Fuses

[MikeT]

I was noticing today that my solar panel and inverter both have a fuse situated very close to the battery.  It made me wonder why the main wiring harness was not fused at the battery as well.  Should it be?  Given some of the poor practices in construction (QC) and the potential for a short in an aluminum structure it made me wonder.

Cheers

Mike

[Merlin]

Interesting point. The wiring between the battery and the main fuse may not be protected from a short circuit. I installed a circuit breaker that also serves as a convenient off switch right at the battery, before the positive wire ever leaves the battery box.

[FastEddieB]

I did go ahead and install fuses front and back.

Seen here on my rear batteries:



Similar arrangement on the front.

I thought the rear was especially important. I did my best to insulate and protect the long run to the front of the trailer, but better safe than sorry!

[Fatdog2]

I was looking at installing a battery disconnect switch, what do you think? The installation instructions of PD4000 Series Power Control Center that's in my 21 BHS says it has, a reverse battery protection circuit, but I can't find anything on circuit breaker protection or requirements for one. The DC panel say it features up to 12 fused positions rated for up to 30 amps for accessories. Would you wire in a 30amp circuit breaker at or near the battery? What about battery cut out switch used between trips? Right now I usually unhook the negative side of battery.  Winter storage I take the battery home and keep it in garage, then charge it as needed. Any recommendations let me know.
Thanks Peter

https://www.delcity.net/store/12V-Auto-Reset-Circuit-Breakers/p_198669.h_198846

[Merlin]

This is what I used for a CB/on-off switch in my battery box right next to the battery + terminal. Works great in the 40 amp version:

https://www.solar-electric.com/mr60ampdccib.html



Here's a good choice for a battery on-off switch (without the CB):

https://www.solar-electric.com/blseabaswon3.html


I'm not a big fan of the auto-reset CB you have in your post, Fatdog2. If something trips a breaker, you need to find out what the problem is before a reset!

[DavidM]

Good wiring practice is to put a fuse near the power source sized to protect the wire from that source. So you need a fuse and I would use a fuse rather than a circuit breaker because it is cheap,  easy and safe for outdoor use. You can buy an automotive type fuse holder from an auto parts store or even better a marine store (which will include a waterproof cover) and splice it in using butt crimp connectors. I am pretty sure that the wire is #10 gauge so use a 30A fuse.

I use my battery like you and it takes maybe ten seconds with a wrench to remove or reinstall the wire to the battery. It will take longer to install that switch than I will ever use up disconnecting it each time.

But if you want a switch, then install a surface mount marine type circuit breaker which will also serve as a switch. You could use this one, even though it is 25A https://www.amazon.com/Bussmann-CB185-25-Surface-Mount-Circuit-Breakers/dp/B01BCZZSX0/ref=sr_1_18?ie=UTF8&qid=1495477542&sr=8-18-spons&keywords=bussmann+circuit+breaker+30+amp&psc=1

Blue Seas makes a 30A surface mount breaker but it is almost double the cost of the Bussmann and I am pretty sure that you will never trip a 25A breaker.

David

[Fatdog2]

Merlin and David, thanks for input, and some great points with automatic circuit breakers and switches.  David, your right about disconnecting the battery with wrench only takes a moment. Lets see $27.00 switch can buy a few 6 packs of beer.  I have to look behind the interior power unit one day to see if they wired in a circuit breaker on main battery line in. I see a lot of them on other trailers next to batteries. I'm going to rethink the battery switch.

thanks, Peter   

[DavidM]

I have to look behind the interior power unit one day to see if they wired in a circuit breaker on main battery line in. 

If they did put a circuit breaker at the converter it isn't doing any good. The converter has a finite amperage output, usually 30A and the wire is sized to take it all day long. It is at the battery end where a short can cause the current to skyrocket that you need a fuse/circuit breaker.

David