Is This Normal For A MorningStar Charge Controller?

rss2q · July 2011

This may be a question to ask MorningStar support but I'll try here first.

Anyway, last night I hooked up my brand new Morningstar Prostar 15 inside my home where I could control the lighting (day & night) very easily.

-The first test was with the bright ceiling fan on to indicate sunlight. When I hooked up my 24v (2x 12v) solar panels to the controller as well as the 24v battery bank, both the green light for the solar indicator was on and the green light for the battery status was on which they should...so far so good.

-When I turned the ceiling light off, the green light for the solar status was "still on".

I then took out my multimeter and touched the terminals that are exposed from the controller while the solar panel was still attached to check the voltage, and the meter displayed 25.9v!! What!

And this is with the lights completely off (DARK 8) ).

So then I checked the battery voltage, and guess what, it too was 25.9v. So I went to the skinny instruction manual in hopes for an explanation, but received no luck. But when I came back to check on the controller 10min or so later, the green light "was off". This again is with the lights off, and this is what should happen since obviously it's night time...so therefore no solar energy is being produced.

My question is, is this normal? Does it take PWM controllers a moment to completely turn off the green LED when you go from day to night? And what's up with the solar terminals reading off the same voltage as the battery voltage when the lights are completely off and the green LED was still on for the solar indicator?

Cariboocoot · July 2011

Re: Is This Normal For A MorningStar Charge Controller?

If there's enough light to see by there's enough light to kick a solar panel's Voc up to normal.
If the battery is charged the controller won't connect so the Voc won't be dragged down.

Cover the panel with something truly opaque and its output should drop to zero.
Put a load on the battery to create a current draw and again the panel's Volts should be pulled down under ow light conditions.

BTW, panels are a current source: what you really want to be doing is using the 10 Amp scale on your meter (if equipped) to measure the current flowing from the panel to the controller and from the controller to the battery. Again, low light = almost no Amps from panel. High battery = almost no Amps from controller.

And I suspect some capacitors inside the Morningstar will keep the LED's lit 'til they discharge.

rss2q · July 2011

Re: Is This Normal For A MorningStar Charge Controller?

Cariboocoot wrote: »

Cover the panel with something truly opaque and its output should drop to zero.
Put a load on the battery to create a current draw and again the panel's Volts should be pulled down under ow light conditions.

I did actually do that. What I used was a towel, and again, the same issue occurred. I also checked the current from the panels and I saw very very very little to no current was passing. What was most startling was the fact that, when this was occurring, my solar panel terminals were displaying the same exact voltage as my battery. I checked to see if my MorningStar Prostar 30 acts in this same manner, but I didn't know if that was normal.

Also, what is Voc?

BB. · July 2011

Re: Is This Normal For A MorningStar Charge Controller?

A pwm controller is basically a switch from input to output.

If there is enough light on the solar panel for Vpanel>Vbatt, then when the charge controller thinks the battery needs charging, it will close the switch. At that point, the Vpanel input will be about the same as the Vbatt output connection.

When the sun is down, and the sky is pretty dark--The solar panel output should drop to near zero volts... If it is completely dark outside and if there is still Vbatt on the solar panel, then either the charge controller is miss-wired or there is a fault in the charge controller (shorted "switch" or transistor).

Covering a solar array with a beach towel during the day may not block enough light to get the panel output to near zero voltage.

-Bill

Cariboocoot · July 2011

Re: Is This Normal For A MorningStar Charge Controller?

rss2q wrote: »

I did actually do that. What I used was a towel, and again, the same issue occurred. I also checked the current from the panels and I saw very very very little to no current was passing. What was most startling was the fact that, when this was occurring, my solar panel terminals were displaying the same exact voltage as my battery. I checked to see if my MorningStar Prostar 30 acts in this same manner, but I didn't know if that was normal.

Also, what is Voc?

Voc: Voltage open circuit. This is the Voltage a panel will produce with no load connected. If there's enough light to see the panel it's Voc will shoot right up. It's the current that really matters here. Put it out in daylight and see what readings you get. If the battery is low and the controller needs to pass current it will, with a drop in Voltage at the panel as the load demand drags it down from Voc to Vmp: Voltage maximum power. Under near zero current flow you should see low (battery level) Voltage at the panel for that reason.

Photovoltaic panels are a bit more difficult to understand than batteries, but only because you're used to the way a battery functions. Panels are sort of backwards from batteries in that they try to maintain a current output while the Voltage fluctuates.

rss2q · July 2011

Re: Is This Normal For A MorningStar Charge Controller?

Here's the scenario as I know for a fact that no light was getting to the panels.

It's night time outside anyway, no lights coming through windows, every light is off in the room I'm testing this, "plus", I put a dark colored towel over the panel. Pitch black in this room.

Regardless of all that, the solar green light stays on for a couple of minutes...maybe less, but I'll time it next time to be exact. I know most capacitors drain quicker, so I doubt that's what is causing it, but again I'll time it to be sure.

Also, should you hook your actual load to the Charge controllers terminals, or hook your load directly to the battery bank? My load in this case would be an inverter. Someone told me a long time ago to hook it directly to the battery bank as the charge controller load section cannot handle a lot of power.

Cariboocoot · July 2011

Re: Is This Normal For A MorningStar Charge Controller?

Disconnect the panel from the charge controller and check for Voltage on the panel's leads. You may be surprised.

LED's are likely staying lit for a while because of capacitors in the unit. Doesn't take much to charge them up and an LED doesn't use much current so won't draw them down fast.

Frankly, testing a set-up under non operational parameters doesn't tell you much other than that the LED's light when there's Voltage present. Hook up the battery and one light comes on saying "you've got battery". Hook up the panel and another comes on saying "you've got panel". More sophisticated displays of actual function require more complex (and expensive) circuitry. Even then they're not all that accurate.

I don't know what you've got for loads, but as a rule they are connected to the battery not the controller. This is because in most cases the load current can be much higher than the charge current, and thus requires heavier wire. In addition each wiring is part of a separate (but related) circuit: controller to battery and battery to load. As such they should have separate fuses, rated according to the wiring and expected current. The exception to this would be low power DC loads that are run off the charge controller's LOAD terminals, if so equipped.

BB. · July 2011

Re: Is This Normal For A MorningStar Charge Controller?

I don't know--it is possible for the controller to take a few minutes to figure out there is no sun... No damage will result to the solar panels--just a very small amount of leakage current back through the panels until the controller turns off.

Where to attach the loads...

There are two places where loads are typically attached. The best place is directly to a properly wired battery bank.

The second place is the "load control" on the charge controller itself. The load control is usually set to turn off if the battery voltage is around 10.5 to 11.5 volts (some units are adjustable, others are not). The load terminals are relatively low current (typically around 8 amp maximum) and cannot support inverters for a few tens of watts).

If it is set to 11.5 volts--it may save having your battery damaged from over discharge. At 10.5 volt setting, the battery is already dead and probably damaged from over discharge.

Most inverters have a battery cutoff voltage of 10.5 volts or so anyway--so there is no reason to connect an inverter to the load terminals.

The last place we usually want to connect a load is at the charge controller itself. Some loads (like AC inverters) have very "noisy" input current profiles which can confuse some charge controllers (may not properly/fully charge battery bank). It is better to make all connections back at the battery bank (with proper fuses/breakers on each + lead from the battery positive bus).

-Bill

rgk1 · July 2011

Re: Is This Normal For A MorningStar Charge Controller?

I don't have the Prostar, but my Morningstar MPPT controller will do the same thing. When I first installed mine and disconnected the solar, the light stayed on for a minute or so and then went off. I have decided, possibly incorrectly, that it just keeps it connected for a minute just to make sure its not a passing cloud or shading and then cuts off if it determins it's really night. But, I never checked for voltage on the solar inputs while the panel was disconnected and the light on.

ggunn · July 2011

Re: Is This Normal For A MorningStar Charge Controller?

rss2q wrote: »

Regardless of all that, the solar green light stays on for a couple of minutes...maybe less, but I'll time it next time to be exact. I know most capacitors drain quicker, so I doubt that's what is causing it, but again I'll time it to be sure.

The rate at which a capacitor discharges (drains) is dependent on the size of the cap and the load to which it is connected. If it is not being drained by a load it will stay charged indefinitely, and if it is a large cap and the load is small (LED indicator lights do not draw much current - very small load), it will discharge slowly.

It's the capacitance in the system that is keeping the lamp lit for a while. You have not discovered a solar panel that produces power in the dark. ;^)

rss2q · July 2011

Re: Is This Normal For A MorningStar Charge Controller?

rgk1 wrote: »

I don't have the Prostar, but my Morningstar MPPT controller will do the same thing. When I first installed mine and disconnected the solar, the light stayed on for a minute or so and then went off. I have decided, possibly incorrectly, that it just keeps it connected for a minute just to make sure its not a passing cloud or shading and then cuts off if it determins it's really night. But, I never checked for voltage on the solar inputs while the panel was disconnected and the light on.

Glad to hear from someone who actually owns a Morningstar controller

and glad in a positive way that you are experiencing similar endeavors. But yeah, I'm going to actually time it this time to get a better idea on how long it's taking.

I've also disconnected to solar panel completely and the light still stayed on, but this time I'll leave it disconnected and time it. Will update later tonight

rss2q · July 2011

Re: Is This Normal For A MorningStar Charge Controller?

ggunn wrote: »

The rate at which a capacitor discharges (drains) is dependent on the size of the cap and the load to which it is connected. If it is not being drained by a load it will stay charged indefinitely, and if it is a large cap and the load is small (LED indicator lights do not draw much current - very small load), it will discharge slowly.

It's the capacitance in the system that is keeping the lamp lit for a while. You have not discovered a solar panel that produces power in the dark. ;^)

Well the thing is, I don't even use the "load terminals" on my charge controller. As some here have confirmed, it's better to have your load devices (inverter in my case) connected to the battery bank. So I wonder if I connect something small to the inverter while the inverter is hooked up to the "charge controllers load terminals" would that help drain the capacitor so we can eliminate any possible issues that may be occurring with the charge controller...?

Cariboocoot · July 2011

Re: Is This Normal For A MorningStar Charge Controller?

rss2q wrote: »

Well the thing is, I don't even use the "load terminals" on my charge controller. As some here have confirmed, it's better to have your load devices (inverter in my case) connected to the battery bank. So I wonder if I connect something small to the inverter while the inverter is hooked up to the "charge controllers load terminals" would that help drain the capacitor so we can eliminate any possible issues that may be occurring with the charge controller...?

Not actually relevant. The capacitors drain through whatever internal circuitry they're connected to. Only Morningstar knows the exact configuration. Nor is it any matter for concern. Disconnect batteries and panels and the LED's may glow for a while. So what? It isn't doing any harm.

The only things to be concerned with are: the controller does not pass current to charge the battery and/or if it leaks current back to the panels at night causing the battery to discharge. As long as it functions, why worry about how long the LED's glow once power has been discontinued?

rss2q · July 2011

Re: Is This Normal For A MorningStar Charge Controller?

Cariboocoot wrote: »

As long as it functions, why worry about how long the LED's glow once power has been discontinued?

Because if it is something that isn't normal for this controller, it could lead to other issues as you've stated. I've owned other controllers and they never did this so it's a concern when it's not something you are use to happening

Considering I spent $100+ on this product, I just want to ensure it's working properly , and additionally, this problem I'm concerned about "is not" listed in the manual as well. All the other possible conditions are...Ex. red light blinking...red light stay on, green light blinking...etc.
In the manual it states that if the Green Light stays on, this means it's daylight or there is sunlight entering the panel. Well...as I've tested, the light stayed on even when there was no light.

I'll try to check the current while the green light is on for the solar indicator tonight as well.

rgk1 · July 2011

Re: Is This Normal For A MorningStar Charge Controller?

I see some talking about bleeding the power off that is held in the capacitors and keeping the light on till then. That is absolutely possible and shouldn't hurt a thing. It looks like you still have the battery connected and are just concerned about the solar input light being lit indicating a charge without a charge present. Is that correct? If so, I will look at mine this afternoon and see if there is voltage present with the light on and present (or not) when the light goes out. Not comparing apples to apples here, but the controllers probably share a lot of the same workings.

rss2q · July 2011

Re: Is This Normal For A MorningStar Charge Controller?

rgk1 wrote: »

I see some talking about bleeding the power off that is held in the capacitors and keeping the light on till then. That is absolutely possible and shouldn't hurt a thing. It looks like you still have the battery connected and are just concerned about the solar input light being lit indicating a charge without a charge present. Is that correct? If so, I will look at mine this afternoon and see if there is voltage present with the light on and present (or not) when the light goes out. Not comparing apples to apples here, but the controllers probably share a lot of the same workings.

Yes exactly! And yes please do, that would be very helpful. Like I said I have the ProStar 30 to which is just a step up from this version but considering I can't really control the light condition it'll be tough to monitor that one unless I take it down (unhook it) from it's permanent spot.

ggunn · July 2011

Re: Is This Normal For A MorningStar Charge Controller?

rss2q wrote: »

Yes exactly! And yes please do, that would be very helpful. Like I said I have the ProStar 30 to which is just a step up from this version but considering I can't really control the light condition it'll be tough to monitor that one unless I take it down (unhook it) from it's permanent spot.

Why don't you just call Morningstar and ask them about it? I've talked to them several times and they were very forthright over the phone. I think you are worried about a non-issue.

rss2q · July 2011

Re: Is This Normal For A MorningStar Charge Controller?

ggunn wrote: »

Why don't you just call Morningstar and ask them about it? I've talked to them several times and they were very forthright over the phone. I think you are worried about a non-issue.

Could be, but it's better to be safe than sorry no matter how small the issue is. As stated in my opening post, I just wanted to ask here first to hopefully run into others with Morningstar controllers even though it's more likely a question for Morningstar support.

Considering this entire project depends mostly on this controller working properply, I need to understand everything about it and those things that aren't discussed in the manual that are happening.

ggunn · July 2011

Re: Is This Normal For A MorningStar Charge Controller?

rss2q wrote: »

Could be, but it's better to be safe than sorry no matter how small the issue is. As stated in my opening post, I just wanted to ask here first to hopefully run into others with Morningstar controllers even though it's more likely a question for Morningstar support.

So, why haven't you called them? I forget the guy's name who I always get when I call them, but he doesn't bite. ;^)

rss2q · July 2011

Re: Is This Normal For A MorningStar Charge Controller?

ggunn wrote: »

So, why haven't you called them? I forget the guy's name who I always get when I call them, but he doesn't bite. ;^)

1. I'm at work and cannot make outside calls, however, I do have internet access and can occasionally browser non-work related websites.

2. I wanted to collect more data about the concern I have so that I can correctly inform the support rep. exactly what is taking place. Some of this info I want to collect some here have suggested (check the current instead of voltage) thus another good reason to start here first.

rgk1 · July 2011

Re: Is This Normal For A MorningStar Charge Controller?

Morningstar support would be the ones for a difinitve answer. Personally I did't call because I considered it to be a normal operation condition. When charging, the solar input has to have access to the battery to put the current through. Just speculation, but I really think that it just takes a minute for the controller to sense that the battery and solar input voltages are the same (because of that solar/battery connection) and deem it night and disconnect the solar. It may not really even "disconnect". Mine just flashes the solar charge light on every five seconds to indicate "night mode". There may always be whatever voltage is present from the panel on those terminals, but once it hits at or below battery voltage it may just indicate night mode. I will test some senarios and post back tonight.

bmet · July 2011

Re: Is This Normal For A MorningStar Charge Controller?

I recently purchased the less expensive SunSaver CC from Morningstar, and it only has a single green light that seemed to stay on no matter what. I thought it didn't really do anything helpful until one time I disconnected my battery from the CC to make a current measurement. Almost immediately the green light began blinking, and the LVD connection stated pulsing On/Off/On/Off etc. After about 5 seconds everything powered down. As soon as I made the (series) multimeter connection to check Current, everything powered back up as tho nothing happened, green light shining bright.

I really hate that the LVD terminals pulse On and Off like some sort of Klaxon horn. It is so disruptive to my 12V ventilation fans. How'd you like to be jerked back and forth in the processing of spinning down?

Cariboocoot · July 2011

Re: Is This Normal For A MorningStar Charge Controller?

bmet wrote: »

I recently purchased the less expensive SunSaver CC from Morningstar, and it only has a single green light that seemed to stay on no matter what. I thought it didn't really do anything helpful until one time I disconnected my battery from the CC to make a current measurement. Almost immediately the green light began blinking, and the LVD connection stated pulsing On/Off/On/Off etc. After about 5 seconds everything powered down. As soon as I made the (series) multimeter connection to check Current, everything powered back up as tho nothing happened, green light shining bright.

I really hate that the LVD terminals pulse On and Off like some sort of Klaxon horn. It is so disruptive to my 12V ventilation fans. How'd you like to be jerked back and forth in the processing of spinning down?

For what it's worth, charge controllers should always be connected to a battery if there's PV present.
Connect battery first, then PV. Disconnect PV first, then battery. Loads should be connected last and disconnected first.
With just PV connected the Voltage at the output (including "LOAD' terminals) will fluctuate wildly as the controller tries to find a proper PW for charging a battery that isn't there. Eventually it should give up and shut down.

waynefromnscanada · July 2011

Re: Is This Normal For A MorningStar Charge Controller?

Disconnecting the battery while PV is active is a bad thing. I wouldn't do it to any of my controllers. Always cut power from the PV's first. Controllers are too expensive to have go up in smoke.

rgk1 · July 2011

Re: Is This Normal For A MorningStar Charge Controller?

Well, for what it's worth, I took the following at the controller terminals:

Solar charge light on solid, 16.99 volts (12v system in my case)

Battery light indicating float mode, 13.16 volts - a bit low, but 102 degrees in the shed so I think that just temp. compensation.

Flipped the breaker from the panel and the the solar charge light stayed on for about 2.5 minutes - 0.00 volts at the solar terminal. Battery voltage after about 20 min. 13.03 volts.

waynefromnscanada · July 2011

Re: Is This Normal For A MorningStar Charge Controller?

rgk1 wrote: »

Well, for what it's worth, I took the following at the controller terminals:

Solar charge light on solid, 16.99 volts (12v system in my case)

Battery light indicating float mode, 13.16 volts - a bit low, but 102 degrees in the shed so I think that just temp. compensation.

Flipped the breaker from the panel and the the solar charge light stayed on for about 2.5 minutes - 0.00 volts at the solar terminal. Battery voltage after about 20 min. 13.03 volts.

Sounds pretty normal except not sure what that 16.99 volts is. Is the 16.99 volts the input from the PV panels? If so, than that sounds normal. Considering the 102 degrees, 13.16 is likely where float voltage belongs. For best battery temp compensation, use a remote battery temp sensor and locate it on a battery, or for best thermal conductivity, right on one of the battery posts.

rgk1 · July 2011

Re: Is This Normal For A MorningStar Charge Controller?

The 16.99 volts was the solar panel voltage into the cc.

waynefromnscanada · July 2011

Re: Is This Normal For A MorningStar Charge Controller?

rgk1 wrote: »

The 16.99 volts was the solar panel voltage into the cc.

Good, sounds like your system is working well. :-)

bmet · July 2011

Re: Is This Normal For A MorningStar Charge Controller?

My SunSaver's manual does not really explain it's single green LED that well. Usually I don't get into my shed until daylight, so that light is on. Last visit was before sunrise, the light was off. The LVD indicator was off as well, meaning that my circulating fans were being powered. A quick check of the battery voltage showed 12.7V, after running the fans all night.

Operation seems normal, but that green light isn't much of an indicator. It's always on when the sun is out, and apparently always off at night. For an indicator that's supposed to show the status of everything, it's rather lackluster.

Is This Normal For A MorningStar Charge Controller?

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