From the model number I would guess you have an older Parallax power panel. The best replacement for that old converter is a Progressive Dynamics 4600 series which is the converter already mounted in the "can" and is a slide in, slide out, affair. It also comes with a new fuse panel that has controls for the charge wizard features of the new converter.
Note that under specifications it says....
Model #PD4655V replaces these
converter sections: Parallax/Magnatek #6345,
Parallax #8345, WFCO™ #8945
Which appears to be a typographical error and should read PD4645V instead. The last two digits are the amperage and unless you have 6 gauge wire from the power panel to the battery (most are 8 gauge) you should stick with the 45 amp version, which you have now.
Here are the instructions (they are for many different models and you need only read the paragraphs that pertain to the model power panel you have).............
This is a multi-stage converter that on a heavily discharged battery will start out at about 14.4 volts (bulk charge rate) and later drop to 13.6 volts (top off rate) and when fully charged will drop to about 13.2 volts to maintain the battery without boiling it. Your batteries will last much longer with this unit.
Other manufacturers (WFCO for instance) also make multi stage chargers that can replace the Parallax unit, but the WFCO in particular is noted for not changing stages properly, I had one that didn't work properly and ditched it in favor of the PD unit which works flawlessly.
If you want to talk to someone about this before making the leap, I would suggest Randy at Best Converter.
DO NOT buy the optional pendant as the features of it are already contained in the new fuse panel that comes with the new converter. It is rare that you will need to force the converter into a charge mode other than what it automatically selects and if you do need to, it is easily done with the button on the new fuse panel, by simply opening the front door and pushing it. The pendant is just necessary if the power panel is difficult or nearly impossible to access. The new fuse panel also has blow fuse indicators on every branch circuit fuse.
I have installed two of these and have been quite pleased with them. I highly recommend them.
This pic is of the panel in my motorhome, which I sold in 2019, with the new converter and fuse panel.
The two bottom pics are of the installation in my Bigfoot Trailer last year. The fuse panel is the same but the color has changed somewhat from the one I installed earlier in the motorhome. Pics are from a write up I did on the Bigfoot Owners Club Forum.