Position: 55°41.41’N, -5°43.42’W

Ten years must be close to the lifetime of our power meters. All nine ran well for ten years but we just had the second failure in two months. On both of these failures, the display shows partial LED number segments and smells bad. Generally, with electrical gear, a bad smell is sign that there was excess heat that could possibly still be a problem. Having seen these gauges fail with overheated electronics, we immediately disconnect them when there’s any symptom of fault.

Position: 55°41.42’N, -5°43.42’W

As the weather models indicated, conditions are wonderfully calm at the Isle of Gigha this morning, while the barometer begins a slow rise.

Position: 55°41.42’N, -5°43.41’W

The lettuce is lasting well, but we’re out of salad dressing. We have been making this delicious and easy-to-prepare French Vinaigrette since we were in Fiji in 2013. We were invited to dinner on the boat of two French brothers and offered to bring a salad. To go with it, we made our first-ever batch of homemade dressing using Felicity Cloake’s perfect vinaigrette recipe.

It’s a good thing we found a quality recipe—one of the brothers turned out to be a chef and the other owned a winery. When said they were “very surprised” about the dressing, we thought we’d messed it up somehow. But they went on to say it was delicious and asked if we’d made it with Dijon. Of course—who would dream of making French Vinaigrette without Dijon? :)

Position: 55°41.43’N, -5°43.40’W

Golden sunset after a calm day at Gigha.

Position: 55°41.41’N, -5°43.42’W

It’s laundry day on Dirona—we usually do it every couple of weeks when we’re away from civilization. Scotland is in a fairly strict lockdown, where marinas and fuel docks are closed for recreational boating and non-locals. We’re lucky that Dirona is so self-sufficient, and that hasn’t been the slightest inconvenience for us. We’ve got a couple of months worth of food, more than a half-year’s worth of fuel, can do laundry on board, and can make water as we need it.

Position: 55°41.41’N, -5°43.42’W

Our operating conditions for the past five weeks have been quite unusual. We’ve been at anchor for the entire period, and haven’t been moving the boat. This has never happened before for this long a period. Normally the batteries will be fully charged frequently, either by moving the boat or being plugged into shorepower. When charging with the generator, we turn start charging at 55% charge and stop at 85%. It’s far better to fully charge lead acid batteries, but doing this daily is inefficient. They can be charged to 85% in around 2 hours but fully charging the batteries takes closer to 5 hours. Certainly, this can be done, but it’s a long time with the generator at very low load and it would mean the generator is running half the time. A recommended compromise is to fully charge weekly, or at most every two weeks.

Short cycling degrades battery capacity. Most, but not all, of the capacity lost by short cycling can be restored with equalization (also called conditioning), a controlled overcharge that de-sulphates the battery plates. We’ve been watching the battery capacity degrade surprisingly rapidly over the past few weeks— it is down by 34% over the last five weeks. We should have fully charged far earlier than this, but we thought it would be an interesting experiment to see how fast and how far the battery capacity degraded and how much would be restored by equalization. Today is laundry day, so we decided to take that opportunity to fully charge and then equalize the batteries and see how much battery capacity is lost in 120 consecutive short cycles and how much is restored in equalization.

Pictured is a the MasterAdjust software used to control our two Mastervolt chargers. The battery manufacturer, Lifeline, recommends temperature-corrected equalization (conditioning), and at our current battery temperatures, we’ll need 31.0V. To achieve that, we have increased the absorption and float voltage levels to 30.9 volts.

Position: 55°41.41’N, -5°43.43’W

With the voltage higher than usual while we are equalizing the batteries, we got a warning that our 12-volt battery system was losing charge. It appears our 24-12V DC-DC Converter stopped charging the 12V battery. Its fairly common for electrical equipment to have sufficiently tight bounds on input voltage that period battery equalization might put them out of range. For example, our converter shuts off anytime the voltage is at 31 or above. Its best that any 24V equipment that’s not needed immediately be shut off during equalization. Well-designed gear should be absolutely fine, but you really don’t want to find out if your equipment is well-designed.

Position: 55°41.41’N, -5°43.42’W

During equalization, our 12-volt battery for the navigation system isn’t being charged by the 24v-to-12v converter, so we charged it externally. We only need to do this if the voltage is sufficiently high to cause the converter to shut down, and the load on the 12-volt system is sufficiently high to require charging.

Position: 55°41.41’N, -5°43.41’W

The Gen Amps graph (second from top at the right) shows generator output over the past 24 hours. Visible are the 8-hour equalization run and two more normal generator runs to the left (click image for a larger view).

Position: 55°41.42’N, -5°43.41’W

Sunrise over the Kintyre peninsula viewed from our anchorage at the Isle of Gigha.

Position: 55°41.41’N, -5°43.43’W

The long-term battery short-cycle test provided some really interesting results. Over 122 short cycles, our batteries lost 34% of capacity, which is far higher than we would have guessed. The equalization appears to have restored very close to all of that capacity. Our average time on battery for the past two days is identical to that of our first week at Gigha.

That shows us two things: 1) 122 consecutive short cycles will lead to rapid battery capacity reduction and 2) after equalization, the effective degradation of those 122 cycles (roughly 12% of the manufacturer’s nominal cycle lifetime) is fully nearly zero.

This is pretty surprising, and demonstrates that the negative impact of consecutive short cycles is remarkably small. Its also pretty interesting that consuming 12% of the manufacturer’s predicted lifetime of cycles shows almost no degradation at all. Closely related to this experiment, we will soon post a blog analyzing battery capacity over the lifetime of the bank.

Position: 55°41.41’N, -5°43.42’W

Sea fog this morning at the Isle of Gigha.

Position: 55°41.42’N, -5°43.49’W

Spectacular pink dawn looking toward the Kintyre peninsula from our anchorage at the Isle of Gigha.

Position: 55°41.42’N, -5°43.49’W

A bright near-full moon setting over the Isle of Gigha. The full moon in two days’ time is called the Flower Moon in the Northern Hemisphere because so many wildflowers bloom in the month of May.

Position: 55°41.43’N, -5°43.49’W

The generator continues to run well at 6,603 hours but currently has three minor issues that will eventually need some attention. The first is that the water seal on the sea water pump has started to seep slightly, so dried white dust is collecting underneath it. The issue is fairly minor, so we’ll leave it in service, but that pump will need to be replaced. Probably not that soon but its time is coming. The second issue is the rear main oil seal has started to leak a bit of oil. These problems usually take years to become anything more than nuisance leaks and some never get worse. However, we’re not so lucky on this one. In a month it’s gone from a barely noticeable oil mist from the generator cooling section to now spreading oil drops around the generator enclosure. It’s still not enough to actually drip but it seems to be worsening quickly. This one is really bad news since changing the rear main oil seal is a very big job requiring separating the generator section from the diesel engine to access the seal. The final issue is more minor. The engine takes a 3 to 4 seconds to start when it used to be 1 or 2 seconds faster. The last time this happened we found the fuel lift pump was loose and leaking air at the diaphragm.

The latest slower-than-normal to start issue is again very likely a fuel issue but, just to rule out the obvious stuff, James is checking the air filter and the glow plugs. Here he is testing the glow plugs by reading the current draw of the plugs. This circuit normally draws 16A or about 5.3A per glow plug. This quick test confirms that they are working normally so we’ll have to chase down the fuel issue since it seems to be slowly getting worse and a healthy engine should start in a couple of seconds.

Position: 55°41.43’N, -5°43.49’W

Whenever James is working the the engine room, Spitfire soon follows him in. He’ll sit on the engine room tray and call for attention whenever James walks past.

Position: 55°41.42’N, -5°43.49’W

Another tasty loaf from our bread machine.

Position: 55°41.43’N, -5°43.42’W

A wonderfully calm evening looking forward, aft, to starboard and to port (clockwise from upper left) around our anchorage at the Isle of Gigha.

Position: 55°41.42’N, -5°43.42’W

Spitfire enjoying the last of the sun’s rays shortly before sunset at the Isle of Gigha.

Position: 55°41.42’N, -5°43.47’W

Yesterday’s loaf was consumed by breakfast this morning, so we’re making another.

Position: 55°41.43’N, -5°43.46’W

We have a media filter in front of our water maker prefilter. The media filter is essentially a small sand filter very siimilar to that used on swimming pools. It’s super effective. In plankton rich waters, water maker prefilters can need to be replaced or cleaned weekly and sometimes as often as daily. With the media filter, we only change the prefilter annually when we change the carbon flush filter. The media filter has pressure guages showing when it needs to be cleaned, but we find it can go a very long time without building much back-pressure, so we just schedule the media filter for back-flushing monthly.

Cleaning the filter is quick and easy process. We reverse the valves, then run the booster pump, which runs seawater through the filter in the opposite direction, cleaning it. Here you can see the brown flush water coming out at the start of the flush cycle. We run the booster pump until the outflow water is clear, then shut it down and restore the valves to the forward flow.

Position: 55°41.43’N, -5°43.45’W

Making shrimp-salad pita pockets for lunch with the last of the celery bought in Portland seven weeks ago. Our produce has really lasted well with the green bag and paper towel treatment.

Position: 55°41.45’N, -5°43.46’W

We’re enjoying some fabulous sunrises here at the Isle of Gigha.

Position: 55°41.45’N, -5°43.44’W

James power-washing the boat while Jennifer follows behind with a bucket of soapy water washing and rinsing.

Position: 55°41.41’N, -5°43.43’W

Watching Boris Johnson address the nation on the UK lockdown plans going forward. Although the UK is slightly easing its restrictions, Scotland remains in lockdown.