A small warning if you are not using the car long periods
 

I have seen several people having trouble starting their cars after they've stored it for an extended period. The car would simply not even crank, even after recharging the battery or trying to jump start it. I believe a Volvo tech mentioned that as the battery gets low, a software may get corrupted and the car would no longer recognize the keys, so the immobilizer stays on. I suggest diisconnecting the Negative (or the Positive) cable at the battery if you won't be using the car for more than 1 week. Remember to have the key in POSII (headlights on) when connecting back the battery. Here's how to lock the car after disconnecting the battery - remember that the V70, XC70 and XC90 don't have a key lock at the trunk lid, so you will have to climb and reach the battery from inside the car. You may also try disconnecting the Power cable from inside the engine bay with a 13mm deep socket (above the ABS unit) but be careful not to touch any metal with this cable - cover it in some cloth material https://youtu.be/rDyxtusEs2Q

Hi
Good advice but i would suggest if your battery cant last a week without use then its past its best.
I posted this week about people being so reluctant to spend a few quid on a new battery when they obviously need one.

Edit
Just seen your reply to my post in the general section.
I see you hold true to my thought on batteries.

That doesn't turn all the power off.
A number of items are powered direct from the battery via the fuseblock sitting at the base of the battery.

If you aren’t using the car for a few days, get into the habit of leaving the car parked with the handbrake off and in gear. Otherwise you might go to drive off and there will be a big BANG and the sound of disintegrating handbrake linings in the rear hub.
Being a separate handbrake system, the shoes can rust into the drum and stick fast. The shoes delaminate and the resulting bits grind into the hub causing damage.
With the handbrake off, the drums will still rust but gentle application of the handbrake whilst driving along will polish this off.

Simple but effective habit to get into.

Something I do myself. I also post a note on the dash to remind myself and others that the car is in gear as I generally reverse park my CR-V in front of the Volvo and leave it as close as 100 to 150mm. I generally dip the clutch when I start a car, but doing that on a car with the handbrake disengaged can let it roll if you don't always apply the foot brake!

On the subject of batteries and prolonged storage, I plug a small solar charger into the rear power outlet on my V70. Sat like that for 3 months when I was working abroad with no issues.

Another issue with prolonged storage is the temporary formation of flat spots on tyres. If it's possible, move it periodically by a foot or so to rotate the rest point on the tyres.

When I stored my old Triumph Spitfire and Herald many years ago, I also wedged the clutch pedal to disengage the clutch for similar reasons to the handbrake, although 3 months on the Volvo didn't seem to cause any issues.

Ive not used the handbrake for anything longer than a few hours, deffo not even overnight, since about 2000 when i used to work at a vehicle defleet center, granted this it only great if you have an auto or park on flat ground, even so, ive always left my manuals in gear and always us the clutch to start anyway, its deffo a good behaviour to get into BUT, not to be used on an incline, if something were to happen and the handbrake was not applied, could be in a world of hurt.... :)

Define extended?

I know it’s not on this sub-forum, but my C70 D3 manual won’t start unless the clutch is disengaged, at least if it’s been left in gear, as mine always is.

Got caught out by this on Friday, after about ten days idle.
I suspect the original battery want in a good way as it was showing under 12v about two months ago.

Any way, I was unable to jump start using the little audi as the battery for the XC90 is in the back and it's reversed up to the gates. With no user manual, I was unaware of the points in the front.
Called breakdown people, prepared the car for a krypton factor worthy assault course in through the front, clamber over the middle seat into the boot.
Mechanic turned up and proceeds to attach a series of batteries and jump starter packs, but only getting enough to power lights, not turn over. Calls a low loader to recover to a garage. Low loader turned up, he checks it and cranks it over using a hand held, put stupidly powerful booster.
My garage has rung me to say the reason for the battery being so crummy (now recording 3 volts) is because it's not charging off the alternator - some diode has gone.
On the upside, it's under warranty which has just paid for itself with the cost of this repair.

As an aside, the little audi appears to be electrically able to cope better with lockdown. Must be because it's less complicated (door activated solenoids for fuel flap? Really?!?)
I will now be alternating necessary journeys between both cars. Though short journeys will add the strain on dpf...swings and roundabouts.

Got caught out by this on Friday, after about ten days idle.
I suspect the original battery want in a good way as it was showing under 12v about two months ago.

Any way, I was unable to jump out using the little audio, as the battery for the XC90 is in the back. With no user manual, I was unaware of the points in the front.
Called breakdown people, prepared the car for a krypton factor worthy assault course in through the front, clamber over the middle seat into the boot.
Mechanic turned up and proceeds to attach a series of batteries and jump starter packs, but only getting enough to power lights, not turn over. Calls a low loader to recover to a garage. Low loader turned up, he checks it and cranks it over using a hand held, put stupidly powerful booster.
My garage has rung me to say the reason for the battery being so crummy (now recording 3 volts) is because it's not charging off the alternator - some diode has gone.
On the upside, it's under warranty which has just paid for itself with the cost of this repair.

As an aside, the little audi appears to be electrically able to cope better with lockdown. Must be because it's less complicated (door activated solenoids for fuel flap? Really?!?)
I will now be alternating necessary journeys between both cars. Though short journeys will add the strain on dpf...swings and roundabouts.