Battery Cut Off Switch Necessary with Solar?

TaftCoach · 05-24-2023, 06:45 AM

I'm rewiring the battery area and considering adding a battery cut off. My dw asked why? Her point was with the battery being charged by the solar, it isn't necessary to keep the parasitic draws from killing the battery.

Are there any other benefits to having a cutoff?

CAG · 05-24-2023, 09:57 AM

I found the cutoff on the toyhauler to be very helpful. I guess if you are parked in the sun all of the time you might not need to but in my case, stored inside my batteries would have been dead in three months without the cutoff.

Texas and Arizona have enough sun most of the time to make the cutoff questionable but if you live in Seattle, well pretty short battery life from solar.

Pauls72 · 05-24-2023, 12:43 PM

It's worth it as you may want to turn the power off to work on something some day.
I would put in a circuit breaker instead of a plain switch just incase of a short.

Radar57 · 05-24-2023, 03:52 PM

I agree with the ability to turn the solar input off if you need to work on something, i.e. remove batteries. Regardless if you have an on/off switch a circuit breaker is a must.

RogerR · 05-25-2023, 08:00 PM

A solar cut off is a must as instructions on MPPT say never connect solar to MPPT without a battery connected. Having a quick way to shut off 12 volts in handy if you work are working on it or just take off a cable after turning off the solar!
On my lead battery I used a post mount screw in cutoff but it didn't fit on my Renogy lithium battery so I just unscrew the cable at the battery.

mrmom · 05-26-2023, 04:47 AM

Agree with others, having a cutoff switch is great for isolating your trailer from the battery . I would add that I have found mounting the cutoff switch outside of the battery box makes it way easier to cut the power, you don't have to open up anything. I also agree that adding an inline fuse is a must for safety. I added mine to the main line from the battery positive to the cutoff switch.

TaftCoach · 05-29-2023, 11:55 AM

Wouldn't pulling the fuse function the same as using a cut off switch?

Vicr · 05-29-2023, 02:58 PM

Licensed electrician here. I Have a Blue Sea Systems cut off switch which can cut off or combine two inputs (I have two battery banks) but this same switch would work to isolate batteries and/or solar. It's a top quality switch and will work well when under load.

https://www.amazon.com/Blue-Sea-9001...64&sr=8-4&th=1

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