Harbor Freight Auto-Darkening Solar Welding Helmet Repair

by on Sep.26, 2011, under Tutorials

A little over a year ago, I purchased one of Harbor Freight’s auto-darkening welding helmets.  For $50, it’s a great deal.


Unfortunately, after less than a year of use, it simply stopped working.  Somewhat ironically, the way you find out that your helmet has stopped working is by getting a flash burn in your eyes when you weld using a broken helmet.

One of the guys in my welding class mentioned that there are batteries in the helmet which can go bad over time.  Batteries in a solar-powered helmet?  Clearly this guy was nuts — but I thought I’d check it out anyway.

Turns out, he wasn’t crazy.  There are two CR2330 coin cells soldered directly to the main circuit board inside of the unit:

batteryChecking the batteries with my voltmeter, I quickly discovered that one of them was completely dead.  The other battery was still putting out a solid 3VDC.

Since soldering in batteries every time they go dead is not exactly a user-friendly solution, I decided to replace them with AAA’s.  Here’s the procedure.

1)  Remove the darkness adjustment knob by gently prying it off with a screwdriver.  Un-screw the plastic nut which holds the unit in place.

2)  Remove the clear plastic shield from the front of the helmet, and then gently remove the electronics assembly by unhooking the retaining spring.

3)  Use a utility knife to pop open one corner of the enclosure.  Work your way around the circumference with a screwdriver, breaking apart the plastic weld, until the cover can be removed.

4) Mark the locations of the (+) and (-) of each coin cell.  Using your desoldering braid, remove the coin cells.

5)  Go to Radio Shack and buy two AAA battery holders.  I used these:


6)  Solder one AAA holder in place of each of the coin cells that you removed.  Be sure to observe polarity.

solder wires in


7)  Using the shaft of your soldering iron, melt a hole in the side of the enclosure so that the wires from the battery holders can exit.  You’ll also want to melt a corresponding hole in the cover.

8)  Mix up some 2-part epoxy, and epoxy the wires to the enclosure.  This step probably is not necessary, but I don’t want to burn my eyeballs again.


9) Wait for the epoxy to dry.  Take this opportunity to clean all the viewing windows with Windex and a lint-free cloth, then  reassemble the unit.  There are four friction pins which seem to hold everything together just fine.


10)   Re-install the electronics housing into the helmet.  Re-attach the darkness adjustment dial.

11)  Glue the two AAA holders to the inside of the helmet.  I initially used the same epoxy that I used to hold the wires in place, but it didn’t bond to either the plastic of the helmet or the plastic in the battery holders.  I ended up using my hot glue gun, which worked very well.



12)   Install four AAA batteries, and then test your helmet.  I found – quite by accident – that the helmet will darken when you look at a halogen light bulb.

13)  Go weld stuff.

Good luck with your repair!


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55 Comments for this entry

  • Palmer Macrae

    The auto-darkening function works. That is probably the most important feature of any auto-darkening helmet. When not darkened, the lens is comparable to dark sunglasses, so one can easily see the work and get the welding tip aligned. While I have no way of measuring how quick the response is, for all practical purposes it does darken instantly. The darkness is adjustable by a knob on the left side of the helmet, and there is a noticeable difference between darkness settings. When the arc stops, the lens instantly lightens, but to get a good look at the weld bead I find it necessary to raise the helmet.


    Ahh… good times. Like the time where our SGT taught us all how to smoke with a sealed gas mask on… or how to improvise CS gas with tobasco sauce and an MRE heater… or how to sleep during the pre-dawn perimeter guard while faking consciousness during a training exercise… does finding out the hard way that an MLRS FCP with water in it will zap the shit outta’ ya’ if you try to test it on the station count? Yeah… station tells you to turn it on…makes you jump backwards a few feet…. fun times.

  • jay

    Thanks for the wonderful writing. This has been bothering me for about a year.
    I will try the trick when I get home.
    Thanks again. great job!!!!

  • Ron

    I was planing on buying one of these figuring that it couldn’t be too difficult to replace the batteries with a better solution. Thanks for showing me that I wasn’t mistaken.

    Very well put together instructions and I should know, I write a lot of instructions for custom upgrades to the equipment we manufacture.

  • partick wilson

    battery acid ruined solar panel!!!! where might i find a replacement????

  • mike kilgallen

    I have the same helmet which has served me well for over 4 years. I don’t weld full time but do use it often enough.
    Today I started to weld only to find it did darken after a second or two. Obviously not good enough. To replace the helmet here in Canada with basically the same unit it’s $100.00. Looking around on the net the concensus was pretty much the same, it’s done, buy another. Seems crazy to replace the unit for the sake of a few batteries.
    Anyway, luckily I found your site and followed your instructions. Yep, exactly the same as your’s, one battery 3.07 V, the other .19V(completely dead). So, I’m off for a few battery holders, and will set up the same as your’s.
    Hell, thanks for the great instructions and photo’s. You just saved me 100 bucks dude.
    Mike Kilgallen.

  • mike kilgallen

    Update on battery replacement. Got the holders and batteries and put it together. Did some welding, works like a charm. Man, bet there are plenty of helmets trashed because of a couple of dollars of batteries.

  • kchan

    Thanks for the info. I was going to use the AAAs but found that to be to be kinda bulky. I got 2 of these instead

    They are CR2032 holders , I found mine off a motherboard but you can get them from radio shack on the link above. This way you can swap out the batteries anytime.

  • Dennis

    Thanks for sharing this. I just performed this mod and it works great.

  • Ivan

    my helmet is exactly like yours it worked fine for
    eight years but its been failing to darken for a
    month now , it will go dark as soon as you trigger
    an arc with the tig welder but a couple of seconds
    later it will go clear and it will burn your eyes,
    it started doing it like ten seconds after i started
    welding but it got worse, believe me it wil harm your eye sight, good idea , i just split open mine open
    i will go for the cr 2330 battery holder and put it
    outside like you did but it will be less bulky, thanks

  • john

    thanks. i just repaird my helmet. works great.

  • Jerry

    I have a question, after you install the AAA battery holders what rechargeable battery did you use?

  • Mart in SoCal

    Eric, that worked great! Thanks for taking the time to share that with us. My neighbor was getting on my nerves about the “flash” he saw while looking over my shoulder….. the lookie loo helmet had a .19v cell too

  • arthur brogard

    This is interesting. I had no idea these helmets could fail like this.
    And how about the flash? I’ve been led to believe that the flash we get is from the UV light and virtually any piece of glass at all will protect us from that.
    So why use a dark lens at all? Well a too-bright light is still a bummer, just like bright sunlight only more so… but not ( I’d been told ) literally dangerous to the eyes once the UV has been blocked out.
    But you guys have gotten a flash while using these helmets undarkened?
    By the way – I got told that because I talked on the web about staring for a couple of seconds or so into the weld puddle before putting my mask in front of my eyes – and yet getting no flash, no aftermath, no problems later. I used to be always doing that – giving myself a flash and yet getting no ‘flash symptoms’ from it.

  • Ed

    Awesome instructions Eric ! Just converted my 2004 Astro 8700 and am pleased as punch with the results. The Autodark module and guts were identicle
    the HF deal ..

    I saw that somebody else asked this .. and I gotta know , did you install rechargeable AAA nicads in your battery holders and do they get recharged ?
    I put regular alklines in and they work fine but am concerned about what kind of life i will get out of vthem and if the nicards are worth investing in. Also do you know iif the only time you are using up battery life is from the time you strike in arc in till you stop weldi ng and the helmet goes light again ?

    Thank you … Ed

  • Nick

    Eric, thanks for the great writeup! Just what I was looking for. Unfortunately, I think my helmet may be beyond help.

    I followed your instructions, amending where necessary (my dimming pot is not retained by a plastic nut but by a small metal screw, and instead of a retaining spring, my electronics assembly was held in place by two plastic tabs around which the helmet had to be bent to clear), and cracked open the electronics case. What I found was a markedly dirtier version of yours.

    There is corrosion on the terminals of one battery; likely the bad one. There is also corrosion at several other locations on the circuit board, including on one side of one of the ICs on the board. Can it be saved? Who knows?

    There’s no knowing what damage (if any) the corrosion may have done to the SMT bits, so I plan to gently clean all I can, ensure the board and traces are not damaged, and put it back together per your instructions. I’ll let you know how it goes.

  • graydog

    My welding helment is a Chinese with no brand name on it. It is somewhat different than HF’s. I bought it off eBay 3 or 4 years ago. It has been doing what you describe. I could only get into the lens’s electronics by cutting it open very very carefully with a Dremel tool and a really thin abrasive wheel. It was not necessary to remove the adjusting knob. I found one (1) lithium 3v battery inside. I think it is a CR2032, but the strap covers the number. Since I always keep in in a box and light cannot reach the solar panel, it could not charge the battery. I would think the lithium battery would still be good and charge up if it had a light source. I taped it back together temporarily to see if exposing it to a light bulb for 24 hours will charge the battery. Another solution would be to clip the straps welded to the battery, and install a CR2032 Battery Holder and 3v battery. In either case, I can close it up and seal it with silicone. I will come back here and report on my progress. Thanks Eric, I had no idea it had a battery inside.

  • Dennis

    Used this repair this morning, works great. I left the switch on for like 2 weeks…barley worked …really P!$$d me off at the time, had a job to do and had to go back to “old” school hood to get the job done. Its great to use “normal” replacement batteries now.. and for 40 bucks hard to beat the price for the HF AD Hood

  • Cheryl

    Eric, thanks very much for sharing this tip. I have a HF (YAY!) mask, and a little prying is well worth the time. I’m servicing my mask in the morning.

  • Jim

    Thank you for your post. My helmet quit working and I did what you said. It appears to be working again.
    Thank you

  • Fred

    CR2330 are rechargeable lithium batteries and so are cr2032
    2330 is a 265 mha capacity where 2032 is 225 mha

    I suggest you get aaa holders with on/off switches

    • Bill Shermqn

      CR2330 are not rechargeable. You can look up the data sheet on the internet. Even HB says the battery will fail after 6 years. I did the repair using CR2032’s in little holders mounted on the module. Works great now.

  • Steve Jones

    Hello people.
    I have an Esab Eye-Tech auto-darkening helmet & it’s had the same problem as everyone else & I too have done this mod but not from this thread. I have put 2 button-cell holders in a memory card case & mounted that in the front of the helmet but I have a problem, I have wired it exactly the same as yourself as basically I’ve just made remote batteries instead of internal ones for ease of maintenance & I double checked the polarity was correct but when I put new cells in the battery holder it goes instantly dark whether I’m looking at light or not & the center of the viewing window is almost a solid black, anyone got any ideas as I could use some help…….

    • Mark Dean

      recheck the battery polarity. Check that you wired the battery wires to the proper place on the circuit board. Check that you didn’t bridge some solder onto another trace on the board. (no big blobs) Check the battery voltage. Make sure the voltage of the new batts are the same as the ones you removed, I. e. lithium, not mercury or alkaline, etc. Over the years I’ve made countless mistakes like this. That’s all I have for ideas. Best of luck! mark

    • Mark Dean

      If you’re in bright fluorescent lighting, then it’s doing what it’s supposed to do, because the lighting is turning on and off 60 or 120 times a second. Take it outside and see what it does.

  • Mark Dean

    Great post! I needed to use my hood, so I did a ‘quick and dirty’ repair with available parts. I robbed some old mini speakers for some wire, and used 4 of the 6 cells out of a fresh 9V battery. If you sand the battery contacts and use acid soldering flux the soldering works much better than just rosin core solder. I reassembled it with dangling wires, then hot glued the batts in place. I’m probably good until the expiration date of the batts, and they’re accessible, so I can now check them with a meter. A heat gun or hair dryer does a great job on hot glue, making it easy to change batts next time. The repair isn’t pretty, but it was fast and dirt cheap. Off topic: I use the cells from 9V batts to replace batts in calculators, timers, even a stop watch.

  • Trent

    Thanks a bunch. Great tutorial.

  • Logical

    Thanks for posting this. For those wanting to save some weight, space, and money (using AAA instead of coin cell), you do not need two battery holders. One battery holder with positive wire soldered to both positive terminals and the negative wire soldered to both negative terminals will do. Save on weight and batteries. Unless you do enough welding to go through four batteries a week.

  • Logical

    scratch that… this is a 6v board. need 3v on each side. wiring them in parallel will just short your battery pack and turn your batteries into a very inefficient hand warmer.

  • Gordo

    Thanks so much for the write up, I need to do this also. FYI: I found 10 pack of AAA battery holders with On/Off switches on ebay for under $5 including shipping. I highly recommend an on/off version so you can just use alkalines and turn off when not in use. Always check your helmet before you begin welding, facing toward any bright light including the sun should cause the helmet to darken.

    • Gordo

      I finished the job successfully, but I gotta say, getting that cover off the electronics assembly was a real pain in the neck using a utility knife and a screw driver. I think if I had to do again, I would have dremeled it…

    • Jim

      I should mention that testing it with the sun didn’t work. I was very disappointed but decided to do an actual weld test and it did GREAT. The sun only darkened it for a couple seconds. So be forwarned not to trust the sun test. So nice to put the old gold leaf window bu helmet back on the shelf.

  • lou

    Great thanks for allowing a French site to translate your article.Several users of that kind of welding helmets tested your solution on thir equipment, itworks perfectly !

  • Bart

    I found 2032 coin cells with the same welded on tabs on EBAY for $5 (with free shipping) Just soldered in place. (Watch the polarity)

    The coin cells seem to last forever if you don’t let them totally discharge. My brother has the same helmet for gosh knows how many years and it’s still going strong.

  • David

    Thanks a bunch! I just had the exact same problem, it woulden have crossed my mind to just use AAA’s.
    Going to try it out now!


  • roger

    Thanks for the info I just finished repairing my helmet and it works great. ArcOne would not replace it but we’re still welding thanks to you!!!

  • Jeb Watts

    Have an Inweld helmet I paid over $100 bucks for and it appears to have the same guts your HF helmet has. Only lasted about 18mo before failing. Doesn’t say much for Inweld products. Did the same repair, works great. Thanks for the tip, was about to can it.

  • Jim

    Great instructions. I used the same RS AAA holders and all went well. I used double stick tape to adhere the at holders just above the window. Clean with alcohol first.
    I have to say as an old do it yourselfers how encouraged I am to see so many kindred souls there are out there that can fend for themselves. We are a dying breed. I have made a pretty decent living over the years repairing commercial equipment self taught and I am constantly amazed at the average persons inability to even use a screwdriver. Sometimes I feel so all alone so it is a thrill to see so many on here that can use their brains. It has gotten to the point that I trust very few folks to even touch my equipment. If you want it done right I suggest you do it yourself.

  • Rick Tanguay

    Good pic above showing one way to repair the helmet, but I did something a little easier. I opened the battery compartment as stated above and used a small knife to pick up the end of the steel strap that is weld to the battery. After lifting the end of the strap, I grabbed onto it with a needle nose pliers and rolled the strap around the pliers similar to opening a sardine can. I was able to separate the strap from the batter and leave the other end attached to the soldered joint. I repeated the same procedure on the strap attached to the bottom of the battery and then did the same thing to the other battery. I took the cr2330 batteries out. Then I straightened out the straps and pushed the bottom ones down where they belonged and reinserted the new batteries. Before reinserting the batteries, I put a piece of electrical tape (about 1/8 inch wide) around the perimeter of the batteries so they wouldn’t short out against the straps. My original batteries had some yellow tape around the batteries for that same reason. After that I put the upper straps on the plus side of the batteries and put a small piece of double sided foam tape on the top of both batteries to stop them from moving. Replaced the top cover and sealed the sides with small strips of aluminum duct tape so I can easily remove the tape and replace the batteries in the future. Worked very well.

  • Pick

    I have a Chicago welding helment same deal one battery at 3.0v and the other at .19 v.I disconnected the batteries.
    I ran 4 small wires out of the lens assembly and soldered on some 3 v batteries ,I need to get a battery holder but this fix works well,for now.
    To test the shield use your torch striker works like a charm.
    Anyone know how to increase the sensativity, on low tig starts sometimes it causes the lens to flicker?

  • Tony

    Thank you for the outstanding set of instructions regarding saving a HP welding helmet. I had no idea that it had two 3volt cells buried inside the unit. My helmet died after only two years of intermittent use. I had a bit of difficulty taking the cover off the unit. I had to use a utility knife to slice through the seam all around and then prying it apart with a 1/2″ wood chisel. Not easy and I was concerned that something might break, but the plastic is very tough. I used the AAA holders from Radio Shack as you did. I used U-Glu adhesive to hold the battery holders to the helmet. I think that double sided foam tape would also work. Also, I removed the two cells by lifting up the free end and touching the solder spots with a 30 watt iron. they came right off.

  • shannon

    Thanks for the post. saved me from having to purchase a new helmet. I tested mine to the sun and it did not darken. tried with the welder and it worked just fine. With the sun, if I put my hand over the sensor and moved it away it would darken for just a second and then go clear again? Anyone have a comment? I did check old batteries and like you said one was almost dead the other just under 3v.

  • Tony the Torch

    Thank you for these instructions. I repaired my HP helmet exactly as you showed and it works fine. Thanks again.

  • russ b wa

    just got done with this great project. I use the cheaper battery boxes from RadioShack that are open in front. I mounted one on each side of the lens using two 2-56 bolts.

    it might have been good too cut the wires shorter, but I got a satisfactory installation by pointing the wire side of the box away and then running the wires back between the box and the lens, thus protecting the wires.

  • Randy

    Slick. One of our millwrights asked me to look at his helmet. Quick search of the web, a little solder job and he’s saved $100.

  • Jason

    Using AAA batteries is a brilliant idea. I will give a try on my helmet. Thank you for sharing.

  • Chris


    Does anyone know if you need rechargeable batteries because it’s solar powered?


  • Doug

    I had a 3V lithium button cell without tabs so I unsoldered the dead battery, carefully extracted the tabs from the cell and then resoldered them back. Now I put the new cell between the tabs, put a piece of foam on top and close the case.

    I may 3D print a protective ring to keep the cell centered in case of helmet drops.

    Thanks for the info to know I can do this.

  • Donny

    Thanks for the info. I fixed my helment for under $5.00 in 15 minutes . This saved me $152.00 for a new one. I think it workes better now than when it was new.

  • Rob

    Hey nice work. I have the same helmet and it recently started working too well. At the lowest setting it is now very dark. My batteries are reading 3.6 volts each. Any ideas?

  • mark

    The welding lens is designed to protect the eyes and face from sparks, spatter ,and harmful radiation under normal welding conditions.Auto-darkening Filter automatically changes from a clear state to a dark state when an arc is struck, and it returns to the clear state when welding stops.The Welding lens with high quality is made from rugged and durable materials that ensure longevity and durability day in and day out. With the massive viewing area, it can allow you to see your weld from all perspectives. find out more Welding Helmet Lens Cover

  • James

    What I can’t figure is you replaced a 3vdc battery for two AAA for each side adding up to 2.4vdc on each side. How did it still work?


  • Dan Laskowski

    I thought that the solar cell supplied the power? I will try this. Thanks!

  • gary

    I have a hf mask -ever since I bought it it darkins ok but it makes no difference in the setting between 9 to 13-i cant see what im welding -could the batts be messing with this also.
    thx gary

  • tom

    Just wanted to say thanks for the info here. I repaired my mask with a couple of remote 2032 holders, some wire, solder and hot glue to mount the battery holders to the inside of my helmet. Works fine now.

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