(no subject)

Improved generator performance since weed clearance and a peak current of 44 amps recorded recently.

If anything the batteries seem to have matured and there have been very few times where they have refused to give enough current to make a tea brew and several machine washes have been done successfully.

The three year life observed with the carbon fibre plate batteries has been replicated on teh stand alone system in the Scottish borders, despite a larger solar array and more sophisticated charge controller. this system is likely to see some work in teh next two months with a change to Rolls batteries - 4 x 450 AH 6 volt units in series.

The 10,000 or more square feet of the building in Bermondsey only had to spend £100 pounds on electricity in the last quater and is due a significant sum in feed in tariff for probably three out of four quarters in the year

A good summer

Electricity imports since march have been negligible. 0.7 KWh in July, zero in June, three in May, 16 in April
Winter imports as one would expect -28 November,45 December, 52 January,46 February.

Electricity production has been good June saw 80 KWh delivered, 52 in May, 61 in July, 51 in April, 29 March, 26 February,19 in January, down to 1.6 in December, with 18 in November.

Some attention today, hacking back the undergrowth to remove a shading problem reducing the array peak power.

As I type nearly 40 amps is emerging from the charge controller, and I am tempted to do a machine wash while the sun shines.

The last month has been a very good one for the big grid connected system in Bermondsey, with the power reaching a peak of 9.9 KW by mid morning, and most of the day around 6 to 7 kilowatts of power export from the building.

The system design is coming good, trading peak power in favour of very low visual impact and longer time running near the inverter peak, and with a system which wrings abit more power out on indifferent days.

(no subject)

Variable performance over recent weeks.

Many days with overcast skies and rain, and typical yeilds of 1.5 KWh or less, with two days down to 0.6.

With the fairing up of the weather at the end of last week 4.3 KWSh was recorded on Firady and 4.0 on Saturday, comfortably in excess of the 1.8 KWh daily consumption with the surplus bringing about rapid recharging of the batteries - the batteries reached the absorb point briefly on Friday and reached the Float point on Saturday.

Completed the setting up and fettling of the solar hot water system in the old central library in Bermondsey. Embaraasingly we ran out of armourflex and were left with some parts of the pipe run uninsulated until further packs were delivered. This has a significant effect. What happens is that this results in a slug of cold water which is moved around as the pump runs, and one gets a reduction in panel temperature co-incident with the tank temperature starting to rise and often resulting in the controler stopping the pump as the difference has fallen below the minimum in the control settings. With all insulation now in place the pump was observed to run more or less continuously and the panel and tank temperatures were creeping upwards.

To take advantage I increased the cut off point for the tank temperature to 70C. AS the tank is a thermal store rather than one where the water is drawn directly, it can be allowed to reach a much higher temperature as there is a thermostatic mixing valve on the output to limit temperature plus all the showers have thermostatic mixers as part of the controls, giving two safety systems between the hot water and a person.

I have also brought the timer function of the controller into use, to inhibit the operation of the backup boiler from around 0810, when the last person is having their morning shower until around 1550, to allow the boiler to bring the store to temperature is required before the first resident gets home from work and wants a hot shower. The intention is to allow the last two showers to cool the top of the tank - it can fall potentially to around 45C before it becomes difficult to have the output water hot enough, and one hopes allows a significant amount of cold water to sink to the base of the store so that the store is most able to absorb heat, especially if the weather is indiffernt.

(no subject)

3 KWh harvested today.
A pleasing 2:45 in Absorb mode.

A particular pleasure tonight dealing with an inquiry for a solar PV installation knowing that the computer and Internet router were running on solar power, as is the steamer presently cooking my supper.