Tried #3 235W panel with 2x 12v car batteries

Checked O/C voltage of panels #1 and #2 in the attic. Both still say 0v. #3 and #4 panels say 36v as expected. #5 I can't get to easily.

It was too windy and rainy to check the cabling for #1 and #2 on the roof so I connected #3 to the 12v/24v charge controller and meter and took two 12v car batteries out of my defunct Vitarras as a load.

Everything worked OK but the sun was too low (at 6 pm) to register above 0.0 A on the meter.

Also, one battery was down to 6v while the other was at 12v. So next I will use the 60W 12v system to charge this one back to 12v so the loads are more even.

Wired up my dual charge controller to 60W and 235W panels

Wired up my 12/24v dual charge controller and meter to my 12v/60W PV system.

Left it all day and the meter finally saw some power. (Though a 60W system should source 5A of power).

Spurred on by this I decided to drop a cable from the attic to one of my 24v/235W PV panels and then wired up two car batteries as the 24v load to the charge controller.

using 15A connector blocks

It's hot and nasty (itchy rock wool everywhere and loose boards) in the attic and the cables are close to the eave run - so little head room

But when I tested the open circuit voltage it was 0V !

My heart sunk. As I'm not sure if I tested all the panels when I received them.


So I tried another panel in the attic. It read 36V open circuit and so I connected it up. But again it read 0v down in the house. Below is the label at the back of each panel:

.

I'm hoping that my cabling is at fault. I'll go up on the roof with a voltmeter this Sunday and check all the panels before my extension cables.


I also found out that while the 300W pure sine wave inverter powers the lights in the extension it cannot get past the fuse box to the main house. I don't know why. Investigation is required.

Raspberry Pi system controller received

Finally received my long awaited Raspberry PI.

I registered my interest with RS Components on 9th March 2012. And was invited to place my order on 31st March 2012:

RS Stock No.	Qty	Description	Unit Price	Goods Value
756-8308	1	Raspberry Pi Type B Single Board Computer	£21.60	£21.60
			Running Total	£21.60
Tax				£4.32
Standard Delivery (Despatch expected within 6 week(s))				£4.95
Order total				£30.87

Just took over 3 months to arrive :)

However, I received it Saturday and fired it up and it looks good.

It provides two USB ports (nominally for keyboard and mouse) a RJ-45 ethernet port and a HMDI screen output.

I used my mobile phone charger as a power supply.

The O/S I downloaded to an SD card.

My aim is to use this as the heart of a monitoring/control system for the wind turbine and PV panels.

It uses 2W and is half the size of my hand. Perfect!

House uses 40W / h for "essential" appliances

I was away during the week and measured my background power usage:
6am Monday 16/7/2012 - ESB meter 31126.40
9pm Friday    20/7/2012 - ESB meter 31130.72
So  4320 W in (4 x 24) + (21 - 6) hours => 4320 / 111 W/h => 39 W/h

I just had the telephone, router, two IP cameras and a hall lamp (the later just on for 2 hours a day).

So I started measuring the power consumption of various items to see if this adds up:

Appliance                                                     Actual                                           Rated
----------                                                      ------                                          -------

bedside lamp                                                    4W (warming up?)                      11W
hall lamp                                                           7W                                              9W
white laptot (Asus EeePC 4G Surf)                 23W (charges internal battery)      22W
black laptop (Samsung NC10)                        43W (charges internal battery)      40W
cordless phone (Philips CD 255)                       0W (I guess fully charged)            3W
IP camera (Edimax IC-3010Wg)                       7W (wired mode not Wifi)         12W
Eircom Wifi router (Zyxel P-660HW-T1v3)    18W                                              8W (huh?)
 

So I'd estimate (4 x 2 x 7) + (111 x (7 + 7 + 18)  W => 65 + (111 x 32) => 3617W (so 703W or 16% out)

My power measurements are not too exact (> 10%) so this seems about right.

The upshot is I need to plan on providing 40W+ per hour from my off-grid system to just supply "essential" appliances ! That's 960 W per day. Or a unit just for a few bits of kit!

So it would be good to make some low energy smart switches (timer or IR sensor based) to turn these on and off on demand. I should then be able to reduce this usage by a factor of 20 for the days I'm away.

Finally installed the 5 solar panels

The showery weather at weekends and working in Limerick during the week had delayed me installing my solar PV panels but I finally got it done with the help of my neighbour Paul today.

This roof faces south, which is good, but the angle is probably a bit shallow to get the most out of the sunshine.

I aim to start experimenting with charge controllers and inverters next weekend on the 60W 12V system (on the ground to the right of the scaffold). Then get a second Varta LFD90 12v 90Ah battery and try them on one or two of the 235 W 24V panels.

Offered up 1KW wind turbine to UK scaffolding post