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Old 11-14-2018, 10:54 AM
metal manny metal manny is offline
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Join Date: Aug 2011
Location: Johannesburg, South Africa
Posts: 509
Default Don't throw away that broken welding helmet!

I own a few auto-darkening welding helmets of varying quality and price.

One of these helmets of reputable quality and situated in the middle price bracket, suddenly stopped working for no apparent reason. As it was out of guarantee, and hardly used, I just kept it with the hope of either sending it in for repair or trying to do fix it myself. A second, cheaper helmet also suffered the same fate and so I decided to see if I could detect the fault as I had nothing to lose.

I removed the lens assembly from the helmet, and carefully split it apart along the glue seam using a box cutter. Inside the electronic workings is a 3V lithium cell with 2 spot welded legs which has been soldered directly to the circuit board. I removed the cell, noting carefully the polarity, and re-soldered two wires in place of the legs as per the attached pic. For a test, I rigged a 3V cell to the wires, and to my delight, the contraption dimmed upon striking an arc.
I repeated this exercise with my quality helmet and herein found two 3V cells, which I duly removed. I also took the trouble of drilling two small holes in the back plate to feed external power leads to the batteries (as shown), as I wasn't going to go through this delicate procedure each time I needed to replace dead cells. Again, upon testing, the second helmet worked perfectly again! Lastly I made a crude battery holder from scrap plastic sheet and bolted it into the helmet

Lithium cells are available everywhere, but the ones with legs as depicted are easily obtained from electronics parts distributors. I bought the two most powerful in milliamp-hours that I could find so as to prolong the periods between renewal.

I am lead to believe that these lithium cells are recharged by the solar panel in the helmet during welding, so if not used often, then the batteries might die prematurely (why the batteries aren't in a holder for easy replacement beggars belief). It is great to know that if the helmet ceases to work, then there's a great possibility that a battery replacement is within the scope of the frequenters of this site...


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