Charge Controller Settings

[Alpine_Junky]

Looking to understand how to set up charge controller -

DIY Battery: LF280K - 16 cell configured for 48V system with Overkill BMS - 18650 Grade A cells

Charge Controllers - 2 Midnight Classic 200's - both running 2 strings of 6 panels rated at 380w each panel (12 panels x 380 = 4,560 watts). Has shunt and whizbang in master controller. One set of panels gets morning sun and the other afternoon. Northern location with crappy aspect...

Inverter is a Schneider 4048 - expect generator run time in winter - paired with Harbor Freight inverter super quiet 9500 genny. Was thinking of adding a better charger down the line if it makes sense -- still sorting through optimal charge rates for gen assisted charging to balance gen run time and battery life.

Understanding Will's settings below - I can easily set the charge controller to these values.

The curve ball that I can't quite figure out how to set up the charge controller. I was able to locate this documentation but its somewhat generic (I believe improperly refers to the BMS doing the charging) https://www.midniteftp.com/support/kb/faq.php?id=75


48V 16S LiFePO4 Battery w/ BMS

• Absorption: 58V
• Float: 54.4V
• Inverter Cut-off: 42.8V-48V

5,000+ Charge Cycle Absorption Recommendation
If you want your LiFePO4 cells to last a long time, you can set your absorption to Victron's custom LiFePO4 charge profile recommendation:

• 48V Battery: 56.4V

You can pull full capacity with the absorption figures above, but the charge rate will be reduced at high SOC.

Float should be 13.6V/27.2V/54.4V

Low voltage disconnect should be 12V/24V/48V

 

[sunshine_eggo]

Give this a read.

"Low current overcharge"

Part of the work (hobby horse) I am doing with my DIY lithium system involves testing the "top and bottom end" responses of the system as a whole. Questions are basically: In the setup, what happens at the top of charge with the sun fully on the panel? Also. What "should" or "should not"...

diysolarforum.com

Charge options are at the bottom.

 

[Rossman]

Inverter is a Schneider 4048

Is it an SW? If so, may God have mercy on you.

 

[Alpine_Junky]

Is it an SW? If so, may God have mercy on you.

Yes, can you please elaborate? Just a crappy inverter or bad because of battery choice? I have one in a cabin now that serves everything needed very well - wanted to switch but need 240 single for well and needs overall are small.

 

[Alpine_Junky]

Give this a read.

"Low current overcharge"

Part of the work (hobby horse) I am doing with my DIY lithium system involves testing the "top and bottom end" responses of the system as a whole. Questions are basically: In the setup, what happens at the top of charge with the sun fully on the panel? Also. What "should" or "should not"...

diysolarforum.com

Charge options are at the bottom.

Very helpful Mr. Eggo! Grateful for you!!

Quoting from Midnight solar:
"Many Lithium systems want charging to stop @ a voltage and start back @ a voltage. This would be accomplished by setting the ABSORB TIME to 4 minutes (3 minutes is the lowest setting) and using the REBULK Voltage to trigger the Classic to go back charging. REBULK is setup under the BATTERY MENU/ADVANCED. ABSORB TIME is set under CHGTIME."

Am I tracking?
Absorb: 54-55V (for good battery life span)
Float: -2V from the absorb setting; 52-53V
Equalize off
Set absorb time to 4 mins (experiment with this a little)

What would I set the "rebulk" voltage to?

 

[sunshine_eggo]

Not sure about the midnite, but I'm not sure I agree with it as I interpret it.

3.45 * 16 = 55.2V absorption
2-3 hour duration
3.375 * 16 = 54V float

Most systems have a re-bulk setting simply if there's poor solar or cloud cover, and it can't maintain float. If PV becomes available again, it will trigger another bulk/absorption/float cycle to try to fully charge the battery with available PV.

Rebulk is typically about 0.6V below float

 

[Rossman]

Yes, can you please elaborate? Just a crappy inverter or bad because of battery choice? I have one in a cabin now that serves everything needed very well - wanted to switch but need 240 single for well and needs overall are small.

Yeah, sorry dude but the SW's are notoriously unreliable. You will find many tales of them failing on these forums and others. It's unfortunate, and crazy because the XW line are real tanks and super reliable. I do hope it works well for you though.

 

[Frank Smith]

Yeah, sorry dude but the SW's are notoriously unreliable. You will find many tales of them failing on these forums and others. It's unfortunate, and crazy because the XW line are real tanks and super reliable. I do hope it works well for you though.

I have the Schneider SW 4048. It has been running for several years with no problems.

 

[sunshine_eggo]

I have the Schneider SW 4048. It has been running for several years with no problems.

Yeah. My neighbor's Trace "lasted" 27 years before he replaced it with a split phase Magnum. It's stored in the basement for backup purposes.