Battery shut off switch

ELK

I have a battery shut off

https://www.amazon.com/Blue-Sea-Systems-Battery-Switch/dp/B00445KFZ2/ref=sr_1_2?crid=3HUS7VDR1QRRA&keywords=blue+seas+battery+switch&qid=1562869125&s=gateway&sprefix=Blue+seas%2Caps%2C165&sr=8-2

      and I have yet to install it. I have spent the last week looking at YouTube and reading instructions on how to hook it up and come away with more info on mounting the thing than connecting it. I need to know what to do step by step...which cable to which terminal and which to the switch etc.All I know is the the shut off should be connected to the ground or negative terminal... Is there a good video or set of instructions I can use?? I will include a photo of my battery.

Thanks for your help!

DigitalSorceress

I do not connect my shutoff to the -  it goes to the +

There appear to be two wires here.. a fused one (with the red that goes to a fuse then green) and an unfused one... My guess is the fused one goes back to the main DC bus and the unfused one likely goes direct to the CO detector... or if you have factory solar, that one is from the solar panel

I only have the one connection (no solar)

SO, if you have factory solar, the direct connection is most likely for that and you don't want the solar to shut off.. so the battery can charge even when D/Cd

I would disconnect both.. then connect the green fused line to the battery disconnect switch and then use a small 6 or 10 gague wire (color coding is important so use red if at all possible) betwen the shutoff and the + on the battery and reconnect the other red one directly

As for mounting, you gotta find somewhere to screw it to.

Sharon_is_SAM

@ELK, I edited your battery switch link.  Please confirm that is the correct device.

ELK

Sharon_is_SAM said:

@ELK, I edited your battery switch link.  Please confirm that is the correct device.

It is. I apologize if there was a link protocol I missed!

ELK

Thank you @DigitalSorceress ... That was very clear and exactly what I needed!!

The other wire is to the ZAMP port. I'm not sure it's useful to me as I have a goal Zero trickler...but I'll leave it alone!!

Why are they so adamant (you tube etc) about connecting to the - ?

Sharon_is_SAM

@Elk, I assume your battery will be covered and contained as you access the battery cut off switch, so you can certainly switch the positive lead.  There are a lot of arguments for both sides, but to keep things simple down the road, do as nuCamp has done and switch the positive side.  

The solid red cable and solid white cable on the right side of the photo lead to the solar port.

The green/red fused cable is the battery positive and the white cable that joins it in the black loom is the battery negative.

https://tab-rv.vanillacommunity.com/search?Search=Installing+the+battery+cut+off+switch

klenger

Agreed that you can put the switch on either the (+) or (-) terminals.  If one of the wires is for the solar, you should leave it connected directly to the battery (through a fuse) so that the solar can charge the battery when in storage, etc.  Both wires should be properly fused.  It looks like one of them is not, and one should be added to that wire.  Since I can't tell from the picture which is which, I can't offer much more right now.  If the un-fused wire is the solar, a 10 to 20 amp fuse should work OK.  

ScottG

klenger said:

...

Both wires should be properly fused.  It looks like one of them is not, and one should be added to that wire.  Since I can't tell from the picture which is which, I can't offer much more right now.  If the un-fused wire is the solar, a 10 to 20 amp fuse should work OK.  

The Zamp port was originally designed to be used with a self contained suitcase having an attached controller. I'm pretty sure that set-up incorporated a fuse in the positive line to the SAE connector. Therefore incorporating a fuse into the Zamp connector harness was unnecessary.

I do agree that if you reconfigure that Zamp harness for a different use, you should ensure that a suitable fuse is in place somewhere.between the controller and the battery.

Sharon_is_SAM

Right now the only solar that Elk is using us a 10 watt Goal Zero panel.  Does she need a fuse for that?

ScottG

I would assume the GZ would have its own fuse as it is a standalone system, but I am not 100% certain of that.

I think the fuse is primarily to protect the controller from overloads coming from the battery side. If I'm right about that, then any controller (regardless of size) should be fuse protected.

pthomas745

At 10 watts does the GZ even have a controller?

Sharon_is_SAM

No controller required for that limited wattage.

ScottG

Listed features of the GZ Maintainer 10 include a "Built-in PWM lead acid charge controller with 3 charging stages: bulk, absorb, float."

It is my understanding that batteries should not be left indefinitely on an uncontrolled trickle charger, regardless of wattage.

Interestingly--though it's hard to tell for sure from the photos and the specs don't indicate--the alligator clip and cigarette lighter harnesses appear to have integrated fuses, while the SAE harness does not.

klenger

The main purpose of any fuse or circuit breaker it to protect the wire from burning up should a short to ground occur.  Protecting any downstream equipment is secondary.  In the case of the wiring shown at the top of this post, should the un-fused hot wire short to ground, high current could and would flow down the wire to where the short to ground occurs.  This can lead to burned wiring and possible fire (not trying to be alarming, that's just the way it is).  Regardless of any fuses at the end device, the wires need to be fused at the power source (battery) with a fuse sized rated for the wire gauge being used. 

ELK

Well...I think the only way my trickler is going to work is with the alligator clips ON the battery... So what then?

ELK

May I repeat the instructions so I know I've got them?

(Mount the switch first in a place where the cables reach)

1.Disconnect the red and green cables from battery.

2.reconnect the green cable to the switch.

3.Use a new red cable to connect the switch to the battery terminal.

Because I don;t believe the solar cable is doing anything...what should I do with it?  I am going to use the alligator clips to see if it is capable. Finally have some sun.

Sharon_is_SAM

@Elk, to make things simpler - if you are not going to use the solar cables, just remove them from the battery and roll them up and secure them so they are there later in case you change your mind.  

If you are going to do the cut off switch yourself, what gauge wire do you have?  Can you strip a wire?  Can you splice?  Make sure you are disconnected from shore power (although the 120 v and 12 v should be isolated systems), remove the negative battery cable first, then the positive cable.  When you hook back up to the battery, the negative cable should be attached last.  You will need enough length of red cable wire to splice onto the green, extend to the switch then extend to the junction box.  I wonder if you can take the entire length of red/green fused positive wire somewhere so they can do the handiwork and you can install it.

I would not attempt this if I were you.  You are better off taking it to a dealer or find someone who can do simple electrical work.  I would hate to see you hurt yourself or your TaB.

ELK

Splice? Why do I have to splice the wires? This is the first I heard of it!

ELK

I did buy a red battery cable.

COHiker06

Your local auto parts store may have the same gauge wire pre-terminated in short lengths or could help you make one. If the Green/red is your positive lead, that wire goes to the input terminal on your switch. The new section of wire goes from the switch output terminal over to the battery. In this case, the wiring is for my solar panel cut-off and is between the battery and charge controller so the wire is not the same gauge as the power lead to the camper, separate circuits. 

ScottG

ELK said:

Splice? Why do I have to splice the wires? This is the first I heard of it!

Assuming the battery cable you purchased is the correct gauge and has the proper-sized ring terminals already attached on both ends, you may not need to splice or crimp anything.

That doesn't mean there aren't other pitfalls. If you give this a go, be sure to follow Sharon_is_SAM's advice, particularly with regard to removing and reattaching battery cables.

Marceline

ScottG said:

ELK said:

Splice? Why do I have to splice the wires? This is the first I heard of it!

Assuming the battery cable you purchased is the correct gauge and has the proper-sized ring terminals already attached on both ends, you may not need to splice or crimp anything.

That doesn't mean there aren't other pitfalls. If you give this a go, be sure to follow Sharon_is_SAM's advice, particularly with regard to removing and reattaching battery cables.

I agree. I don’t see any need for a splice. The existing positive lead should be plenty long enough to get to the switch unless it’s mounted in a weird location and then she can just buy a new cable to run from the switch to the battery. I don’t see where a splice comes into the equation. @Sharon_is_SAM are we missing something? 

Bayliss

Without making any incorrect assumptions, I believe that @Sharon_is_SAM was simply exploring @ELK's general knowledge about electrical wiring, adding an inline fuse, etc.  Depending on @ELK's specific situation and needs, that basic knowledge is helpful since there may be the need to splice or crimp a wire (then again, maybe not.)  If an individual does not have that basic knowledge, or feel totally comfortable with working with electricity and electrical connections, it may be best to leave the work to a professional.  In this particular situation, the cost to have the work done by someone skilled in this area should be minimal.

Sharon_is_SAM

Thank you @Bayliss, that was my intent.  @Marceline, you are right, if the wire is long enough - no splice needed.  May be easier to just start with new wire, but you would need to fuse it.  

ELK

OK. I'm sufficiently confused to have someone else do it!  When I bought the shut off, I bought a red cable as well and thought it was as simple as putting the shutoff in between the battery and the trailer.

Thank you all for your help. This continues to be an opportunity for brain exercise!

Marceline

ELK said:

 When I bought the shut off, I bought a red cable as well and thought it was as simple as putting the shutoff in between the battery and the trailer. 

That’s my understanding, too. 

DigitalSorceress

@ELK 

Based on your image, I'd remove the green wire  from the + on the battery and put the shutoff between it and the + and leave everything else alone.. but

It really should be as simple as "disconnect the main + battery cable, connect that to one side of the switch, connect a small cable from the switch back to the + of the battery" and done.. the rest of it is all just optional in my mind.. Folks talking about fusing.. yes absolutely, best practice is to fuse things, but having a shut off vs not having one is a huge/important thing regardless of any of the rest of the setup.

However, absolutely: If you're not comfortable with electrical stuff, by all means pay someone to do it.

ScottG

If @ELK did what she described above, there would still be the existing fuse in the green positive line from the battery, it would just be on the other side of the disconnect switch. Whether there's some theoretical concern about that is a bit out of my pay grade.  :-)

The hookup really is that simple. However, if you attempt this (and I'm not suggesting you shouId...) I reiterate Sharon_is_SAM's instruction to disconnect the negative cable from the battery before doing any work.

If you fail to disconnect the negative terminal and then accidentally bridge the positive terminal to any grounded portion of the trailer, you will be treated to an impressive fireworks display and a prompt change of underwear. Don't ask me how I know...  ;-)

Obviously the same goes for bridging the positive and negative battery terminals directly. But at least if you've disconnected the negative cable you've only got one spot to avoid instead of several!

davel4wa

I suppose you could disconnect either side of the battery. The result would be the same. You need to be across both sides of the battery for current to flow. This is not like dealing with AC circuits at your home where code specifies that the 'hot' side be disconnected on any switch. The reasoning being that in your home there are just too many possible ways to complete the circuit because the neutral line side is connected to ground at some point and lots of things, like plumbing, are essentially at ground potential. In your trailer it is not likely that something will accidentally be connected to negative side of the battery. It would come down to the physical connections present at the battery. If there are multiple connections on the negative battery terminal then placing the disconnect switch there would be more trouble as you would have remove all of the wires and move them to a buss bar and connect the switch between the bus bar and the negative battery terminal. The positive side runs to a fuse or fusible link and so presents only the single cable to be interrupted. 

tybladesmith

A point of clarification.
With a DC system with negative ground, the negative battery lead must be disconnected first and reconnected last . 

If disconnecting the negative battery connection first, the wrench  makes contact with any grounded surface, no current will flow (no sparks).

If on the other hand one is disconnecting the positive lead first and the wrench contacts a grounded surface the wrench becomes a high amperage arc welder, and the only fuse.... Don't be that person.
   

davel4wa

Yes, if you are removing the battery cables, remove the negative (ground) first. This is about which side of the battery to connect to the disconnect switch.