does not always work anyway--is a real pain.

[Dab-123]

[Guy_]

Hi @Dab-123 - there probably isn't any need to worry about the battery life because as batteries age they normally only hold a smaller charge but continue to work fine.

Depending on how a watch is charged, used and treated the endurance can vary,

After 300 charges, in your example, the capacity may reduce by 5-10%, and so need charging slightly more frequently.

Watches are not made to have batteries replaced and in 3 years a watch with more features may cost less than the cost of trying to find someone to replace a worn out old watch battery without any degree of reliability.

Putting a new battery in an old watch, is unlikely to be worthwhile. 

Also it is unlikely the battery will be why the watch fails.

In short there is no reason to worry about the battery and that is why they are not replaceable.

[Dab-123]

I did not say anyone had to worry about this.

I said cycles are always given by the manufacturer in their specs sheet
and, though imperfect, they give a sense of what to expect. Fitbit should
report it.

You are free to not be concerned, but as I hear people seeing their
batteries die and their fitbit be unusable due to non-performing battery,
I'd like to have a more informed approach. It's really no big deal for them
to report it.

[Guy_]

@Dab-123 - exactly the issue, what many people report as a failed battery is most often due to a different watch fault which causes the watch to draw too much from the battery and gives the impression that the battery is at fault when it is not.

Hence battery longevity is rarely an issue.

My watch after 3 years holds almost the same charge as new, the degradation is barely noticeable.

[Dab-123]

There is really no evidence for what you are saying. Might be so, might be
a battery problem.

I am not sure why you need to take down the point. Every serious
manufacturer reports cycles, with all the caveats in mind. Eg:
https://support.apple.com/en-us/HT201585

It is really no big deal for Fitbit to report it. Or maybe you are from
Fitbit? Because they did try to blow off my point and responded with a
response that totally confuses charge with life.

[Guy_]

@Dab-123 - unfortunately Fitbit don't provide the information, and possibly should, your valid point.

The reality is there is evidence of watches overheating or the seals failing which causes watch problems but no evidence of it actually being a battery problem except in very rare cases which are more likely to manifest themselves during the early stages of warranty.

[Dani0608]

I will tell you I have had 3 Sense in less than two years and today the last one I ordered from Amazon was on Nov 11th 2022 died. Ever since the app update it was not holding a charge properly going from a full charge to 30% in a little over 3 hours. I am a walker, don't do any activity that would cause damage,never have gotten the thing wet either (even though it indicates 50m waterproof). There is no reason for the battery to die in just shy of a year! You are making a great point that too many are confusing life for charge and FitBit needs to let their customers know how long the battery life in its entirety is, it does matter for quality assurance. This however after this I will not be buying another Fit bit again! The new app is awful and while this one is the only one to out right die, 2 faces almost entirely became detached one within weeks. Quality is a weaker point lately, perfect time to pose such qustions ! 

[Dab-123]

Thanks Dani, I hope Fitbit takes note. Perhaps your experience was why Customer Support was so dismissive. They tried to argue (and insisted!) that life varies due to use, which of course it does to an extent--but they were talking about conditions that affect the charge. And that does not change the fact that all batteries have benchmark nos of cycles. 

It seems that the devices are not living up to the promise so they are trying to blame the user.

But the fact that even their info page confuses the concept suggests there is also some level of ignorance/indifference/incompetence involved.  Pretty astonishing others have not made it an issue...