AGM Battery - anyone tried one?

[maturin23]

Hi all,

My 3.6 996 needs a new battery.

Previous owner had installed a Bosch S3 007 which has always seemed a little underpowered and now after some short journeys and cold starts it's given up the ghost.
Gave me a chance to use my Guluman booster pack (which worked faultlessly) - but that's another story...

I've been exploring some options - had narrowed it down to a Varta F18 (85ah 800cca) but the company I've used before (who've given great customer service in the past) have recommended this - https://advancedbatterysupplies.co.uk/product/adva...

Apparently it's based on relatively new battery technology (Absorbent Glass Mat) which is often used on cars with start-stop systems. It's about £15 more expensive than the Varta, so nothing in the grand scheme of things and has a 5 year warranty.

Any thoughts?

[Bennachie]

all new pork have agm batteries, from about 2012. Tech is not new...............

[maturin23]

Thanks Bennachie.

My 996 is positively ancient and didn't have one of these from new. The fact that more recent Porsches are fitted with these types of battery I suppose is an indication that the advice I was given was sound.

Edited by maturin23 on Monday 23 January 15:52

[Steve Baker]

I would check that the charging system on a 996 will not harm an AGM battery in any way. Modern vehicles do have brake regeneration etc which is what enhances the newer tech.

Edited by Steve Baker on Tuesday 24th January 08:27

[s999sws]

The alternator need to be designed to charge up to about 15 volts for the AGM battery. If it's not the correct one you will only get about 14.2 volts or so, and it won't be charging correctly.
Steve WS

[anonymous-user]

Just get the highest CCA Bosch S5 - more than up to the job.

[Green1man]

Yeh the issue you will have is that AGM batteries should be charged at a higher voltage, so your existing alternator/electronics whilst it may charge the AGM it will not charge it fully or efficiently.

AGM batteries in theory should be more capable of taking deeper discharges and providing high cold crank amps, but not 100% convinced myself.

In your position I would stick with a decent standard battery, and if you don't drive much then top it up with a smart charger every so often.