Sunsaver MPPT fails to charge in cold weather...

Hi,

I have two solar systems on my small pickup camper, each one runs it’s own battery, one primary and one backup, using a marine battery selector switch.

The backup system is a Optima Blue top charged via a 40 watt flex panel mounted on my air dam with a Sunsaver SS10L Gen-2, it works perfectly and keeps the backup battery topped off at all times.

The primary is a Sears DieHard Group 31 battery connected to a Sunsaver MMPT controller that has the the remote temp sensor and RM-1 remote readout. It is charged primarily by a roof mounted 135 watt panel with a slide out / removable 100 watt for additional juice.

All of this works great in temperatures down to 40F. Once I get to 20-30F, the backup system works great and the primary simply fails. I go out to my truck in the morning to find the main battery has dropped down to between 12.3-12.6V, I get the solid red LED for the battery SOC and the panel is kicking out over 20V so the charge controller is getting plenty of juice. This has been going on and on since I have owned the darn thing and I thought it was just a cold weather thing until I setup the backup system earlier this year. I have disconnected the RM-1 to save on juice as it is really cold out right now, 0 outside and 22 in the camper with over night lows of below zero but this is driving me nuts, the thing is just not charging the battery and there are no loads on it, not even the CO2 alarm which I a put a switch on for this reason.

Morningstar’s tech support has been the worst I have ever encountered, it took a week for them to get back to me via email when I called with an emergency from the field a month ago, horrible service, they ought to be ashamed.

So I am at a loss as to what to do, this thing is just not working in cold weather and frankly, never has…
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Comments

  • BB.BB. Super Moderators, Administrators Posts: 31,462 admin
    Re: Sunsaver MPPT fails to charge in cold weather...

    Hmm... Sorry to hear about the tech support--In general, heard that they were pretty good.

    Thinks I would do (and you have have done):
    1. Measure voltage on the terminals of the charge controller (Vpanel>15 volts; Vbatt~to battery voltage)
    2. Disconnect solar array, then disconnect battery (just lift the positive leads on both). Wait 1/2 a minute. Reconnect battery + lead. Then reconnect solar + lead (and recheck terminal voltages).
    3. You can disconnect the temperature sensor and use an Ohm meter to see if you get a connection (it is a thermistor with something like ~1,000-10,000 Ohm resistance--If you get zero or infinate resistance, then the temp sensor is bad (not sure if that would cause the controller to "fail" though).
    4. If you can, give MorningStar your Model Number/Serial number for the MPPT controller and see if there are any issues logged against it (at one point, a few years ago--I think I remember MorningStar having a production issue with some controllers).

    Other than the above (you can get a computer interface and talk with the controller)--But I am not sure I would spend the money/time going down that road first.

    I have no direct experience with any charge controllers...

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • GlowormGloworm Solar Expert Posts: 28
    Re: Sunsaver MPPT fails to charge in cold weather...

    I just ran these tests except for the sensor, solid 20.8V from the panel.

    The odd thing is, I turn the motor over for a few minutes in the morning to wake it up and it works all day from then on out, battery SOC readings of 13.8-15V, charge light on just like it is doing now. I should not have to "jump start" the thing in the mornings but if I don't, the system snoozes away and the battery goes well below 13V giving me a red LED on the SOC.

    I wrote the tech support guy about it yesterday morning and have yet to hear back....
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Sunsaver MPPT fails to charge in cold weather...

    "Solid 20.8V from panel" indicates the panel is not connected to the battery, as this is likely the Voc of the panel. If it were the Voltage on the input of the controller would the same as battery. So the question is "why is it not connecting"?

    Thought: the cold temperatures are causing the Voc of the panel to go high enough to cause the charge controller to shut down from over-Voltage.

    Idea: connect the panel (+) to a single pole, double throw switch so that in one position it is connected directly to the battery and in the other to the charge controller input. Switch to direct connection to begin with in the morning, then to the controller's input to get regulated charge (rather than starting the motor).

    Another thought is that with no loads on the battery should not be losing much over night, even in cold. And of course panels do not begin charging first thing either; just because you have Voc doesn't mean you have any current. So check the current output of the panel as well.
  • GlowormGloworm Solar Expert Posts: 28
    Re: Sunsaver MPPT fails to charge in cold weather...

    The reading I was getting from the panel was both from the remote meter readout which is fed by the charge controller and from the leads connected to the controller. I have not taken a reading in the morning but will tomorrow.

    The sun just went behind a mountain but on the 135 watt panel on the roof, I got 16.5V and 5A, charge LED is on and blinking which indicated bulk charge, battery shows 13.4V.
    The 40 watt which is pointed right where the sun set is putting out 19.8V and 6.32A, battery shows 14.8V, this is at 4F.

    I'm not sure about the switch since I need this to be a setup that works unattended, the vehicle can be parked on location in work scenarios for days on end until I return to it.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Sunsaver MPPT fails to charge in cold weather...

    i think i know what may be going on here. it is true that a pv will output a bit more voltage during cold weather, but the requirements of a cold battery jump farther up than the pvs rise. the die hard has different charging parameters than the other battery used. it could be falling short on an optimal mppt voltage level. a test of this may be to try it without the temp sensor. now i don't remember if the cc has a built in sensor too for if it does and it reverts to it from disconnecting the sensor at the battery then this test might be a bust. the only difference here is the battery being employed so the clue is there.
  • GlowormGloworm Solar Expert Posts: 28
    Re: Sunsaver MPPT fails to charge in cold weather...

    The SSMPPT has a built in sensor it will revert to. I did check the dip switches and one was out of place, the Sears is an AGM battery and I had it set to sealed. One other thing might be a power drain. I have this wonky Aopec battery separator that lights up with a bright green light when in operation and it might be pulling too much juice in the Winter. So I turned the battery selector switch to the off position and will see what happens.

    The battery was at 12.43V this am and showing the same red led while the panel was at nearly 22V/7.6A....this part still does not make sense. The backup was at 15V, something is just not right...this was at 10AM, plenty of time for the solar to start doing it's job like it is on the backup battery. It's not kicking over...
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Sunsaver MPPT fails to charge in cold weather...

    What are the specs on that 135 Watt panel? 7.6 Amps I can believe for Imp, but the Voltage should then be about 17 not 22.

    I have a vague recollection of there being a problem with some of the MS Sunsaver 15 MPPT's. Can't seem to find the thread now, though. I believe there was a firmware update for it?
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Sunsaver MPPT fails to charge in cold weather...

    i believe the sears agm batteries have high absorb voltage points too making the cold voltages needed to charge it quite high and probably close to the vmp of the pv after losses through the cc.

    give the specs for the 135w and 100w (slide out?) pv. i'm thinking you trying to run these 2 pvs in series to the cc to see if the is a problem with too low of a vmp to properly charge the battery.
  • GlowormGloworm Solar Expert Posts: 28
    Re: Sunsaver MPPT fails to charge in cold weather...

    I usually don't run the spare 100W, but I will tomorrow, it is snowing out right now.
  • GlowormGloworm Solar Expert Posts: 28
    Re: Sunsaver MPPT fails to charge in cold weather...

    Well, I am at a loss as to what to do other than send the SS MPPT 15L and RM-1 in for service, after exhaustive testing I have arrived at the fact that is is simply not applying any charge to the battery at all. I am getting odd behavior from the RM-1, self test errors from the controller, it simply is not feeding the battery any of the 200+ watts and 21V of juice from the panels. Morningstar did eventually get back to me on Monday but the dialogue is so slow that it is like having a conversation with someone in person and they respond to a question a day or more later, totally *INSANE* at this point.

    So all in all, the SS10L with a 40 watt panel continues to get that battery up to 15V even on the coldest of days and the SS MPPT 15L is not doing a damn thing. Looks like faulty hardware to me, I can not believe this dialogue started with the company over a month ago and this is where I am at, simply ludicrous!
  • tons001tons001 Solar Expert Posts: 71 ✭✭
    Re: Sunsaver MPPT fails to charge in cold weather...

    I would look into the Midnite Kid or Brat when it comes out. The folks over at Midnite have some of the best and most responsive customer service I have ever experienced.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Sunsaver MPPT fails to charge in cold weather...

    The fact that you are seeing Voc on the panel practically all the time indicates that the controller is not connecting it to the battery. Other than being defective the only explanation I can think of is that the controller is for some reason expecting a 24 Volt system rather than 12 (which would explain why pushing the battery Voltage up with the engine causes it to 'latch' and start charging; otherwise it sees the Voltage as being so low that it thinks there is no battery connected). This is automatically detected at initiallization, so it may be getting it wrong.
  • GlowormGloworm Solar Expert Posts: 28
    Re: Sunsaver MPPT fails to charge in cold weather...
    (which would explain why pushing the battery Voltage up with the engine causes it to 'latch' and start charging; otherwise it sees the Voltage as being so low that it thinks there is no battery connected).

    I no longer think that was the case, upon more regular examination, the amp hour feed count on the RM-1 shows no activity. The lowest reading I have gotten from the battery in using the RM-1's readout or my Fluke multi-meter is 12.34V, no where close to the low voltage disconnect setting of 11.5V. The alternator is the only thing that brings up the battery voltage at this point, the controller is doing nothing.

    I just checked the firmware version of the controller via the RM-1, it shows the first one ( .05 ), there have been 4 more since so I think this simply has to go in for service. And I hope the darn battery is not going south now, I ran the truck for 5 minutes 40 minutes ago, it got the battery up to 14.25V and then after I shut the motor off, it dropped back down to where it has been all day at 12.75V. The thing that made me think the truck was making the system "latch" was that it got it up to 15V the other day and then it stayed there once the motor was turned off....but according to the remote meter, no amp hours were being fed to the battery.

    it just sucks how many hundreds if not a thousand dollars in down time I have had because of this over the past month, truly a nightmare...
  • GlowormGloworm Solar Expert Posts: 28
    Re: Sunsaver MPPT fails to charge in cold weather...
    tons001 wrote: »
    I would look into the Midnite Kid or Brat when it comes out. The folks over at Midnite have some of the best and most responsive customer service I have ever experienced.

    Thanks for the tip but after spending a few hundred bucks on this setup and all the time I have into it, I need to give them a chance to make good on their 5 year warranty and stand behind their product. I really do think it is bad hardware, there are other references to these models being bad in the first round.
  • tons001tons001 Solar Expert Posts: 71 ✭✭
    Re: Sunsaver MPPT fails to charge in cold weather...
    Gloworm wrote: »
    Thanks for the tip but after spending a few hundred bucks on this setup and all the time I have into it, I need to give them a chance to make good on their 5 year warranty and stand behind their product. I really do think it is bad hardware, there are other references to these models being bad in the first round.

    Understandable. I had a question about the Morningstar RelayDriver and it took a solid 6 days to get a response that was less than useful.
  • GlowormGloworm Solar Expert Posts: 28
    Re: Sunsaver MPPT fails to charge in cold weather...

    Also, there is another question I can not seem to get an answer to online or via tech support. On the RM-1 remote meter that connects to the SS MPPT 15L, there is a readout in the battery mode that the supplied documentation ( Sunsaver MPPT Meter Map ) refers to as "Battery Watts", the last item of 5 on the battery info display sub-menu.

    What exactly is this telling me? The watts the battery is putting out or the load placed on the battery? Oh, and that stopped working along with the battery amp hours display as of a day or so ago, they now both read zero no matter what, the only thing the battery display shows me now is battery voltage in current state, the min and max seem to self reset sometime during the day.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Sunsaver MPPT fails to charge in cold weather...

    It can only be the Watts going to the battery as the charge controller has no way of measuring Watts of anything else.
  • GlowormGloworm Solar Expert Posts: 28
    Re: Sunsaver MPPT fails to charge in cold weather...
    It can only be the Watts going to the battery as the charge controller has no way of measuring Watts of anything else.

    I'm not sure, in the past I have seen it go as high as 25-55 watts, that makes no sense given the panels have a max of 14W combined and the controller caps it at 15W. Maybe one day Morningstar will give me the answer.....lol!
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Sunsaver MPPT fails to charge in cold weather...
    Gloworm wrote: »
    I'm not sure, in the past I have seen it go as high as 25-55 watts, that makes no sense given the panels have a max of 14W combined and the controller caps it at 15W. Maybe one day Morningstar will give me the answer.....lol!

    If it's broken it could turn up just about any kind of number. :p
    But the controller has no ability to read anything other than Voltage IN/OUT and current through it.
  • PNjunctionPNjunction Solar Expert Posts: 762 ✭✭✭
    Re: Sunsaver MPPT fails to charge in cold weather...

    Since you are switching the battery in and out of circuit, are you also making sure that the panel itself is switched in last?

    Many smart controllers will shut down if they sense panel voltage first. They need the battery attached first to get their logic together. Of the controllers I've messed with, if the panel is attached first, the controller goes completely dumb (as a safety feature to ensure that you aren't trying to charge an undervoltage battery), or may just immediately drop to float voltage and stay there when the battery is finally connected in the wrong order.
  • GlowormGloworm Solar Expert Posts: 28
    Re: Sunsaver MPPT fails to charge in cold weather...
    PNjunction wrote: »
    Since you are switching the battery in and out of circuit, are you also making sure that the panel itself is switched in last?

    Many smart controllers will shut down if they sense panel voltage first. They need the battery attached first to get their logic together. Of the controllers I've messed with, if the panel is attached first, the controller goes completely dumb (as a safety feature to ensure that you aren't trying to charge an undervoltage battery), or may just immediately drop to float voltage and stay there when the battery is finally connected in the wrong order.

    I only disconnected and reconnected the battery and solar leads once this past week...I honestly can not remember what order I reconnected them in....

    So I just went out to the truck / camper to see about trying the above. I disconnected everything, put the battery selector switch to the main battery and ran the truck for about 10 minutes, battery showed charging from the camper's control panel, 14.25V. Turned off the truck and battery selector to off and waited 10 more minutes. Put the battery leads back on, both the controller and remote showed solid green for the battery SOC, controller showed night mode, voltage a reasonable 12.85V. I waited 10 more minutes and it stayed there So I reconnected the solar leads, all seems to look normal, I'll check the status of it all an hour after sunrise tomorrow, thanks for the advice.
  • GlowormGloworm Solar Expert Posts: 28
    Re: Sunsaver MPPT fails to charge in cold weather...

    Just checked on it this morning, 12.7V battery, 21.8Voc, 8.3A, no charging taking place, time for a new one.
  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: Sunsaver MPPT fails to charge in cold weather...
    Gloworm wrote: »
    8.3A, no charging taking place.

    HUH????? Where is the 8.3 amps going?
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Sunsaver MPPT fails to charge in cold weather...
    Gloworm wrote: »
    Just checked on it this morning, 12.7V battery, 21.8Voc, 8.3A, no charging taking place, time for a new one.

    As Wayne implies, this is impossible. With the panel at Voc there would be no current, regardless of how it is connected to the battery. How are you getting these numbers?

    I'd bypass the controller completely and see if the panel actually puts out anything in current. The Voltage should go down to battery level. If it doesn't, there's no connection.
  • GlowormGloworm Solar Expert Posts: 28
    Re: Sunsaver MPPT fails to charge in cold weather...

    Maybe I am using the wrong term then...

    I have disconnects at the panel so I read the voltage the panel is putting out at the connection with a Fluke multi-meter, voltage showed 21.8V, 8.3A. Same readings at the terminals on the controller. Either way, I am getting a replacement controller, this one is just not sending the input from the panel to the battery.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Sunsaver MPPT fails to charge in cold weather...

    Voc: Voltage open circuit. Nothing connected to the panel leads except the Volt meter.
    Current reading take with Ammeter connected between panel leads, panel in full sun.
    You can not read both at the same time.
    You can read Vmp (Voltage maximum power) and current at the same time, as that is the Voltage 'under load'.

    If your meter is reading 8.3 Amps across the panel leads it will not be at the same time as the Voltage reading 21.8 although the meter connections will be the same.

    The 8.3 Amp reading indicates the panel is capable of providing power. To read what is actually going to the battery (if anything) the meter has to interrupt the positive wire from the controller to the battery so that the current flows through the meter. You can also measure current to the controller by interrupting the positive lead from the panel to the controller. If you get 8 Amps to the controller and zero Amps to the battery the controller is not functioning but is shorting out current internally.

    Under the current tests listed above panel Voltage should read around 17-18. You can not have Voc and Imp at the same time.
  • GlowormGloworm Solar Expert Posts: 28
    Re: Sunsaver MPPT fails to charge in cold weather...

    The meter does not read both at the same time, I have to select the mode, two separate readings. Given the post below about the connection order of the controller, how do I interrupt the lead from the controller to the battery to get a reading of what the controller is putting out if it is likely to shut down?

    Another dumb question, the remote meter for the controller reads the same 21.8V for the solar, how am I to get the other reading of 17-18V?

    I am using a Fluke 77 multi-meter...
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Sunsaver MPPT fails to charge in cold weather...

    Okay it's diagram time. :D

    In the example "LOAD" is either the charge controller with the battery on the output or the battery directly. There has to be some sort of load on a panel in order for it to produce current. A short-circuit connection would be 'maximum load' wherein you'd get Isc and zero Volts.

    As you can see you can't measure both Imp (current at maximum power) and Vmp (Voltage at maximum power) at the same time using one meter.
  • westbranchwestbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Sunsaver MPPT fails to charge in cold weather...

    how am I to get the other reading of 17-18V?

    IN order to get VMP showing on you meter, the output of the PV MUST be going to a battery or other load(light).
    When there is no load you get Voc, open current, since there is no resistance hence 'open current'. Other wise you get Vmp.
    As Wayne noted the only way to not get OC readings is when there is a load.

    hope this helps.
     
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  • GlowormGloworm Solar Expert Posts: 28
    Re: Sunsaver MPPT fails to charge in cold weather...

    Ok, I am not going crazy then, that is what I thought.

    I think ultimately the charge controller is failing to apply what should be power to the battery, so I am not getting a reading that would reflect a load even with everything connected, this has been the issue all along. For example after reconnecting everything this morning, when I checked at noon, the remote meter said that the battery was at 14.98V, solar was 21.80V, both amp hours and watts read zero, the SOC is blinking once per second which indicates absorption charge. When this was working the AH would up count as the battery was fed and there would be some number value given on the watts display.

    So the sun goes down, the battery drops in voltage as the panel voltage does but the battery voltage does not come back up in the morning when it used to and the SOC readouts cycle between 1/2 full and dead indicator when the battery is reading 12.7-12.85V. Morningstar confirmed they are sending me a new controller and I will send them the old one.

    ****************

    Now then, I do have another question regarding my main setup, it is a little convoluted and was born of adaptation rather than being designed from scratch like the backup system has been...which works *perfectly*.

    In the attached photo, you can see three panels, the closest one is a 40watt on the air dam that feeds my 55AH Optima backup battery via the SS10L, works fine, is connected via a bulkhead RV connection under the cabover.

    The second panel on the right is a slide out / removable 100watt that was put in after the main install. It is also wired through a dedicated connector next to the one for the 40watt under the cabover. It goes to the SS-MPPT-15L on it's own wiring, directly to the controller. When I have it stowed, I simply unplug the bulkhead connector.

    The third and largest panel is the 135watt on the roof, it replaced the original 85watt that the folks at the camper place put in when I requested solar, it has it's own set of wiring that goes through the roof, down the front of the cabover and then back through the camper to the charge controller which is next to the battery box, like the 100watt, has it's own set of connection to the controller and feeds a 100AH Die Hard Group 31M ( Odyssey 31M PC2150 ). The bummer about this setup is that once into the wall of the camper, I have no way to access that wiring to change the gauge, what is there is there, about 18-20 feet of wire in total from panel to controller.

    So the install history goes 85watt factory, add 100watt, replace 85watt with 135watt, add 40watt backup system. The question is that since I only use the 100watt part time, I wanted to keep the wiring separate so there are two panels attached to one set of terminals on the controller, am I creating efficiency issues by doing this? The reason I ask is that besides all of the crazy issues as of late, when the 100watt is unplugged, I can read panel voltage at the connection that goes from the bulkhead connection to the charge controller, this is coming from the large panel on the roof.

    I have checked it in both modes by disconnecting the wiring for the unplugged 100watt panel from the controller and then putting them back on to see if there is any voltage drop and there is none, since there is nothing connected to the bulked connection and the cap is on, I *think* I am ok.....or am I?


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