Question Inverter replacement

[rayjoanlough]

I have a 2008 Keystone Cougar 278RKS (original owner) with the lights flickering and batteries not charging well. Itis the original 55amp inverter/charger. I bought a 70amp inverter forreplacement with better charging ability. My question is : do I need to worry about the wiring going from the charger to the batteries? E-Trailer said no but I could use some other opinions.
Thanks for the help
Ray