Princess Auto Welding Helmet repair
My el-cheapo autodarkening helmet started acting up over the last month. It was darkening, but it wouldn't get all that dark. Sometimes it would go full dark but not always. When it didn't go full dark, the shade control didn't seem to do anything at all.
Turns out the internal batteries were dead. The shade case was glued together, but not particularly strongly and with a little careful prying I was able to open it. At first the cells seemed OK as they read around 2.8v, but then I noticed when the helmet was activated they would drop down to ~1v. Also the helmet seemed to work fine when powered off the solar cell.
Unfortunately the cells were soldered in, and they're a bit of an oddball size; CR2330. No way to fit a battery holder or even a slighly larger, more common and higher capacity cell like a CR2450. So I headed off to Assaim's hoping to find some common CR2032 which are smaller, but only about 15% less capacity. Assaim's (cross between a dollar store and a pharmacy) turns out to have every battery known to man on the shelf. They're 100% nonames or sort-of-similar-but-different-enough-from-the-brand-name-named batteries, but they're cheap and open on Sunday.
'Course no solder tabs. That was easily fixed with some old tabs taken off a discarded battery pack and spot welding them onto the new batteries. The spot welder was a 63000uF capacitor charged to about 15v. I insulated the negative tab with the blister pack the battery came in. Al Gore would be proud. At least until I tossed the old batteries into the garbage. Be sure to keep track of the battery polarity somehow.
I didn't bother to glue the case back together to make it easier to replace them next time. I'll surely get a better helmet someday, but I don't mind this one and it can at least serve as a backup.
One battery installed. I temporarily desoldered the shade pot for easier access.
Ready for buttoning up.
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