Shorepower problems and batteries

We were just about to go on holiday at the end of January when we suddenly started to have issues with the shore power. It seemed like there was a loose connection somewhere and so we had to trace it back from the pontoon power supply.  It became clear that there was an overheating problem in the plug that goes into the boat. This had caused the plug to partially melt! This was a replacement plug that had been fitted by an electrical engineer in our early months of ownership.  He no longer works for us on Mariadz.  When I eventually got into the melted plug we found that the live had been stripped of all insulation inside the plug and some of the wires were broken. This looked like they had been cut when fitting the plug, since the break was quite sharp and clean. We think with up to 16A going through this wire, it got hot especially with a little water ingress to add some corrosion to the mix. Clearly we couldn’t use this anymore and we were grateful to have found it before something more serious happened, you hear of boat fires caused by this kind of thing.

Still the whole premise of Mariadz is that there should be redundancy in all systems For instance we have seven different electronic means of navigation, as well as paper charts.  So we have a plan and will use the batteries during the day, topped up with a little solar.  If the batteries get too low and definitely in the evening, we would run our generator to provide 240v for the heater, aircon etc and recharge the batteries for the next cycle. That sorts it out while we get a new plug ordered and the cable checked.

Not a bad plan, we have 880Ah of domestic batteries and some energy saving especially around the lighting which is all LED. O think we are in good shape to run this setup for as long as we need with limited additional charging.  That evening, we have the batteries coming back up by running the generator and the boat is warm since we have been running the reverse cycle air conditioning. It gets to bed time and so everything off, remembering to switch off the hot water, because the immersion heater really takes power when run from the batteries. imageSo our overnight load is not great, even with the fridges and everything else running we shouldn’t take more than 10% of the total capacity or 20% of the available capacity running throughout the night.  I get up in the morning to find our battery monitoring reporting 0% capacity! Have I inadvertently left something on? I check everything and there are no problems. Running the generator during the day gets the batteries back up but it seems very strange.

In the evening, after running the generator the batteries are not fully up but they seem to be most of the way there.  We go through the same bedtime routine, and I double check the power usage, it looks fine. The next morning we have the same result. So now we have no shore power and our batteries are failing!

We do have a further fall back position though, we have bought a long extension lead with the right plug for the pontoon power supply so that we have power on board without running the generator. This acts as a sensible short term solution but obviously doesn’t give us hot water, microwave or the aircon units.

I have ordered a replacement Marinco plug from Fox’s chandlery but when this comes it is the wrong one, a simple mistake to make despite our checking and the chandlery checking the order before we placed it! 9D65561D-89F2-4F05-B846-17F21E1A2549Ollie from Seapower usually does our electrical work and unfortunately with me and Maria working hard at the moment, we can’t afford the delays while we sort this out ourselves. We just need it done and can’t wait for me to get back late from work, reorder, wait and then fit.  Ollie comes on board and wires us a temporary solution while the plug is being delivered and also checks the batteries.

When we got Mariadz, the AGM batteries had been fitted in 2010 and we don’t know how well they had been treated. Ollie asked me to review our replacement options particularly around AGM or Gel batteries. We had discounted Lithium because it remains four times more expensive than the other two, however it looks great for the future when the price comes down and I suspect in another 7-10 years when we are looking at our options, lithium will be the choice. So we have discounted the expensive option for the moment and that leaves us with a like-for-like swap of the AGM batteries or a swap to Gel.  One of the main advantages of AGM is its ability to handle a high current drain but this is a large domestic (880Ah) bank and so it is unlikely that we will have drains of this type. The Gel batteries on the other hand are suited to slower discharge rates and warmer temperatures, now you are talking Maria’s language. We decided that the Gel better suited our likely use in the future and went with these. In the end we got a good price for Victron batteries which hopefully will be well suited to our inverter/charger and solar MPPT controller, both of which are Victron.

While we are on holiday, Ollie is able to source the batteries and also get a new plug lost asked for a second plug wired to a 32A plug, the boat can handle both 16A and 32A input and so we should be able to handle either size of supply on the pontoon.  It will hopefully stop issues where they run out of 16A power and we have to share a reduced capacity.

So quite an exciting, and unfortunately, expensive time! One consideration though is that the batteries must have been near their end of life. I don’t think seven years is too bad a lifespan especially when we don’t know if they were treated well in the early years.  We knew we would have to replace the batteries before we left on our trip but had hoped it would be nearer to our departure date. The other thought is that we could have discovered the issue with the batteries at the start of the season when we anchored overnight. Then the delays getting the problems fixed could have stopped us sailing for a few weeks. That would have been frustrating so maybe we should be grateful. Finally, due to Ollie’s swift action we were able to keep the fridge and freezer running and so didn’t lose a lot of food, this was a concern especially going on holiday.

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