Shack Solar Power Update.

 During the past week I have worked a bit on my solar power system. 

A local friend had some panels he could not get much use from. They work fine, so I decided to get some of them and put them to work. The panels are:

2x 130W peak, 17V

4x 100W peak, 17V

Just before going to my friend I purchased and picked up 2x 12V/100Ah LiFePO4 batteries, as they are considerably more efficient than the (gel) lead-acid batteries I already have. For the shack I want to use them in a parallel connection configuration, so I now have 200Ah at 12V.

First step: Setting up some of the new panels.

I started setting up the 2x 130W panels, connected in series, and connected them to the old batteries via a charge controller. This controller is capable of delivering 20A charge current, and capable of accepting up to 55V (open circuit voltage, OCV) input from the solar panels. The OCV from the panels is under 40V, so there is a good margin. The panel setup is just an intermediate step. They are resting on the ground, leaning to the out-house South wall. I will need to build a lasting support, but right now it is a matter of getting the system up and running.

When coming home from the trip I realized that I missed a bit of hardware, so I went and got 2 100A switches, some 16 mm2 cable and some eyelet connectors for the battery. Next problem: The connectors were impossible to crimp with my current tools, so now I am waiting for a hydraulic crimp tool for the connectors.

The initial indoor set-up is them made with some 2x 4 mm2 speaker wire as the connections, so there is still a good deal of improvement to do, but apart from the improvements needed, the system is essentially ready to use, and the two radios originally connected to the old system have been re-connected.

The first test shows that in the good sunlight, even in the mid to late afternoon, the batteries charged from 89% up to 100%, even with the small load of the IC-705. Right now the 10m FT8 has been added, and the remaining sunlight is insufficient to provide much charge (well, sunset is about now (2000 MEST) in Copenhagen). The real test will be adding load, and see how this works long term. 

Here is the experimental setup of the panel:

Given that we are in the summer half of the year I expect the system to be running nicely with lots of surplus energy, even with just the 2x 130W panels. In the deep of winter time it is a different matter. I expect to have to use some supplemental power from the mains, in order to keep the batteries sufficiently charged.

For now I need to make myself a power budget to see what I can connect to the system. This will also involve testing the power consumption of modules, like the Raspberry Pi(s) I intend to use for FT8/WSPR decoding and QRSS grabber(s)

Now it is time to connect some more load - yes, more radios running on pure solar power here. I think that the first should be either:

1) running the QO-100 down converter (satellite LNB), possibly the 739MHz IF receiver - and the Chinese up-converter mounted indoors. Then I need to test the stand-by power drain of the old IC-821 transceiver. ... or

2) running some more stand-by monitoring equipment, such as more receivers and/or raspberry Pi(s) for QRSS/WSPR or FT8 monitoring, first on 10m, then on other bands, such as 6m, 4m or 2m.

A preliminary second solar power system can be used for powering the 2.4GHz power amplifier(booster) at the feed point of the TX uplink dish. For energy saving reasons I should make the voltage for the booster remote switchable from the shack.

Some antenna work will also be necessary, for the lower frequencies. I want to be able to work on as many bands as possible from 160m (630m?, 2200m?) to 13cm, and later 10GHz, maybe 3.4 and 5.7GHz, but I expect the latter two bands to be just experimental as part of my band-QSO-challenge.

Interesting time ahead for OZ9QV