Disconnecting house batteries

[jmai]

What is the best procedure for removing the house batteries in regards to removing the cables?

I have a 2001 Roadtrek 190 Popular and I have to remove the 2 house batteries for a battery box repair. This is my electrical set-up.

Onan 2.8 generator (presently not working and will be removed to diagnose the
no cranking problem)

Standard vehicle alternator

30 amp shore power

Battery isolator

2 AGM batteries

Solar panel system
215 watt Kyocera panel
Blue Sky Solar Boost 25 MPPT Charge Controller

Tri-metric TM-2025 Battery Monitor

I want to be able to remove the batteries and then drive the vehicle a short distance. I'm assuming once the cables are off the batteries, the positive cable ends will need to be insulated (to avoid hitting the negatively grounded chassis). Any other disconnects from the various control boxes?

Any help will be appreciated.

[booster]

Your system has 3 charging sources, so you have to make sure none of them power any disconnected cable while driving, if it could hit anything.


Shore power is easy, don't plug in without the batteries in-maybe put tape over the cord end to remind everyone.


The alternator should be a single cable from the isolator to the rear. Disconnect it at the isolator and just make sure it can't bounce back and hit a the connection on the isolator. Taping optional.


Solar is a bit tougher because of the panels and the battery power. There is a danger of voltage spikes if the solar panels are left connected to the controller and the controller is not connected to a battery. It is especially bad if you come out of a dark garage into bright sun. The solar panels also generate power whenever in the sun and you can't turn them off.



So to disable the solar, you would first disconnect the solar panels from the controller and tape off the ends. You would not need to disconnect the power lines from the controller to the batteries as it will go dead when the batteries are removed as long as the panels are not connected.


The big thing to remember is that you shouldn't connect the solar panels to the controller until you have the batteries back in place and powering the controller.

[jmai]

Booster

Thanks for the info. Its exactly what I needed to know. Slowly I'm educating myself about the ins and outs of the solar set-up in my Roadtrek.

[michaelingp]

I wouldn't worry about under the hood. Don't worry about the wires connected to the negative terminals, or the wire between the positives on the batteries (it's coming out with the batteries). Screw the ring terminals of the rest onto a block of wood, and wrap in electrical tape.

But, most important! Take unambiguous pictures of how the wires are hooked up. You'd be surprised how much you can forget in a couple of weeks, that which seemed so obvious when you disconnected them. (Don't ask me how I know this.)

[Joe]

I installed a battery disconnect on house battery. I did this to disconnect while not in use and attach a trickle charger. Would a battery disconnect be simpler?

[jmai]

Originally Posted by Joe

I installed a battery disconnect on house battery. I did this to disconnect while not in use and attach a trickle charger. Would a battery disconnect be simpler?

I need to remove the two batteries which involves many cables, including a solar set-up and generator.

[Nic7320]

When removing or isolating a battery, you should disconnect the negative wire FIRST. This is an old Fire Department trick, which makes sense; if your wrench accidentally touches chassis ground, and you're on the ground wire, there is no spark because there is no voltage difference. Once the negative is disconnected, you can work on the positive wire, which no longer has a battery connection path to ground (because you disconnected the other side of the battery) so there won't be a spark there either. So ALWAYS disconnect the negative FIRST, and reconnect the negative LAST.

But there's little reason to disconnect the positive red wire if you're just isolating the battery for storage. If you leave the positive connected to the battery, it won't have any chance to touch chassis ground. No need to try to insulate it at all, it's as safe staying on the battery as it was when both wires were connected. Just disconnect the black wire and put it where it won't touch the positive post.

But now you have to ensure your AC battery charger or solar charge controller wont try charge a battery that's not there. With no battery, it can overvoltage anything still connected to your 12 volt house system. Shutting off the battery charger is easy, there's usually a AC circuit breaker for that. Disconnecting a solar charge controller is a bit more effort. Ideally it should have a fuse which you can pull, or it might have a wire to the battery you can disconnect, or it may go through the 12 volt power distribution center, or wired somewhere else. But many charge controllers need the solar panel inputs disconnected before the battery is disconnected, which is an additional step (and battery connected before reconnecting the solar panels).

The remaining charging source is the alternator, which is kept in regulation by the starting battery. It will not overvoltage your house accessories unless the starting battery is removed while the engine is running (a very unlikely scenario with RVs).

[Sehc]

How many wires are on the battery terminals? Order of disconnect is; (1)Solar panels from charge controller and protect the wire ends. (2)Negative from starter battery. (3)Negative from house battery. (4)Positive from house battery. (5)Insulate the positive cable at the house battery ends. (6)Lift the house batteries from the box. (7)Connect the negative at starter battery. Then safely drive to your destination. A real good idea to photo everything before opening the tool box.

[jmai]

Great info

[jmai]

Originally Posted by Sehc

How many wires are on the battery terminals? Order of disconnect is; (1)Solar panels from charge controller and protect the wire ends. (2)Negative from starter battery. (3)Negative from house battery. (4)Positive from house battery. (5)Insulate the positive cable at the house battery ends. (6)Lift the house batteries from the box. (7)Connect the negative at starter battery. Then safely drive to your destination. A real good idea to photo everything before opening the tool box.

When re-installing batteries what is the order of the cables?

[Sehc]

Heaviest draw cable on the bottom closest to the battery, then lighter draw cables. If three or more, it is better to have a bus bar.
Reinstalling is the reversed order that they are removed. Always; negative first off and last on.