Hymotion L5 240V Charging?

The DC/DC converter in the Hymotion pack acts as both the step-up converter during driving, and the charge controller during charging. It can indeed operate off either 120 or 240V. A dozen or so packs were sold in Europe and were always charged with 240V.

My understanding is that all of the parts in the Hymotion pack were rated for 240V, but the pack collectively was never validated at 240. As you noted in my J1772 adapter thread, I am charging off 240V when using the adapter. I also occasionally use 240 at home on weekends, when I'm doing a lot of trips around town to get the most out of the battery.

I do not recommend charging at 240V when ambient temperature is above 90 F or so. There was a guy in Ohio who was using a pack and really pushing it to the limit and experienced IGBT failures in the DC/DC. He was running the car in OOG mode, causing the Hymotion pack to deliver more current than designed for in the first place, AND charging at 240V. After a ride on a very hot day (~105 F), he came home, plugged right in to 240 and about 15 minutes later had a garage full of smoke from burnt electronics. All of that overstress put together (I believe) led to a big solder nugget inside one of the IGBT's melting (this was confirmed by part teardown at the IGBT mfg.) and leading to destruction of the IGBT. Pushing your luck in this sort of way seems to be the only risk in charging at the higher voltage from a pack-wellness standpoint. I've charged at least three different Hymotion cars at 240 on several occasions and never had a problem, but I do avoid doing so when it's really hot out.

The pack does charge roughly twice as fast at 240V. This can be convenient, but it's easier on the batteries (and most times perfectly adequate) to charge at 120V, so that's what I do 95% of the time. I generally use charge stations only when that is the only option available.