In the cold: hard start then runs great. Topic is solved

[mrbrian200]

Is the charging system compatible with AGM on these? It's my understanding charge loads and voltage have to be regulated differently for AGM otherwise the battery life is likely to be reduced. Installing a standard acid battery in a car OE with AGM can cause issues: friend with a F.Focus OE with AGM tried installing a standard battery and the ALT/Battery warning lit on the cluster until he took it back and bought the AGM. He couldn't figure out why the light was on and asked me for help. After discovering the OE battery was AGM I did a pretty thorough net dig regarding AGM batteries and convinced him to spend a little more for the correct battery type. The light went off. Aftermarket battery suppliers don't seem to volunteer this info. probably because it's an upsell, and somewhat shortened life probably doesn't result in many warranty claims as most people don't keep track of the exact date and/or don't hold onto vehicles that long.

[JPM]

Unknown. It came with the car when I bought it in February. Volvo branded, no discernable date code...

[JPM]

Is the charging system compatible with AGM on these?

My poorly qualified understanding is this:

1) AGM batteries require more careful charging voltage regulation than standard wet cells. For example, I've read in several places that magneto-type power generation, like from a lawn mower or outboard motor, doesn't likely have voltage regulation, so can reach near 20V. That would be especially bad for an AGM.

2)They work better when charged at higher voltages, like 15v instead of 14.4.

All that said, I used several battery finder services and they all offered AGM as possible upgrade. I think the odds of being duped are pretty low but time will tell...