Electronics > Projects, Designs, and Technical Stuff
Switch from flat to charged battery while under load
<< < (4/6) > >>
gnif:
I have the opposite problem, I am drawing far more then the solar can produce, I intend to run the batteries until flat. I am avoiding using a grid tie in because the rates in AU suck, better to use the power myself.
NiHaoMike:
It's a 1kW solar array so I would expect it to produce more than most servers use, at least during a few hours per day. It probably won't cover all of the energy use but I would expect some times when you'll have to up the load on the server to actually use the solar, then back it down at other times. I would say that getting enough batteries to store all surplus production probably wouldn't be economical, but dynamically adapting to solar production would be.

There might be a way to tell the UPS to switch to batteries even with the mains present, eliminating the need to actually switch the mains with an external circuit.

If the server has a redundant PSU setup, check if it prefers to draw most/all power from one input in normal operation or load balance between the two. (That could even be adjusted through BIOS in some cases.) In the latter case, there might be some merit to adding a transfer switch to allow one of the inputs to bypass the UPS, allowing some control over how much to pull from the UPS. Ideally, there would be some way to program the power balance dynamically for fine tuning.
Psi:

--- Quote from: NiHaoMike on August 11, 2019, 04:32:11 am ---
There might be a way to tell the UPS to switch to batteries even with the mains present, eliminating the need to actually switch the mains with an external circuit.


--- End quote ---

Yes, some UPS have a serial/USB test command.
You can say, run on battery for X hours or Run on battery until flat.
sleemanj:
You want to limit the current drawn from the fresh battery put in parallel until the flat one is disconnected (some milliseconds later).

No different that limiting the current until big capacitors are charged, ie, this is a soft-start situation with the added factor of disconnecting the flat battery during the soft-start.  You can probably find a soft-start controller (inrush limiting PMIC) that can do that.

Or, use a micro, switch in the new battery in parallel through a suitable resistor, disconnect old battery, short out the limiting resistor so full current is now available.

gnif:

--- Quote from: NiHaoMike on August 11, 2019, 04:32:11 am ---It's a 1kW solar array so I would expect it to produce more than most servers use

--- End quote ---

This is not most servers, is a 16 core threadripper with two GPUs and 4 monitors running an array of 15 spinning disks and multiple virtual machines, it will certainly consume more then the array can produce.
Navigation
Message Index
Next page
Previous page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod