I'm not sure but with most phones and devices like the D2G this is the case...
When pluged in:
-phone runs off AC adapter and not battery...
-Phone onboard hardware sets battery to charge...
-When battery is topped off, the device then stops charging and only maintains Full status of the battery...
I think you should only worry if this happens:
Take the battery out of the device, if the battery is devloping a bulge, its starting to show signs of possible overcharge or being charged too fast...
(Almost Always NEVER happens unless the device hardware or AC adapter failed in some catastrophic way... By then you'll have a new phone...lol)
OR
The battery shorts out internally and melts within the device getting EXTREMELY hot and Melting the device itself in your hand (Happened to me because of a defective XGPS300 with a faulty ground loop in it...lol)
Also, use charging sources and plugs rated in range of the phones input charging current and voltage... This helps increase battery life...
LiIon Batteries are the moost resilient batteries pretty much, here is how:
-The battery life goes by FULL cycles. A full cycle can be 10x10% discharges & recharges to make 1 cycle, or 2x50% discharges & recharges to make a full cycle or 100% dead and full recharge to make full cycle...
-Letting a LiIon battery go to full dead is BAD, because it can quickly decrease batteries life time...
-I say about 10 percent lowest is VERY safe... I usually go to 3-5% charge left then recharge because I am too lazy to plug it back in during the day when I'm able to... (any device with LiIon battery)...
Best storage for a LiIon battery is about 60-80% charge for about 2-3 months NOT plugged into anything...
Storing it at about 30-50% is fine too, but the other range is for longer storage duration between recharging...
Not fully charged, a fully charged Li-Ion battery in storage is bad (From what I'm told) because of the chemical interactions I guess...idk I'm not a chemist...lol
Do not try to store it for long times like a month or two below 30% it is not recommended...
idk what else...
Oh yah, ur fine...lol
I like to type when I actually Can answer an OP with a post...lol