Morningstar charge controller

[RoamingKat]

Lately I have watched my Morningstar is showing low amps when the battery SOS is showing 13.4   The Morningstar is claiming 14.0

I keep wondering if it is the solar panels that are not delivering or the Morningstar that is acting as a damper to keep the amps low.       

Wouldn’t the charge controller keep the amps low if it thought the battery was full at 14.0?  But..at the same time it shows the sos at 13.4

Or...are the panels just not delivering what their spec says they should.    2 panels with 700 total watts.   
Yeah, I get that with the sun so slow in December it isn’t going to be very impressive....but...3 amps at noon?   

So, the question is...is it the panels failing to deliver or the charge controller limiting the amps?   How do I tell?

Oh...this is LiFePo4 batteries.   I understand that at 13.4 I am probably up around 85-90 percent full.....but, it seems that this system cannot/will not push on to 14.0 sos.

[justjim]

interesting

This isn't the first time that this has been a issue for you with multiple charge controllers and panels.

Lately I have watched my Morningstar is showing low amps when the battery SOS is showing 13.4 The Morningstar is claiming 14.0

The charge controller is saying the voltage is 14.0 but the bank is 13.4? That's a enormous difference in voltages. The charge controller is not seeing the voltage of the bank properly. Is the voltage sense line hooked up? Are all of the connections tight? Are any of them warm or worse, hot?

If you still have the same Morningstar that I have, it has no idea what is up with your batteries. It is a complicated voltage controlling timer. It takes the voltage up to absorb levels, holds it there for a certain time and in most cases switches to a lower voltage in float. In your case float has been disabled.

[RoamingKat]

Everything is cool to the touch. (I tend to over engineer wire sizes). I found nothing loose or disconnected.

Yes, float is set at “full”. (14.0). The two indicators are both on the Morningstar. 14.0 on the screen showing me the amps being delivered to the battery, and 13.4 on the battery status screen. So, you think it is probably the Morningstar that is regulating the flow?

I set float at 14.0. So, it makes sense that the amps it delivers is very low at that point. But, why would it think that the battery is at 14.0 when it also shows (same device just on a different display screen) the battery at 13.4

I guess I have convinced myself to replace it with another victron.

(This is new behavior on the part of the Morningstar.... I’ve had no issues from it for the last 2 years)

[justjim]

The reasons that a controller does not see the same voltage as the bank are too small of wiring or too long of a distance. There could be line loss through one of the components that you are using to create your BMS too. That's why the voltage sense lines are important.

The controller will only affect the amps delivered is when the controller itself is overheated. Then it will cut the amps in a effort to protect itself.

Lithium batteries do taper when close to full contrary to popular belief. I have seen it when bringing them up to full with my adjustable voltage charger with a amp meter. 36 amps available yet the batteries taper slowly in the end.

I am going to suggest testing the voltage on both ends of the relays in your BMS to see if you can see where the difference in voltage is. You are not harming the batteries by not getting them completely full but you may want the capacity.

[justjim]

Last thing is that if your batteries have ever shut down while the panels are still connected a Morningstar controller will be damaged. Morningstar at one time said no lithium at one point and I have not included them in my designs for that reason. A BMS can shut them down for a variety of reasons leaving the controller powered by the panels. I will either switch to Victron or create a sacrificial alarm battery back up that will always keep the controllers powered in the event of a shutdown.

The nice thing about Victron is that the smart sense will shut down the charging from the controller if it gets to be freezing or below

[Scott7022]

Lol. Morningstar used to be The Bees knees back in the day. Much of it to do with the quality of the build, early adaptation to MPPT, and much noise on forums and the like from the Angry Solar Bob. Guy used to post to forums all the time. Actually the angry man did a lot for the industry. He loved and recommended MorningStar as the one and only. But alas the old, this is as good as it gets thinking, left them in 2008. So 2000 and late. Victron said lithium sure no problem. And so another American company drops to the bottom of the birdcage because they failed to stay current with the industry.
Damn foreign company’s poaching customers. lol.




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[RoamingKat]

The cable from Morningstar to the power buss is 6 gauge. Everything from there to battery is 2 aught
(Yeah, I did say over engineered....electrical fire scares me)

The battery monitor says 13.4. Yet, the Morningstar is shutting down amps from the panels.

Oh yeah, time to get rid of it.

Is it still OK for lead acid technology? I’d feel guilty giving it away if it is just trouble

[justjim]

Do a voltage check at the terminals of the charge controller. 6 gauge at a distance and no voltage sense line is kind of weak. (controller handles 2 gauge) If the voltage at the controller is 14.0v and it is 13.4v at the batteries then it isn't the controllers fault. At that point you need to work back down the line until you see the real voltage of the bank and work your way back out with better wiring.

The important thing to accept here is that if the MorningStar is not seeing the proper voltage without a voltage sense line, then neither will a Victron charge controller without a Smart Sense voltage and temperature sensor.

Again, the controller does not do anything to control the amps being delivered. It will deliver as many amps being produced by the panels and being accepted by the battery. It can control only the voltage.

[RoamingKat]

The controller I have barely manages 6 gauge....I doubt I could ever get 2 gauge through the hole provided onto the terminal. Besides....it is only 2 feet from the battery (4 if you are counting the round trip) that should handle 140Amps without issue.

I have poured over the installation guide....I do not see any reference to a voltage sensor as a separate wire.

Yeah, it is just time to replace it

[justjim]

there are two sets of mini terminals. One set goes to the temperature sensor, the other to the voltage sense lines. Both my ts-MPPT-45 and 60 takes 2 gauge. I have pin lugs up sizing from 2 gauge to 1/0 on the 60 amp. Both have temperature and voltage sense lines connected.

A Victron 50 amp will save you a few hundred dollars over a 60 amp. Both will benefit from the smart sense.

With a line loss issue I would not feel bad about passing on the Morningstar to someone in need.