that could be normal if you had just started the car and it wasn't warmed up yet. but you need to test with the car warmed up fully

if the temp gauge on the dash only gets up to 25% and 68C is 154F it sounds like your ECT(to ECU) and temp sender(to gauge cluster) sensors are working correctly

but
I have a couple questions for you

and this is after how much driving? at least ten mins?
what happens if you rev the engine to 3000 rpm in park for a couple minutes after driving for 10 mins
the lack of airflow should increase the temp further on the gauge.


the thermostat is supposed to open at 180F

does the car take an usually long time to "warm up"

i think your thermostat is stuck open

causing the ECT sensor to make the car run rich in order to warm up the engine quicker but it cant because the thermostat is not closing

it may have been like this for a long time but in the summer you may not have noticed this because of the higher ambient temps

unfortunately the thermostat being stuck open shouldn't kill the battery... it sounds like you have 2 separate problems going on here

 

Ok so after driving for more then 10 minutes and revving the engine it went to 85C and the guage was at about halfway

Yeah I don't think the problems are related