Hello,
I am working on a project where we use 4 PC-Engines ALIX boards (x86 boards), which are all powered by an 12V-18Ah battery. Each board draws about 300mA current. When everything is running, the system draws about 1.2A. Until now, I was using a Lead-Acid battery, however I switched to a LiFePo4 battery. With the Lead-Acid battery there was no problem. But with the new LiFePo4-Battery the BMS of the battery does not allow turning on all 4 boards at once. It seems that when switching it on, the boards draw more current, and the BMS of the battery disconnects the battery via a P-Channel FET in order to protect it. According to the manufacturer of the battery, the current draw is limited to 8A, before it switches off.
When i connect only 2 boards and a relay-coil to the battery, and the other 2 boards via the contacts of the relay-switch, it works. So it seems, that this small delay introduced by the relay is enough to make it work. But there has to be some better solution than that. I also tried using a series resistor. That does work, but it dissipates too much power, so unfortunately, that's not an option. But sice it works, it seems, that at least the boards don't relly need the high current in order to start, they just take what's available...
Is there some better way to limit the maximum current that the system can draw from the battery?
thanks in adavance,
Sebastian