It’s been on my TO-DO list now for a long time to wire in some current shunts to monitor the solar input, replace the near useless Powertech solar controller with something better, and put in some more outlets.
Saturday, I finally got around to doing exactly that. I meant to also add a low-voltage disconnect to the rig … I’ve got the parts for this but haven’t yet built or tested it — I’d like to wait until I have done both,but I needed the power capacity. So I’m running a risk without the over-discharge protection, but I think I’ll take that gamble for now.
- The Powertech MP-3735 is permanently out, the Redarc BCDC-1225 is back in.
- I have nearly a dozen spare 12V outlet points now.
- There are current shunts on:
- Raw solar input (50A)
- Solar controller output (50A)
- Battery (100A)
- Load (100A)
- The Meanwell HEP-600C-12 is mounted to the back of the server rack, freeing space from the top.
- The janky spade lugs and undersized cable connecting the HEP-600C-12 to the battery has been replaced with a more substantial cable.
This is what it looks like now around the back:
What difference has this made? I’ll let the graphs speak. This was the battery voltage this time last week:
… and this was today…
Chalk-and-bloody-cheese! The weather has been quite consistent, and the solar output has greatly improved just replacing the controller. The panels actually got a bit overenthusiastic and overshot the 14.6V maximum… but not by much thankfully. I think once I get some more nodes on, it’ll come down a bit.
I’ve gone from about 8 hours off-grid to nearly 12! Expanding the battery capacity is an option, and could see the cluster possibly run overnight.
I need to get the two new nodes onto battery power (the two new NUCs) and the Netgear switch. Actually I’m waiting on a rack-mount kit for the Netgear as I have misplaced the one it came with, failing that I’ll hack one up out of aluminium angle — it doesn’t look hard!
A new motherboard is coming for the downed node, that will bring me back up to two compute nodes (one with 16 cores), and I have new 2TB HDDs to replace the aging 1TB drives. Once that’s done I’ll have:
- 24 CPU cores and 64GB RAM in compute nodes
- 28 CPU cores and 112GB RAM in storage nodes
- 10TB of raw disk storage
I’ll have to pull my finger out on the power monitoring, there’s all the shunts in place now so I have no excuse but to make up those INA-219 boards and get everything going.