Battery question!
 

Hello,
I have a 2014 Mazda 3 GT with the i eloop regenerative system fitted.I want to take the car off the road for the Winter,but don’t want the very expensive $550 battery to deteriorate.The car is parked in an underground parking stall,but there is no power point for a battery tender.I was thinking of removing the battery and putting it on a tender at home,would this be possible/safe without any issues with the car’s electrical systems once I re install it in the Spring.I was told that it’s not advisable to charge the battery while it’s connected to the car,any advice would be very welcome,thank you!