House batteries were nearly dead. See House Batteries for their last days.
I have a theory that ice in the bilge may have frozen the switch in the on position, and the motor's overheat protector kicked on and off over a period of weeks, running the batteries down in the dark winter months.
Or maybe they were just old. Or both.
Each one is 62# of lead and acid. They have to come out of the engine room, up the companionway ladder.
Did I mention we're on the hard? The deck is at least 10' in the air. Climbing down a ladder holding a battery is an invitation to a disaster.
We have a little 2-part block and tackle we use to raise the dinghy motor. This can hang from the mizzen boom. Or. I can sort of cheat and hang it from a mizzen halyard and lower the batteries over the side instead of over the transom.
Hoisting is a similarly back-breaking chore of lashing a line through the handles in the tops and using the block and tackle to get them up onto the deck. Then down the ladder. Then wrestle them into their space in the engine room.
Here they are all snug in their beds, waiting for the wires to show up.
I'm going to install the Flow-Rite battery watering separately.
The previous batteries with T105 Plus with non-standard filler spacing.
These are T105, and there's a HydroLink branded version of the FlowRite Watering System.
Then this. Note that the four house batteries are in different orientations. Plan carefully.
Yes, there are a passel of wires and fuses. The color coding is literally the color of the wires, making it easier for me to sort out what I'm doing.
When I was done, the charger was charging them, the voltage was sensible and my back is killing me from all all that lifting and hoisting.