Extremely perplexing solar problem

[Rohan]

Originally Posted by 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 crazy thing is, when I plugged in the new controller it started charging right away - for awhile. Also, during the fault periods I am getting a strong charge when I test it with the multi-meter - but 0.0 amps on the panel. So if it is an intermittent electrical fault, it's like it has a mind of it's own and is purposely trying to piss me off!

I already ordered an MPPT controller. That's the hill I will die on. If that fails to charge then I'll rewire the whole system instead of replacing the controller again.



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[noelex 77]

Originally Posted by Rohan

So if it is an intermittent electrical fault, it's like it has a mind of it's own and is purposely trying to piss me off!

I think every boat owner has felt that way at some stage.

With an intermittent problem such as this it is much easier to find the fault when it is not functioning correctly. So in many ways the charging dropping to zero is a good thing. You can then easily trace the fault.

At least that is my "glass is half full" view of these type of problems.

[GreenWave]

An MPPT controller is only way to go. While Victron is very good you could get another brand but no renogy. My guess is you were exceeding limits of your PWM controller and frying it.

[GILow]

Originally Posted by GreenWave

An MPPT controller is only way to go. While Victron is very good you could get another brand but no renogy. My guess is you were exceeding limits of your PWM controller and frying it.

Yep, plugging a Renogy controller in will exceed its expected operating parameters. I think they were designed to live in their box, unopened.

[tanglewood]

Do the panel tests described by others. Measure open circuit voltage and compare with specs. Then measure short circuit current and compare with specs.

Also, you say that during the fault periods you have a “strong charge” even though the panel says 0 amps. How are you measuring “strong charge”. Is the display part of the controller, or is it separate?

[Rohan]

Originally Posted by GreenWave

An MPPT controller is only way to go. While Victron is very good you could get another brand but no renogy. My guess is you were exceeding limits of your PWM controller and frying it.

Possible of course. But again, it's weird it would be fine for 3 years then suddenly fail two controllers in the same month, then they randomly still work for short periods. Also, I wasn't far outside the recommended maximum wattage, and that's a theoretical wattage, based on 100% solar efficiency which basically never happens.

[Rohan]

Originally Posted by tanglewood

Also, you say that during the fault periods you have a “strong charge” even though the panel says 0 amps. How are you measuring “strong charge”. Is the display part of the controller, or is it separate?

What I mean is I unplugged the solar wires from the charge controller and tested the tips right where they would be plugged into the controller.

[KingRichard]

Have you ever had to wiggle the battery cable to get a car to start? Once the current is flowing it's fine, it just didn't have very good contact and you kind of wipe away the surface corrosion. This sounds a lot like that situation.

I don't know about you'll, but I have had that happen a lot on boats. I even used to have to do it with my navigation lights. I mentioned not liking the connections on my Renrogy controller. I tinned the wires to help with this issue, but the connectors just don't get very tight, so it still wasn't great. You might just have to clean and tighten some connections.

[PNWSalmon]

Originally Posted by 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.

This is the answer, in my opinion. We have five panels, one uses MC4 and it’s always giving me trouble. Low voltage because of some loose connection. I’ve redone them multiple times, they work for a while, then it gets into this low voltage situation.

It sounds exactly like the OPs problem, honestly.

I’m generally pretty good with making solid electrical connections but I must have some basic lack of skills or understanding with these MC4 connectors because they give me nothing but trouble. I need to cut them off and just use a tow hitch plug or something instead

Luckily the fifth panel is just a small addition and not the bulk of our charging, but it’s still another 120 watts and it’s nice to have working.

[sailorboy1]

Originally Posted by Rohan

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.

I went through a similar problem couple of years ago. There was voltage at the controller but no amps, so replaced the controller. It still did same thing. I slooooowly went over the wiring 3 times on the 3rd time in the bright sunlight was able to see that one of the MC4 solar wire connectors looked burnt. Cut it out and reconnected and everything was fine.

Hard to see a little burnt up MC4 black connector in the bright sunlight

The reason there was voltage at the controller was because there was a connection, just not enough to supply any current.

[markcouz]

Originally Posted by Rohan

What I mean is I unplugged the solar wires from the charge controller and tested the tips right where they would be plugged into the controller.

This is exactly what I would expect from good panels with bad connections.

When no amps flowing (open circuit) you will see full panel voltage, as soon as you connect to the load (controller) then current starts flow but you get a big volt drop over the bad connection and voltage at controller is too low.

After installing the new mppt (which is a good idea anyway) you will still need to repair the existing fault before you see the benefit.

[kevin_j]

Just throwing this out there.... wondering if the amperage total of the two panels plus the impedance of panel to PWM controller run is hitting the true sustained limit of the controller? I feel like a 20A controller in this case is a little under rated. Panels are parallel, not series correct?

I can't agree more with previous posts however, MPPT is the way to go. As for the renogy comments, I think it depends on what product from their line. My boat came with a 60A Rover that works pretty well and has so for 4 years. Having said that I'm a gear snob and a Victron lover so that's getting torn out and replaced with two Victron 100/30's to separate the two banks of panels I have (300ea Starboard/Port).

[tanglewood]

Looking at the specs for the Renogy controller and panels, you are running the controller out of spec. In particular, the controller can support a max of 260W of panels and you have 350W. There should be no expectation of it lasting any length of time, and it's no surprise that it has failed twice. What is surprising is that the first one lasted as long as it did.

[tanglewood]

For those using MC4 connectors (most solar panels), they can NOT be connected/disconnected under load. That may be why some people have had trouble with them.

[KingRichard]

Originally Posted by tanglewood

Looking at the specs for the Renogy controller and panels, you are running the controller out of spec. In particular, the controller can support a max of 260W of panels and you have 350W. There should be no expectation of it lasting any length of time, and it's no surprise that it has failed twice. What is surprising is that the first one lasted as long as it did.

I'm not disagreeing that he could be overloading the controller, I didn't look at the specs. However, if he fried the controller it probably wouldn't be intermittent; magic smoke behaving the way it does...