For those vaguely interested in techie stuff and possibly those curious about living on a narrowboat :
What do we do for power?
In the marina or with shore power supplied we basically have one power socket – imagine a home with one socket. Yep. Just one. We can draw 16 amps but you have to be careful what you plug in. Fortunately, most appliances are low power. I changed all the 31 light bulbs from halogens at 10 or 20 watts to LEDs at around 1 watt. The TV, laptops etc don’t consume much. The fridge is mains powered and at worst draws 8 amps but then not all the time, so let’s say 4 amps continuously.
We have 600 ampere-hours of energy in the 3 AGM batteries and not wishing to go beyond 50% of their capacity, to prolong their life, we have 300 Ah to use.
We usually get through 10% overnight or 20% if we watch lots of TV, DVDs etc. I don’t think it’s gone down below 60% ever.
Once the engine is started, the a.c. alternator can give 3,500 watts back, so the battery charger, set to 90 amps makes short work of replacing any usage.
However, if we stop for a few days or even a week . . . ? What then?
We have a solar array of 4 x 100 watt panels and these at their very best will give about 25 amps. So they still will not recharge a heavy usage – imagine you need a 33% recharge – 33% of 600Ah is 200Ah, so with a reasonable 20 amps coming in it will take 10 hours. Possible but unlikely in our climate. All the panels do is keep us topped up enough to not have to start the engine, even after a week of sitting still. Luckily at this time of the year, the juice starts flowing quite early as the sun comes up.
Higher powered appliances? Cookers, washing machines, toasters etc?
On shore power no problem – as long as we remember to count up our total power (washing machine on heat, takes 1.8kW etc). With the engine running and at a fairly high revs, we can do the same, which is why we usually save up our washing, bread making, slo-pot cooking etc for when we’re underway.
Washing: our slimline washing machine only uses kilowatt power for the heating stage, so we have taken to turning the heater off (a useful facility on the Ariston), just setting it to a cold wash but adding 10 litres of hot water from the tap. So we get a 40 degree wash but don’t use any kilowatts to heat the water. The few 100’s of watts the machine uses for turning the drum etc are easily supplied by solar and/or batteries. Neat tip there for liveaboards!
Cooking: we use the gas hob for 99% of all cooking, using a big ceramic coated frying pan with a lid to do almost everything. A 13kg bottle of gas seems to last 6 months or more. If we run the central heating and we do in these not-quite-Summer mornings, it will eat up about 0.5 kg a day. So then a bottle will last for a month. Not bad and no need to service it (ever) and no nasty pollutants either plus it’s so quiet. We do use a bread machine and again this only takes power when heating up at the end, the last 52 minutes and then only 600 watts, so we plan for the engine to be on then. Ditto with the slo-pot, this uses up to 800 watts but only in an on/off cycle. Again a vital piece of cookware as we can do whole joints in 6 to 8 hours and they are so tender.
I borrowed the power meter from our old house and clamped it to the a.c. output of the Victron. So we now have a display in the main cabin of how much a.c. power we are consuming – just a check to make sure nothing has been left on.