I’m in the process of building a UPS and peak-shaving system for my homelab (servers/networking gear). The goal is to charge up the batteries at night when rates are cheap and run the server rack off batteries during peak hours.
I’ve put together a wiring diagram and wanted to run it by you guys before I start wiring everything up. I want to make sure I haven’t missed anything obvious regarding safety or best
practices.
The Gear:
Inverter: Victron MultiPlus 48/3000/35 (120V)
Batteries: 2x Eco-Worthy 48V 100Ah (LiFePO4)
Distribution: Victron Lynx Distributor
Monitoring: Ekrano GX + SmartShunt 500A (decided to use the shunt rather than fight with Eco-Worthy BMS comms)
The Plan: I originally bought a Lynx Power In as well, but realized it was redundant since I can fit everything on the Distributor, so I’m planning to return it.
My specific questions:
Wiring: Does the diagonal wiring for the parallel batteries look correct to ensure equal draw?
Ekrano Power: I realized the Ekrano needs dedicated power (it won’t run reliably just off the VE.Bus cable if the inverter shuts down). I have it fused at 1A going to the Lynx busbars. Is this the standard way to do it?
Fusing: I’m planning on 125A MEGA fuses for each battery and the inverter. Does that sound right for this size system?
Any feedback or “gotchas” would be appreciated before I flip the switch!
You should check the IAC needed for the batteries, mega fuses might not be enough.
The wiring unlimited book explains parallel battery connections pretty well, diagonal wiring is one of the options.
Power for the ekrano can also taken directly from the battery, this way you can adjust settings with the system turned off.
Fusing for the inverter is described in the inverter manual, make sure to check the correct (120V) manual.
If you want to do peak shaving there should be a meter on the grid connection, what exactly is the goal?
Running the system of batteries when price is low should work fine but there is significant loss, make sure you account for that.
In the past i’ve had troubles with a unifi dream machine needing a reboot after switching from grid to battery on a multiplus 5000. The rack was also behind a separate eaton ellipse 1600VA UPS, everyhting but the dream machine worked fine. Maybe the dream machine power supply was on its way out.
Thank you for the link that’s indeed very helpful! Good callout to power ekrano through the battery, I’ll do that.
Could you help me understand why meter the grid connection? I live in the area where power is VERY expensive during the day, and much more reasonable during the night, so battery losses would be a drop in the bucket.
The blip in dream machine might have been because the momentary loss of power when switch between supply happens. I think Multiplus takes like 20ms. I’ll find out if it affects mine and report.
