Sunday, 17 March 2013

Weeds and Lunch

We didn’t half get bashed around by the wind last night.  Both of us had broken sleep whilst Jan also heard one of the fenders on the roof being blown off and bang against the side of the cabin.  Not me… there are a few advantages of slight deafness!

By mid morning things had somewhat calmed and the sun even put in an appearance until mid afternoon.  The other appearance was “Nellie”!

A phone camera photo to my usual high standard!

This duck has a burning desire to become ‘duck a l’orange’

We have been telling ourselves it’s time to have a pub lunch.  The previous proprietor of the Aldermaston Wharf Cafe is now the publican at the Rising Sun which isn’t too far from our current mooring. 

The website claims the pub was established in the 1600’s, although looking at the exterior I suspect you’d be striving to find any of the original building.

During the walk Jan became very animated and wanted me to use the phone camera to take a photo of some yellow flowing weeds.  I couldn’t see the reason for the excitement.  Apparently they are daffodils.  Jan informs me they are one of the first signs of spring.  After all the rain today I can only assume they arrived early!

The weather forecast for the next two days doesn’t make pleasant reading so we’ve decided to defer our planned departure from our current mooring until Tuesday.  Widmead Lock opens without any restrictions from 4:00pm next Friday so that will give us a couple of days in Thatcham before moving on to Newbury.  Well that’s the current plan….. weather permitting!

More of the boring stuff to follow

Part 4 –Charging source options

It would appear our engine alternators are most effective during the Bulk stage where for approximately the first 1.2 hours their combined output is readily absorbed by the domestic battery bank. The battery bank has then reached 80% full and the Absorption stage commences. The batteries require a further 270 amps which will slowly be delivered over the next 4.2 hours at a maximum of 64Ah. So during Absorption the alternators are producing 225 amps and the battery bank will only accept 64 amps. 161 amps (71%) of the output from the alternators is being wasted over the next 4.2 hours. For simplicity I’ll ignore all the inefficiencies. 161 amps at 12V = 1920 watts of wasted power. Rather than “waste” this energy it could be used to power appliances such as the washer/dryer and vacuum cleaner. But only after the initial 1.2 hours of Bulk charging.

Somehow I can’t see us Jan washing or vacuuming for 4.2 hours every day.

Another option would be to use a different energy source for the Absorption and Float stages. We currently have two 100 watt solar panels. 200w at 12V = produces 16 amps (ignoring all the losses and inefficiencies). The panels would take approximately 16 hours to complete the Absorption stage (270÷16). This is highly unlikely to be achieved during 90% of the year.

Recapping, we need an energy source capable of producing a maximum of 64 amps at 12V for 4.2 hours during the Absorption stage. This is roughly equivalent to 768 watts (64A x 12V). Note: I’m ignoring all the losses and inefficiencies!

A small 1kW suitcase generator produces 800-900 watts. This would likely provide sufficient power to complete the last two recharging stages but would not provide any additional power if we were to use consumers (eg, TV, laptop, lights, pumps, etc) during the recharging.  It’s therefore likely a 1kW generator is insufficient for our needs.

There are two other considerations. First, we plan to cruise for 3-3½ hours daily (well when the weather is fine!). But the Bulk recharge will only take 1.2 hours. So the engine alternators will be recharging for approximately 2 of the 4.5 hours during the Absorption stage. The other consideration is the battery bank only has to be full recharged approximately once every week.

Conclusion. The solar panels will not provide sufficient power on their own to complete the Absorption stage but they may be sufficient in the summer for the Float stage. Running the engine during Absorption when not cruising is a waste of energy. If we purchase a generator to complete a weekly 100% recharge of the batteries then we should consider something in excess of 1kW.

Next….. Equalization

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