Did original smoke or just go open on primary? Most blow thermal fuse before smoking.

 

https://www.maximintegrated.com/en/app-notes/index.mvp/id/4322
is how it's done more correct for constant current constant voltage charger
(items to notice)
https://www.maximintegrated.com/en/images/appnotes/4322/4322Fig01.gif
the empty battery not being charged with high current until it develops ability to generate some voltage internally
followed by Const.Current then by Const.Voltage cycles (not exceeding critical 4.2V)

more about LI-Ion http://www.powerstream.com/lithium-ion-charge-voltage.htm

http://www.cadex.com/en/batteries/safety-of-lithium-ion-batteries

basically use more sources for help as just here (http://forum.allaboutcircuits.com)

Hi Mate i put it all together and put the battery pack in the unit it charged just fine ..took a hour intially..i left it on and like you said it was warm at the end of the charging.the entire unit was warm not hot or extreme.i measured the voltage on the battery and it read 5.1 or 5.3v which is normarl for a 4.8v when fully charged.the other two terminals had no voltage so i guess that 14v dc is probably for a another model ..ot was just using the 12vdc out.hopefully happy ending i guess. Thank you sir once again for all your time and info appreciate it.and to all who chipped in with whatever info..you guys rock! Cheers.

 

It is nice to hear that!

some more insight into 4 terminals ! ups - didn't press the Post Button last time
▲it's told there the 2 extra terminals being used for internal thermal "fuse"
... however for yet another battery pack it was told that the batteries are reordered by
external device to make motor run at different speeds (like a gear box)
-- seems no general rule here