How to determine rating of a new converter panel?

The actual rating is probably part of the panel model number.
Post it here for interpretation.

BTW when my 55 amp WFCO failed I replaced with a 35 amp. Works just fine. I went with 35 because there was no 25. Although converter mostly stays off now with solar keeping the battery charged. If you want to recharge from a small 1000 watt generator I recommend 40 amps or less.

Get the same or slightly larger then your current one.
If your rig has a 30 amp, you may need to jump to the smallest PD amperage. (45 amp I think).
Verify size of conductor between the converter and DC distribution panel. Conductor must be able to carry full output load of current. 45 amp should be #6.
Remember size is not only charge rate but the load of your 12 volt DC loads.

myredracer wrote:
Is bigger better? We don't dry camp and don't discharge the battery much.

No. 45 amps is plenty unless the RV is especially large or has some high draw 12v equipment like tank heaters.

Why not get one with the same rating as the WFCO you're replacing?

I have to ask though, if you don't dry camp, why do you care what converter you have?