C70: Battery charging

[0006Andy]

My dash board has shown "Low battery” a couple of times and I am considering buying a battery charger to regularly connect over the winter. The car requires a large draw on the battery on start up so I would like to mitigate this if I can by charging it occasionally.

I am looking for some advice at this point.

1) Can I connect safely with the battery in situ and without disconnecting?
2) Should I consider a particular type of safe charger?
3) I’ve seen comments online about not connecting the negative terminal and instead attaching the negative lead to the bodywork. Is this what you would recommend?
4) I do not wish to fry anything or create error codes by charging the battery, therefore can you confirm this is safe to do without consequences?
5) any tips or recommendations on charging for this model will be welcome. VOLVO c70 >2006 SE T5

i may still require a new battery, and thus if I continue to get “low battery” after charging, I will change it.

For your info, the car has low annual mileage and i think was changed last winter or the one before, via Volvo assist.

All comments and recommendations welcome.