PV solar system charging voltage low

FloridaFlyer86 wrote:
Ok solar gurus - I am experiencing low voltage with my PV solar system. The charging voltage will not go above 12.8V. I'm using a Morningstar SS-6L-12V SunSaver controller (2nd gen) with 4 new Crown 6V 220 AH batteries wired series/parallel for a 440 AH 12V system, and a single 95 watt PV panel (astroenergy). The measured open circuit voltage from the panel is 20.3V. The SS-6L-12V should be charging at 14.4 volts for flooded batteries. The green charging light is on. I’m using a TriMetric TM-2025-RV battery monitor and I do get positive current flow (5A) but I’m going to end up stratifying my batteries if I don’t get the voltage up. I also have measured the voltage at the terminals of the controller and also see 12.8V there. (at rest battery voltage is 12.5V.) This is a new system (so all connections are new and clean, with dielectric grease and proper torque) but the components have been used before… over a year ago so my memory is hazy but I’m pretty sure I saw 14.4V before. I’m not too concerned about any wiring being undersized, I went overkill to avoid that possibility.
So I have an email in to Morningstar but I have no idea how long they might take to respond… and I might just have something stupid going on, unrelated to the controller. Any help is appreciated, hopefully I haven’t left anything out.

I have experience with the SS gen 2 controllers.

Yours is working fine. It is a two stage charger(no 3rd float stage). During Stage-1,bulk, it charges at the panel ISC depending on the panel tilt. The Volts then increase to 14.4 where stage-2, PWM, kicks in and current is tapered down. Your solar panel is not supplying enough daily Amps to raise your battery bank to 14.4V and is not reaching stage-2.

The 12.5 resting Volts is too low and proves that the bank is not being recharged daily. This is an undercharge situation that will result in sulphation and ruin the bank.

Consult the mfgrs manual.

HTH;
John