Extremely perplexing solar problem

[tanglewood]

Originally Posted by Kolchac

A couple of advices from electrical engineer.

1.To measure voltage on a solar controller, you must disconnect the battery. It should be 17 - 20v for batteries 12 v.

2. Better using amp setting on you multimeter, series connection. Use scale 10A. Believe me your 350 W will never exceed 6A. If you expect miraculous result 30A, buy on aliexpress .com a loop DC ampermeter ($30) and hookup only 1 wire, + or -. I have one for my boat 30 ma - 300 a.

3. Do not connect your batteries in parallel if they are not designed for that, - they will discharge each other, even during charging from the solar, if current from solar is too low. Charge batteries one by one.

4. If your panel is 10%in shade, it will loose about 50-70% of current. Also altitude and angle matters.

5. Check setting of your controller - max voltage (13-14v)

Re #1, that will ruin the controller, according to Renogy

Re#2, the Isc for his panels exceeds 10A, and two in parallel doubles the current.

Re#3, most boats have two or more batteries in parallel for the house bank. There is nothing specific about their design to allow or prohibit that.

[mdenize]

Originally Posted by team karst

Sometimes, internet "help" comes in many flavors. lots of well intentioned responses, most with good input. Here is mine: Reading this is like helping one measure tire pressure, without a tire pressure gauge.
My help: Get a clamp on DC ammeter/DMM. Maybe the best $50 you can spend if you live with solar. Isc and system current can be measured directly, not thru some suspect electronic controller and dash gauge....

There is some good advice in this thread MC4 connectors are the first place I would look for a fault like this. Connectors from different manufacturers are not compatible and often leak Especially the inline fuses. A DC clamp meter will help identify that there really is no current but not where the problem is. I have successfully found faults like this using a thermal imaging monocular (the faulty MC4 connectors gets hot) or an IR thermometer but this is not as sensitive.

What happens is either water or arcing in the connector mating surfaces causes a high resistance connection. The controller decides it cannot get what it needs from the panels and shuts down in milli seconds. Sometimes it will work when it's dry enough and then not when it's wet.

The problem with cheaper controllers is they will often not turn on again if the battery gets too low This makes the problem of an intermittent cabling fault worse.whereas a victron mppt will. But you do need to check for a cabling fault first

[Rohan]

Originally Posted by Paul Reading

I don't think that the OP is listening. Firstly he need a properly sized MMPT controller, Victron being the obvious choice. Secondly wiring in series is likely to yield more power for longer.

I'm definitely listening. I ordered a MPPT controller, then I'll try wiring in series. But in parallel is recommended for a PWM controller which is what I was using. Right now I'm not focused on optimizing the system, but instead getting it to work at all.

[Rohan]

Originally Posted by OS2Dude

Try contacting Renogy support. (Online may be easier than phone.) I believe Renogy is based in Asia, so sometimes it can be difficult to get your idea

Per their web site, Renogy was founded in the US and their current HQ is in Canada. That's one reason I bought from them, I try to avoid made in China products.

[AKA-None]

Originally Posted by Rohan

Per their web site, Renogy was founded in the US and their current HQ is in Canada. That's one reason I bought from them, I try to avoid made in China products.

Hmmm well that may prove problematic for many items

[bill good]

Rohan,


You can just fit the MTTP unit without rewiring the panels & it will work. It will produce slightly more power in series but shading may then become more of an issue. You still have to find the real fault. Please check your PM.

[tanglewood]

Originally Posted by Rohan

Per their web site, Renogy was founded in the US and their current HQ is in Canada. That's one reason I bought from them, I try to avoid made in China products.

Their headquarters are in Ontario, CA as in California, not Canada. And don’t assume that an office in the US means that anything is designed or built here.

[Disailor]

II have found on several occasions that the positive wire INSIDE the junction box mounted on the under side of the panel had corroded often completely!
After repairs it takes at least three applications of liquid electrical tape around the seam of the box lid to keep out moisture. Five years now with no problems.

[Snowgoose35]

Originally Posted by Rohan

Per their web site, Renogy was founded in the US and their current HQ is in Canada. That's one reason I bought from them, I try to avoid made in China products.

I've used and sold a lot of Renogy and lot of Victron. I have found from installing hundreds of Renogy panels and MPPT (and a couple of PWM for small installs of like a 50w panel) that their stuff is actually very good and in the UK at least their back up is good too. I use Renogy MPPT and DCDC on my own boat as well as Victron inverters etc.

From experience I chose the Renogy MPPT over the Victron and I get both a trade and was on no budget for my own boat so cost is immaterial

However - the parts for both brands are made in China! Along with every lithium battery or cell ever made and almost most PCBs you'll find in most UK, EU or US made parts. Victron do some assembly in the EU from parts sourced and assembled in the far east (India, China and Malaysia I believe) whilst Renogy are all made in China. Just like the iPhone from US company Apple or the Playstation from Japanese company Sony etc etc

[tomtriad]

Get a couple of Genasun MPPT controllers and install one for each battery. Made in USA. Never fail. Make sure your wires are good and all connections clean.

[lestersails]

Originally Posted by GILow

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?

Thread drift alert!

No, it was not. While there are some older attributions of similar quotes, the version you cite appears to have originated with an Al-Anon volunteer in Nashville, TN in 1981.

Kind of gives the quote a different feel, eh?

[GILow]

Originally Posted by lestersails

Thread drift alert!



No, it was not. While there are some older attributions of similar quotes, the version you cite appears to have originated with an Al-Anon volunteer in Nashville, TN in 1981.



Kind of gives the quote a different feel, eh?

Interesting.

Well, they’d fit in with the average yachtie then.

[kmacdonald]

You need a 30 amp charge controller. If you keep changing the 20 amp controller it will keep destroying them. Or better yet, get two 20 amp charge controllers, one for each solar panel.

[bact0ee]

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.

I agree, check your MC4 connectors. I found that I had intermittent charging and by wiggling my connectors we started charging again. At the marina I unplugged the MC4s and found they had cracked and were not making good connections. Replaced the MC4s and all good now.

[Rohan]

Originally Posted by bact0ee

I agree, check your MC4 connectors. I found that I had intermittent charging and by wiggling my connectors we started charging again. At the marina I unplugged the MC4s and found they had cracked and were not making good connections. Replaced the MC4s and all good now.

Replacing MC4 connectors looks like a huge pain in the a** but I'll try it if nothing else works.

Right now, semi-update, the system is working usually, but randomly drops to 0 amps for awhile, then comes back like nothing is wrong.