Sorry Chris. I was referring to the cables from the controller. Stick the + and - out of the controller directly to the battery terminals. Fuse the + cable. It's unlikely to be an issue in terms of current carrying capacity (fuses are there to break the current in the event of a cable being unable to handle current flow) but it's good practise to fuse a current carrying cable anyway just in case the insulator gets damaged and shorts against the body etc.
Happy for you to stick you noggin inside the bus at the weekend and have a look at our leisure electrics. I took loads of advice at the time and used best quality kit, such as a Bluesea DC distribution panel which has separate fuses for all the connections to all the appliances in the van. I define an appliance as anything that needs powering, from accessory sockets to lighting, propex and water pump. There's also another separated fused distribution box at the dash end that takes care of front lighting, radio and accessory socket...all off the leisure battery. I've got a dedicated fridge socket to wire in, and having the front leisure system box makes that super easy.
Wouldn't it be better to fuse the panel to controller connection? I'm sure I read that controllers do not like panel input without a battery connection.
I thought that is what Neil was suggesting Steve. Does it matter which end of cable the fuse goes, i.e. panel end or closer to controller?
Yours is what? Since posting I'm reading no point fusing the panels, but maybe it would be a convenient way to safely isolate them if one wanted to do that - say you were taking the battery out for some reason. What happens with panels connected to the controller if you take the fuse out between controller and batteries? Does the controller go p in smoke is just dissipate panel power as heat?
That particular fuse is probably half way in the +cable between the panels and the controller. I'll be honest Chris, I put it there coz it's easy to get to inside the top, rear, Westyish book shelf... so it may not be mm perfect in terms of its correct theoretical location.... Note, my cable runs are much shorter that yours as ours exit the roof mounter panels at the rear of the cap and then just drop down to the controller behind the rear glass
Fused between the controller and the panels. In reference to your question/statement Edit, and I did it for maintenance more than anything else. It's a pita having to make/break connections on the controller if the battery has to come out for any reason
I don’t see the point in fusing the panels, even if there is a short circuit, they can never produce enough amps to overload the wiring. My panels are wired direct to the B2B/MPPT controller (per the instructions); the cables are rated for more than 40A and even if the panels worked, they’d only produce about 5A each.
As I said, it's just a quick way to disconnect for maintenance. The currents, cable runs and cable sizes aren't ever likely to cause an issue But, 77Westy, I don't what to be the bloke quoted in a year or so when someone has a fire coz it's a dodgy home made lash up who turns round and says...well, TBM said it would be ok.... Edit 2, not implying that @Chrisd is a dodgy lasher...but you never know who's trolling..
200 watts of heat in a small space. Hmm.. its not the wires its the fact if the solar controller is connected, and you disconnect the battery, when the sun suddenly shines, the leisure supply suddenly turns on unexpectedly! You can pull an arc off my series connected panels. . I like to be able to isolate my panels..
If the battery was disconnected the fuse wouldn’t blow so there would still be 200w, or whatever the panels are supposed to produce, to dissipate. Fine to use a fuse to isolate the panel but it’s not there as protection.
Yes its for isolation. Scariest setup I worked with was 10 panels in series.. 200 volts at 5 amps, only isolator a wet salt water covered plug. Or tarps all over the solar panels. Used to sit bleeping in the workshop as enough sun came through the skylight to fire up the electronics.
