Morningstar TS-MPPT-60 ignores my custom settings for absorption voltage

[BjornM]

My TS-MPPT-60 charger is ignoring my custom settings for absorption voltage for some reason. Perhaps someone has experienced the same thing and can give me some pointers. I've used custom settings for years, but now when I got new batteries, I changed the settings and somehow things don't work anymore.

I've set the dip-switches to allow for custom settings. I've programmed the charger using MSView, and double checked that my settings are indeed in the charger.

Regulation voltage: 27.67 V
Temp comp: 0 (in other words turned off)
Absorption time: 1 minute
Absorption Ext: disabled
Battery Service Reminder: disabled
Float voltage: 26.96 V
Float cancel voltage: disabled
Equalize voltage: disabled
HVD: disabled
Max regulation limit: 28.80 V

With these settings I expect the charger to be in bulk mode (or MPPT as they call it in the Live View) until it reaches 27.67 V, then switch to absorption for one minute, then switch to float and hold 26.96 V. This is not what happens. Instead it stays in bulk until only 27.27 V is reached, then switches immediately to float. So it makes two errors: it ignores the bulk/absorption voltage, and it ignores the absorption stage. How can I fix this?

 

[BjornM]

Also, I can give TS-MPPT-60 owners a warning about something not to do: In MSView there is a tool that allows you to reset the charger after you have updated the settings. As per instructions from the Morningstar website: Right click on the charger device, select Properties, switch to the Control tab, select "Reset Control", and push the "Force coil on" button.

This made my charger short circuit itself and fuses blown. Just a warning to not try it on your own charger. Instead, to reset the charger, simply turn it off and turn it on again.

 

[time2roll]

Are the voltage sensing wires connected? Or are you measuring voltage at the controller?

Otherwise I would temporarily set absorption to 30 minutes and see what happens. Next temporarily set absorption to 28.00 and see what happens.

I do prefer a short absorption period for the cells to balance a bit. One minute seems a bit short to me.

 

[BjornM]

Are the voltage sensing wires connected? Or are you measuring voltage at the controller?

Otherwise I would temporarily set absorption to 30 minutes and see what happens. Next temporarily set absorption to 28.00 and see what happens.

Yes I have the voltage sensing wires at the battery terminals. And I've measured the voltage with a multimeter to double check.

But the actual voltage doesn't seem to be the problem, because you can see the charging parameters in real time, and it has a Battery Voltage (what the voltage is right now) and a Target Voltage (what it aims for). So it should in theory stay in bulk mode until it reaches the Target Voltage. So you can see in real time how it falls short of achieving the Target Voltage and randomly decides to go to float. So there is something more fundamental that is wrong.

 

[Checkthisout]

You have absorption set too short. Are you Lipo4 at 24 volts?

Set absorption for a half hour at 28.4 volts.

What does that "regulation voltage" setting for?

 

[BjornM]

You have absorption set too short. Are you Lipo4 at 24 volts?

Set absorption for a half hour at 28.4 volts.

What does that "regulation voltage" setting for?

Regulation voltage is the bulk voltage, i.e. the point where bulk ends and absorption begins.

What the best charge profile is for LFP is a different discussion. I this thread I just want to understand why the charger doesn't behave the way I configured it. I don't think there is a minimum time for absorption. I can set it to 1 second if I want. They wouldn't allow me to do that if it didn't work.

 

[Checkthisout]

Regulation voltage is the bulk voltage, i.e. the point where bulk ends and absorption begins.

What the best charge profile is for LFP is a different discussion. I this thread I just want to understand why the charger doesn't behave the way I configured it. I don't think there is a minimum time for absorption. I can set it to 1 second if I want. They wouldn't allow me to do that if it didn't work.

No comment other than other chargers that I have dealt with control amperage during bulk, not a voltage.

Set your "absorption voltage" at the "regulation voltage" as absorption voltage is a do not exceed voltage.

Edit: In other words I have never seen a charger that controls bulk voltage. Bulk means the charger is in constant current mode. Charging is Amperage limited and the peak voltage reached during that period is controlled by the absorption voltage setting.

 

[Checkthisout]

And one more.

Are you sure "regulation voltage" isn't a peak voltage not to be exceeded?

In other words out of all the voltage settings during operation shouldn't it be the highest?

 

[yodamota]

yes. any chance you can show us a screen shot of your settings from the controller program?

 

[yodamota]

Maybe these settings will help you?

https://diysolarforum.com/attachments/lithium-iron-phosphate-lifepo4-generic-charge-settings-pdf.123274/

 

[BjornM]

No comment other than other chargers that I have dealt with control amperage during bulk, not a voltage.

Set your "absorption voltage" at the "regulation voltage" as absorption voltage is a do not exceed voltage.

Edit: In other words I have never seen a charger that controls bulk voltage. Bulk means the charger is in constant current mode. Charging is Amperage limited and the peak voltage reached during that period is controlled by the absorption voltage setting.

Sorry for explaining this in a confusing way. Yes, during bulk mode it charges with constant current until it reaches a certain voltage, where it switches to absorption mode. That voltage value is usually called bulk voltage, because that is the voltage where the bulk mode ends. Sometimes it is also called absorption voltage, because it is the very same voltage level as used for absorption. But in this case they call it regulation voltage for some strange reason.

So today when I was observing the charger, I saw that before it had even reached the voltage where bulk should end and absorption should begin, it randomly switched to float mode.

 

[BjornM]

And one more.

Are you sure "regulation voltage" isn't a peak voltage not to be exceeded?

In other words out of all the voltage settings during operation shouldn't it be the highest?View attachment 185343

Thanks for looking into this, but I'm positive that Regulation voltage is the same as bulk/absorption voltage, because when you press the Edit button to edit those values, you enter a series of forms where this value is suddenly called Absorption Voltage instead. They have made it a bit confusing for the user, but that's how it works.

And there is a separate value called Maximum Regulation Limit, that does what you mention.

 

[BjornM]

yes. any chance you can show us a screen shot of your settings from the controller program?

Great idea, here they are:

 

[Checkthisout]

Set your "regulation voltage" to 28.4.

 

[BjornM]

Maybe these settings will help you?

https://diysolarforum.com/attachments/lithium-iron-phosphate-lifepo4-generic-charge-settings-pdf.123274/

Very useful, because it shows an alternate way of setting up the controller to deliberately hit the overvoltage protection, to emulate what happens during a normal bulk mode and float mode. So it is a way to accomplish the same thing. I'll have this as my fallback solution.

I'm still very confused why normal bulk + float doesn't work though. It's such a simple concept that exists in all chargers.

EDIT: The above is not correct, I misunderstood the idea. When using the over voltage protection function to create a charge profile, the charger will first be in bulk mode until OVP is triggered, which disconnects the solar array, and the charger will wait until a lower voltage is reached and then reconnect the array again, and a new bulk charge cycle will begin. Perhaps not exactly what I want, but maybe good enough.

 

[BjornM]

Set your "regulation voltage" to 28.4.

I'd be happy to if you first explain why this would have any effect.

 

[Checkthisout]

I'm still very confused why normal bulk + float doesn't work though. It's such a simple concept that exists in a chargers.

What is the amperage at when it's switching over to Absorb?

 

[Checkthisout]

I'd be happy to if you first explain why this would have any effect.

Limitations in the way chargers work, especially if it's an older charger designed for lead acid.

Edit: can explain later

 

[BjornM]

What is the amperage at when it's switching over to Absorb?

It never switches to absorb. It goes straight from bulk to float. And at that point today the amperage was around 40 A. I have set no limit to the charge current, because the charger can max deliver 60 A, which works fine for my batteries.

 

[BjornM]

Limitations in the way chargers work, especially if it's an older charger designed for lead acid.

What you are saying makes no sense. There are no magical values in the charger that I have to stick to. I can set the absorption voltage to any value I want, and the charger should then behave the way I have set it. If I set it to 27.67 V it should stay in bulk until the batteries are at 27.67 V.