Libre Solar Community Forum

MPPT 2420 LC kit or module for a project

Hi! I’m working on a solar powered boat project - is it possible to purchase a module or a kit for self-assembly of the MPPT 2420 LC somewhere?

Sincerely
Max

You could consider the OSPController. It’s a module level open source MPPT from a power supply and microcontroller for around $40USD. The hardware and software are being separated and a range of power supply units are being evaluated, particularly analog modules in addition to the existing digital modules.

It wouldn’t be hard to develop an open source component level reference design but it would be fairly academic because I couldn’t imagine delivering a power converter that was comparable, scalable, available, cost-effective and simple, with plenty of scope for customisation.

It’s the software that makes it come alive. There seems to be collaboration opportunities with LibreSolar, despite the different platforms.

The MPPT 2420 LC is an outdated design, so I don’t recommend rebuilding it. Please consider the new MPPT 2420 HC design.

I have ordered a small batch for further field testing which should be available in January. Let me know via PM if you are interested to get one.

Hi Martin

Sorry - couldn’t reply in PM, seems like I don’t have permissions for it on the forum - so continuing here.

I would be quite interested in testing the MPPT 2420 LC - is the board already populated (I’m not sure if I could solder the SMD components you have there)?

Also, would it be possible to measure the voltage / amperage on solar / battery / load and have a stable 5V (for electronics) with this design?

Just FYI - the project I’m working on is a solar-powered catamaran:

  • 5V electronics (RPi and all that)
  • 2 12V each thrusters (plus may be additional servos) (thrusters are 17A max, but I don’t expect to use it anywhere close to full power)
  • 4 12V 20W solar panels (for now)

I’d like to be able to change speed (i.e. power consumption) depending on the available solar / battery power, thus the question about the measurements.

Please PM me - I’m sure you will have permissions :slight_smile:

Sincerely
Max

Hi Max, not sure why PM did not work… normally everyone should have permissions to do that.

I don’t have any boards of the LC variant anymore (and I’m not going to order any new boards). But I will soon have some completely assembled boards of the HC variant (linked above) available. They would come with all SMD parts soldered. But I don’t have a final price and date yet.

For your application the MPPT 1210 HUS seems to be ideal (except for the peak power requirement of the two thrusters). You might want to connect them directly to the battery and make sure the battery is not deep-discharged in some way. That board has a 5V USB output that should work very well for a RPi. And you can order a fully assembled board through the Libre Solar website.

All Libre Solar charge controllers measure voltage and current for solar, battery and load ports (USB is included in load output current). You can get the measurement values through the serial port via ThingSet protocol or write your own communication interface / protocol.

Thanks a lot for your answer Martin!

Could you also point me to some docs on how I can get the current / voltage measurements? Is it the same for the MPPT 2420 HC and MPPT 1210 HUS?

Sincerely
Max

Yeah, it’s the same for all charge controllers. You need a USB to UART converter to “talk” to the charge controller with a computer. The RPi has an on-board UART interface. The connector pinout for the MPPT 1210 HUS is specified here.

The protocol is documented in the link above. See Example 4 how to read the battery voltage.