Troubleshooting Solar Panel

[Richard10002]

Have you tested for continuity and voltage at every junction. 

[blythecooper]

I'm not 100% sure how to test for continuity... With an MC4 connector do you mean to separate it, and put one probe of the voltmeter onto male end and one onto the female end?

[reg]

50 minutes ago, rusty69 said:

Soldered mine. The tool only makes it easier to disconnect the two connectors. 

There is a specific crimper tool for making mc4 crimps that was the tool I was referring to, found I couldn't get a decent connection  without this.

It is important to get these correctly crimped. I have had failures with what I thought were adequate crimps using a normal wire crimp tool. I came to the conclusion that for these important connections that was not good enough. Had no failures after using correct tool. 

 

There is another tool, which I haven't got, which helps connect and disconnect the mc4 connectors, is that the one you are referring to.

 

Decent instructables here on how to make a good mc4 connection

https://www.google.co.uk/amp/www.instructables.com/id/MC4-solar-connectors/%3famp_page=true

Edited July 13, 2018 by reg

[Johny London]

To do a continuity check... set your meter to ohms. See what it does when you put the two probes together - whatever is on the display means a good connection. To test say a length of cable, disconnect it from any source of power and put a probe at each end - expect to see the same reading on the meter as you did when you touched the probes together (or at least only a ohm or two). If you get what the meter displays when the probes are not touching each other, that's a full open circuit - ie no continuity = knackered. If you get high ohms (anything more than two or three at a guess), there's a poor connection.

One easier option - if your meter has a dedicated "continuity" mode (sometimes indicated by the presence of what we call a diode (an arrow with a flat end) that will give you a beeping sound for ok, and nothing for bad. If you cant get the meter wires to stretch between the two points you want to test, connect another length of wire (or to test two cables at once you can join the ends at one end and do your probes at the other - making sure nothing else is currently hooked up ie the solar panel!).

Another way is by voltage - if you have say 32v at the panel, check for the same at every point along the line ie the first conncetors, the last connectors, the fuse, right up to the controller. Wherever you find the voltage suddenly drops down, there's your man.

Good luck - you nearly nailed it before.

[rusty69]

1 hour ago, reg said:

There is another tool, which I haven't got, which helps connect and disconnect the mc4 connectors, is that the one you are referring to.

Yep, although i just use long nose pliers 

[blythecooper]

Thanks Johnny London, I've gone away for the weekend now so will check for continuity when I'm back on Monday... Had to turn the fridge off and clean it as batteries are also batttered (figured I should sort solar before looking at new batteries!) so at least my fridge is clean

 

Appreciate all the info folks, I won't be able to call myself a newbie at all after all this learning I'm doing!