How to recharge my car battery after it died?

Either your battery is now defective and won't accept a charge, or there is something wrong with the alternator.

After jumping it, you need to run the engine for about 30 to 45 minutes so the battery recharges. If you are not doing this, it won't be charged enough the next time you try to start it.

If you are doing this, see the suggestions in Roger's post above.

Check the water.

A faulty alternator Epp is indicated by a low current reading during drive. Too bad if you have "modern" car with no ammeter

Another likely culprit is a surreptitious load; say, something plugged in the cig lighter jack

Thanks Izzy, good one. But Epp the newer vehicle might also lack temp gage

I had an old banger that had to be put on charge every night during the winter.