Inverter Farked??

[Journey]

Managed to test the voltage across the DC isolator.. nothing. So clearly an issue with the panel array, not the inverter.

Learning point for the day... the switch on the isolator box needs to be in the off position for rhe cover to come off... previous I had it in the on position, hence why I could not open the box!

You can easily just bypass the faulty panel if it is only one, you just take it out the string. Or try and buy a cheap replacement from eBay used, always loads for sale, less so now that people are cottoning onto them.

EDIT: Obviously you'd ant it to be the same as the others, but if you are just taking it out the string, then just get an MC4 extension cable.

 

[TheFew]

So are the panels simply.. the mc4 connector from one panel goes into the next, which goes into the next... etc... with the final cable going to the inverter? So almost like a daisy chain of extension leads?

 

[LuckyBenski]

So are the panels simply.. the mc4 connector from one panel goes into the next, which goes into the next... etc... with the final cable going to the inverter? So almost like a daisy chain of extension leads?

Plus the initial wire from the first panel going to the inverter also. Think of it as a stack of batteries all lined up, with a wire from the negative of battery 1, and a wire from positive of battery (let's say 6), both going to the load.

 

[Mercenary Keyboard Warrior]

Unless you use one of the other techs.
Solar edge for example you can have a panel fail and all the others will carry on.
(you can retrofit solar edge but your talking like £3k for a typical install)

Its one of the considerations when you install now
Do you go for a more expensive system that will cater for a panel being damaged / partial shading (such as bird poop) / failing completely, or do you risk the more basic chain install.
IMO its probably worth the premium going for solar edge (or micro inverters) unless you have very easy access
Ofc you may find someone willing to go up with a ladder but most firms wont now as they fail to comply with working at height legislation.

I did see something but haven't got the link to hand that the percentage failure rate of one component over the typical fill install lifetime is very high. Hopefully your failure is an easy to access cheap part.
The better techs seem to also have longer warranties as well as opposed to the cheaper generic components.

 

[TheFew]

Plus the initial wire from the first panel going to the inverter also. Think of it as a stack of batteries all lined up, with a wire from the negative of battery 1, and a wire from positive of battery (let's say 6), both going to the load.

Ah thanks. That makes sense. Will see if I get a quote from a guy to come and take a look and what that quote is like - won't be too cheap as it will need scaffolding.

May also grab the ladder at the weekend and see if I can see any obvious issues. Won't be able to see all of the wires and connectors as some are in a double stack, so hidden too far up the roof for me to easily inspect.

Here's hoping it is one of the panels adjacent to the flat roof!

 

[TheFew]

Unless you use one of the other techs.
Solar edge for example you can have a panel fail and all the others will carry on.
(you can retrofit solar edge but your talking like £3k for a typical install)

Its one of the considerations when you install now
Do you go for a more expensive system that will cater for a panel being damaged / partial shading (such as bird poop) / failing completely, or do you risk the more basic chain install.
IMO its probably worth the premium going for solar edge (or micro inverters) unless you have very easy access
Ofc you may find someone willing to go up with a ladder but most firms wont now as they fail to comply with working at height legislation.

I did see something but haven't got the link to hand that the percentage failure rate of one component over the typical fill install lifetime is very high. Hopefully your failure is an easy to access cheap part.
The better techs seem to also have longer warranties as well as opposed to the cheaper generic components.

Thanks for the info. May be moving home soon, so just looking to get it up and running for now.

 

[Journey]

So are the panels simply.. the mc4 connector from one panel goes into the next, which goes into the next... etc... with the final cable going to the inverter? So almost like a daisy chain of extension leads?

Yes they are daisy chained, however as already said you also have the cable from the first panel as well, so you have a positive and a negative.

If you are getting a quote for a look/inspection make sure it includes roof access and panel testing if required, as they might try and tell you otherwise but you'd have already paid them once. A pal of mine had a chimney sweep go up and check his for him, as they go on roofs all the time and don't use scaffold, he just showed him what to do and found out he had a connector that had failed causing moisture/water ingress. Cost him less than £100 all in with the spares.

 

[TheFew]

Thanks for the info Journey all useful to help me get a decent quote.

Re thr chimney sweep, I thought they did it from ground level using brushes and vacuums.

But having said that I had a roofer recently who I called back to adjust some tiles. He just ran up the ladder and spent twenty minutes standing on the tiles faffing around without a care in the world. All it would take is one simple slip.....

 

[TheFew]

Well just go the ladder out... the good news is that the problem (assuming it is just the one) was easy to find and the closet to the lowest point of the roof. Seemingly also at the end of the string, on the panel before the grey wire enters the house.

So what does the problem seem to be? Well the last connector seems to have burnt out and split apart. See pictures.

So hopefully a new connector will sort the problem. The question is...

1) how does one replace such a connector, balance on a ladder without getting killed?

2) if one connector is burnt out, are their likely to be more or other damage?

Thanks

https://i.imgur.com/C3okRgX.jpeg

https://i.imgur.com/udP5G0S.jpeg

https://i.imgur.com/mOJbA6m.jpeg

https://i.imgur.com/lpVVNbK.jpeg

 

[LuckyBenski]

Firstly, be careful!

Solar panels are powered by light (obviously) but this means they're always "on" and so a full array will be live when you're working on the wires.

I must admit I don't know the safety/isolation procedure for a roof array as I've only got hands-on with individual panels in workshops etc. Just make sure you know how to be as safe as possible please

 

[gpuerrilla]

Yeah the label sort of says in the second pic 'do not disconnect this under load'.

You will have an isolation switch. Double check and always test for dead. I still have a set of test lamps for any works like that.

 

[Journey]

If you can, as it as at the end of the chain, disconnect both the cables from the inverter, and then also disconnect the previous panel in the chain so you have only the one faulty panel and cable to work on. You'll need a replacement MC4 connector, and a crimp tool to do the actual work. You can buy cheapish kits including all you need from eBay/Amazon and there are plenty of guides and videos showing you what to do.

Just take your time, and obviously have a person securing your ladder at all times, once you've replaced the connecter you should be able to measure the voltage on the panel to check your work before reconnecting it to the rest, then you'll want to do a read on them all before connecting it to the inverter again.

 

[TheFew]

Thanks for the posts chaps. I've had a look at a few videos and fitting a new connector does not seem that bad, assuming the crimping tools work OK.

So if I isolate the inverter, by turning off the AC supply and the DC isolator and remove the MC4 connections from the panels to the inverter... does that mean the system is safe to work on... or will the affected cable still see the full voltage from the panels?

Appreciate what Journey said about disconnecting the incoming panel connection. Presumably they reduces the total voltage in the array to just the one panel?

 

[LuckyBenski]

Appreciate what Journey said about disconnecting the incoming panel connection. Presumably they reduces the total voltage in the array to just the one panel?

This is the right idea, it's reduced to one panel. You should be able to throw a blanket over it to lower the voltage a bit too. It's not a bad idea to check the voltage of the rest of the array to confirm this is the only damaged cable you've got.

 

[TheFew]

Thanks for the thoughts and comments. Still waiting for an engineer to get back to me with a quote, and the more time that passes, the more I am inclined to do it myself.

One more question however... if I isolate the panels from the inverter and then look to disconnect the faulty panel from the rest of the string... Will I have any issues disconnecting the panels whilst they have light on them? Is there any risk of shock etc?

 

[Journey]

Thanks for the thoughts and comments. Still waiting for an engineer to get back to me with a quote, and the more time that passes, the more I am inclined to do it myself.

One more question however... if I isolate the panels from the inverter and then look to disconnect the faulty panel from the rest of the string... Will I have any issues disconnecting the panels whilst they have light on them? Is there any risk of shock etc?

You'd have to try really hard to get a DC shock from an MC4 connector on a solar panel while disconnecting it, even in full sun. I am not saying it is impossible but if they are fitted well, and you use a disconnect tool, then the risk is tiny.

 

[kinetic747]

With all due respect, working at height, on something you're unfamiliar with, sounds like an accident waiting to happen. Personally, I'd get someone qualified to take a look, but then again I have lost a relative to a fall from a ladder.

 

[Rroff]

With all due respect, working at height, on something you're unfamiliar with, sounds like an accident waiting to happen. Personally, I'd get someone qualified to take a look, but then again I have lost a relative to a fall from a ladder.

Reminds me of the time my dad was up a ladder, would not listen to me that the branch of the tree he was leaning it against wasn't sound, stubbornly went up *crack* there is me desperately trying to hold the ladder upright against his weight from ground level... how he managed to get low enough to jump off with minor injuries I have no idea.

 

[LuckyBenski]

My dad fell off a "Two ladders tied together with string" contraption and broke his foot where it got trapped in the rungs. Be careful!

 

[TheFew]

With all due respect, working at height, on something you're unfamiliar with, sounds like an accident waiting to happen. Personally, I'd get someone qualified to take a look, but then again I have lost a relative to a fall from a ladder.

It is a fair point. And for me will depend on how easy it looks to disconnect the panel from the rest of the string. I've not been up to look at this aspect yet. I do have a scaffold tower that I may be able to work from, but all depends if I can reach what I need to without setting foot on the roof - that's outside my comfort zone.

I do tend to run up and down the ladder a lot here.. so I am probably getting a bit too complacent.

I have asked an engineer for a quote, but not had a response yet. So may have to look into another Wiltshire based engineer.