Solar Charge Control

I used, 4mm solar cable from the panel to the controller.  The controller is next to the battery.   Solar cable is relatively bulky similar to coax aeria cable.    I was able to route my cable invisibly to the controller.  I think that this is the best way of doing it. But as I stated before I am not sure how much real world difference it makes. 

My shopping list included the following.

A length of solar cable which has a male mc4 at one end and a female at the other.

A MC4 disconnection tool (cost a couple of ££’s) 

A port cable entry gland

A hole saw to make a neat hole in the roof 19mm iirc

Adhesive/ sealent I used Sikaflex 512

All of which is available online. 

Fitting is straight forward Drilling the hole takes nerve.   Cut the solar cable in half mark up the end that will be connected to the +ve output from the solar panel run the cables to your controller.   NB the controller should be connected to the battery first.  Connect up the cables from the solar panel and you are done.   Don’t forget to seal the entry gland to the roof, friend had a panel fitted to his new caravan by the dealer and the didn’t do this and his ceiling came down!!!

It is an easy job, must be if I can do it!

Cable size will depend on how far your controller is away from the battery. Mine is less than 1 meter and I think I was supplied with 4mm square with the kit I bought. i wouldn't use anything below 2.5mm square but that is not based on any scientific calculation just my own feeling.

peedee

"NB the controller should be connected to the battery first."

I agree in that my controller's instructions labour that point, however, with most portable units the controller is stuck on the back of and pre wired up to the panel, so can't be used that way. Even stranger, it that one brand used the same controller as I was!

As I said so much commercial stuff takes an expedient rather than an optimised route.

TBH.  I have had the situation whereby the panel has been connected and the battery hasn’t been and no harm has occurred.  But I think you might as well do it according to best practise but not to panic if you don’t .  Actually I think that the installation and operation is quite be quite sub-optimal and still work.

After posting about optimal cable sizes I remembered that my first portable panel was wired in with a cable harvested from a scrap flymo 1.5mm still worked. 

I use my EHU cables as the panel to van connection, with the panel and van wiring configured to exploit all three cores. So can set the panel 10, 15 or 25 metres away seeking optimum avoidance of shadows.

I take the view not both an EHU and a solar panel are going to need the leads at the same time and I already carry all that heavy lot of copper anyway neatly on reels, so why another very heavy cable?

All part of de-cluttering this hobby as much as practical.

Before any body screams unsafe, I use the right polarisation so have the solar "socket" [not plug] at the van, and I am still bright enough not to connect a live EHU lead into my panel. Plus the panel would never be deployed from its cassette if there was an EHU, so no other dumb mischievous  individual could do that either.