Can Fitbit Charge 2 time be changed to 24hour?

yes , you can by direct from Fitbit or you can by aftermarket from online retailers such as Amazon.

Hi , you can download the Fitbit 2 manual here.

hi Sonja.
How do I change the time and date on my Fitbit?

1. From the Fitbit app dashboard, tap or click the Account icon ( ).
2. Tap or click Advanced Settings.
3. Tap or click Time Zone.
4. Turn off the Auto option and select the correct time zone.
5. Sync your tracker.

Help article: How do I change the time on my tracker? - Fitbit Help

https://help.fitbit.com/articles/en_US/Help_article/1176 Search for: How do I change the time and date on my Fitbit?
or read up more at this link.
How to reset time and date on fit bit watch Google Search

https://help.fitbit.com/articles/en_US/Help_article/2084


pictorial instructions link above

Jessica, 1. From Time Telling Mode, press and hold 'D'. Press 'B' simultaneously to select either 12 Hour or 24 Hour (Military) Time. NOTE: 'A' indicates 12 Hour Time is selected. 2. Release 'D' to return to Time Telling Mode.
Try the links for manual on this watch.
"I hope this helped you out, if so let me know by pressing the helpful button. Check out some of my other posts if you need more tips and info."

http://fitness.manualsonline.com/manuals/mfg/armitron/wr_165.html

http://www.angelar.com/~jeremy/ArmitronLadiesDigital.pdf

Try this link: http://world.casio.com/wat/download/en/manual/

For the AD0802 watch, press MODE until the standard time appears, then press START/STOP to set the time and date. In that state, press RESET to change the current setting (hold it to scan values) and MODE to move to the next setting (seconds, then hour, minutes, year, month and day of the month in that order). Press START/STOP again to exit time setting mode. At any time while in time-setting mode, you can press the LIGHT button to toggle 24hour time on and off (the 24H indicator will turn on and off to show the current mode).

I contacted both the eBay seller of the watch and the watch maker and what I got back was a complete joke so I figured it out and made my own manual but there doesn't seem to be any way to attach it to this posting.

military time:
1. When setting the time on your watch, IF you watch can change to Military time(and most can)
2. when you are adjusting the hours go through a full 24 hour cycle. You'll notice that the 2nd time through it is on military time.. 3rd time through back to 12 hour day AM/PM cycle .. 4th time back to Military.
So you can do this as many times as it takes to get to the right time ..
In 24 hour time you will see an "H" displayed where you normally see and "A" for AM and "P" for pm.

the instructions for getting your watch out of the (military)24hour mode to the 12hour mode are on this page

http://www.grudknows.com/inanemutterings/watch_baby_bgr210.asp