Based on my recent experiences with the Solas, the charger is working, right?
If that's fine, it could be the charging contacts on the light. They do look in need of a clean. You might want to try and mix of white vinegar and water to start with. I've used that successfully to clean those types of deposits.
Without wanting to do down, L&M, I've just taken delivery of a new Sola 800 Photo for a trip to the Red Sea next week. The charger doesn't work. No indicator lights, no power, nothing. All the tap-tapping did nothing.
The supplier, through Amazon.fr, turned out to be in the US and has sent two replacements (I'm in Paris) which I really appreciated although it has cost me $35 in additional express shipping costs. But even then we can't be sure if it'll arrive in time.
At the same time I contacted L&M via their website, explained the issue and asked if they could help. They responded by email overnight saying I must be "stoked" at my new light - and sending me the contact details of two stockists in France. But sadly France closes for August and the general response is "we have none in stock until the distributer reopens in September" (said in French of course) . Happily I did track one down - another €29, thank you - and hopefully that'll reach me before I fly to Egypt.
Ironically, the morning after contacting L&M I got an online customer survey from them asking for my thoughts on their service.... I said, fingers crossed, it will all be fine but to suggest that I was "stoked" at my new purchase, which didn't work, was perhaps over-egging things a little (please note the fine British sense of irony here).
So some you win, some not quite so much. It does look a great product though..... Come my trip I might have a total of 4 chargers - or, alternatively, just one that doesn't work.