|June 6, 2023
12 volt power supply and DC UPS controller for use in cars and buses, 5 amp 4A charge rate
Automotive battery backup controller.
More battery backups for buses, emergency vehicles and vehicle instrumentation
Click here for the 12 amp DC UPS controller.
Complete UPS with control module and 1.2AH lead acid battery
We have several models of the DC/DC auto UPS control module. This one is similar to the 5A controller, but has a higher 4A charge current. It is designed for 12 volt systems, and has a throughput of 5 amps.
This is a microprocessor controlled uninterruptible power supply control module. You can connect the module to the car's electrical bus and it will charge an external 12 volt lead acid battery of your choice. Your equipment, for example, 60W small computer, video recorder, or a car alarm, is connected to the module. This equipment runs off the automobile's electrical bus until the voltage from the car drops below a preset voltage, the "N" voltage (from 13.1 to 11.9 volts, depending on your needs). Then the external battery takes over. When the external battery drops below the "P" preset voltage (Between 10 volts and 3 volts depending on your requirements) the power is cut off to either prevent damage to the external battery or to run your equipment as long as possible.
These controllers can charge an auxiliary battery from the car's alternator system or SLI (starting, lights and ignition) battery.
The auxiliary battery is isolated from the car's electrical system so that it will only operate the equipment attached to the load terminals of the controller.
The load terminals power your equipment from either the vehicle or the auxiliary battery, acting as a battery backup (BBU). The switch position depends on the voltage levels of the two inputs. This allows your equipment to be powered from the car when car power is available.
The DC UPS controller protects the auxiliary battery from being over-discharged.
The control set-points of the DC UPS controller can be set so that the equipment switches to auxiliary power when the car is shut off. It is not necessary to run an extra sense wire to the ignition, voltage sensing takes care of the decision making.
The BBU detects the vehicle's electrical bus voltages, so does not need an extra wire to connect to the ignition. The set-points can also be set so the the crossover voltage is lower, say 12.0 volts. This allows the load to run off the car's battery but cut off while the car's starting battery still has enough power to safely start the engine.
One of the most popular applications is to run a small appliance such as a refrigerator from a separate battery when the engine is off.
The PST-UPS4 can be ordered with a range of "N" and "P" values, as explained in the following table.
Hook up diagram:
Dimensions, but the connections for the PST-UPS4 are wire leads.
The charge current depends on both the car voltage and the state of charge of the battery. When the car is running the blue curve applies.