battery disconnect switch

I'm completely new to solar and most things electrical. I just picked up an RV/trailer, and as a very first step in improving the electrical (eventually adding solar) I want to wire in a little switch by the battery box. The idea would be that I can flip a simple switch and cut all power from the battery, without having to disconnect and reconnect the wires on the battery every time.

I was trying to reconnect the battery few weeks ago and got some sparkage while attaching leads to the battery, not a fan of that at all. The idea would be that in the spring while installing the battery, I could turn the switch off, connect my leads to the battery without the fireworks, and then flip the switch on. And then while traveling, it's just a matter of flipping switch off/on as needed during the summer months.

Simple stuff right?

It's a small trailer, only 1 standard 12 volt deep cycle battery. Anyone have any idea on where I can purchase such a switch (I've seen guys use/install them on youtube) and where to wire it in (positive/negative + best location)?

I like using the BlueSea switches which handle the amperage and are designed just for this type of use.

Thanks for the link! So I tracked a dealer down for those, close enough to me would be Kitchener ON.

- I just get the "9003e", right? Single circuit, no battery combine, no alternator field disconnect?
- It doesn't matter that this would be sitting somewhat outside, inside a cheap plastic battery cover?
- And this goes on the negative/black?

Had boats for decades and they all had a switch like the one mentioned. Has to be a ton on line if locating one is an issue. Heck if you lived near me I have two brand new ones still in the box that I have accumulated over the years and I would give you one.

US Amazon link:

silver billet said:

Thanks for the link! So I tracked a dealer down for those, close enough to me would be Kitchener ON.

- I just get the "9003e", right? Single circuit, no battery combine, no alternator field disconnect?
- It doesn't matter that this would be sitting somewhat outside, inside a cheap plastic battery cover?
- And this goes on the negative/black?

Click to expand...

Use the red one and put it between the positive battery terminal and the rest of the system right after the fuse.
That assumes your system is negative ground or not grounded.

silver billet said:

Thanks for the link! So I tracked a dealer down for those, close enough to me would be Kitchener ON.

- I just get the "9003e", right? Single circuit, no battery combine, no alternator field disconnect?
- It doesn't matter that this would be sitting somewhat outside, inside a cheap plastic battery cover?
- And this goes on the negative/black?

Click to expand...

I use these on the Positive line. I'm a land lubber so it's all indoors in the powerhouse and weather safe.

I tried the ampper switch from Amazon, it stated a continuous 275amp rating. At a continuous 130amp load it was getting so hot it felt like it was going to melt. Was fine for a load of 75amp and under..

There is a switch made for the purpose that attaches to the battery post, you could probably find it at a auto parts store.

I bought this one for my golf cart.

JoeHam said:

US Amazon link:

https://www.amazon.com/Blue-Sea-Systems-Battery-Switch/dp/B000MMC914/ref=sr_1_3?crid=2QPMKB109A9JB&dchild=1&keywords=blue+sea+systems+9003e&qid=1589145728&sprefix=9003e+blue+%2Caps%2C166&sr=8-3

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These are rated 275 A continuous at DC 12V, 455 A Intermittent at DC 12V, 1250 A momentary at DC 12V. (w econ price


I am going test em for volt drop (every few months, just twice to confirm A-OK performance), to see how they hold up between a 24v battery set and an All In One that might see up to 125 amps. ... This one had OK reviews

I am a bit of a noob here. I was looking for switches and this post appeared. I also would like to find a DC switch small and convenient like the one in the photos I added below; but apparently I only find them for AC. I learnt that DC switches like this do not exist due to the high currents that circulate through and the warming up effect. I don't want one like the posted earlier as it is quite bulky and expensive. Aiming to the 2 eur/dollar zone.

Could I at least somehow build by myself a safe DC switch, just as mentioned earlier, to connect/disconnect the battery pack elegantly and conveniently? Do you have any idea how?

As my battery pack is not going to reach 30A, could I buy one switch meant for AC with a max current allowed of 35-40A? It would be what I want and yet quite cheap.

Blue Sea has a M-Series switch that is appropriate here.

Jordi said:

I am a bit of a noob here. I was looking for switches and this post appeared. I also would like to find a DC switch small and convenient like the one in the photos I added below; but apparently I only find them for AC. I learnt that DC switches like this do not exist due to the high currents that circulate through and the warming up effect. I don't want one like the posted earlier as it is quite bulky and expensive. Aiming to the 2 eur/dollar zone.

Could I at least somehow build by myself a safe DC switch, just as mentioned earlier, to connect/disconnect the battery pack elegantly and conveniently? Do you have any idea how?

As my battery pack is not going to reach 30A, could I buy one switch meant for AC with a max current allowed of 35-40A? It would be what I want and yet quite cheap.

View attachment 24970

Click to expand...

You would need to utilize a switch like those with a DC rated contactor, preferably a latching one where it won't draw power when closed or open.

Dalton Bourne said:

The Ampper Am-CBS01 is the best battery disconnect switch for RVs on the market. This is an easy solution to keep our travel trailer batteries from getting discharged while in storage. I have never been concerned about its compatibility, either. The device works with 12-volt systems just as it does with 48-volt battery systems. I just drilled 4 holes and mounted it to the top of one of the battery storage boxes and routed the cables through the molded openings.

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What makes this one ^ the best?

These are pretty good

Jordi said:

As my battery pack is not going to reach 30A, could I buy one switch meant for AC with a max current allowed of 35-40A?

Click to expand...

NO!

Jordi said:

I don't want one like the posted earlier as it is quite bulky and expensive. Aiming to the 2 eur/dollar zone.

Click to expand...

they are not very expensive.

Bulky: the bulk is what gives them the internal layout, distance, and temperature resistance that is required to keep 30A DC safe. $5 won’t get you there. The blueSea switches are probably the least expensive of the safe DC disconnects you can buy.