Battery Charge Problem

 During my visit to re-install the ship's clock and barometer I discovered that the entire electrical power system of the boat was in disarray.

The boat has a serious 12v Battery setup as follows:

Mastervolt Mass 12/60-1 charger                       (located in electrical panel behind nav station)
Starter Bank: Century N120 MF, 900 CCA       ( Located under the starboard quarter berth)
House bank1: 2 x Century C12-270DA AGM   (One battery under each cabin berth)
House bank2: 1 x Century C12-270DA AGM, 1 x Fullriver DC210-12 AGM  (stbd quarter berth)
(Total of 1080 a/h rating for the house and 135 a/h for the starter) 

One of two batteries of House Bank 1

Two batteries of House Bank 1 below,  Starter Bank single battery above.  Note the firm strapping of the batteries to withstand a rollover.

 

 

 

 

 

 

 The house banks were reading 11v, the starter bank was at 7.1v, the VSR (Voltage Sensitive Relay) was off, and the solar panel and wind charger controllers were off. 

 I used the switches to combine the various battery banks somehow got the solar and wind chargers working again, but all of the battery bands went to 0 volts.

 Nothing made sense.

I remembered that the boat surveyor been careless about turning switches (such as to the power hungry refrigerator) off and had on closer examination realized that the switches in the sub panel at the front of the cabin were all "On", meaning that all of the mast lights had been on.  Worse, before leaving the boat I had for some reason combined the house and starter banks, meaning that they all went down together.

I then connected the boat to shore power and switched on the Mastervolt 60-amp charger which displayed a red "Charge Failure" light, which left me in a very difficult position. 

I left the boat with every switch off and the three battery banks isolated,  I remember looking at the Mastervolt charger wondering whether to turn it off or simply leave it on all night displaying its "charge failure" light.  I decided that there was no harm in leaving it on, which turned out to be a very fortunate decision.

The next morning I set off with with a plan to expose all of the batteries then telephone Brenda's son Stephen who would join me to connect one of his chargers directly onto the "starter" battery.  We would then use the starter battery to start the engine which would then charge the entire system with its 80-amp alternator.

Fortunately, from the car I was able to reach Greg, the marine electrician who had supported Pachuca since I had purchased her in 2005 and had totally rewired her during her refit.  He told me that using the alternator to charge a set of dead batteries would probably burn it out.  This was the reason why the Mastervolt was not charging: its logic would not allow it to charge until it sensed something out there to charge.  I visited Greg's home where loaned me a trickle charger and two larger 60am chargers.  The plan was to trickle charge each battery to 10 or 11 volts then apply a bigger charger.  I notified Stephen and I set off with the club with the plan that we would trickle chargetwo batteries at a time, a process that would take days.

The first thing that I checked after entering the boat was the Mastervolt charger and to my amazement instead of the red error light, all 5 "progress" lights were green.  I then checked the battery voltages and they were averaging 12.5v.  A thunderstorm was expected so I turned off the Mastervolt then disconnected to boat from shore power because I could not risk damage to the boat from a lightning strike.

This morning I returned to the boat, found that all batteries were still over 12v, checked the instrument, including the radar, and the lighting, and all was working OK.  I then started the engine and witnessed 35amps of current pouring into the batteries, which dropped down to 23amps after about 45 minutes. 

I then tidied up the boat, waited for a heavy shower to pass, and noted that the batteries were at 13V before I left the boat.

I had a talk with Greg about the "miracle" recovery when I visited him to return his chargers and we both agree that the wind charger and solar panels must have eventually provided just enough power to bring up one or more of the battery banks above the threshold that enabled the Mastervolt charger to kick in. 

 Greg told me that the week or two of low voltage would have introduced some sulfation on the battery plates, but I will not be able to determine the amount of degradation until I have done some load tests.  At this point I am not too concerned because there is enough battery power to tolerate some degradation.