The process of making the setup:
The 8mm2 cable was rated for 40A to be used in car stereo. Finding the correct cable diameter or area is kind of difficult on the internet, since there are many different views on how much is enough. What I knew before I started is that in houses in Norway you would need at least 2.5mm^2 for 16A current in installations. Some would put almost 60A through the same wires. Personally I am a bit skeptical to do that. Using my 8mm^2 cable was difficult, since neither the XT60 connectors or the Anderson connector could fit that wire. What I ended up doing was to solder as much I could fit in the connectors, then use the heat shrink tubes to clamp the remaining strands to the connector. Soldering was a bit tricky with the XT-60 connector starting to melt while heating the wire enough. Soldering the Anderson terminal was fairly easy with a 60W solder iron, as the plastic housing is attached later.
The usage of XT60 connectors prohibited the rectifiers being placed directly upon each other. I guess it may be possible, but having an angled connector would be preferable.
The Anderson connectors could also be crimped in its terminal (squeezing the metal part with a plier after inserting the wire).
What the first attempt showed:
First of all, to be able to charge at all, the bike needs to be keyed on when starting, even though the Eltek rectifiers is supposed to start slower than the internal charger, the bike will need to be keyed on at first. When everything has started, the bike can be keyed off. I guess this is what most people has reported, so no big issue with this.
I started charging at 50% charge on my SR, so in total about 50A was delivered to the bike. The charging went nicely up to around 80% before it started slowing down as it should. At about 86% the charging went at a pace close to the internal charger, so I disconnected the charger (I did not plan on leaving the whole setup for the night). When I reconnected the internal charger only, the charging status went directly to 98%.
My box should stay open to let out heat while charging. I will probably add some holes to the casing to let more air out, but it will likely be open anyway to avoid heat building up.
During charging the rectifiers went hot, too hot to hold long, but not too hot to touch. The rectifiers suck in air at the front, and blow it out on the backside where the PCBs are. This makes the PCBs the hottest part. It was a bit difficult to reach the connectors on both rectifiers, but it seems the XT60 connectors and the part of the PCB transferring 40A was the hottest. I would say they got about as hot as I would dare. The hot melt glue I used on the bottom of the PCB to prohibit anything to touch the 40A solder terminals did melt slightly- that is it got much smoother, without dripping.
The 8mm2 wires I used barely got warmer while charging. The Anderson connector did not show signs of heating up much either.
Author
Topic: 4kw DIY charger for 2015SR (Read 1649 times)