What's your charging current/speed on 6s Pro? (half than older 645)

Two days ago I received my new Fenix 6s Pro (sapphire). Since then I noticed how slow the charging time is.

I then used my USB amperometer to check the values, for the new toy and my older FR 645. Both around 70% of battery life when measuring.

Fenix 6s Pro: 0.11A
FR 645: 0.18-0.20A

So basically the charging speed for my older 645 is twice as fast then the newer Fenix 6s Pro.
Tried both the original cable and a compatible one bought from Amazon: same values.

Is it the same for you or is my Fenix faulty? Note that I received it with 0% battery life, which in general is not good for lithium-ion batteries.

I'm now on version 12.20. I don't remember which version was it when unpacked.

Serial: 65405XXXX

Top Replies

Labronico over 3 years ago in reply to Hexxer +1

I don’t mind slow charging times on watches.

I do mind having to wait twice the time compared to my previous Garmin mid level watch.
andrejs_v over 3 years ago in reply to Labronico +1

Another guess is that there is some frequency at which the current is drawn. So that in the end the active intervals of periods shortens. In such scenario your tester will not catch up the current correctly…
bluefish over 3 years ago +1

Labronico said:
I received it with 0% battery life

It would have been good to call up the service menu and see the current voltage. At below 2.5V you can say that the battery has been damaged.

All Replies

0 Labronico over 3 years ago

I just upgraded to 12.77 beta, just in case.

It still charges at 0.11A on a different high quality USB charger.

0 andrejs_v over 3 years ago

That could as well mean better efficiency and less heat. Just a thought.

Or different algorithms (slower charging in the end).

0 Labronico over 3 years ago in reply to andrejs_v

I totally get your point of view, however 1W in a mostly metal case, for short periods every 5-10 days for my knowledge is barely harmful for any kind of battery.

Even my older Garmin vivo-something sport band was charging faster than the current premium fenix, unless the solar version is different or my specific model is flawed.

0 Federonic over 3 years ago

My Fenix 6 pro charges from 20% to 80% in 1 hour and 20 minutes exactly.

0 Hexxer over 3 years ago

The loading speed of the watches is generally an absolute joke.
I still don't understand why Garmin uses such cheap hardware. Without Wifi, the basic version, the data transfer is slower than a 56k modem from 1990. That multiple hundred Dollar Watches. A 100€ China-Watch from Huawei ist loaded 10 times faster.

0 Labronico over 3 years ago in reply to Hexxer

I don’t mind slow charging times on watches.

I do mind having to wait twice the time compared to my previous Garmin mid level watch.

0 Labronico over 3 years ago in reply to Labronico

Today I tried to reach 100%.

Around 90% it went from 0.11A to 0.09A, which is odd, since most batteries decrease current a lot towards the end of the capacity.

When it reached 95% it stopped charging, or at least the amperometer read 0.00A, so maybe the current was below the instrument error. The watch still had the bolt icon and went from 95% to 98%.

0 andrejs_v over 3 years ago in reply to Labronico

Another guess is that there is some frequency at which the current is drawn. So that in the end the active intervals of periods shortens. In such scenario your tester will not catch up the current correctly. Use oscilloscope instead.

0 Labronico over 3 years ago in reply to andrejs_v

That's a good point, however half the current measured is perfectly in line with super slow (maybe twice the time) charging times.

Otherwise, unless 6s Pro batteries are huge compared to the ones in a 645 (I don't think so), the residual energy should be converted in heat.
I would dismiss the last point since the watch stays cool during the charge.

0 bluefish over 3 years ago

does the 645 have a 3.7v battery with an end-of-charge voltage of 4.2v, or a 3.8v battery with an end-of-charge voltage of 4.35v?