Trojan L16 Battery issues

Assuming that you are using distilled water (or filtered rain water after a the first showers have cleaned the roof), you have clean/tight terminals, good cables, and are monitoring SG over time...

Yes, there have been a few people here that have seen their FLA batteries seemed to be positionally sensitive in series strings.... And they have addressed this by "rotating positions" of the batteries once a year. (I have no idea why this was happening to them--No obvious environmental issues such as batteries next to windows/hot engine/etc.).

I always like to go back to basics... And see what the charging current is. Typically 10% to 13% rate of charge is probably optimum for FLA batteries. 5% can work for weekend/emergency backup. And >13% (to 20% or 25% max) can work (highly suggest a remote battery temperature sensor to keep the bank from overheating).

Also, confirm that the solar array is wired for Vmp~60 volts "optimum" minimum for your 24 volt battery bank. And your array is mostly in the sun without ANY significant shading during most of the day.

Don't know what your existing array wattage is, but based on rate of charge, the suggested array sizes would be:

• 3 * 370 * 29.0 volts charging (4 series * 3 parallel strings of batteries) * 1/0.77 panel+controller deratings * 0.05 rate of charge = 2,090 Watt array minimum
• 3 * 370 * 29.0 volts charging (4 series * 3 parallel strings of batteries) * 1/0.77 panel+controller deratings * 0.10 rate of charge = 4,181 Watt array suggested Full time off grid minimum array
• 3 * 370 * 29.0 volts charging (4 series * 3 parallel strings of batteries) * 1/0.77 panel+controller deratings * 0.13 rate of charge =5,635 Watt array typical cost effective maximum array
• 3 * 370 * 29.0 volts charging (4 series * 3 parallel strings of batteries) * 1/0.77 panel+controller deratings * 0.20 rate of charge = 8,361 Watt array near maximum array

Don't know what your daily loads are (by season), or where the system is installed (near Denver?)... What is your typical discharge cycle (discharge often below 50% or below 20% State of Charge)? Or do you shallow discharge a lot (less than 10% or so discharge)?

Not that this would help the batteries--But this is a pretty large battery bank (1,110 AH @ 24 volts)... Even a 10% rate of charge is 111 Amps... Not a small amount of current--An an 80 Amp charge controller would be around (80a/1,110ah) 7% rate of charge (if you currently have just one Outback 80 amp controller. If so, then adding more charging current/array/charge controller would probably help battery life/SG.

Another option... Look at a 48 volt battery bank (and AC inverter/backup AC charging with genset)? That would get you down to (for example) 8s * 2p for (16x batteries) for a 740 AH @ 48 volt battery bank... And a 10% rate of charge would be 74 Amps (just one Outback 80 amp controller).... Especially if you plan on "growing" the system (large inverter, larger battery bank storage, larger array, etc.).

-Bill