Wiring without MC4-connectors?.

[bear85]

Hi guys?,

is it okay to wire two 160w, 18v solar panels without MC4 connectors? Connecting ++ and -- together to form one wire of each. For the connection using only shrink sleeves with a copper wire connection underneath. Thus forming in the end one - wire and one + wire to pull to the solar charge controller. Would a 20amp fuse be okay??

 

[iamrich]

What are you connecting them to? By doing what you are suggesting you would be running the panels in parallel. 160w/18v is 9 amps, so you would have 18v and 18a at the end. You might be better off wiring them in series (Negative of onr panel to Positive of the other). You would still have two wires, but the output would be 36v and 9a and you could run a 15a fuse or no fuse at all. You don't need MC4's either way, but they are nice to have and inexpensive for a simple kit.

 

[bear85]

Hi, I am connecting them to a 100ah battery with a PWM 30a charger and a 20a fuse. 6mm wire?

 

[toms]

A well crimped splice with adhesive lined heat shrink is a much better wire join than any MC4 connector

 

[Diysolar123]

A well crimped splice with adhesive lined heat shrink is a much better wire join than any MC4 connector

not sure how it could be "much" better as the specification for MC4 connectors only have a max resistance 0.5milliohms and sure make changing things a lot easier than a splice. They are water proof and not hard to make.

It is always a good idea to have connectors on components that will likely need to be worked on.
I think the MC4 weakness is that they are "low current" connectors (20a max) so that they are really only for getting power to a heavier duty bus bar/combiner and, this is the big weakness, they cannot really survive disconnects when under load.

 

[JeepDaddy]

Here is a vote for soldered splices with heat shrink. Crimped connections won't stand the test of time as well as solder.