Here is a 3D photo of what I have mocked up so far:
It is sized to fit inside a dual SSR heat-sink. My idea is to mount the TO-220 packages onto the heatsink, using screw holes in the PCBs to gain access. Prior calculations show this will be a massive overkill, as the way the FETs are being driven there really is very little switching loss. But such a heatsink does make a well protected package.
Currently, have the following features in the design:
- Monitor Volts, Battery temp, and Alternator Temp. Adjusting as needed.
- Monitor Amps - allow for precise capacity reduction say for small DC generators, but also gives another way to decide transition between different charging modes (ala, Exit ACCEPTANCE phase when amps reduce to 2% of battery capacity) in addition to time-outs. Maybe make this optional, as it would require an external amp shunt be installed.
- 3 stage charging, optional 4th 'overcharge' mode for AGM batteries.
- Feature-in input - can be used for verity of things: selecting Equalize? Reduce alternator output? Other??? It would even be possible to have more than one input into the regulator, via simple resisters. (It is how I do local switches on the larger engine controller)
- Feature-out output. Low driving signal that could be used to drive a ALT lamp when there is a fault? Or???
- Configurable to support 12v to 48v systems.
- Configurable to support P-type alternators (High Drive) in 12v systems.
- Configurable to support N-type alternators (Low Drive) in 12v - 48v systems.
- Could drive very high amp alternator, or even more than one? FETs will support 20A+ of field current.
- DIp switch, or jumpers for selecting predefined profiles - or custom one.
Changes from the integrated controller would include dropping:
- All engine control and monitoring functions. Just an alternator regulator.
- Switching from one-wire temp senders to 10K NTC ones. But not decided on this one. Part of it is I found a source that makes the NTC probes already in a copper sleeve!
- No remote panel. (Hum - wonder if a CAN bus would be possible??? That drives NMEA-2000!)
- High Drive limited to 12v only systems.
Is anyone else interested in something like this?
UPDATE Summer of 2014: Did move forward with this project, see full details here: