qwerkus said:
Also what I noticed: bought a cheap one on aliexpress. Went for one trip: dead! Perhaps I should use some sealing foam with the next model.
If it's a fan-cooled or open-frame design, that's a good way to seal in all the heat and probably kill it. If nothing else it's likely to cause any thermal fuse inside the main transformer to blow.
There are thermally-conductive (but electrically insulative) potting compounds, but they are heavy (dense) and not every design will work well with them; some simply need airflow on the parts, or bigger heatsinks on the outside, etc.
If you're going to pot a non-potted charger you're better off just getting one designed and built that way to start with (like those Meanwell LED drivers; I use the big heavy HLG-600H-54A types but they make much smaller ones like the HLG-100 or 150 series, and possibly smaller ones than that. They just won't give you much charging current.
The 600 is 600w max continuous output, so at 58v I get about 12A out of it, around 700w. It gets pretty warm, but not so hot you couldn't hold it. I don't have any other size to test, but the 150 series would probably do up to about 160-170w or so, possibly more, so at 54v it'd be around 3A. So the 100 version would probably handle around 2A.
Since they're solid, they're not lightweigth, but they're not physically huge, and they are weatherproof I think IP67 for the nonadjustable ones and IP66 for the adjustable ones.