March 24, 2018

Solar Cluster: ADSL powered by the sun

So, I’ve now moved the ADSL and router onto the battery supply. This has added an extra amp of load, but really, the solar panel handles this easy.

I dug up one of my spare switchmode PSU modules and then got to thinking about how I’d mount the thing. In the end, double sided tape… to keep the terminals of the adjustment pot from shorting, to a piece of old copper clad PCB from the project graveyard, with some wires soldered on.

The donor PCB already had regions cut out for terminals around the edge, so I could use those for drilling mounting holes. I just made additional terminal pads for soldering the input and output supply rails. Initially I tried putting a 1mF capacitor across the output, but evidently the one I grabbed was crook as it presented a 10Ω load. I don’t think the cause was due to it charging. The PSU has a 220µF there already, so let’s see how it fares.

Fairly simple, +12V comes in via the orange wire into IN+, the “LM2596” steps that down to 5V, comes out the red wire. Screw terminals allow me to swap input and output.

Before hooking it up to the ADSL modem, I made sure to dial it in to 5V.

Meh… who’s going to care about 3mV. 🙂

As it happens, the original PSU puts out 5.3V. I think I’m closer. I can always dial it up if needed.

I put the lid on the case and made up the rest of my wiring harness. One 5A blade fuse, a bit of work around the back of the rack, and it was installed.

In the meantime, I have my old server busy pushing its last daily back-up across to a newly provisioned virtual machine on the cluster.

One problem this presents is that this one VM occupies about 70% of my usable storage cluster capacity. The cases can take one 2.5″ HDD, which unless you’re willing to risk it with Seagate (I’ve had too many of them fail), top-out at 2TB.

There are SSDs too, but I’m not made of money, and I’ve already spent the cost of a small car on this cluster as it is. My thinking is I might look at modifying the cases with a new lid to accept a 3.5″ HDD. If I make the case a wee bit taller, a 3.5″ HDD would fit in the lid, and I could add fans around it to cool it.

The other option is to make external eSATA 3.5″ DIN-rail mounted cases. I did look online, but didn’t see any for sale. That said, space is getting squeezy on that DIN rail, and I do have to be mindful of cooling.