New Battery: AGM vs. Wet
 

Hey gang,

The battery in my TL is on it's last legs (no idea how old it is, it was in the car when I bought it 25 months ago); my plan all along has been to throw a new AGM 24F battery into it and call it a day. Prior to pulling the trigger on the new battery, I thought I'd do a little research, and said research has given me pause.

• Per my research, relatively late model cars have circuitry to prevent overcharging AGM batteries, the 3G TLs have no such safeguards.
• When an AGM battery is overcharged, and once the hydrogen catalyst has been consumed, overcharging will end the life of the battery in pretty short order.
• As a general rule, AGM batteries are pretty good plug in replacements for flooded lead acid batteries, but only for cars which make a lot of short trips.
• When an AGM battery is used in a car not designed for that type of battery, the battery will typically have a very short life if the car it is in does lots of long-distance highway driving.

Given I do a lot of highway driving, say 10-12 trips of 20+ miles per week, I am concerned if I opt for an AGM battery, I'll destroy it in a matter of a few months. With that in mind, I have a few questions for the collective here:

• Should I simply stop overthinking it and put a wet battery in?
• Is there a relatively easy way to enhance the Honda charging systems of the early to mid 2000s to play nice with an AGM battery?
• And most importantly, for those of y'all who've already taken the plunge into the AGM world, what has your experience been?

Those are all good questions that I don't know the answer to. What I do know is you need a special battery charger for those batteries. IDK if you already have a charger for one though. I'd probably put a standard wet type battery in it, and not worry about it too much. Batteries are kind of fickle these days, as they don't last as long as they used to. About 7 to 9 years is about the max any more for a good one.

Thanks, I pretty much came to the same conclusion. I ended up going with an EverStart Maxx 700CCA battery in Group 24R size from Walmart; they had them marked down to $93.76; the car is much better now. :)

Funny thing, I picked the car up from the airport yesterday after sitting for a couple of days and the old battery just managed to get the car started; same story this morning. When I got to Walmart after over a half-hour of driving, I went in and asked for a new battery. "Don't you want us to test it and the rest of your charging system first?" "No," I said, "it's definitely the battery."

The technician took my keys out and then came back in after a few minutes, "We need to jump start your car, the battery is totally deal."

Sounds like you got the last start out of it, and picked the right place to shut it off. :D Yes, it definitely sounds like the battery died.

"Timing," as the old sage once said, "is everything." :p

AGM in my Saab but the car has circuits for that.

One really annoying thing is exactly that "protection" circuit. If the battery voltage falls too low during starting, it disconnects. That effectively removes the ability to get "one last weak start" out of the battery. And removes the warning that you get from the starting current getting weaker.

One more argument for 3 pedals. Saved the day when the battery died in a parking deck 300 miles from home. Car was pointed uphill, so I just let it roll back & popped the clutch...

I think every 3-Pedal car my wife and I have had which was manufactured since roughly 1998 (a total of 6 cars) all have language in the Owner's Manual suggesting starting the car by rolling it and popping the clutch was discouraged. Silly me, I still do it and it still works well. :)

Dad used to do that on our driveway (hill) ever since … well forever. The car company lawyers didn't find out and the world hasn't come to an end.

Yup, I had that happen in a gas station in St.Louis on my way back from Texas years ago. I pushed the car up the hill (leaning into the door post and walking backwards), got a running start and popped the clutch. It fired right up and I continued on my journey. When I stopped for a few hours outside Indy, I made sure I backed into a parking spot with a hill in case I needed to do it again (I didn't).