I'm planning to power both my OVMS module and a dash cam from a USB power bank I have lying around with two outputs. For the dash cam I am doing this so I can capture footage while I'm parked. For the OVMS module I'm doing this to reduce the risk of running down the 12V0 battery in my car (even though I realize the current draw is low).
To do this, I will plug my power bank into the 12V0 USB adapter I have and then plug the dash cam and OVMS module into the other end of the power bank. I realize that the OVMS module power input is OR'ed between the USB and the 12V0, so my plan was to remove D1 so that the only power option was through the USB port.
Is the USB port enough to power both the OVMS mainboard and the modem? Based on this stack exchange post, SAE J1962 states that the OBD terminal can supply at least 4.0 A, so it has much higher current capabilities than the USB. I imagine that the modem transmission can cause some large transients. Is there a power model for the OVMS module anywhere?
Thanks for any help
You can power the module incl. modem from USB.
Power requirements: https://docs.openvehicles.com/en/latest/userguide/warnings.html#average-power-usage
Regards,
Michael
Thanks for the confirmation! I noticed that the link only includes the averages powers for the module; I don't see anything estimating the maximum current consumption. Had that work ever been done? Would that be valuable?
Can you testing the OVMS modul with usb powerbank? And what kind of your powerbank?
Yes, any standard USB powerbank should do.
Peak with 1 second average is around 400 mA @ 5V (on GSM burst). If you can measure with higher accuracy, go ahead.
I'm considering getting an extra extension obd2- cable with switch to prevent battery drain on my Niro EV. If the OVMS module powered via usb (f.i. power bank) should work if the switch on OBD2 cable if off?
I just want to ask before I ordered a cable...I mean the switch on cable should be wired on live, so when the switch is off and the power bank is connected to OVMS module, the power should be from power bank instead of OBD2 connection of the 12V aux battery?
Am I right?
Thanks!
Regards,
Alenux!
blueprint for implementation
You're right, when the OBD power is off, the module is automatically powered from USB. Switching is seamless if USB power is connected when switching off OBD power.
Take care to choose a cable that switches the +12V line, not GND (and of course no data lines). Ask the vendor/manufacturer if unsure.
If you want to build one yourself, here are the OVMS OBD plugs:
https://github.com/openvehicles/Open-Vehicle-Monitoring-System-3/tree/master/vehicle/hardware/Electrical
+12V is always pin 16 on the OBD connector & pin 9 on the OVMS DB-9 connector.
Regards,
Michael