2 cranking batteries and 1 domestic?

[Refueler]

Dissimilar batterys ?

Connecting two batterys together ? The only factor that makes this a bad idea - is when the batterys are of different voltage range. As long as the 'chemistry' of the batterys are same - you can in fact connect a small capacity with a large capacity ... try to have them at similar charge levels and of similar amp capability .....

If this was not true - then someone explain why many boats go around with dissimilar capacity batterys that can be combined whether VSR system or the old 1-B-2-Off switch.

You can of course combine different 'chemistrys' but then BMS and other factors come into play. The main factor is that full charge voltage level is similar ...

 

[Refueler]

Of course, you could leave the whole lot ”as is” for now & wait until you actually need new batteries. You have recently bought a new, to you, boat & there will be plenty to splash the spare cash on

Contrary to some - that would be my suggestion as well .... get to know the boat - get things sorted as YOU want them ... then consider the systems. There will be enough calling on the wallet as it is .... listing priorities of where money goes is how I look at it.

 

[moresparks]

I am probably way off the mark here, but I wonder if you have an Anchor Winch and how is power supplied to that? In some quarters they recommend a Cranking Battery for the Anchor Winch!

 

[Bouba]

I am probably way off the mark here, but I wonder if you have an Anchor Winch and how is power supplied to that? In some quarters they recommend a Cranking Battery for the Anchor Winch!

That’s interesting... and when I think about it, I have no idea which battery my winch is connected to

 

[Daydream believer]

..

 

[Tranona]

That’s interesting... and when I think about it, I have no idea which battery my winch is connected to

It could be either the start battery or the house bank if it does not have its own battery. Follow the wires. The suggestion for a cranking battery is when it has a dedicated battery because like a starter it draws high current for short periods. However many like me use a decent size (110Ah) leisure battery which also powers the windlass and is charged by a B2B from the start battery. This setup avoids long runs of heavy cable when using the ships batteries which are usually located towards the rear of the boat.