[tom255]

to determinate wattage is simple Voltage multiply by Curent.
989 On 4S 14,8V*7.1Amps makes = ~105W actualy it charge not on 3.7V pec cell maybe bit more but power not exceed 118W
And I allready wrote here 989 powersupply is 150W charger consume max 118W so changing PS not help rise charge current.
If you still suspect that PS not feed your charger hook it to Lead Acid CAR battery and check what max amps you get.
Paralyzed if you want buy exact PS what can charge 18,5V pack you need 185W but add 10% for losses you get ~200W

I bought switchng PS from ebay for my 0610i, chinese tends to overrate their products i bought more powerful PS than needed charger max is 250W i bought 350W PS to be sure that it will feed it in any case and wont overheet or something.