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

[yodamota]

bjorn. while this seems silly. have you contacted morningstar? they have been responsive to my requests. I have always emailed them. It does seem odd that you are not seeing close to the absorption voltage. Knowing how annoying it is to change setting on this controller. What if you changed the absorption value to 10 minutes? Maybe you will than see it absorb or your voltage rise. Ive noticed my lithium battery will spike to my absorption voltage rather quickly when its near it.

I do wish these charge controllers had a way to end absorption based on the current/amps. As it stands right now it will always absorb the same time.

 

[BjornM]

bjorn. while this seems silly. have you contacted morningstar? they have been responsive to my requests. I have always emailed them. It does seem odd that you are not seeing close to the absorption voltage. Knowing how annoying it is to change setting on this controller. What if you changed the absorption value to 10 minutes? Maybe you will than see it absorb or your voltage rise. Ive noticed my lithium battery will spike to my absorption voltage rather quickly when its near it.

I do wish these charge controllers had a way to end absorption based on the current/amps. As it stands right now it will always absorb the same time.

Yes, I've been in contact with them, and their support is excellent. Before they take a closer look, they want my charger to collect a log showing this issue, and that will not be possible in the upcoming days because it will be overcast, so hardly no charging at all. So I thought I'd check with people here too, to see if anyone had experienced the same issue. To me it looks like a configuration problem, but now I've looked into every detail you can configure. Only thing that is left is to try settings that make no sense but might work any way due to bugs in the charger software. I don't actually want any absorption at all, I just picked 1 minute because I suspected that it might have a bug that prevented the absorption time from being zero. I could try 10 minutes like you say.

The charger behaves strangely in general. When I turned off float all together, it immediately went to absorption even though absorption voltage wasn't reached yet. It stayed there for 17 minutes, although my absorption time is only 1 minute. Then went to bulk. Crazy behavior.

Some details make me think that this product isn't so well designed. In Live View the bulk mode is not shown as "BULK" but "MPPT", as if the MPPT algorithm is only applied in bulk mode, which is obviously wrong. In the MSView summary of the settings they call the absorption voltage "regulation voltage", which is confusing.

This makes me think that the only thing left to do is setup my Arduino to control it over RS485 so it is forced to obey my commands, because now I do not trust the charger to do the right thing and I don't want my LFP batteries to suffer because of it.

BTW this issue (prematurely switching to float) is not a fluke, I observed it three times in a row.

 

[Solar Guppy]

Some details make me think that this product isn't so well designed. In Live View the bulk mode is not shown as "BULK" but "MPPT", as if the MPPT algorithm is only applied in bulk mode, which is obviously wrong. In the MSView summary of the settings they call the absorption voltage "regulation voltage", which is confusing.

Mppt is only active in bulk as all other modes are reduced power levels and by definition maximum power point can only be held if there is a place for the energy to go to.

Possibly you have a misunderstanding of the states?

Bulk ( Maximum power point tracking ) will have both current and voltage vary until the termination voltage is reached when solar is the power source. Current can have a set point, but is usually related to a AC power sourced charger, but current is limited to the setting if there is extra energy.

Absorb is the Bulk termination voltage for a time period

Float is another constant voltage, typically lower than the Bulk for a time period

Disclaimer: I was on the development team for the charger you are discussing, this product has been in the market for 14 years now and is very mature.

 

[Checkthisout]

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.

As a test, set your absorption time for a half hour and see what happens. If that doesn't work, set the voltage at whatever the inaccuracy is.

The strategy is probably designed to cut charging and take a battery voltage measurement after being in bulk for a certain period. It cuts out, sees battery voltage is above float voltage and just goes right to float.

I would extend absorption time to a .5 hour and see what happens.

Edit: Also, you're being too gentle with your batteries. (I think). They are not treated with kid gloves in electric/hybrid cars and last for years and years with easily a million "mini" cycles.

 

[BjornM]

Mppt is only active in bulk as all other modes are reduced power levels and by definition maximum power point can only be held if there is a place for the energy to go to.

Possibly you have a misunderstanding of the states?

Bulk ( Maximum power point tracking ) will have both current and voltage vary until the termination voltage is reached when solar is the power source. Current can have a set point, but is usually related to a AC power sourced charger, but current is limited to the setting if there is extra energy.

Absorb is the Bulk termination voltage for a time period

Float is another constant voltage, typically lower than the Bulk for a time period

Disclaimer: I was on the development team for the charger you are discussing, this product has been in the market for 14 years now and is very mature.

View attachment 185466

Thanks for the feedback. Since you were on the dev team, I'll take your word for it when you say that MPPT is only applied for the bulk stage. That seems like a sub optimal solution though, and I don't understand why you would design a charge controller that way. MPPT is just the algorithm that kicks in for the DC-DC converter when there is more demand for power than the charger can supply, and this has nothing to do with what charge state it is in. For example if I'm in the bulk stage and I have an over powered solar array, the DC-DC converter will not be power optimized (MPPT) because the 60 A max current limit is already reached. I'd say that for my system the charger is hardly ever power optimized when the sun is shining, even though the Live View says "MPPT". That is why I think it is a misleading label, and should be called "bulk" instead. And lets say I'm in absorption mode and some clouds cross the sky. Then I definitely want the charging to be power optimized (MPPT algorithm) to be able to keep constant charge voltage. Although you say MPPT is not happening here, I suspect you are wrong, because why would your design team deliberately make the charger worse off when it doesn't have to be? The same for float. The charger is in float and I turn on a 3 kW appliance. Of course the charger will be MPPT optimized if that is needed to be able to keep up the float voltage.

I have a very old firmware version in my charger, and that could be why it is acting weird. Perhaps there are bugs that were fixed in later firmware. Need to get me a RS232 cable to update it, because it seems like I can't do it through MSView, is that correct?

 

[BjornM]

As a test, set your absorption time for a half hour and see what happens. If that doesn't work, set the voltage at whatever the inaccuracy is.

The strategy is probably designed to cut charging and take a battery voltage measurement after being in bulk for a certain period. It cuts out, sees battery voltage is above float voltage and just goes right to float.

I would extend absorption time to a .5 hour and see what happens.

Edit: Also, you're being too gentle with your batteries. (I think). They are not treated with kid gloves in electric/hybrid cars and last for years and years with easily a million "mini" cycles.

Yea, since it was switching to float at 27.27 V when it should have continued to 27.67 V (0.4 V higher), I could program it for 28.07 V instead, and perhaps it will switch to float at 27.67 V. But this seems like a big headache. What if it suddenly starts to honor my settings?

I will discuss this further with Morningstar support, and if there is no solution, I will remotely control this charger from my Arduino instead. You can put it in slave mode so you send the target voltage tough RS485/Modbus, and it should in theory ignore its own charge profile.

The reason I go gently in the charge profile is that my charge rate varies widely from 0.1C down to 0.02C. The 0.02C rate is very common for my setup, very common with slightly overcast skies here. The lower C-rate you have, the earlier (lower voltage) you need to stop charging, to prevent the cells from getting over charged. I was initially planning on charging to 3.50 V, but lowered it to 3.45 V, which at a 0.1C rate will get to around 96% SOC, which is good enough, and at 0.02C the cells will get slightly over charged, but I hope not to a detrimental degree. Over charging is a thing, but undercharging is not, so better safe than sorry. I've seen recommendations to keep LFP cells at 3.50 V indefinitely, which in my opinion will definitely over charge them.

 

[Checkthisout]

Thanks for the feedback. Since you were on the dev team, I'll take your word for it when you say that MPPT is only applied for the bulk stage. That seems like a sub optimal solution though, and I don't understand why you would design a charge controller that way. MPPT is just the algorithm that kicks in for the DC-DC converter when there is more demand for power than the charger can supply, and this has nothing to do with what charge state it is in. For example if I'm in the bulk stage and I have an over powered solar array, the DC-DC converter will not be power optimized (MPPT) because the 60 A max current limit is already reached. I'd say that for my system the charger is hardly ever power optimized when the sun is shining, even though the Live View says "MPPT". That is why I think it is a misleading label, and should be called "bulk" instead. And lets say I'm in absorption mode and some clouds cross the sky. Then I definitely want the charging to be power optimized (MPPT algorithm) to be able to keep constant charge voltage. Although you say MPPT is not happening here, I suspect you are wrong, because why would your design team deliberately make the charger worse off when it doesn't have to be? The same for float. The charger is in float and I turn on a 3 kW appliance. Of course the charger will be MPPT optimized if that is needed to be able to keep up the float voltage.

I have a very old firmware version in my charger, and that could be why it is acting weird. Perhaps there are bugs that were fixed in later firmware. Need to get me a RS232 cable to update it, because it seems like I can't do it through MSView, is that correct?

The charger is old.

How cool is it that an engineer who worked on developing the charger responded to your question on an internet forum? ?

You may want to consider a newer charger.

 

[Solar Guppy]

I'll take your word for it when you say that MPPT is only applied for the bulk stage. That seems like a sub optimal solution though, and I don't understand why you would design a charge controller that way. MPPT is just the algorithm that kicks in for the DC-DC converter when there is more demand for power than the charger can supply

I'll try again in the explanation, and this has nothing to do with "this" charger, its is ALL products that have mppt.

1) Mppt is point the power source can deliver the most energy
2) Mppt can only be achieved if the load can sink the power required from the solar panels
3) Absorb by definition is a limited power mode by the load, otherwise the voltage would continue to rise. You can't have mppt as it is limiting power to maintain a programed fixed voltage with declining current to maintain that voltage.

Solar only provides energy when there is a load, no load, you have what is know as VOC, which is voltage open circuit. As the load on Solar increases, the voltage decreases but the current increases. As some point know as voltage maximum power the voltage multiplied by amperage yields the most power at that moment the solar panels can provide

As far as charge controllers go, nothing has changed since the XW-mppt-60 or the TriStar Mppt have been released to the market, getting a "newer" one would have the same features.

What has changed in now most systems are know as an all=in-one or AIO, where the charger and inverter are in one package.

 

[Daddy Tanuki]

The charger is old.

How cool is it that an engineer who worked on developing the charger responded to your question on an internet forum? ?

You may want to consider a newer charger.

sorry I got 6 of them total 5 of the 60 amp and one of the 45 amp models.... being that they work flawlessly every time for me why would i go but the hot garbage that most of the forum tends to gravitate to? the only other two SCC i would consider are midnite solar and victron... and they are not really that much better construction wise, just better newer coms in the case of victron.

 

[Checkthisout]

sorry I got 6 of them total 5 of the 60 amp and one of the 45 amp models.... being that they work flawlessly every time for me why would i go but the hot garbage that most of the forum tends to gravitate to? the only other two SCC i would consider are midnite solar and victron... and they are not really that much better construction wise, just better newer coms in the case of victron.

I mean for the level of refinement he's after in his charger settings.

I think the OP is being paranoid about how he wants his batteries charged.

Caution is good but I don't think the charger is capable of doing what he wants it to do.

 

[Daddy Tanuki]

I mean for the level of refinement he's after in his charger settings.

I think the OP is being paranoid about how he wants his batteries charged.

Caution is good but I don't think the charger is capable of doing what he wants it to do.

well he does come from Sweden... I have heard they are only slightly more relaxed than the Germans (Joke Bjorn you actually seem pretty chill.)

 

[Checkthisout]

well he does come from Sweden... I have heard they are only slightly more relaxed than the Germans (Joke Bjorn you actually seem pretty chill.)

Right? How do we get him to be more of a careless hack like those of us in the United States? ?? ?

 

[BjornM]

I'll try again in the explanation, and this has nothing to do with "this" charger, its is ALL products that have mppt.

1) Mppt is point the power source can deliver the most energy
2) Mppt can only be achieved if the load can sink the power required from the solar panels
3) Absorb by definition is a limited power mode by the load, otherwise the voltage would continue to rise. You can't have mppt as it is limiting power to maintain a programed fixed voltage with declining current to maintain that voltage.

Solar only provides energy when there is a load, no load, you have what is know as VOC, which is voltage open circuit. As the load on Solar increases, the voltage decreases but the current increases. As some point know as voltage maximum power the voltage multiplied by amperage yields the most power at that moment the solar panels can provide

As far as charge controllers go, nothing has changed since the XW-mppt-60 or the TriStar Mppt have been released to the market, getting a "newer" one would have the same features.

What has changed in now most systems are know as an all=in-one or AIO, where the charger and inverter are in one package.

View attachment 185503

"3) Absorb by definition is a limited power mode by the load, otherwise the voltage would continue to rise. You can't have mppt as it is limiting power to maintain a programed fixed voltage with declining current to maintain that voltage."

Yes, but you don't take into account what happens when the controller can't maintain the desired voltage for the absorption and float stages because the solar array isn't producing enough power. It could be an overcast sky. Or suddenly someone turns on a large consuming appliance.

MPPT is an algorithm that controls a DC-DC converter between a solar array and a battery bank. It tries to find the optimum voltage/current point of the solar array so that more power can be extracted than would otherwise be possible with an "unintelligent" controller that doesn't track this. The input parameters of the MPPT is not only what voltage and current the solar array has, but also what voltage and current is requested by output/battery side of the DC-DC converter. This request comes from the charge profile. However the MPPT doesn't know or care what charge stage the controller is in, it is only interested in the requested output voltage and/or current. It will always try its best to provide the output that is requested. In some cases it doesn't have to optimize the input, because there is abundant energy available, and in some cases it maximizes the input, and in some cases it stays in between (slightly optimized, slightly better than an unintelligent charger).

So if we look at what happens during absorption when more and more clouds start filling the sky, the MPPT algorithm goes from not optimized at all (abundant solar energy, more than is needed to keep the absorption voltage), then to slightly optimized (the algorithm needs to find a voltage/current point that is better than an unintelligent charger would have found, or it would not be able to keep the absorption voltage), to maximized (the MPPT algorithm squeezes out as much as it can from the array, but this is still not enough to keep the absorption voltage).

 

[BjornM]

sorry I got 6 of them total 5 of the 60 amp and one of the 45 amp models.... being that they work flawlessly every time for me why would i go but the hot garbage that most of the forum tends to gravitate to? the only other two SCC i would consider are midnite solar and victron... and they are not really that much better construction wise, just better newer coms in the case of victron.

My charger has also worked flawlessly until now. Very happy with my purchase. I'm eagerly waiting for someone to tell me "but you forgot this setting you idiot". Then I can just move on and still be happy with my charger.

 

[BjornM]

Right? How do we get him to be more of a careless hack like those of us in the United States? ?? ?

Just trying to get the most out of my battery pack. And I have a lot of free time on my hands to do it.

I agree that your settings would probably work fine. However it isn't the specific settings I'm obsessing over here, it is why my charger doesn't do what I tell it to do. I know that women usually don't obey me, but this is an inanimate object.

 

[Checkthisout]

Just trying to get the most out of my battery pack. And I have a lot of free time on my hands to do it.

I agree that your settings would probably work fine. H

Where you reading the voltage from?

 

[BjornM]

Where you reading the voltage from?

The charger has an ethernet LAN cable connector, so you can use your computer and connect to it using a web browser and get a page with all the updated values, second by second.

 

[Solar Guppy]

Yes, but you don't take into account what happens when the controller can't maintain the desired voltage for the absorption and float stages because the solar array isn't producing enough power. It could be an overcast sky. Or suddenly someone turns on a large consuming appliace.

The charger will return to Bulk state if the battery goes below the absorb voltage at any time during absorb timer is active and the mppt feature will resume.

 

[Solar Guppy]

However it isn't the specific settings I'm obsessing over here, it is why my charger doesn't do what I tell it to do

Because the charger is knows what you don't

You are making assumptions or conclusions that lack an understanding of operation?

MorningStar has 30+ years of experience with charge controllers

 

[MisterSandals]

The charger has an ethernet LAN cable connector,

That unit is a youngster! Mine has a 9 pin serial port.

I'm eagerly waiting for someone to tell me "but you forgot this setting you idiot"

I have been following along but cannot identify a problem with what you are doing. I do have the detail of my settings and files I got from morningstar. Maybe helpful?

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