Trojan t-105s customized charge setting .

pyana1pyana1 Solar Expert Posts: 39 ✭✭
Out of curiosity, what would happen if i customized my 4 trojan t-105s (tied in 12 volt) to absorp at 14.15 volts instead of the recommended 14.8 by manufacturer? I'd also customize the float to 13.7 as opposed to 13.5 by manufacturer .


  • BB.BB. Super Moderators, Administrators Posts: 31,684 admin
    Setting the absorb charge so low on a Solar Based charging system that is used daily--I would fear that the battery bank will end up chronically under charged. You will will also use less water.

    With limited hours of sun per day--For flooded cell batteries, you really need to crank up the charging current so that they can get all of the current available by the sun (forcing more time in Bulk charging and higher average charging current during absorb).

    If the system is "floating" on utility power (24x7) and used only in emergencies, dropping the absorb/charging voltage can cause the batteries to use less water... But you also may have stratification issues too (no enough "bubbling" to stir the electrolyte).

    If you want the batteries to last longer--Keep them cool. For every 10C you drop (from ~25C room temperature), you will get ~2x the storage life out of the batteries.

    We have some Canadian members here that seem to get upwards of 2x longer life in their batteries that are near or below freezing for 3-5 months of the year.

    In the end--Batteries age and batteries "wear out" from cycling. It is the nature of the beast. Use them as needed.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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