The Libre Solar Project
Hi everyone.
I almost got my solar test system with a MPPT1210HUS set up. I’ll post about it once it’s working.
What would be the next step towards a nano grid? Can I hook a second MPPT1210 to the 12V bus? Where can I get more information?
Any input is welcome 
Best, Dan
Hi Dan,
The MPPT 1210 HUS is probably not the most ideal charge controller for a nanogrid.
We’ve made some experiments with the MPPT 2420 HC where two controllers in parallel communicated over CAN to follow the same charging profile. But the 1210 HUS does not have CAN. Also for droop control the PWM resolution of the STM32L072 is too low.
Maybe you could still connect two of them in parallel with the same settings and see if they interfere with each other. I guess it would work, but I’ve never tried it out…
Cheers,
Martin
Hi Martin,
thanks for your fast response. Ok, I’m up for trying the MPPT 2420 HC.
How many MPPT 2420 HC would make sense for a test nano grid? I want to try/see the droop control and CAN bus in live action 
Maybe two or three?
As far as I know they are out of stock. Are there any updates on that?
Please let me know if I can help. I’m an embedded system engineer (10y+) and can do PCBs and write code.
I hope that it will be possible to find a way to offer more and new libre solar boards.
Best,
Dan
Hi Dan,
great that you are so interested in the Nanogrid development.
Actually, the ideal hardware for the Nanogrid is this board with the STM32G474 because it can use the high-resolution PWM peripheral (HRTIM). We developed a dedicated Nanogrid controller in the EMBLEM project based on that board (I would not recommend building the old board anymore).
The project is currently on hold and the final Nanogrid controller hardware is not (yet) open sourced. But let me ask the project partners if they agree to open source it. At the end of the project the hardware was working quite well, but there was some room for improvement for the droop control on the software side.
Cheers,
Martin