Is a higher Amp Charger quicker to charge a 12v battery?

Those numbers don't make sense. A 10 ampere-hour battery should charge in a bit under one hour at 12 amperes (perhaps slightly more due to loss). Did you mean 100 Ah? If not, something is seriously wrong with your setup.

The charge rate depends on the charging voltage, not the maximum available current. A higher current rated charger has a higher charging voltage, as well. The battery's temperature also affects the charge rate.

Keep in mind that the faster you try to charge a lead acid battery, the more Hydrogen it will release, and more heat will be generated. Push it too far and you'll have lead and sulfuric acid all over the place, along with a Hydrogen fueled fireball. Find the charge rate recommended by the battery OEM and stick to it.

Probably but...

In theory a _constant_ 12 amps should charge a 10AH battery in around 10/12 hours or about 50 mins. A constant 22 Amps should take 10/22 hours = 27 mins. The problem is that as the battery voltage rises the charger reduces the current it delivers to the battery. That (and losses) is why the existing charger is taking much longer than 50 mins. The two chargers might _average_ similar charge rates. It all depends how the regulator inside each works. You won't really know how much faster until you try it. You might expect to see most improvement if the battery is put on charge very flat - eg the first half of the charge is improved by switching to the bigger charger. The last 25% to full will probably still take the same amount of time.

One trick might be to use a 20AH battery, charge it for the 4 hours you have available and use it with however much is in there (even if not full). This might work because the first 50% of the charge (eg 10Ah) will go in faster than the last 50%. The problem is that lead acid don't like being deep discharged. They don't live as long as when they are kept full or nearly full.

Have you considered switching to NiMH cells? You could fast charge those much quicker than lead acid and they are happy being deep discharged. Depending on the application you might get better performance out of a

Nothing wrong with his numbers. A 12A lead acid charger does not deliver a constant 12A to the battery. That's just the maximium it can deliver.

Thanks everyone for your replies.

I think I may just have to be more patient :-)

Regards

Dave