I have a 24v 2kw lithium, off-grid, solar station. I would like to be able to charge my EB3A overnight with the power stored on my 24v battery system. I could use the 110v inverter and plug my EB3A into that but it loses a lot of power going from 24v to 110v and then down to what ever the EB3A is built too.
If I connect a 12/24v car accessory dongle directly to my 24v battery pack it becomes less wasteful. I hope to use this same dongle with my portable 12v fridge, except the fridge has a low voltage cutoff (3 settings actually) to prevent me from depleting my 24v lithium pack too low.
My question is, how low will the EB3A let the 24v battery pack get to? Is this something I will have to monitor continuously to ensure it doesn’t kill my 24v lithium pack?
In short: the EB3A will pull DC power to charge its internal 268Wh battery until the voltage it receives drops below 12V or its battery reaches 100% SoC.
If your 24V lithium battery system does not have a built-in BMS with an automatic low-voltage cut-off then you will need to monitor the voltage closely when charging your EB3A. This is because the EB3A accepts a DC input voltage range of 12-28V. To protect your 24V battery pack you don’t want to let it get below 21.5V or whatever the manufacturer recommends.
This is what I suspected. I doubt I will do this too often as I hope to keep the EB3A topped up with the solar panels. I will keep an eye out for the battery levels if I do attempt this. I did try to charge it via the 110v inverter and it took quite a toll on my off grid battery pack. The loss of power from the Victron inverter was more than I’d like to see.