good batteries dead system

[hall]

Saling yesterday on my 1986 Pearson 28-2 when radio and all electronics went out. I trided to start engine and not even a crank. Checked batteries and connections, nothing loose and they had a full charge. Sailed back to marina. Any ideas as to wha happen?
Thanks

[PBzeer]

My first thought would be a ground fault.

[sailorjim99]

Do you have a main or master fuse that connects to your batteries BUT before any power goes to any item?

This happened to my, dare I say it,car, and it took me a long time to sort that out.

Everything just died.

Jim

[I33]

This is just me--others may have equally good methods.
1. Measure the specific gravity of your battery electrolyte. This will reveal if you have a dead cell.
2. Using your portable Volt-Ohmmeter, measure the voltage at each point along the circuit. This should reveal a bad connection. First keep the negative lead of the meter on the negative battery post while checking points along the positive path. Then reverse this and keep the positive lead on the positive post, working the negative lead down it's path. Hope this helps!

[sailingdog]

If you have wet cell batteries, it is probably a very good idea to check each cell's specific gravity, using a hydrometer. You can get one for a few bucks down at any auto parts store.

If the batteries are fine, and are holding voltage... then I would look at a ground problem. One problem that is common on older boats, is that the PO used welding cable, instead of marine battery cable for some of the connections. Welding cable tends to corrode internally, get rather stiff and then break from fatigue. The combination of a break in the wire and the corrosion is often enough to break the circuit for any significant loads. This is also a serious fire hazard... so I'd check all the major battery cables, on both the hot and ground sides.