48 V DC power for fiber ISPs
You have between a handful and a few dozen cabinets, each with a small DC plant nobody has opened in three years, and the batteries are the part that fails first.
The pattern we see
The pattern is consistent: the network grew faster than the power documentation. Nobody has a current inventory of which rectifier is in which cabinet, the VRLA strings went in at different dates, and the first sign of trouble is a node dropping on a grid dip that should have been survivable. When you ask the OEM, the answer is a new plant — for cabinets whose rectifiers are fine.
What this actually requires
- An inventory of what is actually installed, cabinet by cabinet: rectifier, controller, firmware version, string age.
- A straight answer on whether the existing shelf can charge lithium, before buying any battery.
- Replacement modules for the cabinets that do fail, without replacing the whole plant.
- A migration you can do node by node as budget allows, not as one capital project.
How we approach it
We start with the sites you are least worried about, not the most. A pilot on a non-critical node, with the old VRLA string kept on site for thirty days so the change is reversible, tells you more than a specification does — and gives you a documented result to take to whoever signs the budget.