Single Port BMS MOSFETs Explained

Tags: Electronics, Solar

I'm writing this post since it seems there seems to be some confusion on why both MOSFETs in a typical single port BMS (Battery Management System) are controlled individually and why/how this works when they're in the same series circuit. It will hopefully also show why just controlling both MOSFETs at the same time to try and accomplish this is not a good idea.

Low Cost 10kW Solar System - One Year Later

Tags: Electronics, Finland, Hardware, Solar

A little over a year ago I published an overview of my off-grid solar system consisting of 10kW of panels and 28kWh LiFePo4 battery. The set-up consisted of all the components to run this solar system - including charge controllers, inverter, BMS, etc. The target goal was a cost of under €10K, which I managed to achieve with some cash to spare. Now that it has been in operation for a year, let's see how well the system held up, any issues that were encountered, and what the current price of the system would be were we to build it again today.

Panel Ground Mount

 

Partial Solar Eclipse over Finland Today

Tags: Other

Eclipse 2021

Building an off-grid 10kW solar system with 28kWh LiFePO4 battery, inverter, BMS and charge controllers for under €10K

Tags: Electronics, Finland, Hardware, Solar

Over the past decade or so I've been working on off-grid solar installations big enough to power a house, even during the long, cold (and dark) winter months here in Finland. While November, December and January remain challenging, it can actually be done - and pretty well. The issue in the past has been that doing this was quite expensive. The first implementations I built for this ran in the multiple tens of thousands of Euro and required quite some attention to keep going. These first systems relied on expensive components and difficult to manage and heavy lead-acid batteries. Over the past few years however, the landscape has changed and there are possibilities that I could only dream of even as little as a year ago. The post below details the components, where to get them, requirements, and the cost to get an off-grid solar system with several days of autonomy running for under 10K Euro. 

Solar Power

STM32 Minimal Development Environment

Tags: ARM, Embedded, Programming

In the past I have written on the advantages of minimal development environments (read: Makefiles and GCC, no IDE, minimal abstraction layers) for ARM processors. One of the advantages of working this way is easy integration with existing processes such as build systems, production line, testing, etc. Using this in a virtualized environment also allows one to make sure every developer uses the same tools, and that the tools are tested and qualified for the intended project with a ready made virtual image available for each developer. They can then add their favorite editor and user interface, but the underlying build environment is fixed for everyone and archived as such on a per-project basis. This means that if a customer comes back a year or two later and wants to make a change, all the tools are there as we left them ready to make the change. In this blog post I'll write down a possible scenario for a typical STM32 project, in this case using a NUCLEO-L152RE board as a target. It should be easy to adapt to other STM32 boards/chips, and in general other ARM microcontrollers as well.

Programmer on chair