Any reason to not switch to AGM?

[Carmudgeon]

I think the choice depends on several factors:
1) Do you like a truly "maintenance free" battery that never needs fluid checks?
2) Do you never want to deal with the risk of corroded or crusty terminals?
3) Did the car come with AGM originally, is the charging profile optimized for it?
4) Do you daily drive the car? (that tends to lean toward flooded for a car that came with flooded)
5) If the car is a rarely driven car, then alternator charging profile probably has less impact, since it will be on a battery tender more than being charged by the cars alternator.
6) Budget, is the $50 or $70 going to break the bank?

I'm liking AGMs more and more, after going through a couple flooded East Penn batteries in my old daily driven BMW (2001) in short order. I have a AC Delco "made in germany" AGM now for four years, and still tests great on my load tester, exceeding its rating. I'm not finding the charging issue to be a big deal...I wonder if it really is. I noted that Consumer Reports in their testing, like AGMs and discuss their typical better performance and life. Though there are still some excellent performing flooded batteries, but depends on what size or application. They never mention the potential shorter life of AGM if charging profile is not optimal.

1) I've been told by a battery distributor, and concur, there is no such thing. Unfortunately, many modern battery cases don't have easily removable caps, and/or have ports covered by stickers, clearly intended never to be cracked open.

2) Not an issue. Vented trunk mount.

3) Nope.

4) It can sit for 1, 2, 3 days at a time, before mostly in town duty.

6) Nope.

I've considered the AGM question before, and now EFB, but it's not difficult to reach the same conclusion. Given the application, plus the fact that FLAs have served 6-7 year terms in the car with no issues, and such usage, I find it hard to justify the additional 50% cost of jumping from a $120 FLA to the $180 AGM battery. Or more, outside of a Costco or Walmart.

Exide, or their new parent, seem to be only one pushing EFBs in the U.S. currently, and the H6 I'd need is $230 with a Duralast label, or $220 with an Interstate label. The one with the Exide Marathon label seems to be only available through distributors, or as a catalog part, and that comes at the cost of convenience, if not price as well.

Clarios provides more information on the benefits of EFBs on thier site, mainly more cycles and better suitability to deeper cycling, targeting stop/start applications, but they also seem to have their own charging preferences, which merit further investigation.

At this point, a Duralast H6 AGM is only $10 more than the EFB, so whatever cost benefit they may have in Europe doesn't apply here, and given the other advantages AGMs have, particularly in newer applications, there's little incentive to refuse that option instead.

While EFB would seem to be a really good fit for me, the cost/benefit ratio isn't there yet, and may never be, unless the OEMs equip more vehicles here with them, and create a larger and more competitive aftermarket demand for them.

For now, neither pencils out for me, but as they say, YMMV.

 

[2strokeNorthstar]

Just replaced my agm bought in 6/2015 , it didn't get that memo. Still cranked fine but cca was getting low according to the tester.
2012 Toyota Sienna oem battery was wet cell.

Error. Disregard

 

[Y_K]

One of the advantages of EFB over AGM is better thermal stability, i.e. EFB will live longer in hot states.

 

[The Critic]

One of the advantages of EFB over AGM is better thermal stability, i.e. EFB will live longer in hot states.

Plus supposedly not requiring different charging methodology.

 

[RAR]

My Jeep came with a factory AGM but I think that’s due to the stop/start feature it has (and that annoys some people; I’m indifferent to it).

I put an AGM into my Mini last year with no issues. Mine does not have a battery sensor or other electronic monitoring system for the battery, just a set of connectors. So there no battery reset required. I’ve had excellent performance from that AGM, starting in very cold temperatures without problems. It’s an FVP I got off RockAuto when they blew them out for $86 per battery, sized Group 48 / H6. Some on here will clutch their pearls over FVP, but it’s not their car or cash, and I’m not selling it to them .

Just like the “awful” Exide Group 49 in my Charger. I put that in two years back and all it does it keep starting that car without a hitch. I don’t worry about it failing. It’s not AGM, but some people might think it’s bound to fail just because it’s Exide.

Bottom line: if you want to use an AGM, go ahead (all those months later, and anyone else considering it). Your car, your money, your peace of mind. Just be sure if it needs programming that you get it done with a proper scan tool or a dealer.

That’s my experience.

 

[slomo]

Main reason NOT to switch to AGM is your vehicle might of not came out factory with one.

All these new battery chemistries require different charging algorithms to charge properly and not boil the electrolyte out.

Other than that I love the fact the terminals don't corrode from leaking acid. Off road vehicles like Jeeps, these AGM's are a must.

 

[wings&wheels]

Just to add my experience;

I switched to AGM's in the fun fleet starting in ~2006. So far I've gotten 10 years out of the AGM in the '74 Triumph (replaced due to the effects of an internally shorted starter, 7 years so far on replacement), and 9 years (so far) out of the '99 911. The AGM in the '72 Land Rover (granted w/ a higher output alternator...maybe 50amp) is coming up on 8 years. All are still performing well, and I will say that for my usage profile of fair-weather use and ~5-6 mos storage AGM's have lasted longer than FLA's.

 

[mr_boring]

My H6 760 CCA battery still tests well above 800 CCA every time. It's 5 years old and I live in a hot state.

Battery tenders/minders are your friend.

I turned off the BMS in my F150.

 

[JHZR2]

I'm sure battery manufacturers took this into consideration.

I’m not sure how you can unless one doped the chemistry to somehow have marginally different voltages. But that’s a tenth of a volt or less.

I think the flip side is that the battery just won’t charge as fast (you’re still providing an overpotential). And since the impedance is lower, side reactions and self discharge are slower, the performance for starting stays high for a long time. If you formally tested impedance and capacity, it may not be great, but it works because of the overall AGM performance.

 

[SubieRubyRoo]

There is no way that your vehicle runs for any period of time at 12.4-12.6VDC. 12.6VDC isn’t full-charge voltage. The only time I see this is when driving after the battery has been on a charger and fully charged. Otherwise, the voltage should be 14+ VDC or at least in the 13s for a proper float voltage.

The F150, and a few Audi/BMW/MB rentals I have, absolutely “idle” the alternator into the mid-12s voltage to maximize mileage. If you are on the ForScan site, they’ve actually found the ECM/BCM codes that control this, and you can increase the factory programming from the 80% charge that the OEM programs to, but you will have a negative impact on mileage due to higher duty cycles.

The Germans show this on the instantaneous readout with the charge/battery mileage indicator; if you coast it will up the commanded charge some to offer some “engine” braking, and if you gently press the brakes it will send the alternator into max charge state to help slow the vehicle. The F150 doesn’t really indicate this to the user, but the in-depth forums document the charging scheme and how it’s tuned to maximize mileage, NOT battery health.