986 AGM Replacement Battery Exact Fit
 

NAPA The Legend Premium AGM Battery BCI No. 94R 800 A Glass Mat, was a perfect fit for my 2000 S. US Made.

Any AGM 94R/H7 should fit. I went with a Bosch version that Pep Boys carries.

Hi,

I've seen 110 (317mm width) and 096 batteries (278mm width) fit the 986s. You just move the clamp positions of which there is 3!. Just wondering if the 027 battery fits with the 3rd clamp position? 027 is 253mm in width. I have seen people fit the odyssey PC680 which is only 280cc I believe surely a 027 batter would be OK? I don't mind not having a large capacity as I am thinking to add an isolation switch anyway. I do hope that without the switch it could last a few weeks.

I think the three clamp positions correspond to H6, H7, and H8.

I’ve got a DEKA H7 AGM

Check that the "outermost" position on the battery mount is threaded. My 987 has a hole for the H8, but it wasn't threaded and needed some work to make it usable (pain in the butt, worried me about scratching the paint, and ending up with rust eventually.......)

-Eric
99 986
09 Cayman S

Sorry to Hi-jack this thread..But I have a AGM battery thats dead..can they be recharged from dead, I put my charger on it and it just shuts off after a few minuets shows about 4 volts when it check's the battery...?? Thanks Frank

I have had some luck by charging them while also having a second (good) battery hooked up to boost the voltage.

Here: https://grassrootsmotorsports.com/forum/tech-tips/reviving-an-old-battery/73611/page1/

It also helps to use a charger/maintainer that specifically was designed/built to charge AGM batteries .

Thanks Guys I have a diehard charger that has the AGM setting and it still shuts off maybe I will change the power setting and bump it up some it was on the lowest setting.. Thanks Frank

Optima has just introduced its battery in H7 size.

AGM battery charging
 

Typically, to recharge a deeply-discharged AGM battery, you’ll need a fully-charged battery of the same voltage, connected in parallel, NOT IN SERIES, i.e. negative to negative, positive to positive with jumper cables, then connect charger. This way the charger ‘sees’ approximately 12 volts so the safety circuit doesn’t trip it out and stop charging.
Better yet: old-fashioned charger with no fancy-@ssed safety circuit.
Darn newfangled gadgets…