Charging Battery question

goldendaze

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Jul 21, 2012
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Hi all,

I recently got this watch. I don't sleep with it on and was wondering if it is harmful to the battery to put the watch on the charger every night (even if it is at 80%) or should I let it run down to a certain level before charging?

Thanks!
 

amyf27

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Oct 24, 2015
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Hi all,

I recently got this watch. I don't sleep with it on and was wondering if it is harmful to the battery to put the watch on the charger every night (even if it is at 80%) or should I let it run down to a certain level before charging?

Thanks!
You'll get all sorts of answers on this one. Personally, I don't leave mine on a charger overnight, and don't charge mine until it's fairly low, roughly under 20%. Charge lasts a long time :)
 

Peter621022

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Sep 25, 2013
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I charged my S2 every night over night (usually the battery was at 50-60% at the end of the day) and after three years of doing so the battery was as good as at the beginning. So I think that shows that modern batteries can stand every day charging very well.
My GW 46mm BT looses 10-15% of battery life a day, so there's no need to charge it every day.
So I guess you have a choice. Do what you like, the battery won't go bad.

I wouldn't drain it down to zero before charging it, though. A friend of mine did that with her S3, didn't wear it for weeks after draining it down and couldn't charge it anymore when she decided to wear it again. The battery had to be replaced.
 

NIckkr

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I charged my S2 every night over night (usually the battery was at 50-60% at the end of the day) and after three years of doing so the battery was as good as at the beginning. So I think that shows that modern batteries can stand every day charging very well.
My GW 46mm BT looses 10-15% of battery life a day, so there's no need to charge it every day.
So I guess you have a choice. Do what you like, the battery won't go bad.

I wouldn't drain it down to zero before charging it, though. A friend of mine did that with her S3, didn't wear it for weeks after draining it down and couldn't charge it anymore when she decided to wear it again. The battery had to be replaced.

^^^^^^^^^^^^^^^^^^^^

This.

For max battery life ...i.e time to battery replacement.

In summary
Don't frequently deep cycle 100%-10%-100%-10%-100%-10% etc etc.
Basically never let he battery run down to less than 10%
Don't routinely charge it to 100% and LEAVE IT CHARGING
Try to maintain change between 70 - 90%

All the science published regarding this battery technology supports this approach.
 

k3m1c6

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Sep 11, 2014
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I wear my GW 24/7 the only time I take it off is to shower each morning. I drop it on the charger, its usually at 80 to 85% and when I'm ready to head out (about 20 minutes later) its around 98 to 100%.
 

Peter621022

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Ok, so I was triggered by this thread to do some research. This graph shows why it is unwise to go below say 20% charge, because your battery will loose power rapidly when you keep using it after that point, and the chance that you damage the battery increases if you go too low.
Li-ion%20Discharge%20Voltage%20Curve%20Typical.jpg
This article gives some insight in how to prolong your battery life. The lower you go before charging again, the less cycles you get, but - obviously - the longer your watch performs per discharge. So suppose you charge to 100% and then use the watch until there's 20% left (that would take say 4-5 days on my GW46mm BT) that should give you according to this article around 900 cycles, or - with 4 days per discharge - at least 3600 days before you need to replace the battery. That's almost 10 years. Nothing to worry about, I'd say.
If you charge your battery every day, and let's assume there's still 80% left when you recharge it, that would give you 9000 cycles or 9000 days. That is indeed much longer, over 25 years before battery replacement. But assuming you'll replace your watch every 4 years or sooner, you can do what you want, as long as you don't go too low.

If you want to store your watch, make sure it has around 50% charge left. 100% charge in storage can damage your battery apparently and too low a charge can damage your battery as well because of the ongoing self-discharge of batteries (1-2% a month for Li-ion).

Li-ion batteries can be damaged when overcharged, but a good Li-ion dedicated charger will stop charging when the battery is full. So charging over night should not be a problem, although I guess you could consider your watch being "in storage" over night at 100%. In that case, you may want to either start wearing it immediately once full or prevent it from reaching 100%, e.g. by charging it daily while taking a shower only. The article mentions an ideal charge range of 30-80% for optimal battery life. But again, even if you loose some battery life while charging over night, I strongly doubt you will notice it, assuming you will have replaced your watch after 4 years anyway.
I charged my S2 over night for 3 years and the battery was still going strong when I sold the S2 to someone else.
 
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NIckkr

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Well done for finding that research. It is very similar to what I found but your summary is very good and far easier to understand than some of the technical papers I found.
Everyone should take heed and dare I say it Samsung (and others) should offer such advice to owners of their battery powered products .
The cynic in me thinks it is not in their interest to promote anything that will not ensure owners will be tempted to replace their product in a few years as the battery in knackered.
 

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