Weird Issue Sterling Error Light, Solar Stops Charging

[simonpickard]

Hello all,

Please bear with me in this thread as I'm very green when it comes to electrical systems. I'm trying to learn as I go but a lot of this stuff is above me at the moment any advice would be amazing.

My issue is quite hard to describe. I have 300 watts of solar going into a solar controller box. I can charge via shore and by the engine.

There's a red sterling box,shown below, that keeps showing a red warning light

What seems to happen is when on shore power everything works fine. The volts for house go up to 14.5 and everything charges well.

When I disconnect from shore the solar seems to do its thing. I can see it on bulk and the voltages rise slowly as well. The red sterling box will show a green and blue led for this.

When the volts get to around. 13.7 ish via the solar the blue controller box goes into float mode. Again all seems well.

The volts then slowly drop until they reach 13.4ish. At this point the blue solar controller box moves into bulk mode again. At this point the red sterling box switches off the green and blue LEDs and a flashing red comes on.

From here I'm not sure really what is happening. The volts seem to slowly drop when in bulk they should rise?

Connecting back to shore power, or running the engine for a while at 1500rpm resets things.

Any idea what is going on? If I can provide any more info I will of course but it seems like the bulk mode of the solar controller is throwing up a warning light on the sterling box for some reason.

Regards,
Simon



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[h the boat]

Hi Simon, as this is a relatively new installation for your vessel, there are two possible faults, No 1. which is most likely, is that there is a poor connection from the control box to your battery system. Remove and reconnect the cables, one at a time, starting from the control box end. If this does not find and cure the problem, (assuming that your batteries are not dried). Then the problem is probably within the control box itself, and needs to be returned under warrenty. The electronics within the control box, although relatively simple, are not designed to be adjusted or repaired. The flashing red l e d , indicates that there is solar power available but is not reaching your battery system.. Rgds, h the boat.

[simonpickard]

Thanks,

The issue with returning is that we're cruising the med. Don't really want to get stuck somewhere for a week if possible.
I'll check the contacts.

Thanks,
Simon



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[h the boat]

Hi again Simon, A work round in an emergency, although not to be recommended, is to connect the solar bank direct to your battery system for a limited time.. YOU WILL HAVE TO MONITOR both the charge rate and the developed voltage, manually, with a multimeter, if your system does not already include these items. You will very quickly discover how long you can leave them connected to get a reasonable charge. if the initial charge is too great, then you will need to screen part of the panel. The maximum charge voltage should not be allowed to exceed about 14.5 V. let me know how you get on. h the boat.

[colemj]

Isn't that Sterling device just a simple VSR? It doesn't have anything to do with the solar regulator (or shouldn't). A VSR is used to combine battery banks when charging sources are present. I can't tell from the picture, but it doesn't look like it is connected to the solar regulator at all - they both look like they are connected to a battery or busbar. Also, I believe the voltage connect/disconnect voltage setpoints are adjustable on it, as well as the high voltage alarm point.

Mark

[CharlieJ]

What does the label on the "Red Sterling Box" say? It appears to be a ProLatch R latching relay, but with one less LED. How long has it been installed?

[simonpickard]

It's been installed since we got the boat new in march.

The red warming light says "Warning adverse event".

Looking at the wiring you might be right, the solar doesn't look to be connected to that box? But when the solar blue box does go into bulk mode the red light turns on and then I seem to start losing voltage?



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[simonpickard]

Just noticed this as well.. Not sure I've seen this before but there's a little bit of, I'm guessing, water near the - contact?





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[Ex-Calif]

Originally Posted by colemj

Isn't that Sterling device just a simple VSR? It doesn't have anything to do with the solar regulator (or shouldn't). A VSR is used to combine battery banks when charging sources are present. I can't tell from the picture, but it doesn't look like it is connected to the solar regulator at all - they both look like they are connected to a battery or busbar. Also, I believe the voltage connect/disconnect voltage setpoints are adjustable on it, as well as the high voltage alarm point.

Mark

Bingo - Sterling calls this a VSRB (digital model) - manual here http://ku.sterling-power.eu/acatalog/VSRB.pdf

@Simon - You should spend some time surfing the internet and collect all the manuals for all your systems. I did this over the course of several weeks when I bought my boat.

In reading the error codes the unit will detect undervolt on both batts at startup, overvolt and severe voltage disagree between the batts.

Also a slow red flash is normal and indicates both batts are below the engage level of 13.3 volts and the unit is "sleeping" - it will only parallel the batteries if 13.3 volts or greater is available and will unparallel at 13.0

If your MPPPT goes into "float" and the panels get shaded or something you could drop below 13.0, the system unparallels and will not parallel again until 13.3.

The code Simon describes (solid red led) appears to be undervolt of both batteries but it appears this code should only be set during start up of the system. It makes sense that starting the engine and reving up clears the fault as presumably the alternator gets the voltage up on the charge side battery.

I am presuming all the charge sources are on the house side and the VSR is used to charge the start batt.

This is a pretty butt simple device - Bottom line is that it should parallel (CLICK) at 13.3 and unparralel at 13.0. Basically parallel when charge source is available.

It does have user settable levels - PO may have done that but I would not know why.

[simonpickard]

So there might be nothing wrong then? The slow red flash means the system is just idle?

What I don't get is why the volts drop then? Shouldn't the solar just keep throwing charge into the bank to try and keep it at 14.5v?

Also is that water an issue?



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[Ex-Calif]

Originally Posted by simonpickard

So there might be nothing wrong then? The slow red flash means the system is just idle?

What I don't get is why the volts drop then? Shouldn't the solar just keep throwing charge into the bank to try and keep it at 14.5v?

Also is that water an issue?



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You need to clarify the Red LED - Is it a slow red blink or solid red?

Slow red blink is normal for batteries not being charged - i.e. below 13.0

The next part of your question is the behavior of the MPPT. You said it "cycles" from bulk to float - I don't think that is what is happening. I haven't read your MPPT manual but assuming it is a 3-phase charger there is bulk (max amps), absorption (lower volts so the battery can take time to "absorb" amps) and float (minimal volts above "static" battery voltage to keep getting the last amps in there)

What gets the amps in is volts. Think of a faucet and an empty jug - max faucet in the beginning, slower nearing full and a trickle to finish up.

The battery does this due to the speed at which chemical reactions can take place inside the battery, all affected by heat (resistance) near the end you want low heat/resistance so you can trickle the last in.

So, yes. The solar array is paralleled in with the start batt - the charger is measuring the combination of both batts. When absorption is passed and float is reached the voltage is cut back - the VSRP may detect this as charging source not available and take the batts out of parallel - all normal. Now the MPPT is only measuring house!

Not sure that this should kick the MPPT back into absorption but it might - and the absorption phase may not be enough to kick the VSRP back into parallel - you wouldn't want it to or it would cycle back and forth like crazy.

I am not saying this is what is happening. I am saying all of this is plausible. It could all be operating completely normally.

BTW - Battery condition comes into play here but it should not really change anything fundamentally and if you have been reading between the lines, by definition the slaved battery never gets a float charge and never will get to 100% and in pure terms will suffer a "shorter life" - the downfall (slight) of parallel relays taking care of the start batt.

[simonpickard]

Sorry it's a slow flashing red yes.
Thanks for the reply. I think it's all starting to make sense!



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[simonpickard]

There are three LEDs on the solar controller so I think you're right that it's a three phase but I've only ever seen it in float or bulk mode.

Also this little bit of water is worrying me, or is that what batteries do? Should I just clean it up?



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[Ex-Calif]

Try this observation to appease your mind. Once the VSRP goes to sleep this means the house is nearing full and the MPPT is cut back.

Use amps over night and the house is "down" - the next day the solar detects low batt, goes into bulk (14+ volts) the VSRP wakes up and says, "charger available" and goes into parallel. The start batt is still fulle but the VSRP doesn't care. It's a dumb device.

The MPPT does it's thing now sensing all batts (combined) at some point absorption voltage is detected and the MPPT goes into absorb - it stays there a while (hours?) and eventually trips to float. The VSRP says, "No charger available." unparallels and then goes to sleep.

The MPPT sits there in float mode until you use up some amps.

Now shore charger and alternator are just other charge sources competing for "turf" they coexist happily but have different charge profiles. They all should be reading batt voltage (sense) and be trying to apply their charge regimes. They don't synchronize but they coexist because they are all sensing the same batteries ensuring the batteries can't/aren't getting 3X the charge they can absorb.

[simonpickard]

You know, thinking about it. I don't think I've ever seen that solar charger go into absorption. It's only ever in float or bulk.



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