Nice to see more people building these. Another youtuber building these is Will Prowse. You may find his version may have less soldering. [1] Just use a bigger battery to get the same Kwh. Here is a smaller version. [2]<p>[1] - <a href="https://www.youtube.com/watch?v=4ypDwMYO1rU" rel="nofollow">https://www.youtube.com/watch?v=4ypDwMYO1rU</a> 3.5KWH<p>[2] - <a href="https://www.youtube.com/watch?v=WFLYIlCwE6w" rel="nofollow">https://www.youtube.com/watch?v=WFLYIlCwE6w</a> 640WH