Zero volts in my battery?

January 17, 2011

I was on the boat recently and checked how many volts are in one of my batteries, a 120ah one which is 4 years old. It showed zero volts. I left it on charge for 24 hours and it was still zero volts. I presume it's dead?

How big a battery do I need as a replacement to start at BMC 1.5, could I get away with 85ah? They are a lot cheaper.

Antares_9 · January 17, 2011

It's really down to the cold cranking capacity than pure AH as some batteries will fail quickly if you drag high loads from them regularly, have a look here for a detailed explanation.

http://www.hoon.tk/tech_tips/batt.html

mjt · January 21, 2011

It showed zero volts. I left it on charge for 24 hours and it was still zero volts. I presume it's dead?

Most definitely. Once a lead-acid battery has been discharged to that extent it rarely recovers. Even if it could be charged it's capacity would be severely reduced.