Setting Absortion Time and Voltage

[mgnat]

I love my 3-Step+ Regulator!

I just replaced a bank of three (3) 4D Lifeline AGMs with 4D Exide lead acid batteries wired in parallel , and I have several questions (besides when will the economy improve):

1. Absorption time setting:
a. How is the absorption time setting determined for a 540 AH lead acid battery bank?
b. How is the regulator set to the proper time using the set screw?

2. Using the Absorption Voltage Setting screw, I can't seem to get the Adsorption Voltage to "set" exactly where I want it - at 14.37 - 14.40 for 90
degrees F. It will "set" at either 14.36 or 14.45. I tried working the screw back and forth to elimiate a "flat spot" if one developed, but it didn't help. Should I select the higher or lower choice of setting, or should the screw give me the exact voltage I am looking for?

Many thanks for providing access to the Forums.

[Coulomb]

Absorption time depends on the charge rate, and how full you want to charge before shutting off the engine.

This may be helpful:
http://www.amplepower.com/primer/sarv3/index.html

There is little difference between either voltage that you get. Both seem high for AGM batteries given the temperature.

[mgnat]

Thank you, Coulomb. The new bateries are lead acid, not AGMs. The target voltages are taken from the 3-Step+ manual. I read the content at the link you provided. Thank you again. Is it corrct to assume that after the absorption time has expired based on the screw setting, the bateries will continue to charge below the gassing voltage and last longer? Thus on a long motoring leg, if I understood correctly, it would make sense to dial the absortion time DOWN? Assuming charging at anchor or on a 1-2 hour motoring leg, what would be a good target absorption time and how many turns of the screw starting from full-stop down (counterclockwise) would it take to get there?

[Coulomb]

The manual explains how to translate the voltage at the time test point into actual minutes.

For maximum battery life, spend as little time as necessary in absorption - just long enough to reach full. You don't have to do that every time, but once a week or there about. At other times getting close to full is OK.