Battery health question, and observation

[radarcontact]

Over the last few days I have hooked up a Schumacher Battery Charger to my car in preparation for a MHD flash. I never got to flash, but for this post that is a moot point, irrelevant.

OBSERVATION: when I hooked up the charger and set it to "%" the charger showed 68, 76, and 74% (hooked it up three separate days in a row, having driven it to/from work, 52 miles round trip, in between hook-ups). It took over an hour to charge to 100% each time on AGM mode.

QUESTION: is this normal, or do I start looking for a new battery?

note: I hooked up my battery tender to it this morning at 8:30am for a slow charge (0.75 amp rate)...it's 4:20pm now -- 8 hours -- and it's still charging.

// Radar //

[jtbgonesailing]

The IBS will charge the car to a 80-85% state of charge by design. How old is your AGM battery? There should be a sticker somewhere on the case or a date code stamped into one of the battery posts. Or if you have Carly code reader, you can see the last battery registration date.

[pshovest]

Sounds normal to me. Most chargers will continue to charge as long as they are hooked up. Now the charging rate will drop to 1-2 amps as the battery charge rises, but it never goes to zero. Nothing you have posted confirms a good or a bad battery. You don't need a 100% charge to reliably start your car. INPA reported my SOC as 39% and I had no difficulty starting. Check your battery voltage before starting after engine has been off for 6-8 hours. There are charts that show voltage vs % charge.