You would want an MXS 7.0 minimum to recondition a discharged battery. I saw the Optima Rep on a Youtube video use the Ctek 7.0 so that's what I bought. It does everything I need it to do. Its fully automatic, reconditions, and even acts as a power supply. It charges fairly quickly too. A 10 Amp would be the best all round charger but it was a bit more expensive than the 7.0 at the time at over $200.
You can pick up a MXS 10 these days for the price that I paid for my 7 back in May 2013.
They are on sale on Ebay right now for a limited time only at $149 delivered!!! That's a frikken bargain! Aussie seller too. http://www.ebay.com....=item258136618a
I used to have a low amp trickle charger before (think it was 1A or something) and it was good for keeping the battery topped up when the battery was in good condition. But sooner or later you'll find yourself having to charge up a discharged battery. Whether it be your AGM, GEL or your everyday wet type battery, you will end up needing a decent Amp battery charger with a bit more grunt to kickstart your battery back to life. This is why its good to have a charger that can do all types of different batteries and provide good amperage. A small amp trickle charger is good for its sole intended purpose as maintaining the battery's charge, but unfortunately they wont rescue an Optima battery that's been discharged under a certain amount of volts. If you try to charge a discharged battery it can take days on a low amp charger (if it can rescue it) and that's no fun if you need your car on the road quick. That's when you need the recondition mode on a Ctek charger with minimum 7 Amps. If I were to buy another Ctek tomorrow, I'd get myself a 10A which I think is the maximum rated charger that Optima recommend for their batteries. It will charge a battery within a few hours, or if you want you can leave it overnight and be guaranteed the battery is fully charged ready for hitting the track the next morning.
Edited by EVO-00X, 28 November 2013 - 11:02 AM.