Thought I would share a recent battery nightmare that we had.
We had a 30 hour passage from Canet-en-Roussillon to Mallorca earlier this week, this involved quite a few hours of motoring. We arrived and dropped anchor mid morning . That evening we had a discharge of the batteries to around 82% the genset was started as usual and the batteries brought up to 100% before bedtime.
The next morning the batteries were at 92% charge and I started the genset again over breakfast and went for a swim. After 30 mins I noticed that the charge was still 92% yet the Victron Color Control indicated that the charger was in bulk phase. I went to check the batteries only to find that the outside of the battery compartment was extremely hot. I immediately shutdown the genset and disconnected the batteries and opened all the ventilators and then opened the battery compartment. On inspection the battery boxes (Victron AGM x13) we’re melting, bulging and distorted. Some time ago I invested in a laser spot thermometer and used this to check the surface temperature of the batteries all except a few were greater than 50 degrees centigrade the rest being in the high 40s. I then proceeded to disconnect the interconnecting wire between each of the 6 pairs of house batteries, to effectively isolate all the batteries from each other. Fortunately we we able to keep the fridge and freezer running off the 450watt solar panels. After a few hours the temperatures had dropped to mid 40s. We were then in the predicament that we were at anchor with no way of starting the motor or lifting the anchor. It was clear that all the batteries were lost but we needed to try to salvage a few temporarily to allow us to get into port. So I then decided to test each of the batteries using a load tester and marked each of the completely destroyed batteries with a red cross and marked the load amp result on the rest. This left 5 functional batteries- the motor (311 amps) , and 4 others - around 150 amps each. So I hooked these back up into the system and turned the battery switches on again. Interestingly our Victron panel reported a 100% charge with absorption phase. Over the next few hours the temperatures continued to drop, we managed to start the engine, lift the anchor and went into port. In port we disconnected all batteries except the best 2 house batteries as we were advised that it would not be safe to run the Victron Quattro without batteries attached (like a 24 volt supply as someone suggested) and we needed to keep fridges etc going. With the boat well ventilated the batteries continuing to cool and on the boat connected to shore power we then just had to source some replacement batteries . The following day kitted with locally sourced goggles etc, and the batteries down to sub 30 temperatures, I had to use a large screwdriver and hammer to gently separate the batteries and remove them one by one as they were stuck together. There was around 1cm of battery acid in the battery compartment after all the batteries had been removed. The Victron Quattro supplier suggested that one of the 3 year old Victron battery cells probably failed and caused this. We have decided to go back to sealed lead acid batteries this time around. I am interested in the lithium discussions as these batteries have such a high degree of self monitoring, because of their potential dangers, which more traditional batteries don’t have. Yet all batteries have there dangers. I was very glad to have the spot thermometer and battery tester at hand.
Currently puerto de Soller