So, what is it?
The Motobrain PDU (power distribution unit) is a small form factor, next generation power distribution unit. You can install the PDU in your car, truck, motorcycle, RV, boat, or pretty much anything that runs on a 12V DC system. The PDU will supply power to any sort of accessory, like aux lights, heated gear, pumps, fans, relays, or DC motors. What’s really amazing is that the PDU will pair to your mobile phone or tablet via Bluetooth 4, so you can monitor, program, and even control everything right from your touchscreen. The PDU also supports switch installations so you also have the option of controlling circuits via a dash mounted toggle switch, button, or rheostat.
Motobrain allows you to wire vehicles a whole new way. It is like networking for your vehicle’s electrical components. Similar to adding a circuit breaker box and home automation system to your vehicle. It also reduces reliance on fuses by creating current limited circuits that will shut down automatically in case of an over-current situation.
- Eight 15A circuits with PWM
- 100A maximum current
- Fixed 20A maximum transient current
- Programmable over-current protection on all outputs
- Real-time telemetry via Bluetooth 4
- System voltage
- Total current
- Channel current
- Channel PWM
- Channel current limit
- Channel status
- Programmable default output behavior
- Turn on outputs based on key, ignition, or low voltage
- Turn off outputs based on key, ignition, low voltage, or high voltage
- Modulate output duty cycle to create pulsing effects
- System wide over current circuit priority
- 8 programmable analog signal inputs
- Can behave as a digital or analog input
- Digital input can sense GND, 12V, or disconnected
- Analog input can sense any voltage between 0V and 20V
- Turn outputs on or off
- Delayed output turn on after signal
- Toggle outputs
- Adjust output PWM in steps
- Link output PWM to input voltage linearly or logarithmically
- Can behave as a digital or analog input
How does it work?
Power distribution – The PDU has 8 independent positive voltage outputs. Each circuit is rated at 15A @ 12V continuous current and the total nominal load the PDU can source is 100A @ 12V. To install, you only need to connect the PDU to your battery’s two terminals, connect a wire from each Motobrain output to the positive terminal of your accessories, and then make sure everything has a good connection to ground. In this way, only one wire for each accessory needs to come back to the PDU. This helps keep the the installation tidy. We suggest you install ground bars to terminate your accessory grounds in groups rather than bringing each individually back to the negative terminal on the battery. Again, to keep the install tidy.
Hardware control – This device supports non-radio control methods. We have developed input circuitry that can sense when the input is pulled to either ground, 12V, or left disconnected. It can also sense any arbitrary voltage when in analog input mode. The PDU interprets these signals and performs actions you program via a Bluetooth device. Eight signal inputs are available for you to design into your own electrical system.
This allows you to link circuits logically while keeping them electrically isolated. You can even link the status of one circuit to the status of several others. For example, you can connect the horn and the high beams to two of the Motobrain inputs and then tell the Motobrain to turn on the auxiliary lights when the high beams are turned on and to flash the auxiliary lights when the horn is activated. In this way, with the installation of four wires (two signal and two power) you have created a way to operate auxiliary lights without adding a new switch and have created a safety system by making my vehicle easier to see when the horn is activated. Other input setup ideas:
- Attaching an input to the low fuel light circuit and turning on a pump to pump fuel far an auxiliary tank automatically as the fuel is low.
- Using a simple rheostat as way to arbitrarily adjust voltage to an input and link that voltage to the current that flows through the output. In that way I can install a simple knob that controls the current flowing through a device without running any current through the knob.
- Install a switch on your dash that toggles circuits on and off.
- Activate a relay linking in a spare battery when the system voltage is low.
- Replacing the entire electrical system of classic cars.
- Activating an air horn with your standard horn switch if your OEM horn is pressed for an extended period of time.
- Automatically turn off accessories when the battery is low.
- Automatically turn on fog lights when the wench is powered so you can see what you are doing.
- Add a photo diode to your setup and you can turn circuits on based on ambient lighting conditions.
- Add a temperature sensor and turn on a fuel line heater to prevent your diesel from freezing in the winter time.
Bluetooth connectivity – You can pair a Bluetooth Low Energy 4 device with the PDU using the MotoBrain app for iOS or Android. The connection allows you to have control of your PDU at your fingertip. Using the app you can turn items on, off, or dim via pulse width modulation (PWM, as applicable). The BT4 connection allows you to have visual, real-time feedback on the status of all accessories controlled by the PDU. This is also how to program the device inputs and setup default input and output settings.
Real time telemetry – In addition to seeing everything that is receiving power from the PDU, the PDU will also keep you informed as to how much current is being used per channel and the current system voltage (which can inform you of battery problems). This is great information to have if you have a limited current capacity on your vehicle (like on some motorcycles). You can even setup the device to turn off low priority circuits automatically if the total current draw is too high. There is an API available so you can write your own client software. Some prospective customers have even expressed an interest in writing software to log their Motobrain telemetry data in remote data centers over cellular networks and even use the Motobrain as a remote reset tool for sensor packs running in their commercial vehicles.
Where can I install this?
We have tried very hard to keep the size as small as possible. The PDU is made of two PCBs stacked on top of one another, one for power distribution and one for processing and BT4 radio. When mated together the assembly is about the size of a deck of cards. You can mount the PDU in tight spots by cable ties, or hard mounting through the mounting tabs. The unit is 100% encapsulated in an epoxy resin and is waterproof so mounting in exposed locations is no problem.
Safety is an important thing to consider when designing any electrical system, this is especially true in vehicles. While Motobrain provides four types of over-current protection there is still a chance that a catastrophic failure could create an unprotected system. Fuses must be used to create a fail safe environment. They should be placed between each Motobrain output and the loads as well as between Motobrain and the negative battery terminal. With regard to the output fuses, we are relying on Motobrain to provide the first level of protection so we can select a fuse size that will only blow should Motobrain fail. In all cases we want to use a fuse that will blow before the load or wires catch fire. Motobrain’s negative wire only provides a path to ground for Motobrain itself (its current draw is <35mA). A 500mA fuse will suffice between the negative battery terminal and the Motobrain.
It is important that we remember that wire has only so much current carrying capacity and we should follow best practices. This is true for all the nodes of the circuit. Remember that all the current flows from the positive battery terminal through one wire to Motobrain and it needs to be able to handle that current load. Size matters here and you may be surprised by the size of wire you require! Check the specification.