Charge settings recommendations for S6-460 AGM

[Froostix]

Hi gang,

I recently installed an off-grid system, with 3000W PV array, MPPT 60 150, SW-4048 and a 48V battery bank made of 8 S6-460AGM batteries. Everything is hooked up, batteries are charging on solar and inverter is inverting.

I am looking at some expertise to review the charging graphs attached and have some feedback. I have contacted Rolls customer support who gave me the following parameters:
Inverter Settings Must be set to Custom.

Equalization support: current = "disabled"

Equalization voltage: 58.8V

Bulk voltage: 58.8V

Bulk Termination voltage: 58.8V?

Absorb voltage: 58.8V

Float voltage: 55.2V

Battery temp comp: 96mV/C

They said that low battery cut out and high battery cut out were a personal choice, even though I specifically asked for a 50% depth of discharge... I setup LBCO = 49V and HBCO = 59.5V. When the sun kicked in today, the inverter threw an error stating that it hit the high battery cut out. I raised the HBCO to 62V and cleared the error. Please see below for the graphs of the day (not sure what happened between 2pm and 4pm...)

They also told me to use the manual to calculate my absorption time, which I did:
- with CC at ~40 amp: 0.38x415/40 = 240 minutes
- with inverter at ~30 amp: 0.38x415/30 = 315 minutes.

I also contacted Schneider support but they have not been much help so far...

Anyone having a similar setup? Any feedback appreciated, thanks!

P.S: I'll post a updated pic of the charge graph tomorrow.

 

[sunshine_eggo]

Hi gang,

I recently installed an off-grid system, with 3000W PV array, MPPT 60 150, SW-4048 and a 48V battery bank made of 8 S6-460AGM batteries. Everything is hooked up, batteries are charging on solar and inverter is inverting.

I am looking at some expertise to review the charging graphs attached and have some feedback. I have contacted Rolls customer support who gave me the following parameters:
Inverter Settings Must be set to Custom.

Equalization support: current = "disabled"

Equalization voltage: 58.8V

Bulk voltage: 58.8V

Bulk Termination voltage: 58.8V?

Absorb voltage: 58.8V

Float voltage: 55.2V

Battery temp comp: 96mV/C

If the above numbers are from rolls, good; however, the temp comp number is typically entered in as a negative as you want HIGHER voltage when cold and lower voltage when hot. You should enter -96mV/°C, and you should have a temperature sensor(s) interfacing with all chargers.

They said that low battery cut out and high battery cut out were a personal choice, even though I specifically asked for a 50% depth of discharge...

This is impossible. Voltage varies with current. At a 20A load, your 50% voltage will be below your 50% voltage when only drawing 5A. You need a battery monitor that actually counts current in and out of the batteries, adjusts for Peukert's law, temperature efficiency, and reports a true % state of charge based on the rated battery capacity.

I setup LBCO = 49V and HBCO = 59.5V.

Big mistake. Under load, you'll likely dip below 49V even at high states of charge. See above.

At -96mV/°C, you'll need to charge at 59.5V when the temp is only about 18°C. At lower temperatures, higher.

IMHO, there is no reason to set HBCO cut off below 64V or whatever the inverter is rated at. At -20°C, you'll be charging at >62V.

When the sun kicked in today, the inverter threw an error stating that it hit the high battery cut out. I raised the HBCO to 62V and cleared the error. Please see below for the graphs of the day (not sure what happened between 2pm and 4pm...)

Per above HBCO is too low, but that spike is very odd.

They also told me to use the manual to calculate my absorption time, which I did:
- with CC at ~40 amp: 0.38x415/40 = 240 minutes
- with inverter at ~30 amp: 0.38x415/30 = 315 minutes.

I also contacted Schneider support but they have not been much help so far...

Rolls is infamous for long absorption times. You have correctly calculated the time. What are you asking here?