There are two Kem Battery places less than a quarter mile apart. The one that's more West of the other is run by Sarkis, a guy who has bad customer service and over-charges on batteries. I was quoted $35 for a Mercedes battery with a core. The core I provided was a first-rate Varta battery sold by Mercedes for over $275. The battery had just gone bad over the years and I decided to go with a used one rather than forking over serious loot for a battery that would give me a good seven years of service.
Kem Battery West wanted $55 for a Mercedes battery, including a core. I looked at the AC Delco battery he offered me, and it looked good and passed the battery test machine (although I know better than to trust one battery tester--you need three different tests to determine the quality of a battery).
I decided to see if the other Kem Battery East was still there. Guess what, the original location was still there and still running. I walked up to the bench and the Mexican dude who worked there found me an AGM battery for my Mercedes. As you know AGM batteries are much better, last longer, and are maintenance-free. He gave me a near-new looking AGM battery in the correct group size for my car, for $30 including core, and he also gave me a 6-month warranty. A warranty I won't be needing, because I daily drive the Mercedes that this battery is going into, and it will be constantly re-charged from driving.
The only reason I gave up on that Varta battery I traded in, was because every home-brew method of recharging didn't work. I used my trusty Schumacher Battery Extender (one of the best rechargers on the market right now) on this battery for over week, doing the disconnect/reconnect method over and over. The best I could do was get it to charge to about 25% of its capacity. Not even Kragen/O'Reilly's professional heavy-duty recharger/tester could bring this battery back to life. So it was time to replace it.
At any rate, my newer Mercedes is running perfectly with the near-new AGM battery supplied to me by Kem battery. Remember that places like this will at first always try to give you the battery that they 'touch the first' in the correct group size. I had a group 49 battery, and so the first one they could find in their inventory, they brought it out to me. Don't be afraid to tell these folks that the battery they show you, just doesn't look new or doesn't look good. Tell them to show you another and another, until you see one that looks new. Then have them do a load test on it.
Like I said before the load test is not a sure-fire way to know if a battery is good, but these guys do provide that 6-month warranty. You can't expect a used battery to last more than two years though, unless you daily drive the car or put it on a float-charger. If you have a lot of cars, and you don't drive some of them, you need to be float-charging the batteries to maintain the charge. The model and brand I recommended above is the best for that job.
And for $30 plus your old battery, you can't beat that price for an AGM battery. Look up AGM versus Lead-Acid batteries and decide what's best for your car, then ask a place like this if they can hook you up with an AGM battery. Although AGM's cost much more brand new, to a place like this, a battery is a battery is a battery, and they won't charge you more (until they catch on to that fact)
PS. I used to go to 'The Battery Station' in Sun Valley prior to going to Kem Battery. Now Battery Station charges $45 for their batteries including core, and the owner is a mean, mean guy you want to avoid. read more