Battery Disconnect Switch

[Crmsn18]

Has anyone installed a battery disconnect connect switch? If so, which model did you go with and has it worked properly for you? I'm storing my 2018 in offsite storage unit with no power access. I have an AGM battery that I'm told won't freeze as long as it isn't discharged completely. I'd rather not have to keep removing negative terminal frequently.

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[John S]

I'm using a Flaming River 500 Amp Big Switch for my quick disconnect needs. I made a new negative cable from the battery to the switch input and flipped the original negative cable over and connected it to the switch outlet. (I made a jumper from the switch outlet to the fender tab junction, next to the washer fluid cap, so I didn't have to mess with modifying the OEM negative cable.) Packaging is tight and be aware if you reverse the "direction" of the original negative cable, the BMS sensor coil has to also be reversed (ask me how I found out, ha ha.)

https://www.flamingriverheavyduty.com/fr1048-500-amp-big-switch-for-racing

 

[John S]

...Note, the battery tender plug in the second image can be wired before or after the switch, I don't know how the BMS system works well enough to know if it matters? Reversing the orientation of the BMS sensor was challenging because of the way Ford's harness supplier used so much tape.

 

[Crmsn18]

That looks like a really clean install. I'd need a product with step by step instructions. I'm normally dangerous in "just figure it out" situations.

 

[jheissjr]

The S550 uses about 10mA of sleep current. A 96R battery has 590A which is 6.7 years until the battery depletes from sleep current. Now add the internal self discharge of the battery. Self discharge is about 5% per month which is 50mA. The 6.7 years drops to 1.1 years. With a disconnect switch the battery depletes in 1.3 years and 1.1 years without. The battery lasts the same with or without being disconnected in practice.

 

[Crmsn18]

The S550 uses about 10mA of sleep current. A 96R battery has 590A which is 6.7 years until the battery depletes from sleep current. Now add the internal self discharge of the battery. Self discharge is about 5% per month which is 50mA. The 6.7 years drops to 1.1 years. With a disconnect switch the battery depletes in 1.3 years and 1.1 years without. The battery lasts the same with or without being disconnected in practice.

When it comes to electrical components I'm ignorant as hell. I was told that if I stored the vehicle without a trickle charge that the battery would be dead inside of two months. The car will be stored for approximately six months per year without moving. I just installed an Odyssey Performance Series Group 96R battery. I just don't want any problems.

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