Prep for battery exchange under steps

[OurVenturez]

Hello,

I have a 2016 Tiffin Open Road and it has four 6v batteries crammed under the steps and a rats nest of wires. I am replacing all 4 of these batteries with one 460 Ah LiFePO4 battery in the stairs and another in the bay behind the stairs with a short 2.5' connection wire to parallel them. I am afraid to put both in the bay behind the stairs as it's 170 lbs and no real frame. I would expect that 84lbs is alright though.

On to the question. It's 84 out here today and the AC is running off the shore power.
My plan was to turn off the salesman 12v switch, turn off both solar controllers, and then go to the magnum inverter/charger and turn off the inverter and the charger while I work on the actual replacement.
Are there any steps I am missing to prevent shocking myself or the rig? Will the AC keep running or should I turn it off too? Should I unplug from shore or are my steps enough?

Thanks
OurVentures

[creativepart]

I can't tell exactly what you mean about the A/C but if you think you can turn off the 12v "salesman's switch" and run the A/C you are mistaken. The A/C may run on 110v shore power, but the thermostats run off of 12v. The minute you turn off the DC power the A/Cs will stop. Plugged into shore power or not.

You want to unplug from shore power, turn off the house and chassis battery disconnects and disable the solar charge controller before unhooking the batteries.

It's standard practice to disconnect the negative battery cable first BUT Magnum instructs owners to disconnect the POS battery terminal first to prevent the inverter from being damaged. However, many RV manufacturers put a separate rotary cutoff (salesman's switch) on the positive cable between the inverter and the battery bank. If you have one of those you can turn that to OFF and then it won't matter.

The problem with the Magnum Inverter is that if you have the positive and negative connected to the battery and you remove the negative cable servicing the inverter the Inverter will "hunt" for a path to negative and in doing so it can ruin the inverter's circuit board trying to run chassis negative through tiny circuit board traces.

Even though you're replacing 4 batteries in series/parallel configuration and changing to one big single 12v battery it's always wise to take photos of the existing install just in case you need to revert the installation at some point.

[Persistent]

12 volts is not very shocking. However, unexpected sparks are never appreciated.

Post make and model of inverter/charger or converter/charger for better advice.

Many converter/chargers will work fine providing 12 volts while the battery is disconnected. Some inverter/chargers will not.

If you have a battery disconnect near the battery bank, switch it "Off". If not, pull the inverter charger high capacity fuse and then disconnect the negative battery cable.

Switching "OFF" other 12 volt power sources like solar controllers is good.
Engine start battery may be providing 12 volts. Usually it is "OFF" when engine is stopped.

Put the end of the battery cable in a plastic bag and secure with a rubber band.
Next, disconnect the positive cable and protect it as well.

Now you can remove the old batteries and install the new ones. Do any necessary wiring modifications.

Follow lithium battery installation instructions. Reconnect the new battery positive first and the negative second.

Replace the inverter/charger fuse last. See inverter/charger instructions for connecting inverter 12 volt cables. There may be a capacitor that needs charging slowly.