More new boat advice please

[Lightwave395]

I'm still finding my way around my new to me boat, now trying to get my head around the charging setup. I have an MD2040 engine with the standard 55 A alternator and a Sterling 3 output split charge diode .
In the pile of new bits that came with the boat is a brand new 90A Balmar alternator and an equally new 3 output Sterling Pro split R.

The service batteries are not just the usual 2 but I have 4 X 100Ah Gel batteries ( plus a 5th spare ) and a Sterling 'Pro charge ultra' battery charger. There is a bow thruster battery and a new 100Ah Bosch engine start battery.

My dilemma is thus : We're gentle sailors in the autumn of our sailing years, when we get the boat to her home in Quiberon we'll be doing day and weekend sails to the local islands, a few one or two week cruises down the Atlantic coast, mostly marina based with occasional 1 or 2 nights at anchor, I'm a firm subscriber to the KISS principle, do I really need all this 'stuff' ?

I'm wondering about installing the 90A alternator and the Pro split (I know some are hot fans of sterling but I had their stuff on my previous boat and it was all fine) - if I do and kept the 4 service batteries will I need to upgrade the belt / pulleys or will I need to do that anyway ?

I'm wondering why not just remove 2 of the service batteries - we did fine for on our previous boat with 2 X 110Ah service batteries and a solar panel...

I fully appreciate Mastervolt or Victron would be great but I'm not really interested workload or financially in any 'fork lift' upgrading

 

[Tranona]

The standard alternator will be fine for 2 or 3 batteries based on the rule of thumb of 10% of capacity - that is 300Ah would be unlikely to absorb more than 30 amps unless heavily discharged. 4 batteries and it might be worth considering upgrading the alternator. However if you can live within 200Ah capacity you are unlikely to put a heavy load on the alternator particularly if you keep the 4 batteries. I think I would keep them if you can maintain a high level of charge as you are unlikely to discharge below say 65%. The bow battery and engine start need very little to top them up after use.