Morningstar Sunlight controller issue

garynappi

My first and second Sunlight controller are SL-20-12v but the first had a problem with the load not coming on at all, and Morningstar replaced it. 

The replacement has worked perfectly for a few weeks (load set on dusk to dawn setting) until the last two days which were cloudy and perhaps the battery had not taken a full charge. Then for the last two nights the LVD circuit kicked in shutting off my load at 12.1 (should be 11.7) volts on my 95Ah battery. 

I picked Morningstar as an above average cost model over some of the ~$35 options available online, and now I'm thinking I'll go to another brand, but my exterior equipment box was laid out for the Morningstar controller and I'll have to gut it to make brand changes. 

Are there any Morningstar owners using the load who experienced similar issues with their solar controller? 

PS, my loads are light consisting of 24 (one watt LED) Malibu path lights (on dusk to dawn) and a small water pump in a fountain that uses only a few watts.

Photowhit

garynappi said:

 Then for the last two nights the LVD circuit kicked in shutting off my load at 12.1 (should be 11.7) volts on my 95Ah battery. 

PS, my loads are light consisting of 24 (one watt LED) Malibu path lights (on dusk to dawn) and a small water pump in a fountain that uses only a few watts.

Voltage under load will be lower than the voltage with no load. I suspect the Morningstar is working just fine   or at least within tolerances. You may want to invest in an adjustable controller. I think the   Midnite Brat is adjustable.

https://www.solar-electric.com/midnite-solar-brat-pwm-solar-charge-controller.html

mike95490

If there is no sun to recharge the battery, you can't blame the controller when the battery is low.   I'd trust morningstar over just about anything else.

mcgivor

 When a battery is under load the voltage will be under the no load voltage, the controller may have disconnected at 11.7V but quickly climbed to 12.2V, it's no load voltage, the reconnect voltage for loads is 12.8V to prevent loop cycling.

garynappi

Being that my first CC had a faulty load circuit I suspected it, but this AM I looked at the voltage drop, and you're right, it may be on the edge though the battery was fully charged yesterday it still cut off early this morning. 

Today I added a second 80 watt (2x40's) panel(s) and if that cures it I'll go for a second larger panel.

 

Solfyr

Doing the math : 95Ah x 12V ~ 1100Wh .
24 lights x 1 W x 10 hours ~ 240 Wh ...

Adding a pump with 10 W and 10 hours ~ 100 Wh + 250 Wh + losses of 1.3 times ~ 400 Wh 

Since the panels might produce only 2/3 of their 80 Watts peak power , the Voltage might drop too low under 
hot conditions , while the Amps may climb s little above 4.5 A .

The charge controller could be able to handle up to four 80W panels and still be below 20 Amps DC input .

4 Amps input x 7 hours of sunshine ~ 28 Ah , and the battery is empty when 28 Ah x 12 V ~ 350 Wh after some
time , in your case a couple of weeks ....

garynappi

Well, the 100w and 2x40 watt panels kept the battery up and after two days of mostly sunny weather and one partly cloudy the CC shut off the load at 11.9 or 12.1 volts all three days (I watched the battery DC just seconds before the CC LVD shut off the lighting) I bought another CC. 

The Morningstar just isn't my cup-o-tea for my purpose.

ShawnDmi

garynappi said:

Well, the 100w and 2x40 watt panels kept the battery up and after two days of mostly sunny weather and one partly cloudy the CC shut off the load at 11.9 or 12.1 volts all three days (I watched the battery DC just seconds before the CC LVD shut off the lighting) I bought another CC. 

The Morningstar just isn't my cup-o-tea for my purpose.

How much did you spend on CC? Can I find any on https://forum.solar-electric.com/ ?

BB.

Shawn,

The forum here does not have a store here.

Or host, Northern Arizona Wind & Sun can be found here:

https://www.solar-electric.com/

While I am sure that they are more than willing to work with you, if you are in the UK, you may find lower costs for products and shipping.

Bill

mike95490

garynappi said:

Well, the 100w and 2x40 watt panels kept the battery up and after two days of mostly sunny weather and one partly cloudy the CC shut off the load at 11.9 or 12.1 volts all three days (I watched the battery DC just seconds before the CC LVD shut off the lighting) I bought another CC. 

The Morningstar just isn't my cup-o-tea for my purpose.

The load disconnect function is critical to have & use, to prevent damage to your batteries.  11.9V is a DEAD battery and further discharge will quickly destroy it. 
Any quality controller will act nearly the same way.

mike_s

mike95490 said:

11.9V is a DEAD battery and further discharge will quickly destroy it. 

Of course, making a blanket statement like that without specifying the temperature makes it meaningless.

Assuming the industry standard of measuring at 25C, not even close. Trojan would put that at about a 35% state of charge, and that's measuring "open circuit" voltage.  SoC would be even higher if it were being measured under load. 

Morningstar's spec for LVD on the SL-20-12v is 11.7 V. But that controller supports temperature compensation, and 11.9 V would be the equivalent for a temp of ~18C (65F). The 12.1 V mentioned in the OP would be correct at a temp of ~10C (50F), so it was probably working exactly as designed (there's no mention of location or temperature). And that's still over 20% SoC if measured open circuit. Morningstar's LVD is set pretty aggressively.

garynappi

Thx all for your comments, since evenings here in south Florida are warm, I thought that a loaded voltage of 11.9 volts for a deep cycle on occasions at our night time temps is not an unreasonable expectation. 

I'll set the lighting loads for fewer on hours at dusk and near dawn and see how it works out.