Quote:
Originally Posted by ohrly?
We used a second 12v-5v power converter ( http://www.andymark.com/product-p/am-0899.htm). It was a problematic because if the compressor and shooter motors were both running at the same time, there wouldn't be enough power left for anything else. |
The specs for the power converter says it only operates down to 10v. I think almost any robot will draw the battery down below 10v at some point. The 7805 circuit that was posted will work down to a little more then 7 volts, which may be good enough. You can also use a low dropout linear regulator with the same footprint as the 7805 which will lower the required input voltage a little more. Both of these have the heat caveat that Brian mentioned. The 5v supply on the PDB will operate down to 5.5v and supply 3amps. This is probably the easiest, if you aren't already using it.
The gold standard is the boosting type of converters that Brian recommended, however they are probably unnecessary.
You can use the
Driver Station Log Viewer to see what the battery drops to, which will help determine the required minimum voltage.
The current logic power converter works for the radio because the 12v power supply on the PDB for the radio is a boosted power supply, and will stay at 12v until the battery dips below 4.5v. The power converter probably isn't a great solution for other devices on the robot, however.