I did a baseline measurement of the battery voltage on my 2014 & 2003 5.4L
(measured at battery posts)
both batteries are about 1.5 years old - top quality - 850CCA (OEM old style, flooded)
both Expo's have been driven under various conditions over past month
I like to do this periodically, to check the health of the system … see how it changes over time … and have an idea what to expect as normal if "things go wrong".
resting (no headlights) 2003=12.4 2014=12.2
resting (headlights) 2003=11.9 2014=11.7
starting (no headlights) 2003=10.3 2014=10.1
running (no headlights) 2003=14.3 2014=14.6
running (headlights) 2003=14.2 2014=14.6
I did my annual battery health check today. 2003 & 2014 Expy's
I would rather know how the battery/charging system is doing, than have it be a surprise.
2003 is daily driver, 2014 sits around a lot this year due to COVID
resting (no headlights) 2003=12.0 2014=11.97
starting voltage drops to 2003=9.4 2014=9.9
running (no headlights) 2003=14.6 2014=14.6
running (headlights) 2003=14.6 2014=14.6
update 1/21:
I put the Battery Tender on the 2014 and let it cook overnight. It charged up to 12.6V. Last year I put the 5amp trickle charger on it and it went up to 13.4V. I dunno if the difference is Tender vs Charger or if the battery (being 3 years old) is just starting to have reduced capacity and that shows up in the max voltage. I think I'll let it rest for a day, see where it ends up and then maybe do a run with Trickle Charger and see what happens there.
I put the Battery Tender on the 2003 for 7 hours and it charged it up to 12.6V. Will let it rest for a day (may drive it) and measure again.
I think I may put the Schumacher 6A trickle charger on both these batteries in a couple days, fully charge and see what I can get out of that.