SOK LiFePO4

[GonzoRock]

I am looking to find where the SOK line of batteries keeps their specifications.
Specifically, what is the highest charging voltage that the BMS can handle?
I have a Midnite Classic charge controller for about 600 watts of solar at 30 volts VMP
and since switching from Leadacid I'm a bit concerned before I smoke $2k of batteries.
I hope this is not too basic for the forum.
Thank you!

 

[acdoctor]

What voltage battery? Looking on currentconnected.com looks like they have charging voltage right on the batteries. @HighTechLab can probably help.

 

[rmaddy]

Go to https://www.us.sokbattery.com/products and select the specific battery that you have. On the battery page you will find a link to download the spec sheet.

You can also go to https://www.currentconnected.com/ and navigate to the battery specific page. There you will find a tab for "Charger & Inverter Settings".

 

[GonzoRock]

Thanks, guys. That really helped and got me going.

Now I'm a bit confused about how a MPPT controller shuts down when the Li battery is full. The built in BMS on the SOK batteries say it prevents overcharging... So set the MPPT for 14.6 absorb and 14.4 float and not worry about the details? I own a Midnite Classic and would like to use that.

 

[acdoctor]

Settings for Victron MPPT Charge Controllers:​

Battery Voltage: Set depending on system, normally 12v.
Max Charge Current: OK to set as high as desired, but no more than 50a per battery
Charger: Enabled
Battery Preset: User Defined
Expert Mode: ON
Absorption Voltage: 14.6v
Float Voltage: 13.8v
Equalization Voltage: 14.6v
Rebulk Voltage Offset: 0.40v
Absorption Duration: Fixed
Absorption Time: 15 Minutes (This allows for proper cell balancing)
Tail Current: Disabled
Equalize Current: 0% (For safety we don’t want equalization at all.)
Automatic Equalization: Disabled
Equalize Stop Mode: Automatic (On voltage)
Maximum Equalize duration: 0 Minutes
Manual equalization: DO NOT CLICK START
Temperature Compensation: Disabled
Low Temperature

 

[GonzoRock]

Settings for Victron MPPT Charge Controllers:​

Battery Voltage: Set depending on system, normally 12v.
Max Charge Current: OK to set as high as desired, but no more than 50a per battery
Charger: Enabled
Battery Preset: User Defined
Expert Mode: ON
Absorption Voltage: 14.6v
Float Voltage: 13.8v
Equalization Voltage: 14.6v
Rebulk Voltage Offset: 0.40v
Absorption Duration: Fixed
Absorption Time: 15 Minutes (This allows for proper cell balancing)
Tail Current: Disabled
Equalize Current: 0% (For safety we don’t want equalization at all.)
Automatic Equalization: Disabled
Equalize Stop Mode: Automatic (On voltage)
Maximum Equalize duration: 0 Minutes
Manual equalization: DO NOT CLICK START
Temperature Compensation: Disabled
Low Temperature

 

[GonzoRock]

Thanks. That is interesting!
Mine is a Midnite Classic 200

 

[rmaddy]

and 14.4 float

Much too high. 13.6V is a better choice.

 

[GonzoRock]

Much too high. 13.6V is a better choice.

I've been starting to hear that on other forums... this is all so damn interesting... and confusing LOL

for example:

14.6 v seems pretty high, please double check the battery specs, and the recommended voltages for longest cycle life. Longest cycle life is usually 80% of full, to just 20% of full, leaving 40% of unused capacity, untouched. But this Greatly extends cycle life to 10,000 cycles instead of 3,000.
13.6 v is a more reasonable absorb voltage & 13.4v for float. Absorb time should be about 5 minutes.

and someone else:

In general no lithium chemistry needs an absorb or equalizer setting, and that should be turned off.

I like to set the full voltage about a half a volt below the maximum battery setting.
There's very little energy in that top half volt and you reduce the electrochemical stress on the cells by running a little bit lower.
Always check with the manufacturer specs but you can often increase the lifetime by reducing the peak voltage setting.

I like to hold a new pack at peak voltage for a day or so to get the pack controller to equalize all the cells.
but unless you see an imbalance on your battery controller monitor this does not need to be repeated.

Spec says 14.4 recommended charging, 11.2 recommended cut off. I would float them at 14.0 just to add a little safety margin at the top.

 

[acdoctor]

I've been starting to hear that on other forums... this is all so damn interesting... and confusing LOL

for example:

14.6 v seems pretty high, please double check the battery specs, and the recommended voltages for longest cycle life. Longest cycle life is usually 80% of full, to just 20% of full, leaving 40% of unused capacity, untouched. But this Greatly extends cycle life to 10,000 cycles instead of 3,000.
13.6 v is a more reasonable absorb voltage & 13.4v for float. Absorb time should be about 5 minutes.

and someone else:

In general no lithium chemistry needs an absorb or equalizer setting, and that should be turned off.

I like to set the full voltage about a half a volt below the maximum battery setting.
There's very little energy in that top half volt and you reduce the electrochemical stress on the cells by running a little bit lower.
Always check with the manufacturer specs but you can often increase the lifetime by reducing the peak voltage setting.

I like to hold a new pack at peak voltage for a day or so to get the pack controller to equalize all the cells.
but unless you see an imbalance on your battery controller monitor this does not need to be repeated.

Spec says 14.4 recommended charging, 11.2 recommended cut off. I would float them at 14.0 just to add a little safety margin at the top.

Slower charging is also less stress on the battery.
Absorption is not necessary but, you can bulk charge less aggressive with a little absorption time at the end and get the battery to the same state of charge.