The caps are the motor caps you see on your motors.
The caps will limit the AC current going to the rectifier. You would need an armfull of caps to over load the genny.
So yes, if you cut the ext cord, and placed the capacitors in series with one of the two ac lines, and then connected to the bridge, you will have your 110X1.4=154v peak dc.
The batts will drag this straight down to their voltage the same as it loads a windmill stator.
The genny won't worry, as the current will only rise in line with the capacitive reactance of the caps... ie the caps will current limit it, and drop the voltage the batteries don't need over the caps.... they will not heat up like a resistor, as they are not dropping the voltage via resistance, but by the reactance instead.
This sounds rough and ready and it is, but is also used extensively in a small scale in tons of electrical equipment to provide small voltages to scr and triac circuits in particular, and lots of other even sensitive circuits in AC equiptment.
The down side is that it means in that equipment, the low voltage electronics must be double insulated from everything that a person can touch, as it is not galvanically insulated from the mains as in a transformer application.
In this application, the genny is not really grounded in the same sense as the mains... unless it is hard wired to one or the other of the floating 110v leads from the genny core.... and I don't see that in gennies over here, their earth lead goes to the chassis, but not to the designated N terminal of the machine.
I don't think you should go this route, as you don't have the necessary background to make sure that you are safe..... but that is how it works..... it is dangerous in the sense that the output from the bridge is 150v or so, until it is connected to the batteries....... so although it will work, I think in your case you should find another method.
Also it will need a lot of uf to make serious current.
Jerry ( from this board) charged his EV in this fashion for years, and i recollect he mentioned about 20uf per amp of current.... could be wrong, but rings a bell.
If you search this board, he has diagrams and information here. .... but it is best left for those used to playing with mains voltages on a regular basis I think.
Here is one of his stories on his charger.... this board is crap for older posts.. I see it mentions 24uf/amp.
................oztules