Designing a MPPT-4820-RC

Hi!

I’m so happy to find this project! I’m hoping to make a windmill and, if conditions allow, a water mill that generate electricity, and I prefer to also make the electronics surrounding it.

I expect my windmill, however, to deliver more power than your MPPT-2420-RC can handle, namely peaking at about 1 kW.

My initial question is therefore: How difficult would it be to size the design up for the task? 1kW is really the best case scenario, so keeping the current spec at 20A and just increasing the battery voltage from 24 to 48 V should be good enough. I’m only interested in some fast pointers for now. I’m hoping it’s as simple as finding new components that can handle the voltage (and of course redo the layout, since they will be bigger).

If things go as planned, I’d be happy to contribute with my design for the benenit of Libresolar. Which I guess brings the question whether there will be a “Librewind”? :slight_smile:

Thanks in advance!

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Hi,

I’ve built one MPPT-2420-RC and planning some redesign. Also interested in 48V version.
My brief comments:

  • With current heat sink max output current is around 14A. This is without force cooling. So my be larger heatsink on bottom is good solution.

  • Current MOSFET and Caps are 100V rated and this gives max input voltage around 80V

  • The power supply of controller needs some redesign. There was some issue regarding switching between solar and battery input. Also DC-DC buck IC is only 65V rated

  • I have some doubts regarding output inductor. It gets really hot. Not sure whether can handle 20A.

  • There are some minor software issues.

I have no long-term tests, but controller works well up to now. Martin has done excellent work!
I think that current design can handle around 300-400W. Doubling the output voltage and with better thermal management can reach 1kW.
So we can start share ideas about device upgrade. Not sure what is needed for water/wind application

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Hey both and sorry for my late reply.

@ulf that’s great to hear that you are interested in developing a version that’s more suitable for wind. It has been on my agenda for quite a long time already, but I’ve been busy with some projects related to solar charging and didn’t get really far with the support for wind turbines. But with joint effort we might be able to do that.

I’m in regular contact with the people from Erni Kollektiv who started with some charge controller firmware adjustments for a wind turbine some time ago. They are currently measuring the performance of a generator on a test bench so that the characteristics could be programmed into a charge controller. But there is still quite a lot of work to be done. I will point them to this thread :slight_smile:

@yasen I’m currently working on update of the MPPT 2420 which I will publish soon. Based on that we can maybe start to define requirements for a higher-power wind-enabled version. That would be cool.

Cheers,
Martin

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Thanks for your answers! Indeed would be very cool if we could help each other out with this!

@yasen: I’m not sure I fully understand your point about voltage levels. 80 V should be plenty I guess. 65 V is on the edge assuming max 16 V per battery. Do you think we need more head room?

@martinjaeger: Nice to know that somebody else is working on an MPPT for wind. I’ve also been looking at a project using an arduino which looks very promising, and appears to have been fully tested. Then I noticed that you’ve seen it as well :slight_smile:
https://github.com/philippedc/Arduino-Uno-Wind-Turbine-MPPT-Regulator/issues/2

Did you come to a conclusion regarding using buck or boost?

I’ve also been thinking about splitting the design into “control” and “power”, which would allow using the same control circuitry and just switch power board depending on your need. Each variant would be simpler to design, and the more complex control part could be perfected in parallell. Any drawbacks I’m missing?

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@ulf:First to clear some things - power part of MPPT 2420 is designed with components rated at 100V, so I think can handle 80V without problems. DC-DC buck regulator which supply control part is limited to 65V. Current design allows control part to be powered from HV side when there is no battery and this limits voltage on HV port. I was searching for another high voltage buck converter and will give a try on LM5163DDAR which is 100V rated. Another solution is to power control part only from LV port.
Regarding wind applications of MPPT 2420 I’m quite new to this topic and can’t help much at the present moment.
@martinjaeger: I’m happy to hear that there will be an update of he MPPT 2420. I was thinking about some improvements and will share my ideas in my build topic.