E Z Peaces wrote:
ransley wrote:

Years ago I got a "great" charger, only to find out many years later
it was never calibrated to charge 100% or went out of calibration, My
batteries never lasted or turned over the car when -20f. One day after
learning about what 100% charge is I luckily inside found a screw that
adjusted the voltage up. I think most new units are computer chip and
probably unadjustable. Not having a battery maintainer has ruined many
batteries for me.

I think the screw was for temperature compensation. At -20F, a typical
battery may require 16V. At 30F it may require 15V and at 110F, 13V.
Chargers and regulators used to be set manually, taking the estimated
temperature into account.

Use a hydrometer to check the specific gravity
of the electrolyte in a lead acid battery if
it's one that you can open. Some batteries
actually have a little indicator that turns green
when the specific gravity is within the proper range.

TDD