Battery upgrade

Think of a battery as a [water] reservoir, the size of the reservoir determines how much water it can hold (capacity) and the more water it can hold the bigger the flow when you need it (starting current).

If the reservoir is filled by a large river, it will fill up much faster than if it is filled by a hosepipe, think of this as your alternator.

A larger battery will take longer to charge from your alternator, but will not damage the alternator or the charging system. If you start off with the battery fully charged (charge it in the garage first) then it will not go flat as quickly as the smaller one, especially if you don't use your Jimny much in lockdown.

I should have fitted a bigger battery last year when mine apparently died, but it had just got very discharged in lockdown when I didn't use the vehicle and didn't initially want to re-charge. Now I have two, both 45Ahr, but a spare is always handy, even if it isn't as good.