Keeping Fingers Crossed

For anyone who regularly follows this blog will know we have for been having a few problems with the electrics on-board Hadar. A quick summary follows.

For many reasons since we set off I have had suspicions that our electrics have not been performing correctly, in particular our Victron Multiplus Invertor/Charger. Things deteriorated rapidly towards the end of last year, resulting in our buying 5 new batteries. Now I rightly assumed that by replacing our batteries which we had doubts about especially the 2 which had originally been on the boat when the 3rd battery blew it’s top off. However all indications since then pointed towards the batteries not holding a charge, in that considering the amount of energy consumed between recharging, and the voltage readings indicated, before charging, as low as 11.1volts, the rapidity of the charge voltage raising to the Absorption level of 14.4volts, and having run the generator for an hour to charge the batteries, the battery voltage was only going to 12.5volts and not the expected 13.1-13.2volts.

For the best part of our stay here at Welford, I have been trying to work out what was going on, all the indicators were saying a bad battery, all the characteristics of, for example, one cell in one battery being down. Yet surely brand new batteries could not be failing? One of the reasons for fitting them was to eliminate the possibility that our problems were due to the batteries. Even with a 24 hour charge on a land-line didn’t seem to improve things.

To say I was having sleepless nights is an understatement, it is very difficult to get to sleep when volts, amps, batteries, chargers, etc. are buzzing around in your brain! For the past few days I have been monitoring and noting down much data, well not much else to do whilst frozen in.

Thursday I decided to reset some of the values I had changed within the Invertor/Charger just to eliminate the possibility that they were causing the problems. Usually when I take the front panel off it is easy enough to see most of the panel, but the lower part, especially the section below where all the connections are, are a bit obscured. Usually I move our spare toilet cassette and animal water bowl to give me better access, but this time we actually removed the steps by the engine room door, so I could get right down to floor level. I had the manual in my hand, and was referring to the diagram showing where everything of importance was located. With this I noticed that the set of 3 connectors which are used for connecting the Voltage sense, Temperature sensor and starter battery trickle charge, had only one pair of wires connected, the trickle charge pair. Now I know I had removed the temperature sensor some time back as it was this that caused the charger to overvoltage and damaged the battery. However I was surprised to see no connection for the Voltage sense.

Now the Voltage sense is a pair of wires connected across a battery so the Invertor/ Charger can more accurately measure the voltage across the battery, rather than relying on the voltage it sees at the main cables that go between the battery bank and the Invertor/Charger. Now thinking deeply about this, during last year I fitted the Victron BMV, which, to be able to measure Current, has a Shunt which goes between the battery bank and everything else. Any electrical meter is a voltmeter, so to be able to measure Current a voltmeter us used to measure the voltage across the Shunt, which is basically a resistor, and by measuring this voltage the meter just needs to be calibrated in Amps or Milliamps accordingly. Hence without the voltage sense connected the Invertor/Charger was not actually measuring the voltage across the batteries. Could it be as simple as this? Surely not.

Fortunately I still had the temperature sensor and it’s cables on the boat, so used the cable for this to connect across one of the batteries and then to the Voltage sense connector in the Invertor/Charger. I still reset one of the setting within before refitting the front panel.

Fingers Crossed.

We reconnected to the shoreline for another 24 hours charge. Well what a difference. For the first time ever the Charger stayed in Absorption mode for the full 4 hours maximum setting, this looked promising.

Friday morning we got up, did all our morning stuff, breakfast, dog walked, cat and dog fed, fires made up, and then I turned off the shore line, hey presto, after 10 minutes 13.1volts! Throughout the day things just looked more promising, the voltage stabilized and by the time it got to running the generator for it’s evening run I measured 12.33volts!

Amazing. Truly amazing in fact.

Even overnight last night the voltage had only dropped to 12.1volts, far better than the 10.5volts we had been experiencing.

The new batteries are perfectly fine and working well. Even during the day yesterday, with some energy being supplied by the solar panel.

Now I realise for the non-technically minded this may all seem gobble-dee gook, but basically all our electrics are now performing correctly, and in more ways than I have mentioned here.

Both Jo and I cannot believe how such a simple thing could cause so many problems. It is nice that we can relax quite considerably now all this has been sorted, for me it is a heavy load off my mind.

I am definitely now looking forward to this coming year, more than I have since we have been on the boat.

Keith.