the e wind wrote: ↑
Jan 17, 2018 10:29 am
The only issue with using a CA to measure solar is that the solar power reads negative,
That depends on which way you hook up the shunt. If current flows from the shun'ts BATT end to it's LOAD end, it's positive. The other way is negative.
I think the CA has enough juice to handle the task if wired & programmed properly.
You can pay Grin to write custom firmware; just talk to them about what you want it to do, and the cost.
The problem you'll encounter is that the CA's MCU only has a few analog inputs, so you would have to sacrifice one of them from it's normal purpose to read the second shunt (like the Aux Pot), and then modify the CA hardware to go with the custom firmware.
Another problem is the MCU also only has so much memory, so the new features would probably require removing others to make room for the code.
You'd have to talk to Grin about the specifics of all of that, when working out the custom deal.
FWIW, there's a relatively simple way to ensure you only ride "solar":
If you have a battery on the BATT end of the shunt, and the solar output on the LOAD end of the shunt, and ride so you always show zero Amps on the current display, then you're riding so that the net power usage is only what is provided by the solar.
If you ride so it shows a negative Amps, then you're letting the solar charge the battery.
If it's positive, then you're exceeding the output of the solar, and using up your battery.
If you also watch the Ah (or more accurately, the Wh), it will keep track of the net usage, which you want to keep to zero or negative. If you see it creeping positive, then you need to reduce power usage until it's not.