Day 42 – 6 weeks!

Fairly short cruise this morning to waterpoint below Atherstone locks. A bloke on a narrow boat said his mate on a short Springer would be along soon and we could do the locks together. So we did. Still took all morning, I think we cleared the last one about 1pm. After that another long lock-free section down to Marston Junction (Ashby Canal) then about 3 miles further to Hawkesbury Junction where I turned onto the Oxford Canal via the Sutton Stop Lock.

Moored just past Sutton Stop, sandwiched between David and (wife?) who accompanied me through the locks earlier and their friend +1 +another (mother-in-law?) who is very old, crooked and unsteady on her feet. They’ve all gone to the pub at the junction to eat but I had stuff in the fridge to use up.

The fridge is still giving me grief. I’ve done a few measurements with the gear I have and come to the following hypothesis:

The fridge uses 0.6A at 220-240V running off mains (at Llangollen) or off the inverter.

To get 12V from the battery to 240V the inverter steps up 20 times the input. Therefore the current must go up the same. 0.6 x 20 = 12A

But the inverter is about 80% efficient so consumes more like 15A.

That’s more than my little meter can handle so I can’t check, I’ll buy an ammeter when I get home.

I suspect 15A is close to the charging current into the battery from the alternator (via split diode circuit) and solar panel (200W or about 15A on a sunny day).

So in the morning if I check the leisure battery voltage it’s usually around 10-12V. Start the engine and wait a while for the alternator to replenish the engine battery and the relay to close to start charging the leisure battery and it goes up to 12.x or even 13V. But that’s from the alternator and solar panel the battery state is still showing empty. (Or close to empty, it’s not very precise).

Now I can switch on the inverter and the fridge and it works. But if I have a prolonged period without the engine running (waiting at locks for example) the fridge goes off even though the inverter is still running and draining the battery. I need to repeat the morning routine to get it working again. Turn it off. Run the engine, wait for the voltage to rise and restart the inverter.

By the end of the day the battery state is showing a low charge, or if I’ve not had the engine on much, empty. I can run the fridge for a few minutes – ½ hour maybe, but then the volts tail off and the fridge stops working.

When I get a real ammeter (using a little multi-meter at present) I’ll check the alternator output and charging current into the batteries. I might need a more powerful alternator (I think it’s a standard car model and few people have fridges in cars). I might need another battery in parallel with the first to hold more charge.

Anyone reading this got any more ideas / info, please comment below.

Day 25 – Chirk Marina

The last time I didn’t move Seren was at Wellingborough when the rain was pouring and the river Nene in flood. Today there is brilliant sunshine and I’m stationary. My ‘wing man’ Phil Robinson is coming tomorrow to help with the narrow sections on the final stretch into Llangollen but today is a rest day. And a cleaning, washing, greasing, emptying, watering day but that’s not very blog-worthy.

As a break from all the chores I’ve been investigating and number crunching some technical issues on Seren.

First, the leisure battery/inverter/fridge problem. I realised days ago the fridge was killing the battery in the evening, the fridge itself stopped working the lights dimmed especially when using water (electric pump). So for a while I’ve been in the habit of turning the inverter off in the evening, it’s been so cold at night the fridge hasn’t really got that warm anyway. Then after a few minutes of engine time in the morning putting it back on.

Today is unique in two respects, it’s sunny and I haven’t started the engine. Early morning the volt meter showed 11.7V, lights etc fine but fridge still off. Waited until the solar panel had pushed that up to 12V then switched the inverter on, but left the fridge off. Voltage dropped to 11.9 but soon recovered, current consumption by un-loaded inverter is about ½Amp. Voltage continued to climb, not only is it sunny, I washed the solar panel too! At 12.3V I switched the fridge on. Three hours later the battery indicator shows full, the fridge is working fine.

I think the issue is the weather. On the last big trip it was sunny into the late evening so even when the engine was off the battery was topped up until sunset then held enough charge to last the night, especially as the sun was up again a few hours later. Most of this trip it has been gloomy all day so probably very little boost from the solar panel and the battery has started to discharge as soon as I stopped the engine in the afternoon/evening. Need to do proper bench tests when I get home.

Then there’s the fuel consumption. I’ve dates, quantities and type of waterway and find that:

From Buckden to New Mills (Mostly river some canalised in the fens) Seren used about 4.8l per day (about 2l less than last year).

From New Mills to Whitchurch (mostly canal) she used about 3l per day.

The reduction on canals is probably due to two factors; the speed limit is lower so Seren trundles along at about 1600rpm rather than 2250rpm on rivers. That doesn’t seem like a lot of difference but at river speed she is pushing up a bow wave and trailing a wake, both mostly absent on the canals. And secondly on long lock flights I often leave the engine off for hours and haul her in and out of locks.

Day 15 – Progress is good(ish)

This should have been published days ago, but owing to unidentified tech gremlins it wasn’t. So here’s hoping it works now and I can catch up. It’s been an eventful couple of days…

Still 2½ days adrift but getting on well. I started on the remaining 11 Hatton Locks and as I left the fifth one of the day three CRT volunteers turned up to help. The remaining six were a doddle, I stayed in the cockpit and they did all the work opening and closing paddles and gates.

Then a nice long cruise in weak sunshine (better than heavy rain) through Shrewley Tunnel and on to Tom o’the Wood and Kingswood Junction.

My Canal Plan route continues up the GU Canal but when I was planning I decided to go left/right onto the North Stratford Canal into Birmingham, it goes through Edgbaston and is reckoned to be prettier than the newer GU route through Solihull. It came down to locks. On the GU they are large, if I’m by myself I only open one side but the paddles are big, hard to operate but fast. One the Stratford the locks are narrow which means I have to open both gates, which means walking up the lock and down again, twice. So I stuck with the GU. The next set of locks at Knowle were a slog, and it started to drizzle. Thankfully there are only five.

Next stop Copt Heath wharf where I bought some diesel. Seren’s fuel consumption (and tank capacity) is a mystery. Yesterday and the day before I put in 10l from a jerry can, before that I hadn’t filled up for nearly a week so I reckoned it must be nearly empty. But at Copt Heath we could only get just over 4l in the tank. I suspect foaming is the problem. I refilled the jerrycan with >9l so I’ll try putting that in sometime tomorrow.

Then on in the pouring rain to stop for the night at Catherine de Barnes Bridge.

Still having problems with the fridge. During the day with the engine running it works OK, but as soon as the engine is off the load on the ‘leisure’ battery is much too high and the battery soon starts to fade. My multimeter only reads up to 10A and it goes off the scale. I think the problem is the inverter but the only way to be sure is to plug the fridge into a proper mains supply and measure its current consumption. Transforming up from 12V to 240V one would expect a current increase of x20 so if the fridge takes 0.5A then the inverter will draw 10A plus a bit for inefficiency. But as far as I can see the fridge is taking more like 0.1A. I’ll organise a mains ‘hook-up’ in Llan (or Chirk Marina) and see how the fridge performs then.