Battery Drain

[DougM79]

Hello!
I installed an additional 12v deep cycle battery (95Ah) in our Jayco Eagle 5th wheel. It now has three. I also installed a 500 amp Renogy battery monitor/shunt, and a battery cut-out switch.
When sitting, with the cut-out switch allowing current to flow, the battery bank drains in about 24 hours. With the cut-out engaged the draw is zero amps. when not engaged the trailer draws about 3 amps as shown on the monitor. the math does not add up, it should not drain for 90 hours. Any ideas why this is happening?

[chuckster57]

3 batteries wired in parallel? Trailer leads on each end of the bank?

[NH_Bulldog]

Understand that a lead acid battery is considered fully charged at 12.89 volts and fully discharged at 12.23 volts. You will never get 95 ah out of your battery since that would be to a zero state of charge which will ruin a lead acid battery.

Also, adding a new battery to an existing battery (or two) will limit your capacity to no more than the worst battery in the group.

Unlike a lead acid battery, a lithium battery with 100ah capacity can be discharged to near zero without harm. So three 100ah lithium batteries will provide more than twice the power as three roughly equal sized lead acid batteries at half the weight.

As for the draw, it can be a light left on, the CO/Gas leak detector, the control circuit for water heater, AC, maybe Jayco’s version of InCommand, the refrigerator, etc.

[DougM79]

Yes. Leads on the ends. Parallel hook up.

[DougM79]

Ps I pulled every 12volt fuse and still had a current draw🤔

[LHaven]

Originally Posted by DougM79

Ps I pulled every 12volt fuse and still had a current draw🤔

Some items may have in-line fuses. Some are not even disconnected by the battery disconnect switch, like the CO/propane detector (by code). Some don't go through your fusebox, like the tongue jack and the breakaway brakes, so if you left your jack light on, or used your emergency brake switch as a "chock," you'll draw. Some rigs have solar systems with inverters, and if you have switches in the wrong position, your batteries can end up running the refrigerator or water heater when you didn't mean to. Those are just four examples of "vampire loads" off the top of my head.

[DougM79]

Use the emergency brake as a chock?!�� Genius!

[flybouy]

Originally Posted by DougM79

Use the emergency brake as a chock?!�� Genius!

One mistake that some folks have made is to treat a trailers "emergency " brake as they would a vehicle parking brake. Pulling the pin and energizing the emergency brake will lead to a rapid discharging of the battery and possibly melting of the wires and or brake electromagnets. Just a word of caution if anyone unfamiliar with how trailer brakes work decide to "give it a try".

[chuckster57]

Originally Posted by flybouy

One mistake that some folks have made is to treat a trailers "emergency " brake as they would a vehicle parking brake. Pulling the pin and energizing the emergency brake will lead to a rapid discharging of the battery and possibly melting of the wires and or brake electromagnets. Just a word of caution if anyone unfamiliar with how trailer brakes work decide to "give it a try".

Yup. Seen it a few times, never use the break away switch as a parking brake. It’s called a BREAK AWAY switch for a reason…