AGM BATTERY - THE ARMY USES WILL KEEP MY G37 GOING!

[PHX08G37]

I live in Phoenix, AZ. I've got batteries from Infiniti Dealerships; that I replaced (under warranty) every two years. Frustrated, my service advisor said, "he could put in a battery that will last longer because it is an AGM battery that the ARMY uses in their vehicles that sit for long periods of time. The AGM battery didn't even make it two years!

Anyway, after an Infiniti Dealership installed a new AGM battery, later that night I went out to check out the new battery and started up the G37 and heard a quite high-pitched squeal/noise, almost couldn't hear it at first, coming from the engine's passenger side under the hood which slowly got noticeably louder.

I researched the noise, and a possible reason was the battery was not fully charged. You ever heard of such a thing? : confused:

Thx, Gloria

[VStar650CL]

Alternators all whine when they're working hard, and they're supposed to work hard right after startup (the starter motor depletes a lot of battery energy). That's normal. Your batteries dying every two years isn't. Chances are you have a case of your "smart charging system" getting stupid, which is undercharging your battery and eventually killing it. Sadly, it's a common problem on every Nissan/Infiniti model that uses smart charge. Using an AGM battery only exacerbates the situation, because AGM's have a "death zone" around 12.8V where they self-destruct. When the smart systems malfunction, they often drop into the high 12's ~ low 13's, right in the heart of the death zone. What you need to do (or have done) is clip the "smart" control wire between the IPDM and the alternator, it's a Yellow wire on pin 76 of the IPDM. Just sever it and tape or cover both ends. That will put your alternator on internal governance, so it will output 14.0~14.5V all the time.

[PHX08G37]

Wow, that's a great reply diagram and all! I did not know about the smart start system - I guess neither did the dealership! I'll try it.

Thanks, VStar650CL.

Gloria

PS - I got a giggle out of your Darwin statement, it makes you think.

[VStar650CL]

You're most welcome. The dealerships know about it but they won't generally do it for you. Even out of warranty, Corporate will frown on it because technically it's affecting fuel mileage and thus indirectly affecting emissions. There's only one vehicle series we're secretly allowed to do it on, Y62 Armadas and Z62 QX80's (and even then we're supposed to report it to our FOM or TSM). Those were designed with such big batteries that the smart charge destroys them just from being driven infrequently or for lots of short trips, and I guess Engineering decided there was no other good fix.