Trend Airshield Pro DIY Battery Mod!

[seaco]

Hi All

My Trend Airshield Pro's battery has slowly died on me and on looking I couldn't believe they are £35-£40 so I opened mine up very easy apart from the elastic glue they use to hold the batteries in, just unclips and inside there is three batteries (cells) a bit larger than AA's so I went online and one place showed that they are 3.6v, 3500mah Nimh so I thought that can't be to hard to replicate.

So looked on eBay and came up with these AA's I couldn't find 3500mah only 3000 but I thought that will do so I bought 4 for about £4.00

All I did was copy the original layout I scratched the connectors then heated a blob of solder onto the wires then as soon as the solder melted onto the battery I removed the heat do this as quickly as possible so as to not damage the battery, I'm so dumb when it comes to electrics that I have no idea what the little white box that I've soldered even is, so if I can do it anyone can?

Then clip it all back together switch on and depending on the state of the batteries when you get them charge wise you should hear the fan I let mine run right down and then gave it a full charge and all is going well can't say if you will get 8hrs like the original states I never did but I've had it on a few hours today and it's going fine, a few more charges and it should last almost as well as the originals and all for the princely sum of £4.00 but sshhh! don't tell anyone...

 

[Jonzjob]

The white thingy looks like a heat protection device? Probably a bi-metal switch to protect the battery if it gets too hot in charge or discharge. A very good idea if you get a short, it will stop it going BANG!

 

[jpt]

Thanks for this Lee mine are going now and I opened them up to have a look and decided to leave it till later, might have a go now.

john

 

[dickm]

Can't find the name of the company just now (something like Eurobattery?), but it's possible to get NiMH and NiCd cells with solder tags already attached. And they come in a wider variety of sizes than the standard AA, AAA etc. so might be closer to your originals. The main advantage of the tags is that you can get a decent solder joint without such a danger of overheating the cells.

 

[Jonzjob]

And if you could get Li-on Lithium-iron batteries you will get better caoacity and they won't discharge if you don't use the cap for a while which is one of the naff things about Nmh batteries.

 

[seaco]

And if you could get Li-on Lithium-iron batteries you will get better caoacity and they won't discharge if you don't use the cap for a while which is one of the naff things about Nmh batteries.

Thought of using Li-on batteries but I didn't think I could use the original charger but I'm probably wrong?

 

[Dalboy]

If you have problems finding batteries try you local Model shop that deals with radio controlled models as quite often they get them

 

[seaco]

Hi All

OK you may remember a while back I got all cocky about replacing my Trend Airshield battery with my home made solution, all was well at the beginning but slowly the charge got less and less until now I'm back at square one, now as you may have guessed I'm no electrician so I'm trying to find a reason that the batteries wore out so quickly?

There must be a way to replace these cells with ones that do last maybe Li-on (but I've heard you can't solder to these) is the way to go but it still needs to be 3.6v and it would mean I would have to get a new charger, can you even get a Li-on charger that would just plug in, I don't even know where to look?

Any help to get over my embarrassment really appreciated...

 

[doorframe]

I'm no expert on batteries, but my own experiences may help. I've re-celled loads of power tool batteries and learned the hard way.

I suspect your original batteries may have been sub-c. If so, the rating can be confusing when compared to AA. A 3000mah sub-C will be higher rated than a 3000mah AA. This is because the stated mah is measured at a different discharge rate according to the battery size/type. This can / will lure the unsuspecting user into thinking they are of equal power.... THEY ARE, BUT FOR DIFFERENT AMOUNTS OF TIME! AND, if you're using them above thier rating they will fail fast! And faster! And faster! And... oh, they're kn*ck*red!

There are some industry standard battery types / sizes, and some non-standard. Some manufacturers do use non-standard to try to stop you from re-celling the battery packs... eg Bosch used mini-sub-C (as I call them). Very hard to find and very expensive when you do! It may be that if your originals were NOT sub-C, then Trend may be using non-standard types for this very reason... so you are forced to buy a NEW set from Trend... MONEY MONEY MONEY!

You can allways make your own set from any suitable batteries (sub-C 3500mah NiMh) and if they don't fit use a custom made package / belt clip and just use all the old connectors from the original pack. In order to use the original charger just make sure you use NiCad if replacing NiCad and NiMh if replacing NiMh.

As mentioned already, model shops do sell all types of standard batteries.

HTH

Roy

 

[doorframe]

To add to the above, I almost always chuck the original NiMh's and replace with NiCad's. You simply do not get the mileage out of NiMh's. NiCad's take much more abuse and are cheaper to replace and can be revived quite easily (most of the time). When a NiMh is dead, it's dead. When a NiCad is dead, a few extra Amps (correctly administered) will very often give it a kick in the proverbials and it's good to go! It just needed waking-up.

Also, a NiCad will (normally) charge fine on a NiMh charger, but not the other way around.

Please remember, these are MY experiences... NOT SCIENTIFIC FACT :wink:

HTH

Roy

 

[Jonzjob]

Almost all you need to know about batteries?

http://batteryuniversity.com/learn/

 

[seaco]

I'm no expert on batteries, but my own experiences may help. I've re-celled loads of power tool batteries and learned the hard way.

I suspect your original batteries may have been sub-c. If so, the rating can be confusing when compared to AA. A 3000mah sub-C will be higher rated than a 3000mah AA. This is because the stated mah is measured at a different discharge rate according to the battery size/type. This can / will lure the unsuspecting user into thinking they are of equal power.... THEY ARE, BUT FOR DIFFERENT AMOUNTS OF TIME! AND, if you're using them above thier rating they will fail fast! And faster! And faster! And... oh, they're kn*ck*red!

There are some industry standard battery types / sizes, and some non-standard. Some manufacturers do use non-standard to try to stop you from re-celling the battery packs... eg Bosch used mini-sub-C (as I call them). Very hard to find and very expensive when you do! It may be that if your originals were NOT sub-C, then Trend may be using non-standard types for this very reason... so you are forced to buy a NEW set from Trend... MONEY MONEY MONEY!

You can allways make your own set from any suitable batteries (sub-C 3500mah NiMh) and if they don't fit use a custom made package / belt clip and just use all the old connectors from the original pack. In order to use the original charger just make sure you use NiCad if replacing NiCad and NiMh if replacing NiMh.

As mentioned already, model shops do sell all types of standard batteries.

HTH

Roy

Hi Roy

The original batteries were a little larger than AA's and I saw somewhere that they are rated at 3500mah, I see what your saying about ratings and this must be the problem I think such a shame you can't just use the AA's as it seemed a simple solution I have had a look and can't seem to find the kind of batteries you speak of, I would like them to fit in the original holder if possible so do you think I should go for Ni-cad, Nimh or Li-on also am I right in thinking that I can't solder to Li-on batteries due to the danger of explosion?

I will try to find a model shop somewhere but being in rural Minehead it's a bit of a problem...

 

[seaco]

Almost all you need to know about batteries?

http://batteryuniversity.com/learn/

Hi John

Thanks for the link but as I say I'm a dunce when it comes to electricity I still think made by wizards, so I don't think this will help me much I just need a wizard to say buy that battery and that charger!..

 

[doorframe]

Take a look at...

http://uk.farnell.com/gp-batteries/gp330schhb/battery-nimh-sub-c-3300mah/dp/1321917

It's got dimensions there as well.

You CAN'T go for Li-on as they need a special charger.

Roy

 

[seaco]

Thanks Roy, probably a silly question as you wouldn't have linked me to them but I'm just checking, will they be suitable i.e better than the AA's if so I will order them tonight...

Ahh! just seen there size I don't think they will physically fit in the original battery holder which is a shame do you know if you can get similar cells that are nearer to AA size, the originals where a little bigger than AA's and there was three of them?

I don't mind using Li-on providing I can get a similar charger?

 

[doorframe]

Try this one for dimension......

http://uk.farnell.com/varta/55140201060/battery-nimh-1-vh4000/dp/8636281

Roy

 

[Racers]

Hi,

Maplins sell tagged cels in industrial sizes. http://www.maplin.co.uk/tagged-industri ... ries-30959
I have used them my self and recomend them.


Pete

 

[Eric The Viking]

I will try to find a model shop somewhere but being in rural Minehead it's a bit of a problem...

It's a bit of a distance from you, but try Bristol Batteries (near Temple Meads Station here, but have branches in Exeter and Plymouth too).

Their Swindon branch can 'tag' batteries, in other words spot-weld solder tags to them. This is a much better alternative to DIY as they don't overheat when soldered, and they tend to use better-quality (industrial) cells to start with.

Two thoughts:

1. Ordinary NiCds should theoretically be charged at the rated energy capacity(AH) / 10 (in mA), so a 2AH battery should charge at 200mA current. This gives a nominal 10 hour charge.

There's no reason you shouldn't use different cells to give a battery of the same voltage, but much larger capacity. You will either need to charge them for longer, or decrease the series resistance in the charger, so that they charge faster. Bear in mind the charger will get hotter, although the cells themselves shouldn't.

2. NiCds dislike being left charged for long periods, and 'top-up' charged. It's a nuisance, but best to charge up before use, and only recharge when flat.

Don't run the thing till it stops altogether. This risks reverse-polarizing the weakest cell in the battery, and will knacker it prematurely. Stop using it when it noticeably slows down and charge it then.

The above is a bit of a counsel of perfection. If you're using it for work, it needs to be always available ready to go, so optimal charging isn't always possible. But the above will keep the battery pack in good condition for as long as possible (if it's a NiCd).

Cheers,

E.

 

[seaco]

Thanks Eric I have sent them an email...

 

[seaco]

Hi,

Maplins sell tagged cels in industrial sizes. http://www.maplin.co.uk/tagged-industri ... ries-30959
I have used them my self and recomend them.


Pete

Hi Pete

Can't seem to find a suitable cell on Maplins??