Why does the Dewalt 18V DW9096 XR+ Battery have 3 contacts?

Question edited for a lot more clarity. All questions need full 'make model (what it is)' please.
Question moved from Garden to make model category.

It is this one with wildly differing prices!

https://www.google.com/search?q=Dewalt+DC9096+charger

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No it only fits the models it is designed to fit. Go on eBay to check this.

Any dewalt similar type will be fine. A 18v NicD type dewalt one with this male socket is perfect.

Brand New Cordless Drill Battery for DEWALT DE9098Type: Ni-MHVolt: 18VCapacity: 3000mAhColor: BlackWeight: 1160gDimension: 136.80x85.43x113.00mm

http://www.drillbattery.com.au/buybattery.php/dewalt_DE9098_power+tool+battery.html

Check the voltages with a VOM and use the info here:
http://www.powerstream.com/NiCd.htm

As long as the voltage of the battery is the same as the tool, the tool won't mind if the power is coming from a NiCd or lithium battery. You do have to have a charger that works with lithium batteries to charge them up. Chargers that can charge lithium batteries can also charge NiCd and NMH batteies. NiCd chargers are not always programmed to detect when lithium batteries are full and may continue to charge them to the point of melting or starting on fire.

Yes. Dewalt says the 18volt XRP battery is compatible with all Dewalt 18volt tools

Have a great day.

if it is under warranty ,take it back .if it isnot then bite the bullet and buy a new battery ----try TOOLKING

Are batteries for the dewalt cordless drill interchangeable? Will an 18 volt battery fit in a 12 volt drill?