I have a Haibike Sduro e-bike which is powered by a Yamaha 36v 400wh battery, charging when on hookup is not a problem but when I tried charging it via the leisure batteries using my fitted 1000w inverter it sucked the power at an alarming rate, I was literally watching the battery levels going down even in full sunshine and with 230w of solar panels. I am looking at a 12v portable inverter now, I have a 150w Kensington 12v inverter but I don't think its rated high enough to charge the battery. Anyone have any advice/suggestions? Bosch supply a 12v charger for their e-bike batteries but not Yamaha, typical!