I got hands on a batch of server-equipment that uses -48V power-supplies as is commonly used in telecommunications. In this equipment this positive DC (battery) terminal is grounded. I want to use this equipment to build an offgrid, solar-power powered homelab.
SmartSolar MPPT 150-35 explicitly mentions in the manual that it supports both positive and negative DC grounding. However MPPT RS 450-100 and Multi RS Solar 48/6000 do not specify it.
How can I verify that these systems also support positive DC grounding?
What kind of equipment do you use?
I use Eltek chargers, for example… these have a normal voltage of 48V… only that the +48V is simply connected to the frame at the ‘distributors’ and you then have a positive ‘ground’.
You probably also have the option of simply changing the + and - terminals in relation to the ground… otherwise it won’t work on the Victron system!
We design and build systems based on the Huawei telecom platform to work in parralel with the Victron platform. Technically that’s based on both the PSU’s themselves as well as the accompanying 19" rack mount power distribution systems. Generally speaking the adaptation from -48V to +48V platform can be as simple as removing the single grounding connection from the isolated positive busbar and rewiring it to the negative busbar. Not that there isn’t more to it when it comes to integrating the Huawei control systems as well but electrically that’s pretty much all there is to it.
With respect to Victron MPPT hardware I’d advice to make sure only to incorporate the DC-to-DC isolated products.