MAKITA / PORTER CABLE BATTERY ADAPTERS Li-ion and NiCd

[Toolish]

OK, here is the situation...  I have some older (a few years) Porter Cable 18v cordless tools.  All these NiCd batteries have died and will not recharge.   I have since bought new Makita 18v Li-ion tools, but not all the tools that I had before.

Do they make an adapter that will allow me to use my Makita 18v lithium batteries in the Porter Cable tools that used Nicad batteries? 

Thanks!

[Toolish]

Anybody?

[Eric - TIA]

I haven't seen one.  I am sure there can be something you can rig up but not sure how much I trust all that.