My ipad loses time

How much time is it losing?

It shouldn't lose time at all. Make sure the battery is always charged.

Apparently you aren't alone. https://discussions.apple.com/thread/2388117?start=0&tstart=0

Take the iPad to an Apple store or Apple certified repair shop.

The iPad has its own clock which is not regularly synchronized with a standard time source. If the OP is talking about a few seconds after a week then this could be normal. If he is talking about minutes off per day it is not.

The thread you posted is a good one to read but it is a bit stale and has been dormant for almost a year.

Need more input from the OP here (amount of time lost, charge level, etc.)

Wifi-only iPads do not have access to any internet time sources and their own internal clocks will indeed slowly drift off and need occasional correcting. Your only real option is to reset it yourself manually, in Settings, but you can install any of a number of Time related apps (including one called just that) which will connect to internet time reference signals and tell you what time it is and how far off you've drifted ... but not, sadly, adjust the time themselves, as the current iOS doesn't allow that.

3G iPads do have access to time signals through the cellular network, but they will only stay sync'ed when 3G is up, i.e., when Cellular Data is ON in Settings and you have a signal. If you have that model and normally keep cell data OFF to keep those annoying little charges from trickling in, then just turn it on momentarily: As soon as you see it connecting to the local network you'll also see the time update itself.