Rob_E

I recommend going through the return process as long as they are willing to work with you. When the light works, I think it's great. Mine hasn't had a problem since my initial return. If I were going to start from scratch, I might not do the combined unit. I'm not anticipating another problem, but it's unfortunate that sending it in leaves you without a light or a charging device, even if the light was working before. Also, if I remember correctly, the charge port was the first thing to fail on my light. Eventually the light stopped working as well. So if they are willing to replace it, I'd say do it, rather than thinking that at least you have a good light.

SquireBlack 

IIRC, the early-model Luxos had an electrical socket on the light, into which one plugged the button-switch and USB receptacle. This socket was prone to failure when water penetrated it. Because the socket was on the light, there was no real way to protect it from water.

B+M changed this design so that the button-switch and the USB socket were hard-wired into the light, and the connection protected with a rubber grommet. The result is less elegant, but also less prone to failure. This is the kind of Luxos U that I have ... keeping my fingers crossed

Tourist in MSN

The first June 15, 2016 post at this link mentions water coming in the spade connectors in the back.
https://groups.google.com/g/randon/c/qob5ex7lrWg

I assume you have fenders to keep the tire spray off of your light? If not, tire spray from underneath the light may still get into the light.

Rob_E

Mine had the USB and button hard wired into the light. About a year after getting my replacement light, the replacement failed. Only the USB/handlebar switch failed. I eventually just cut the switch off and used it as a headlight. Then the tail light connections rusted off. Now the tail light is connected directly to the hub, parallel to the light.
It all works, but my headlight used to work in combination with the tail light, giving it a brake light effect by brightening for a moment when slowing down. I don't think that works with the tail light mounted parallel. Also, I had never fully appreciated the functionality off the button until it was gone: No floodlight/"high beams" setting anymore. I didn't use it a lot, but I did miss it when it wasn't there. But that's minor comparted to the other issue: It is so much easier to toggle between settings when the bike it in motion and the light is powered. Since the Luxos U shows you it's mode with an LED, when there's no power, you can't tell the mode. My solution is to put the light in standard, night mode, and just leave it there. The problem that's come up multiple times is that I lock up my bike, walk away from it, and someone helpfully thinks, "That poor person left their light on." And they find the headlight button and turn it off. If I'm lucky, they tell me about it and don't waste time looking at my connections to see if something has come loose. Either way, once I've figured out that light is getting power, the result is that I'm standing in the dark, lifting the front of my bike off the ground, spinning the wheel, and toggling the button to find the correct setting to get my headlight back.

I now have a new B&M light and have combined that with a Sinewave. I don't have that much time in with the Sinewave yet, but it seems functional. The light has a dial switch that is easily readable whether the light is powered or not, but it does lack a couple of the features of the Luxos U that I enjoyed like being able to easily toggle between modes while riding, and the High Beams mode. But after killing two Luxos U lights, I think I'm done with the idea of a light/charger combo.

Rob_E

When I moved my headlight to a new bike, the new bike didn't have fenders. First ride in the rain, and my light started acting crazy: blinking on and off long after I stopped moving. I think it was still going when I went to bed. It was better as soon as it dried out. Now I have a small fender that seems to keep it protected, but then I don't make a habit of riding in the rain. Still, even when it was on my full-fendered bike, a good downpour could make it temperamental. I don't know if other B & M lights have that problem. I'm running the Cyo T Senso Plus on my commuter, and I haven't noticed a similar problem with that one. But then I haven't done a ton of commuting lately.