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Mark M · 09-05-2007, 02:19 PM

Just bought two Interstate U2200 6v batts to replace the original set of 12v in my '02 G37. Install was easy BTY, for those who want to make the switch. When I ordered them, I told my local tire/battery dealer, "make sure they're fresh". When I picked them up, the burned in stamp was A233N. I read on 'The 12 volt side of life' the first letter is the month, Jan, the second the year, 02. The dealer called the distrubitor. He told us to look on the lead, next to the post. Sure enough, there was a stamp in the lead, J7 (the code skips i). So I bought & installed them. Any shock heads know the real skinny on this dating stamp ? They did read 12.38v.

Thanks
Mark

Mark M · 09-05-2007, 02:19 PM

Just bought two Interstate U2200 6v batts to replace the original set of 12v in my '02 G37. Install was easy BTY, for those who want to make the switch. When I ordered them, I told my local tire/battery dealer, "make sure they're fresh". When I picked them up, the burned in stamp was A233N. I read on 'The 12 volt side of life' the first letter is the month, Jan, the second the year, 02. The dealer called the distrubitor. He told us to look on the lead, next to the post. Sure enough, there was a stamp in the lead, J7 (the code skips i). So I bought & installed them. Any shock heads know the real skinny on this dating stamp ? They did read 12.38v.

Thanks
Mark

John_Canfield · 09-06-2007, 12:31 PM

Hi Mark,

J7 sounds like the right date code. That would be September, 2007.

12.38 volts means they are about 60-70 percent charged. I use 12.3 volts as indicating approximately a 50 per cent charge assuming the battery is at rest (no loads/charging) for 24 hours. ~12.9 volts is about 100 percent charged.

The very best way to measure the state of charge is with a hydrometer measuring specific gravity.

Welcome to the forums

LK23 · 09-06-2007, 05:09 PM

In August, I bought three Trojan batteries for my coach. Each had the date code I-7, which I interpreted as September 2007. I called Trojan and the Trojan Rep said you just stumbled onto one of our secrets. Batteries are forward dated by 45 to 60 days, so a battery dated as September was probably manufactured in July or August.