I have queried "East Penn Batteries" with the questions below. I will advise as to their response.
FLOAT CURRENT DEGRADATION
These are questions concerning GC10 215 AH FLA batteries.
(1) Assuming a reasonable absorb time, once given a float voltage of 2.35 vpc, the float current should eventually stabilize @ approx 450ma (for a very healthy battery). SOC=100% TRUE?
(2) If the stabilized float current is above 450ma it is an indication that the battery can no longer achieve 100% SOC. TRUE?
(3) Is it possible to assign approximate numbers to question (2) ? IE 600ma = 95% SOC 900ma = 90% SOC
Thank you for your consideration
Barry Fields
Lettuce know what they say
Unfortunately I had to correct myself. Updated email questions below.
On further thought, I believe that I should rephrase questions 2 & 3.
(1) Assuming a reasonable absorb time, once given a float voltage of 2.35 vpc, the float current should eventually stabilize @ approx 450ma (for a very healthy battery). SOC=100% TRUE?
(2) If the stabilized float current is above 450ma it is an indication that the battery no longer has 100% of it,s original AH capacity. TRUE?
(3) Is it possible to assign approximate numbers to question (2) ? IE 600ma = 95%AH capacity 900ma = 90% AH capacity
(4) In a parallel battery bank, the bank with reduced AH capacity would achieve 100%SOC (with reduced capacity). ????
(5) That battery would contribute less amperage to the total bank discharge currents and probably require more current in the charge cycle. (efficiency degradation) ???
Answers from East Penn
(1) Assuming a reasonable absorb time, once given a float voltage of 2.35 vpc, the float current should eventually stabilize @ approx. 450ma (for a very healthy battery). SOC=100% TRUE? True
(2) If the stabilized float current is above 450ma it is an indication that the battery no longer has 100% of its original AH capacity. TRUE?
The stabilizing current of the GC10 will increase as the battery ages. When the battery is new the stabilizing current will be 450mA. Unfortunately, the rate at which the current increase over time is not linear. The rate of stabilizing current increase is affected by ambient temperature and usage (# of cycles & DoD of each cycle). Taking specific gravity readings is the best way to verify the batteries are fully charged. Page 5 of the attached I&O manual details the ratio of specific gravity to SOC (state of charge).
(3) Is it possible to assign approximate numbers to question (2) ? IE 600ma = 95%AH capacity 900ma = 90% AH capacity
Unfortunately, the charge current can not be used to determine SOC of the battery for reasons stated in the above response. Specific gravity reading are the only way to get an accurate SOC.
(4) In a parallel battery bank, the bank with reduced AH capacity would achieve 100%SOC (with reduced capacity). ????
Correct
(5) That battery would contribute less amperage to the total bank discharge currents and probably require more current in the charge cycle. (efficiency degradation) ???
Correct