Recent content by EwanC

I've also made some progress on the light sensors - I actually designed and assembled these a couple months ago, but hadn't got around to posting. They consist of a PCB with a small STM32 μC, 4 OP950 photodiodes 90° apart (chosen because they have a viewing angle close to 90° and reverse light...

I've finally found some time today to work on this prototype. I've built a full-sized prototype as discussed above, using 25.4mm ID * 1.35mm wall thickness aluminium tube with 4 slits roughly cut on each end with a hacksaw. I made some timber plugs to insert into the DragonPlate connectors and...

Maybe I'd get away with a rigid attachment and a nice wide tyre on the trailer, I'm not sure. It was easy enough to include the suspension in the design though, it's not very heavy/costly, and my chosen air shock has a negative pressure chamber for light-load applications. So I'm hopeful it'll...

Yeah I've used MyUS.com quite a bit for having things shipped to NZ, but the cost does still add up. They add a bunch of fees to each parcel that you might not know about if you only look at the "shipping calculator" section. Still, they often end up significantly cheaper than many US-based...

No worries, you don't owe us anything :) Interesting results though. I'd have expected the Genasun to be a little better steady-state too, figured they'd have better MOSFETs than the CTK-EV-300. I guess the additional cost still gets you a very robust, well-engineered unit with excellent MPPT...

Okay, so after spending several hours in Fusion 360, I've updated the model to lower the panels. I managed to get the panel height above ground (assuming panels are parallel to the ground), down from ~775mm to 690mm. I achieved that by reducing the distance between the top and bottom booms by...

Yes, it's very productive! I should have posted my Fusion360 model weeks ago, it seems to have prompted a fair bit of discussion. I think I could cope with adding a layer or two of 45° braid to the OD of an existing tube (though yeah, it'd be all new for me!). Exterior would be stronger too of...

Another thought I had overnight - why not just add a key to the connector faces? i.e. mill a slot, say 3mm deep and 6mm wide, into the faces of the relevant connectors. Then press in a piece of, say, 6x6mm key steel, with some retaining compound to hold it if needed. I couldn't mill the slots...

No worries. They're great panels. It's hard to find semi-flexible Chinese panels that actually meet their specifications, but these ones seem to (though I don't have the insolation meter necessary to prove it). I'm guessing that someone in Australia has bought a few container-loads of these...

Thanks! Though I was thinking that maybe congratulations should be withheld until I've actually built the thing and proven it works :LOL: Good to hear you've got some positive experience with this connector system. I thought it was a little suspicious that I haven't come across anyone else...

Thanks, and I appreciate the consult. This design (bespoke single-wheel CF) certainly seems like it'll be harder to get right, but the weight savings will be very noticeable. I promise I won't blame you for the inevitable failures before I get it right! I did a tour over the summer with the...

Thanks for your thoughts. I'm definitely concerned about torsional flexing down the length. It was pretty easy to add bracing to help with the 'vertical' rigidity. On the Mark 1 trailer, 'vertical' flex down the length was a problem so perhaps I've gone overboard with 'vertical' bracing on the...

Thought I'd better offer a progress report on this project. I've spent a lot of time learning enough Fusion360 to design the trailer in CAD, so that I could calculate the carbon fibre tube lengths and avoid any expensive screw-ups. I'll need to use quite a few DragonPlate CF tube connectors...

I spent some time looking more at the MPT-7210A and CTK-EV-300. Interestingly, with the MPT-7210A, if you have a panel Vin > battery Vout, it doesn't error out - it basically shorts the panel to the battery while panel voltage > battery voltage, so the resulting charge current can be read off...

Thanks @dominik h and @kudos . I hadn't really considered that CTK-EV-300 model tbh, I knew it existed because Grin used to sell that model but they've discontinued it. Are you certain it's a buck-boost topology? Afaik, even the very costly Genasun units are boost-only (i.e. they won't start if...