And as I don't have a charger, what is best to do? A long drive?

Wpoll already gave you the best advice, get a battery charger. The second best advice will be not to charge the dead battery with the car alternator. A car alternator is meant to just keep the battery in a good state of charge. An alternator was never meant to charge a dead battery. You will ruin the alternator if you try to charge a dead battery.

+1 to what UAN said - a long drive *might* do it but long is something like 1,000-1,500kms. And yeah, you risk cooking your alternator.

Grab yourself something like this...

SCA Smart Battery Charger - 3 Stage, 12 Volt, 4 Amp - Supercheap Auto

or better...

SCA Battery Charger - 7 Stage, 12 Volt, 15 Amp - Supercheap Auto

But how do I know the battery isn't already dead?

The chargers listed are expensive, wouldn't a new battery cost almost the same?

Will a generic trickle charger on ebay also helpg?

Any chance this will help? I have one Fishing Monthly Magazines : Powertech 5-in-1 Power Station

You can get the battery load tested, either at a battery shop or you can test it yourself.

https://www.topmaq.co.nz/shop/automo...y-load-tester/

But to load test it you must first fully charge it... catch-22. :D

A new battery in a LOT more than $170 over here - more like nearly $400 - it's a BIG battery!!

BTW, an $85 charger is nothing in the world of BMW ownership - it's just the tip of the iceberg. I spend nearly ten times that on servicing every 10,000kms.....

Yes - most will work fine. Will take a long time to charge though - like a week.

Nope - that's not a charger, just a power source.

Ok, so would this work to save my battery? https://www.ebay.com.au/itm/400932548399

Or do I need specific amps? I don't care if it takes a week to charge, not in a rush

That looks like it will do nicely.

Connect it to the jump terminals under the hood (bonnet) then plug it into the mains (230v). Leave it overnight. Job done. :thumbup:

Certainly, you can pay $400 for a battery and maybe that's the cost of a battery in Australia. Shop for batteries with same or greater ratings than OE. Doesn't have to be a BMW battery.
I'm all for having the right tools/equipment but I remember times when I couldn't afford to make those purchases and had to find other ways to address the problem.

I recall a time when jumper cables had to do. However, as soon as 'tools' like a battery charger and tester fit the budget it is one of best DIY investments. In my experience the low end chargers are not a value. They fail quickly and lack important features. My suggestion is to buy as close to state of the art as you can afford or don't buy one. Higher end chargers do all the testing and types of charging you will ever need. Another option is to just purchase a full featured tester and a good set of jumper cables. Determining if a battery is failing rather than charging it and hoping you don't get stranded is worthwhile to consider as the first step.

If you charge the battery with the alternator it will not burn out the alternator and after about 30 minutes idling with everything turned off and verifying by unlocking the cluster that the alternator is putting out around 14 amps the battery should be charged enough to start the engine without a problem. Then, if you don't drive short distances all the time, like 5 miles with most of what is draw on the battery on, you will be fine if battery is good. As mentioned, first step is to get the battery load tested.

Just make sure that unless its a trickle charger don't leave the charger on the battery for more than a day. Left on long enough will boil the acid right out of it. Even modern "smart" chargers will fry one eventually if they are normal battery chargers.