Extremely perplexing solar problem

[Rohan]

My boat has 350 watts solar. It's not a complicated set up. 2x 175 watt panels hooked in parallel to the charge controller, and from the charge controller, two wires to the batteries.

Here's the short version of the problem:

The charge controller reads zero amps, even though a multimeter says there is power in the wires coming from the solar panels. So I figured my controller went bad. I got a new controller, which worked fine - for a couple hours. Now it's doing the same thing. Zero amps!! I have no idea what to do now.


Here's the long version:


It's Renogy panels and a Renogy Voygager 20A PWM charge controller. Altogether its about 25ft of 10 gauge copper wire to 2x AGM batteries. This is my third year with this, never had any problems until this month. It always kept batteries topped off.

But this month, I returned to the dock to find my batteries almost drained, and the solar charge controller saying I'm getting 0.0 amps, even though its daylight. OK, so first thing is, I checked the fuse between the controller and battery. It looked fine, but I replaced it anyway. But no change. I checked all the connections to make sure they were tight. They were fine. I checked the length of the wires, nothing was broken. Come back and now I'm getting amps again, so I figured maybe something was loose and I fixed it. OK.

That worked fine for a day, then it went back to zero amps again. I checked all the wires again, this time nothing worked.

Finally, in exasperation, I removed the wires from the charge controller and checked them all with a multimeter. The wires to the battery read the same as the battery voltage, just as they should. The wires from the solar were giving off a very strong charge. So I figured the problem must rest with the charge controller, and I ordered a new one, same type. When it arrived swapped that out, and I was getting amps again. It was running beautifully - for about two hours.

Then back to 0 amps again!! And yes I checked with multimeter again, I have solar power, it's just not going anywhere. Not getting any error messages on the charge controller either, which would be the case if I had crossed polarity or some other major error. What can I do now? This doesn't make any sense.

[Chotu]

What are you seeing within the device itself?

You have only discussed the amps.

What about the solar panel voltage reading from within the charge controller display?

Is it possible the controller thinks your batteries are completely full? What are your settings for charging cutoff voltages?

You should post everything highlighted in the screenshot I took. Except temperature. That’s probably not as important.

[Rohan]

Originally Posted by Chotu

What are you seeing within the device itself?

You have only discussed the amps.

What about the solar panel voltage reading from within the charge controller display?

Is it possible the controller thinks your batteries are completely full? What are your settings for charging cutoff voltages?

You should post everything highlighted in the screenshot I took. Except temperature. That’s probably not as important.

Yes, I could have included that info. The batteries are NOT full. At the moment, they are showing 12.6v, and typically during a clear day (like now) they go up to 14volts or so. But even if they are full, I would normally see at least a trickle amp charge, like 0.2 or something.

Right now the controller is saying I have 12.5 array voltage and 12.7 battery voltage. There's not really a setting for cutoff voltage. This is a very simple system (which is one reason I got it). The only actual thing to set is the battery type, and I set it on AGMs.

Everything's normal except that I'm getting zero amps. And the charge bar isn't flashing like it does if batteries are charging.

[akexpress]

Originally Posted by Rohan

Yes, I could have included that info. The batteries are NOT full. At the moment, they are showing 12.6v, and typically during a clear day (like now) they go up to 14volts or so. But even if they are full, I would normally see at least a trickle amp charge, like 0.2 or something.

Right now the controller is saying I have 12.5 array voltage and 12.7 battery voltage. There's not really a setting for cutoff voltage. This is a very simple system (which is one reason I got it). The only actual thing to set is the battery type, and I set it on AGMs.

Everything's normal except that I'm getting zero amps. And the charge bar isn't flashing like it does if batteries are charging.

Your array voltage is lower than your batteries voltage therefore it will not charge. My previous renology panels were low voltage like 15 volt panels at good sun angles. Victron controllers need a 5 volt differential to begin charging I now have 41 volt panels and the differential is easy to option even with out direct sun.

[Chotu]

With the voltage information I think we have the answer already.

I’m not familiar with that particular charger, but in order to increase the input voltage to the charge controller to try to get it to charge, put those panels in series instead of parallel. I know. You might have some shaded panel problems. But you will get charging if you can get them in some sun.

I think the poster before me is correct.

By putting them in series you will double the input voltage to 24 V. It will have no excuse but to get charging.

Just make sure you don’t exceed the maximum input voltage of the charge controller. I am not sure what it is for that model but I’ll take a quick look.

Edit:

Max. PV Input Power: 12V @ 260W / 24V@520W

You have 350 watts solar at 12v? Through one controller? Or one for each panel?

Also, they do suggest keeping them in parallel in the literature. So, maybe you can ask them why the panels are not putting out enough voltage to exceed your battery voltage.

[Rohan]

Originally Posted by akexpress

Your array voltage is lower than your batteries voltage therefore it will not charge. My previous renology panels were low voltage like 15 volt panels at good sun angles. Victron controllers need a 5 volt differential to begin charging I now have 41 volt panels and the differential is easy to option even with out direct sun.

The multimeter was showing 20.4 volts coming from the panels though.

In addition, under midday conditions, it has never failed to charge before. Even late in the evening I get at least a tiny amperage showing.

[Chotu]

Originally Posted by Rohan

The multimeter was showing 20.4 volts coming from the panels though.

In addition, under midday conditions, it has never failed to charge before. Even late in the evening I get at least a tiny amperage showing.

Disregard my last post. You are getting a lot closer here.

If the multimeter shows 20.4 V (at the end you connect to the charge controller??) and the charge controller shows an internal reading of the panels at 12.5 V there is something wrong between the input wire and the circuit that measures the panel voltage.

Do you have pictures of the connections that you made? Where we transfer from solar panel wire to the connector on the charge controller? How do you prepared the wires and such?

Because definitely the options are running out here. It would be quite amazing if all of these charge controllers went bad. But that is what your voltages in this post to say.

[Rohan]

Originally Posted by Chotu

Max. PV Input Power: 12V @ 260W / 24V@520W

You have 350 watts solar at 12v? Through one controller? Or one for each panel?

One controller for both, and 12v. I just separately noticed this myself. So I am above the maximum recommended wattage. I'll get a different controller. However, it still doesn't make sense. I was fine for years and suddenly two controllers fail this month?

It's the exact same sun this year as previous years!

[smac999]

Originally Posted by Rohan

One controller for both, and 12v. I just separately noticed this myself. So I am above the maximum recommended wattage. I'll get a different controller. However, it still doesn't make sense. I was fine for years and suddenly two controllers fail this month?

It's the exact same sun this year as previous years!

get a victron smart mppt. and maybe put them in series for 20v panels, but I would try parellel first. parallel is better if any piece gets shaded. renogoy is cheap garbage.

also test the voc and short circuit current of each panel to see if they are working or not.

[GILow]

As said already... toss the Renogy stuff. It is utter crap.

I've lost track of the number of failed Renogy controllers I've seen now. And even while they are working they have very little in the way of control.

Buy Victron, you won't regret it.

[KingRichard]

I would pile onto the 2 posts before me, I didn't think much of the Renogy controller that I had. The connectors to the panel were fine, but the inputs and outputs for the controller were junk. I was always fighting with them.

[Rohan]

So now I cut crusing short to return to the marina, because you know, no solar power. As soon as I tie off to the dock out of nowhere it starts working again!! It's so random arrrgh

Well, I've ordered a better one. My choices are somewhat limited because I need it to be robust enough for my wattage, but also fit on my on my instrument panel to cover the hole I had to create to accommodate the Renogy controller...

[GILow]

Originally Posted by Rohan

… My choices are somewhat limited because I need it to be robust enough for my wattage, but also fit on my on my instrument panel to cover the hole I had to create to accommodate the Renogy controller...

This is insane logic. The wattages you are dealing with are trivial. Absolutely basic stuff.

Plug the hole with Perspex or something and just buy a decent controller.

Wasn’t it Albert Einstein who said the definition of insanity is doing the same thing over and over again and expecting a different result?

[noelex 77]

There is obviously an intermittent fault somewhere in the system. Intermittent electrical faults can be frustrating to track down.

Given you have replaced the solar charge controller with no improvement, it is likely the issue lies elsewhere and replacing the charge controller with another brand is unlikely to solve the problem.

The low array voltage of 12.5v reported in post #3 suggests the problem is with the solar panels themselves or the wiring between the panels and the controller.

The first thing I would do is check the Voc and Isc of each of the solar panels. There are YouTube videos explaining how to test solar panels. Try these tests at the solar panels themselves and at the input leads of the solar controller. This will show up any problems in the wiring between the solar panels and the controller.

As you have an intermittent problem you will need to repeat these tests when the fault develops.

[markcouz]

Before throwing money at the problem I suggest that you cut out the MC4 connectors and hard wire as a test, if it solves your problem then replace the connectors with new.

Also do you have any fuses between panels and controller? Those glass tube fuse holders are often a failure point and only required fore more than 2 parallel panels.