How much current can I source though the OBD2CAN???
Posted: Mon Aug 14, 2017 3:17 am
Howdy,
I am using the Race Capture Pro 3 with a 96 Dodge Neon. Previously we were piggy-backing our existing mechanical gage cluster with the race capture on an android.
For this race we are proposing two big changes:
1) We've decided to go "all-in" on race capture and dump our analog gage cluster.
2) We purchased the OBD2CAN harness and hope to use this to get MAP and RPMs directly.
Many of our sensors are NOT on OBDII so we'll still need to power secondary sensors. This includes fuel tank level, oil pressure, oil temp, H20 temp and trans temp. In addition, we hope to add a brake light sensor so we can grab GPS coordinates when we brake.
We have the cheap low resistance gauges (the one's that Brent doesn't recommend). I have characterized the resistance as a function of the measured value for each of them though.
I'm planning on using roughly 250 ohm pull-up resistors as shown in my schematic below.
Previously i was powering these sensors via 12V so that the old analogue gages would still work - but now I'm assuming I need to use the Vref (5 v).
Can I still source enough current through the OBD2 cable to power all these sensors? It would seem that the load per sensor is still pretty low (V=ir - V = 5V. Rmin = 250 ohms. i max = .02 amps).
Mechanical engineer here so I just want to make sure I'm not missing something.
I am using the Race Capture Pro 3 with a 96 Dodge Neon. Previously we were piggy-backing our existing mechanical gage cluster with the race capture on an android.
For this race we are proposing two big changes:
1) We've decided to go "all-in" on race capture and dump our analog gage cluster.
2) We purchased the OBD2CAN harness and hope to use this to get MAP and RPMs directly.
Many of our sensors are NOT on OBDII so we'll still need to power secondary sensors. This includes fuel tank level, oil pressure, oil temp, H20 temp and trans temp. In addition, we hope to add a brake light sensor so we can grab GPS coordinates when we brake.
We have the cheap low resistance gauges (the one's that Brent doesn't recommend). I have characterized the resistance as a function of the measured value for each of them though.
I'm planning on using roughly 250 ohm pull-up resistors as shown in my schematic below.
Previously i was powering these sensors via 12V so that the old analogue gages would still work - but now I'm assuming I need to use the Vref (5 v).
Can I still source enough current through the OBD2 cable to power all these sensors? It would seem that the load per sensor is still pretty low (V=ir - V = 5V. Rmin = 250 ohms. i max = .02 amps).
Mechanical engineer here so I just want to make sure I'm not missing something.