a refresher on battery removal

[lumina]

Hi All,

We are a 12v boat. We have 2 battery banks, one for the stbd engine and one for the port.

Each bank consists of two 8d batteries linked together. The port bank is also the house bank.

This is the configuration as it came from Hatteras. There are no permanently mounted inverters.

We have a xantrex (?) intelligent charger that monitors the banks and does it's thing.

I'm going to replace both banks and just wanted to refresh my memory on how to disconnect and re-connect the batteries ie positive on the first battery then the second etc, one bank at a time ??????

Any recommendations on things that should be checked and replaced while I'm at it would be great.

 

[Angela]

For all things "battery", Sanctuary is equipped with a gizmo much like Staples' Easy Button. We fondly call it the "Pascal Button." I just push the button, and battery help arrives.

 

[Pascal]

8Ds are 12v so on a 12v boat if you have 2 per bank they are connected in parallel (pos to pos, neg to neg) not in series (pos to neg)

But double check when removing, make a diagram or in this digital age, take a picture...

Make a note of any other wires you may have on the battery terminal as sometimes charger wires and even batty float switches can be hooked up directly. Not ideal but common. When multiple wires are connected to one terminal I usually zip tie them together so none are forgotten.

While in there check for corrosion on the terminals, cables, etc

 

[Genesis]

Turn OFF the AC charger's breaker and then the master DC switches for both banks. This isolates the batteries other than for the bilge pump and alternator circuits. There should now be no current coming to or from the batteries (and thus no sparks, which can ignite hydrogen if there is any present.)

If there is any possibility of contacting a grounded item while disconnecting the batteries (e.g. with the wrench you're using) disconnect the grounded side (in this case, NEGATIVE), first. Remember that the bank is not isolated until BOTH negatives are disconnected and secured away from the battery posts. Disconnecting the negative first prevents the possibility of shorting the battery across your tools which is very bad juju if it occurs. If you contact grounded metal while disconnecting the negative you will do no harm and once the negative is disconnected there is no longer a current path back to the battery if you accidentally do so while disconnecting the positive side.

My batteries were on centerline under the cockpit hatch with fiberglass fuel tanks on both sides and no metal that could short out so it didn't matter. YMMV depending on your boat.

Once the negatives are secured away from the posts disconnect the positives from that bank.

Repeat for the other bank, then remove the batteries.

Reinstallation is the reverse. Note that during the time you have the batteries disconnected, that is, the DC bus is completely unpowered, there is no bilge pump power.