Saturday, 16 May 2015

Leighton Buzzard and Solar Update

It was always my intention to replace my 240v fridge with a 12v one, but after having fitted my solar panel I was a little optimistic that I wouldn't need to, but having tested it for a few days now I find I have to switch it off overnight or run the engine next day. The primary concern for me is if I wish to leave the boat for a day or two I don’t want to return to flat battery’s and a stinky fridge full of rotting vegetables and sour milk.
The problem is not just the fact that it’s a 240v fridge but that it is a fairly old inefficient one as well ‘B’ rated, a modern ‘A++’ or ‘A+++’ (how many plus’s will they eventually add?) would probably be as good as a 12v one but if I am replacing it anyway I think 12v is the way to go.

For those interested here’s how it all pans out (skip this bit if volts and amps are not of interest).

Getting accurate figures is difficult but this is my understanding of the situation now and what it should be after a 12v is installed.
Currently my fridge is rated at 70watts, although it is 240v stepped up from 12v via the inverter, so watts/volts=amps 70/12=5.83amps then allow for the inverter being inefficient (gets vague here I’ve read anything from 5% to 75%) say 25% =1.45amps so total draw = 7.28amps per hour, the fridge cycles on and off so assume it’s on 50% of the time, 7.28*12=87.36 amps per 24 hour period, I have 6x 110AmpHour battery’s of which roughly 30% is actually useable so 220amp hours and I don’t want that to drop below 50% charge if I can help it, so 110amp hours ( soon disappears doesn’t it). You can see now that with roughly 110Ah available 87.36 for the fridge is a very large chunk, add the water pumps, lights, maybe CD player or a bit of TV and hence the need to run the engine daily.
Ok the solar has improved it, dramatically, but what if I choose to leave the boat for a couple of cloudy days, back to that stinky fridge. So a 12v Shoreline fridge of the type I need has a rating of 27.36amp per 24 hour day ( I know they lie, but you have to accept something’s!), that’s less than a third of the draw of the 240v one and no need to have the inverter on 24hours a day (with risk of failure), so my available 110amp hours without any input from the solar should be ok to keep the fridge running for 4days, and the solar on an average day will easily replace that loss, so in theory during the summer I should never need to run the engine just to charge the battery’s and in winter probably only every third day at worst. But the Big plus is the fridge will be on 24hours every day, not as now off overnight.

Right come back all those who skipped that bit.

So having got sorted with a Post office to accept parcels I ordered the wiring bits to run a 12volt supply around to my fridge position, I also ordered a remote switch for the inverter, (at the moment to switch the inverter on/off means moving the stairs to gain access to the electrical cupboard, a bit of a pain twice daily). The wiring turned up yesterday lunchtime so it was get down to running that from the battery bay to the fridge recess in the afternoon, having completed that job I walked back to Grove Lock to see if Carl was there, he was and after a chat he suggested a pint at his ‘local’ in Leighton Buzzard, so I set off walking (about 30mins from his boat) and he came whizzing along later on his electric bike, they zip along at 14mph, we went to the Black Lion in the High Street where he was greeted as if he’d been to the Amazon not Aylesbury, anyway after a couple of pints I left them to it and returned to cook and eat, that being done by 7pm I promptly fell asleep waking at 10:15, I hate it when that happens!

Back to the post office today I collected my inverter remote and while I was there this delightful wedding car was doing a few circuits around Market Square (where the Church and Post office are located) and I couldn't resist taking a snap
 
it had a bubble machine somewhere at the rear much to the delight of the children present and a few adults J and the exhaust tailpipe was in the shape of a heart, awwww. 

Back on the boat a 10 minute job to fit the switch and a lazy day followed, apart from dusting and sweeping throughout, this afternoon Gary on the fuel boat came along so I waved him down and took the opportunity to top up, just about 50 litres but I like to keep it full when I can and give the trade boats my business, I misheard him and wrote a cheque out for £20 too much, he pointed out my error immediately, honest chap, thanks Gary.

I am staying here tomorrow and moving on Monday weather permitting to try to find a mooring with vehicle access nearby  to get the new fridge delivered, fingers crossed. 

Leighton Buzzard is a very pleasant town more ‘boaty’ than Aylesbury but not quite as much as Berkhamstead, and I have enjoyed my time here and the peaceful mooring away from the town.

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