Leisure batteries, how to fit? Help!

[RobBradley]

Hey all,

So, I own a Bayliner Capri 1952, it has a single battery for the engine.

I want to fit probably 2-3 100ah batteries for leisure, so that when I am anchored, anything I use on 12v comes from the leisure batteries, not the engine battery, so in the hope that when I need to move on, the engine starts without issue.

So I know how to wire the batteries in parallel to increase the amps, but then how do I wire them in?

I know I will take all the 12v connections from the boat and move them from the starter battery over, but then how do I wire the batteries to charge when the engine is running, do I simply run another pos and neg from the engine?

Is it that simple?

What have you done?

Many thanks

Rob

 

[simonfraser]

wire them in parallel with a VSR in the positive lead, like this

Victron Energy Cyrix-ct 12v / 24v 120A Voltage Sensitive Relay (Batt Combiner)

Plenty of YouTube info

And more detailed info in here in a mo I recon

 

[Plum]

wire them in parallel with a VSR in the positive lead, like this

Victron Energy Cyrix-ct 12v / 24v 120A Voltage Sensitive Relay (Batt Combiner)

Plenty of YouTube info

And more detailed info in here in a mo I recon

Agree, a VSR is a good solution.

 

[PaulRainbow]

Hey all,

So, I own a Bayliner Capri 1952, it has a single battery for the engine.

I want to fit probably 2-3 100ah batteries for leisure, so that when I am anchored, anything I use on 12v comes from the leisure batteries, not the engine battery, so in the hope that when I need to move on, the engine starts without issue.

So I know how to wire the batteries in parallel to increase the amps, but then how do I wire them in?

I know I will take all the 12v connections from the boat and move them from the starter battery over, but then how do I wire the batteries to charge when the engine is running, do I simply run another pos and neg from the engine?

Is it that simple?

What have you done?

Many thanks

Rob

If you do that, all the batteries, including the engine battery, will be in parallel.

This is a good way to do it :

 

[ylop]

You might want to consider LiFePO battery for the domestics. For the equivalent usable Ah you need less physical space and weight, and the costs are fairly similar. This thread will now dissolve into an argument about Li batteries, for which I apologise, but one of the reasons people don’t change chemistry is because they can literally drop in another AGM battery as a replacement when a LiFePO will need some adjustments.

 

[RobBradley]

wire them in parallel with a VSR in the positive lead, like this

Victron Energy Cyrix-ct 12v / 24v 120A Voltage Sensitive Relay (Batt Combiner)

Plenty of YouTube info

And more detailed info in here in a mo I recon

Found this on eBay, would this work ok?

On eBay

 

[simonfraser]

Found this on eBay, would this work ok?

On eBay

Might work for a while, depends on the quality, is v cheap, cables probably on the thin side
You can’t just step out of your boat if it all goes tits up

 

[Phil_boat]

You might want to consider LiFePO battery for the domestics. For the equivalent usable Ah you need less physical space and weight, and the costs are fairly similar. This thread will now dissolve into an argument about Li batteries, for which I apologise, but one of the reasons people don’t change chemistry is because they can literally drop in another AGM battery as a replacement when a LiFePO will need some adjustments.

I’m of the same mind. Even if not going lithium now I’d probably fit a DC-DC charger rather than a simple VSR to give the option in the future.

 

[jointventureII]

@PaulRainbow
Question regarding the Victron Cyrix - the data sheet indicates that the charging range (ie relay closed) is from 13.0 to 13.8v

This seems a little low (13.8v) - wouldn't an alternator usually kick out more than that? And this be above the limit and never close the relay?

Edit - I've just tested on my boat and yes it did start off at 14.3v but quickly settled to 13.5v with the engine on.

As you were!

 

[Skipper Felice]

You should learn some basic boat electric: A very good source is Victron Energy: They have some excellent books to download about batteries, boat wiring and all the basics.
Technical information - Victron Energy

and the book about all wiring and installations on board:
https://www.victronenergy.com/uploa...imited_book/43562-Wiring_Unlimited-pdf-en.pdf

This is all valid information also for other brands and products you may chose.
The basic schematic from @PaulRainbow is an good start and easy to install on your boat.

 

[Skipper Felice]

Found this on eBay, would this work ok?

On eB

For me this looks like kids play for a camper: - I would never install this on a seagoing boat. Please use some gear from the marine sector and with some proven usage for a watertight environment.