New member (charge controller settings SLA)

[Aaave]

Hello all,

I'm a total rookie with solar systems but trying to learn new things every day. My first "project" was to power a couple of fans. A month has passed and everything seems to be working still, no dead batteries yet. The major issue for me is to understand the SCC settings with certain batteries. I have used the default settings for sealed till today. Recently I bought a MPPT (Epever). It has a default for S,G,F and manual for User. Three parameters that puzzle me the most (default sealed) are: "Over voltage disconnect 16.0V, Charging limit voltage: 15.0V and Low Voltage Disconnect Voltage 11.1V). From different internet sources it says: never discharge below this level (some say 80%, some 70%... 60-50% or in volts: 11.4V, 11.96V, 12.1V...) and also do not overcharge beyond X. My current system is 12V and battery for experimenting is a cheap 80Ah SLA. The question is:

1. Should I use/trust the default settings for SLA or use the User settings and manually type different values? Maybe I am missing something but the default low disconnect and charging limit sound too low & high if I compare to the many tutorials online. Why is 11.1V disconnect default and acceptable? Isn't the battery somewhat damaged by then?



Thank you,
Have a sunny day.

[Mike90250]

unless you have the specs for your specific battery (try going online to the mfg) stick with the pre-programmed setting for SLA on the controller.

What was your old controllers settings that you used ?

[Aaave]

Ok thanks. The old pwm had a low voltage disconnect @ 12.2V and the charge limit was 14.4V. So basically I set these values based on some recommendations. Defaults were 10.4V & 14.4V.

[Bala]

The low V disconnect setting will only apply if you have connected the utility relay into the system. if you are running fans direct off the battery they will not do anything.

The low V setting disconnect really depends on your system. It can have say a 12.2 shut off prevent battery damage or have a low setting like 11 to prevent tripping when a high current draw starts, like a fridge or pump. Some have adjustable time delay in the cut out. Or if the item its running is deemed more critical than battery damage like a fish tank.