Battery charger settings

[oceanjake]

I’m installing a new battery charger now. The charger has settings for agm/gel and lead acid. It also has settings for 3-stage charging or 13.25 constant. My problem is I have one bank agm and the other two are lead acid. Which settings should I choose for now? And why?

[wpc691]

I’m installing a new battery charger now. The charger has settings for agm/gel and lead acid. It also has settings for 3-stage charging or 13.25 constant. My problem is I have one bank agm and the other two are lead acid. Which settings should I choose for now? And why?

Mix-n-match on a charger is a bad idea. You need separate chargers for the AGM and FLA.

[Scarlett]

AGM batteries use a higher bulk charging voltage than lead acid and can take a bit higher float voltage also. Lead acid bulk around 14.4 give or take a couple of tenths while AGM are 14.6 give or take a couple tenths, so if you set the charger to the lead acid setting you will undercharge the AGM batts a little at bulk. At float they are close enough that it doesn’t matter much. John

[oceanjake]

Thank you for the replies. Clearly I know it’s best not to mix battery types across banks. Not my setup...I inherited this last year. The agm in question is from 2013 and the other two banks have new batteries this year. I would prefer to kill the agm if anything and replace with a fresh flooded 8d when that happens. I set the charger for lead acid and constant 13.25 for now. Seems to be working well in supplying my bridge electronics.