Trend Airshield Battery Charger

[Greg Ketell]

Thanks to Ken Glass for his great article on how to repair Trend Airshield batteries on the cheap (http://www.sawmillcreek.org/showthread.php?187222). I've used that to fix two of my three batteries. But while doing so I realized that I had now killed 4 very expensive Trend batteries by leaving the Airshield plugged in too long. This makes me think that the charging circuit in the helmet is pretty stupid. Combine that with wanting to charge one battery while using another and it got me going on a quick little project.

First I bought one of these Universal Smart Chargers for 2.4 - 7.2v NiMH/NiCd batteries:
http://www.sawmillcreek.org/attachment.php?attachmentid=234227&d=1339450416
from here: http://www.batteryjunction.com/unsmchfornib.html ($23)

Then I roughly (very roughly) threw together a quick holder for the Trend battery:
http://www.sawmillcreek.org/attachment.php?attachmentid=234228&d=1339450417

Which is just scrap wood glued together with a couple of pieces of wire going through two holes in back (strengthened with epoxy) and then down into two holes in the bottom and tinned:
http://www.sawmillcreek.org/attachment.php?attachmentid=234229&d=1339450418

The battery charger connects to the base using the clips that are included with the charger:
http://www.sawmillcreek.org/attachment.php?attachmentid=234226&d=1339450415

And then you set the battery into the base and plug it in.
http://www.sawmillcreek.org/attachment.php?attachmentid=234225&d=1339450414

Now you have a charger that stops charging when the battery is full AND you can charge one battery while using the other. It isn't fast (about 6 hours) but it works and the packs don't die if you forget to unplug them.

[Allen stagg]

Pretty Cool idea!

[Paul Williams]

Thanks Greg, I just recieved my Trend Airshield Pro and was thinking about the same problem. Looks like it could also be fixed with a plug to charge the battery while in the helmet.

[Greg Ketell]

Maybe. I'm not sure how the smart charger would work through whatever circuitry is already in the helmet.

[Paul Williams]

Good point, I'll verify what circuitry is involved before leaving it on th helmet.

[Mark Levitski]

I can't be sure, but I don't think there's' any "circuitry" to consider in the helmet because I bought their cradle to charge my second battery in instead of using the helmet. It looks like a simple plastic version of Greg's wooden holder.

[Dick Mahany]

Greg,

Nice work. I really like my Trend Pro and haven't had battery problems yet, but your idea looks like a must do, given the bat cost.

[Josh Bowman]

I like it! Going to order a charger tonight!

[Tom Winship]

I just bought a Trend Pro with charger and extra battery. Is the external charger a "smart" one or should I build this?

[Dick Mahany]

My Trend pro instructions say not to charge the battery beyond a certain number of hours, so I think the factory unit must not be "smart", hence want to build one like Greg did.

[Greg Ketell]

I can't be sure, but I don't think there's' any "circuitry" to consider in the helmet because I bought their cradle to charge my second battery in instead of using the helmet. It looks like a simple plastic version of Greg's wooden holder.

If it is a direct feed to the battery that means two things: 1) no wonder it kills batteries; 2) since the charger comes with multiple attachments, it will be easy to modify one to have a helmet-compatible connector while keeping the 'gator clips for your charging base.

[Michelle Rich]

Ok I'm lost..I have a trend & the seperate charger unit...does that also "overcharge" the batteries? Seems amazing to me that trend put it out if it does.

[Josh Bowman]

Got mine in and the mod was simple. Just to verify how smart the charger was, I measured the amps during the charge and after tbe light turned green. The amps are holding at zero. Great tip thanks.

[Jim Burr]

That is super crazy Greg!!! You smart types always come up with the coolest ideas!

[Greg Ketell]

Michelle, as far as I can tell, yes it does overcharge. They just made a simple "Power in, power to battery" setup. Charges the battery fine. But will over-charge if left on too long. MOST battery chargers are this way. My dewalt 18v XRP charger does the same thing. The new Lithium-Ion chargers are all Smart; they have to be or the batteries blow up. But most nicd/nimh battery chargers are dumb. Cynicism:ON ... Look at it this way: they sell you a cheap battery charger for lots of money-> they make lots of money. You don't follow their instructions and burn out your batteries -> they make lots of money on replacement batteries. Cynicism: Off.

GK

[Jim Underwood]

Trend could improve their whole setup a good deal if you ask me.

As you point out, the charger is kinda stupid. And the battery doesn't last as long as it should. True it lasts better than the old unit did, but still.

And since buying a Bionix face shield yesterday, I also think that Trend could take a few cues from that company and make some positive detents in their helmet position so that it actually stayed up when you wanted it to.
IN addition, the adjustments are rather limited. Mine, no matter how tight I screw it down, pushes down on my glasses as soon as I tilt my head forward. ON the Bionix, there are plenty of adjustments to prevent such a thing.

Trend's customer service is really good, but I think they could make some tremendous improvements on their product.

[Faust M. Ruggiero]

I addressed the issue of battery overcharging by connecting a 24 hour timer to a receptacle. No matter what battery I am charging, I plug into that circuit and set the timer. The good part is it works for all my chargers.
faust

[Greg Ketell]

Great idea, Faust!

[kurt sligh]

Greg,

This will work great for me. I bought a Trend Airshield Pro for $49 off of Amazon. But it was missing the charger (and carrying bag). I'm building the cradle when I get home and hopefully the smart charger has arrived. A $25 solution that's much better than the $70 charger :-)

Thanks,
Kurt

[Ken Glass]

Greg,
I really like your idea. I used a Christmas lights timer plugged into a 120v outlet and set the battery to charge for only 14 hours and then it shuts off power. The only problem would be if I didn't go to the shop everyday to turn, which will only happen after the day I die, so I shouldn't be overcharging mine. lol I also figured, at $3.99 a battery, I can replace them every year if need be.

[kurt sligh]

I made mine last night and sat the battery on it. It charged up fine!!!

Has anyone heard of someone making a whole new battery pack. I'd like a spare, but don't want to buy one just to get the plastic molded outside part.

Thanks,
Kurt

[Ben Darrah]

Greg,

Is this still working well for you? I just bought a A S P and was thinking about doing this.

Thanks
Ben

[Greg Ketell]

Yes, still works great. And many others on SMC have followed suit and I've heard no complaints yet.

[Dick Mahany]

After reading Greg's original post, I made one last year. I have 2 battery packs and they're still going strong and give many hours of run time. Each battery has had many charges with no adverse affects. My original Trend charger went to the recycler!

[Ben Darrah]

Thanks, I ordered a smart charger.

[Mike Peace]

Thanks, Greg. I have not been using my Trend as much as I should partly due to charging issues.

[Mike Peace]

Ok, I made one and it charged up the batter back just fine. Is there a particular advantage of setting the Tenergy switch to .9A or 1.8A?

[Greg Ketell]

Ok, I made one and it charged up the batter back just fine. Is there a particular advantage of setting the Tenergy switch to .9A or 1.8A?

The instructions say to use 1.8A for battery packs greater than 2000MAh. Since ours are over 3000...

GK

[Darryl Hansen]

build one definitely. Less expensive and works like a charm. I don't know if the Trend charger will shut off. This one does. You can also charge directly into the helmet so a charger probably is not needed. When I charge in the helmet and then put in this built charger there is still some charging necessary after the helmet has been used for 12 hours or so.

[David G. Jones]

I just found a smart charger on Ebay that has a plug that connects directly to the Airshield Pro battery charger cradle. I'll post again if it works. Here's the link: http://www.ebay.com/itm/Ni-MH-Ni-Cd-3-6-4-8-6-0-7-2V-Battery-Charger-Intelligent-Smart-Auto-control-USS-/320716675698?hash=item4aac341a72:g:-yMAAOSwNSxVIiTb

[Jim Seyfried]

I just found a smart charger on Ebay that has a plug that connects directly to the Airshield Pro battery charger cradle. I'll post again if it works. Here's the link: http://www.ebay.com/itm/Ni-MH-Ni-Cd-3-6-4-8-6-0-7-2V-Battery-Charger-Intelligent-Smart-Auto-control-USS-/320716675698?hash=item4aac341a72:g:-yMAAOSwNSxVIiTb

Nice find! I would also suggest labeling this and other chargers that use the same connector in your shop. Otherwise you might burn up a laser pointer for the hollowing rig. DAMHIK :o

[Roger Chandler]

I got the Tennergy charger back about a year ago, and it has made a great difference in the battery performance on my Trend Airshield pro........that smart charger will keep it from frying the battery, and I have 3 battery packs, which one was almost fried. The new charger has rehabilitated it to some degree. It won't last as long as the other two, but will go for about 4 hours now, where at one point I was lucky to get 30 minutes out of it!

[John Grace]

I recently acquired a used Airshield Pro and while I've not experienced any 'battery killing' yet I am cautious and am preparing to replace the charger. Question...can the 'Tenergy' smart charger be used while the batter is still in the helmet or does the battery need to be removed? Thanks...John

[John Grace]

Question...Can the Tenergy smart charger plug directly into the Airshield Pro helmet or does the battery pack need to be physically removed? Thanks...John

[Roger Chandler]

Question...Can the Tenergy smart charger plug directly into the Airshield Pro helmet or does the battery pack need to be physically removed? Thanks...John

I have the battery stand which uses the same plug in as the helmet. When I got the Tennergy charger I cut that plug and most of the wire off of the charging unit, and spliced it onto the wires of the Tennergy charger. Getting polarity correct is essential for the Tennergy charger to operate. I used a couple of small wire nuts and taped it securely with electrical tape.

This battery craddle is the only way to really use the Tennergy charger or make one like was mentioned earlier in the thread.

[Jim Seyfried]

Question...Can the Tenergy smart charger plug directly into the Airshield Pro helmet or does the battery pack need to be physically removed? Thanks...John

I plug mine directly into the helmet, as I don't have the battery stand. The plug is fairly standard, I think used one from an old wireless house phone so I would still have the original charger.

[Roger Chandler]

I plug mine directly into the helmet, as I don't have the battery stand. The plug is fairly standard, I think used one from an old wireless house phone so I would still have the original charger.

Good info, Jim......I should have clarified that I use mine with the cradle, so I can have one charging while I have one in the helmet, so always have it available and don't have to stop to charge before I can return to sanding, etc. It will plug directly in the helmet if one hooks the Tennergy smart charger to the wires that have the plug on the end.

[David Delo]

I just found a smart charger on Ebay that has a plug that connects directly to the Airshield Pro battery charger cradle. I'll post again if it works. Here's the link: http://www.ebay.com/itm/Ni-MH-Ni-Cd-3-6-4-8-6-0-7-2V-Battery-Charger-Intelligent-Smart-Auto-control-USS-/320716675698?hash=item4aac341a72:g:-yMAAOSwNSxVIiTbFor 10 bucks I couldn't resist and ordered one also.

[David Gilbert]

No, the Terergy smart charger can't be plugged directly into the helmet. The battery pack has to be removed. I built a cradle to hold it for charging.

Cheers,
David

[Roger Chandler]

No, the Terergy smart charger can't be plugged directly into the helmet. The battery pack has to be removed. I built a cradle to hold it for charging.

Cheers,
David
One has to change out the plug first in order for it to work with the Tennergy Charger, but the charger does not come with the correct plug, so one has to make a hybrid using the plug off the original charger or getting a plug of the same size for it, and wire it up to the Tennergy unit.

[David Delo]

I just found a smart charger on Ebay that has a plug that connects directly to the Airshield Pro battery charger cradle. I'll post again if it works. Here's the link: http://www.ebay.com/itm/Ni-MH-Ni-Cd-3-6-4-8-6-0-7-2V-Battery-Charger-Intelligent-Smart-Auto-control-USS-/320716675698?hash=item4aac341a72:g:-yMAAOSwNSxVIiTbMy smart charger arrived today. Plug didn't fit my (non-Pro) battery so I snipped the wires from the dumb charger and attached to the smart one. I didn't time it exactly but right around 2.5 hours to charge a fully drained battery. Kool

[Dane Riley]

My solution to a non pro Trend Airshield was to buy a plug on a cord the same as the battery has and a 3 AA battery holder(Digikey or Radio Shack has them), and some Velcro. May look a bit funny, but AA smart chargers are cheap and work great. No more waiting to charge the batteries.

[Harold Wright]

Mike Peace has a video on YOU TUBE. Trend Airshield Smart Charger.

[Dane Riley]

While better than continuing to destroy batteries from Trend, it is still nuts to continue to buy low quality but high priced batteries from Trend. Get an inexpensive battery holder that holds the right number of AA batteries and wire it in. Then you can recharge the batteries in a smart charger that will protect the batteries and can be used for many devices. And spare charged batteries are always available.