I am currently building an Amateur Radio project that will run off batteries. In order to stop over-discharging that battery I need a controller to cut the power before damage occurs. I wanted something "off-the-shelf" so I bought a Battery Charger Discharger Board from Ebay.
The instructions are abysmal so I did some testing and managed to figure out how to operate it.
|U-1||V < Lower Limit||V > Upper Limit||Controlling a charger|
|U-2||V < Lower Limit||V > Upper Limit or Timer Exceeded||Controlling a charger, with timer|
|U-3||V > Upper Limit||V < Lower Limit||Preventing the load from over-discharging a battery|
|U-4||V > Upper Limit||V < Lower Limit or Timer Exceeded||Preventing the load from over-discharging a battery, with timer|
|U-5||Lower Limit > V > Upper Limit||V < Lower Limit or V > Upper Limit||Only supply power when the voltage is within the set range|
|U-6||V < Lower Limit or V > Upper Limit||Lower Limit > V > Upper Limit||Only supply power when the voltage is outside of the set range|
By default the unit will send out the current voltage, time the relay has been enabled and relay status every second. CL means the relay is open. OP means it is closed...
|get||Gets the current status||U-2,11.8,14.0,001 - (Mode, Lower Limit, Upper Limit, Timer)|
|off||Disable logic, turn off relay||None|
|start||Start sending status updates every 1 second||None|
|stop||Stop sending status updates every 1 second||None|
|000||Set the timer period from 0-999 minutes. Only works in timed modes.||down|
|dw11.8||Set the lower limit voltage, must be used in conjunction with up, e.g: dw02.9,up10.1||None|
|up13.8||Set the upper limit voltage, must be used in conjunction with dw, e.g dw02.9,up10.1||None|
|State||Current Consumption (mA)|
|Relay closed, Display on||91|
|Relay open, Display on||10|
|Relay closed, Display off||87|
|Relay open, Display off||3|