Giovanni,
Welcome to the BAC Forum and RVing in general. Batteries are the heart of your coach so it is important to get them right. Most important: Take a picture of both sets of batteries BEFORE disconnecting any cables. I also strongly recommend drawing a diagram of the cable hook up and labeling each end of each cable so you are sure you can replace them exactly as they were originally. I would also recommend applying a baking soda and water mix to each cable end to remove any corrosion. I immerse the ends in the solution to ensure it attacks any corrosion inside the cable terminal. After cleaning and attaching the cables, apply a battery corrosion protector, available at all auto parts stores. Again, Be Sure to get the hook up correct as an incorrect hookup can cause multiple electrical issues that can take many hours to track down.
Your batteries are most likely lead acid flooded post style (the cable terminal fits over/around the post). IMHO lithium are extremely expensive and will probably outlive your coach. AMG batteries are also pricey and, assuming you take care of your standard flooded batteries, are not really cost effective. Your battery set should last 5-7 years with normal maintenance (checking water level).
Your coach probably has 2 chassis batteries and 4 house batteries. The chassis batteries are 12 volt, probably 900 to 1000 CCA each and hooked up in parallel (2 negative terminals tied together and 2 positive terminals tied together) giving you 12V and 2000 CCA (cold cranking amps). The house batteries are 6 volt (golf cart batteries), 200+ AH(amp hours). They are hooked up in a parallel/series configuration. 2 each are hooked up in parallel yielding 2 banks at 6 volts and 400+ Ahs. Then the 2 parallel sets are hooked in series so the coach sees 12 volts at 400 AHs.
Hope this helps.
