# Homemade Trend Airshield Pro batteries?



## Toller (Jan 7, 2014)

My 10 year old battery doesn't hold much of a charge anymore; but $70 is a lot of money.
I've googled and people rebuild them, replace them with battery packs, do something I don't understand with a battery charger, and probably other things.
So, what has anyone here done that they are happy with?


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## ibewjon (Oct 2, 2010)

There are places that rebuild battery packs, with some savings. I don't have a name to call or any experience doing it, but I don't think the savings was much over 25%.


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## Joel_B (Aug 14, 2014)

Batteryspace.com is a good place to buy rechargeable batteries


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## mike02719 (Jan 13, 2008)

Most rechargeable batteries from that era are made up from individual nickel cadmium cells connected in such a way to provide required voltage. Back in my working days, I repaired lots of ni-cads at a fraction of battery replacement costs. If you are lucky, the batterypack will be held together with screws. If this is so, simply open it up and expose a group of cells soldered together. These can be replaced with the correct ampere hour cell and you are back in business. You need some electrical and soldering skills to do this, so be careful.


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## Rich_Aldrich (Apr 10, 2020)

I tried putting new batteries in my battery packs and it didn't work for me. I cant remember where I got the batteries.

Rich


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## JoeK1 (Apr 7, 2017)

I have 5 Trend batteries and the best run time has been 4.5 Hrs. I replaced the cells in one bad battery with (3) 4/3 AF NiMH Battery with Tabs (4500 mAh) Item # 15738 $6 ea. from OnlyBatteries.com. That p/n was the highest current rating of several choices. The average run time is about 2hrs with the replacement cells. Replacement requires soldering the taps and wire, reinstalling the original current limiting device and insulating with shrink sleeving. It is not a trivial change out. The replacement cells are slightly larger in diameter but will fit w/o shrink sleeving covering all 3 cells as a pack like the original. I'm not exactly thrilled with the run time but it will recharge in 3-4 hrs.
If you change battery chemistry then you should change to a compatible charger. Three 3.7V Lithium Ion 18650 batteries w/tabs wired in parallel will also fit. These cells do not appear have integral current limiting devices. I also purchased the Li-Ion cells $14 ea, but decided that the potential of a thermal runaway on the top of my head might be distracting.


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## tvrgeek (Nov 19, 2013)

Batteries Plus has about everything, plus they rebuild. First, you need to know what the cells are. NiMH, NiCad? Chargers are unique and the wrong charger is how yo get a fire. Sometimes, you can rejuvenate a NiCad with reverse polarity, but sometimes it explodes. Sometimes freezing them helps. Sometimes not. Fact is, batteries have a life span so anything using them you consider as disposable at some point in time.


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## CWWoodworking (Nov 28, 2017)

70$ for 10 years of use and the battery is too expensive?


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## LittleBlackDuck (Feb 26, 2016)

Simply buy a new battery… Put a $ value on the time you waste on an cheaper alternative and it'll cost you twice as much.


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## TheDane (May 15, 2008)

> Simply buy a new battery… Put a $ value on the time you waste on an cheaper alternative and it ll cost you twice as much.
> 
> - LittleBlackDuck


Amen … well said!


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## RobS888 (May 7, 2013)

> Simply buy a new battery… Put a $ value on the time you waste on an cheaper alternative and it ll cost you twice as much.
> 
> - LittleBlackDuck
> 
> ...


This is true, but many have the model with discontinued batteries, so make 'em or set aside the mask.


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## splintergroup (Jan 20, 2015)

If you know the voltage, you could see if one of your cordless drill batteries could be adapted (probably with a belt hook for the battery and a power cable to connect up).


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## LittleBlackDuck (Feb 26, 2016)

You'll probably find that the Trend Airshield Pro could be one of your best lines of defence in this time of the *19* crisis…

Just get off your arse and buy a battery to maybe save your life… or aren't you worth $70… Not for the workshop but when you go outside. It's not like you have the opportunity to travel around looking for a battery builder.


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## SMP (Aug 29, 2018)

I am the kind of guy that rebuilds battery packs. Actually was going to even rebuild the packs on a Honda Civic hybrid. But i mainly do it since they usually last 2 or 3 years, and I can rebuild for around $6 per cell. If ai knew it would last 10 years I would probably just pay the $70. As a lot of times taking apart old packs the little plastic clips break and then they don't stay together right etc.


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## RobS888 (May 7, 2013)

> I am the kind of guy that rebuilds battery packs. Actually was going to even rebuild the packs on a Honda Civic hybrid. But i mainly do it since they usually last 2 or 3 years, and I can rebuild for around $6 per cell. If ai knew it would last 10 years I would probably just pay the $70. As a lot of times taking apart old packs the little plastic clips break and then they don't stay together right etc.
> 
> - SMP


I'm really suspicious of the 10 year claim since my wife went though 4 in 5 years. But they don't make them for her model anymore, so this thread is pretty timely for us.

So could you guys back off the admonitions to just buy them and let people that need to cobble something together talk about it, please?


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## CWWoodworking (Nov 28, 2017)

> since my wife went though 4 in 5 years.
> 
> - RobS888


It's time for a new system unless she's driving screws 8 hrs/day.

These things are so cheap compared to everything else now days, IMO, it's silly to mess with rebuilding batteries.


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## Tony1212 (Aug 26, 2013)

There are plenty of videos on YouTube that show how to break a battery pack down and replace them. It requires a bit of skill in soldering, though.

You can get a 12V Ni-Cad battery pack from Harbor Freight for around $15 before a 20% off coupon. Open it up and there are about 10-13 cells in there.

That what I plan on using to re-build a battery pack for my "inside the house" drill.


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## RobS888 (May 7, 2013)

> since my wife went though 4 in 5 years.
> 
> - RobS888
> 
> ...


The masks are about $400 dollars! That is a considerable investment. Do you suggest just setting it aside? I think perhaps you are thinking of a cordless drill. We are talking about a mask many turners use. The batteries for the newest model are $70. But they don't make batteries for the older model anymore.


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## RobS888 (May 7, 2013)

> There are plenty of videos on YouTube that show how to break a battery pack down and replace them. It requires a bit of skill in soldering, though.
> 
> You can get a 12V Ni-Cad battery pack from Harbor Freight for around $15 before a 20% off coupon. Open it up and there are about 10-13 cells in there.
> 
> ...


My first attempt melted the plastic holder, so I'm going to try again…


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## LittleBlackDuck (Feb 26, 2016)

*Toller*, if you can get a new battery for your Trend model, I sincerely suggest you do so… if you can't, good luck with a refurbished battery… pick a re-packer and give him the job… finding another that may save you a few extra shekels would just be a waste if you cost your time.


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## Underdog (Oct 29, 2012)

From memory over at Sawmill Creek… the guys who rebuilt their battery packs did so because the stock battery pack didn't last for 8 hours as advertised. So they rebuilt them for cheaper and got longer times between recharges….

And I could be dis-remembering, but some of the rebuilds were lighter. Which is a big deal when you put the whole shebang (motor, batteries, fan, shield) on your head and expect your neck muscles to hold it up for 8 hours…


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## splintergroup (Jan 20, 2015)

> There are plenty of videos on YouTube that show how to break a battery pack down and replace them. It requires a bit of skill in soldering, though.
> 
> You can get a 12V Ni-Cad battery pack from Harbor Freight for around $15 before a 20% off coupon. Open it up and there are about 10-13 cells in there.
> 
> ...


I bought a stack of those HF NiCad battery packs to rebuild an older Makita 9.6V drill. The price per cell was a fantastic bargain. They soldered well enough and fit fine, but failed after only a few uses.

What I later discovered is the HF NiCads were the slow charging (24 hour trickle charger) type and my Makita 1 hour charger is what killed them.

The "best" type of NiCads to buy are the units used by RC racers, they take a fast charge and are of a higher quality.

For your mask, the voltage isn't super critical you just need to be in the ballpark. I'd find a battery holder for the appropriate number of "C" cell NiMH type batteries and get one of those cheap wall plug chargers that charge 4 or more at a time. If you need an odd number of cells, you can just wire in a bypass for the last cell if all you can find is a cell holder with an even cell count.

A single NiCad cell has about 1.2 volts and is fairly steady until depleted. NiMH has 1.5v and drops to 1.25 at about 50% capacity.

I assume the original battery pack clips onto the helmet? If so, you could use lighter weight "AA" cells.


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## RobS888 (May 7, 2013)

> There are plenty of videos on YouTube that show how to break a battery pack down and replace them. It requires a bit of skill in soldering, though.
> 
> You can get a 12V Ni-Cad battery pack from Harbor Freight for around $15 before a 20% off coupon. Open it up and there are about 10-13 cells in there.
> 
> ...


They go inside the helmet.

I was just reading where a user used a cell phone power bank to run the trend Airshield pro via a usb cable that terminated inside the battery pack with the cells removed. You carry the power bank in your pocket or on the belt. I'm going to try this on the my wife's trend airshield.

https://modeleng.proboards.com/thread/10757/trend-airshield-pro-battery-conversion


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## SMP (Aug 29, 2018)

> These things are so cheap compared to everything else now days, IMO, it's silly to mess with rebuilding batteries.
> 
> - CWWoodworking


$70 for $10 worth of batteries is hardly "cheap", but if so I got stacks of alder i'll sell you for $30 bd ft!


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## Toller (Jan 7, 2014)

The original battery, well, at least my 10 year old, is 3.6v and 3.5ah. 
My understanding is that a new NiMH is 1.5v fully charged, but drops quickly to 1.2v.
Mine is 4.2 (1.4×3) fully charged. I only used it occasionally when sanding bowls; do it doesn't have many recharges on it.

I bought a 1.8ah battery pack for a cordless phone and a charger for it. The charger won't be in for another week. I intend on sticking the 1.8ah battery pack in the existing case, and charging with the new charger. Hopefully I will get a few hours of use on the 1.8ah batteries, and they are cheap to replace when they age.

I don't think I would wear it to go grocery shopping. I stay well away from anyone and wear a surgical mask. That ought to be adequate; so far there are only 3 cases in my county.
I have a P100 mask; might wear that if it gets bad.


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## RobS888 (May 7, 2013)

The USB approach seems to be working, my wife used the trend air shield for 2 hours tonight running off a 10,000 MA power bank. No batteries in the helmet, the power bank was in her back pocket with the cable running down her back.

It dropped from 64% to 53% over 2 hours. Not bad at all.

This is the power bank we used:

https://amazon.com/gp/product/B07K42BR9Z


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## DaffyBandit (May 14, 2020)

RobS888,

What is the output voltage on the power bank you are using? Mine has a 5v output…maybe all of them are 5v? Will that damage the fan motor? Did you notice any increase in fan speed?

Brad


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