E2V Argus thermal imaging camera battery/charger help

[Argus]

I bought an old thermal imaging camera model Type P4438 to mess around with and it has come with an aged rechargeable battery and no charger. I have limited self-taught electronics knowledge.

The seller said:

The unit comes with the rugged case, instruction manual and one battery. There is no battery charger but I managed to charge the battery with couple of wires into a 12 v power supply. This charger setup is not included for health and safety reasons but easily made yourself.

The battery does not hold a massive charge and only gives about 10 to 15 minutes viewing but I understand from the manual that it can be used with LR6 batteries in the correct holder.

The camera works well.

The battery has three pins. This confuses me a bit. The voltages are (reference), -9.81, -10.3.

I can find mixed information online suggesting mostly that it is 12V but this doesn't match my measurements.

I am wondering what voltage should I charge the battery at and how should I connect the pins?

The battery appears to be totally sealed.

http://www.ebay.co.uk/itm/251823015408?_trksid=p2059210.m2749.l2649&ssPageName=STRK:MEBIDX:IT

I think this is the datasheet for this model and suggests 12V running voltage.

 

[MaxPower1]

Is this your camera?
http://www.e-tell.info/myact/doc_man_lincs/argus thermal camera.pdf

If so, 12V makes sense since it runs off of 8 AA batteries (8 x 1.5V = 12V). The rechargable pack was an accessory but the datasheet isn't specific. Judging by the age of the camera, optional rechargable pack was probably a NiCAD pack. Since it only holds a charge for 15 minutes, it's probably time it be replaced (I wouldn't even try to re-charge it at this point for safety reasons).

If you want rechargable batteries, your best bet is to purchase some rechargable AA (LR6) size batteries and a charger. Or you can just run the camera off of 8 AA (LR6) alkalines (assuming the link above is the same camera). Your link has me confused since it's for an Exergen Infrared IR Temperature Scanner which doesn't appear to be the same thing.

Enjoy!

 

[Arouse1973]

These batteries will last longer. I have tested these batteries and found them to be very good. They replace Alkaline with Lithium technology.
Adam

https://www.google.co.uk/?gws_rd=ssl#q=lithium+iron+disulfide&tbm=shop

 

[Argus]

The problem is that the unit is so old that I cannot buy the casing which allows the insertion of AA batteries into the camera.

The battery I have is like this, it is NiMH

 

[Arouse1973]

Ok so you are going to have to take it a part if you can to replace the batteries?
Adam

 

[Argus]

It's sealed but if I have to then I will.

Can you shed any light on the voltage discrepancy I'm seeing?

 

[Arouse1973]

It's sealed but if I have to then I will.

Can you shed any light on the voltage discrepancy I'm seeing?

No not sure. The third pin might be a temperature sensor for the pack. This was quite common for chargers for Ni-cads. this was used as a charge termination method if the delta V method didn't work.
Adam

 

[MaxPower1]

Two of the three pins are your positive and negative terminals and the third is most likely a thermistor terminal for monitoring temperature. Have you measured across all combinations of the three terminals? The highest value you measure would mean your measuring across the + and - terminals instead of the thermistor and + or -.

 

[Argus]

Righto, yes so the highest voltage is 10.3V

I opened the battery, it was securely glued so I had to use a hacksaw to "score" the circumference of the casing 17mm from the top.

The cell is apparently 9.6V inside!

 

[MaxPower1]

Hopefully you can re-purpose the casing to hold 8 new cells (Alkiline or NiMH). If you want new NiMH cells, you will have to remove the individual cells from the casing again to re-charge them on a third-party charger.

I'm surprised the camera doesn't have standard alkaline battery contacts since the info I found states it will accept alkiline cells. I guess yours must be a later model?

 

[Argus]

You can use alkaline cells but you need an adapter which is no longer sold.

Can I not hook up some 1.2v NIMH cells to the charging circuit which is attached to the current cells?


Thanks for all your help

 

[MaxPower1]

Oh! I didn't see your picture! Yes you probably could use the same charging circuit, but since you now have information on the origin of the battery you should try contacting All batteries UK to find out if they still carry this item.

 

[Bluejets]

Identical to an R/C transmitter battery, except they have a lead and plug for connection.
Bought one only last week off Ebay....
http://www.ebay.com.au/itm/TX-Pack-...Radio_Controlled_Vehicles&hash=item4d18275d3f

 

[Argus]

Identical to an R/C transmitter battery, except they have a lead and plug for connection.
Bought one only last week off Ebay....
link

Thanks for that suggestion. Would I be able to charge this with a constant 12v supply or do I need to use
a proper charger? I am thinking I could because this circuit board is attached and that regulates the incoming power?

Could I use any battery with a suitable voltage and dimensions below 100 x 33 x 35 mm (the casing internal measurements)?

I was thinking 11.1V might give higher performance as well as the advantages of LiPo. Can anyone see any reason this would cause problems if the unit can accept 12v from alkaline cells?

Thanks again for all your help

 

[Arouse1973]

No you must not connect a power supply straight to the batteries unless it is current limited. You could damaged the cells. A proper charger is always the best option but if you have some electronics knowledge you could make a constant current charger for 160 mA quite easily. The cells really need to be charged correctly so you get the most out of the cells so a proper charger is the best option I think. I would look at replacing them with nickel metal hydride batteries of the same type if possible. Contact them and see what they say.

http://www.allbatteries.co.uk/rechargeable-battery/industrial-nimh-rechargeable-battery.html

Adam

 

[BillbertGilbert]

Hey. Signed up just to help. I bought several of these on eBay that came with battery cases which accept AA batteries, totaling 12v. Ignore your measurements and send 12v without worry.

 

[Argus]

Just to post the resolution - I caved in and bought a replacement 9.6V 2500mAH battery and a balance charger rather than risk damaging anything. Thanks again for all your help.

 

[mike b]

Thank's argus
i have now replaced the battery in mine and it is as good as new your photo helped and the little circuit board inside was reused.
regards mick

 

[mww]

A bit late but some background...
The 'AA' option needs a different battery carrier (red labels) which does have springs etc for AA cells (LR6 or as suggested FR6 are OK)
The 3rd pin is not a thermistor feed, it is a voltage to drive the battery indicator. In the 'AA' carrier it is a resistor divider into the camera, in the rechargeable pack it is a gas gauge output scaled to look like the discharge of an 'AA' pack.

New website www.fire-tics.co.uk suggesting some hope of spares supply ?

Bill