When would you switch to Battery 1?

[Rustic Charm]

Originally Posted by Sunsetrider

In my opinion of you don't use an ACR with an on-off switch you are just guessing as to the charging of the batteries and taking an unnecessary risk. The variety of opinions here on which position to use and when is an indication of the guesswork going on.

Can you perhaps explain what your advising here a little more, you have confused me a bit

Why don't you use an on-off switch with an ACR? How do you turn everything off without an on-off switch? How do you select your heavy duty starter battery to start up without a switch? ( I know there is an optional wiring system to do this with my Blueseas but I've not chosen that option).

[Rustic Charm]

Originally Posted by hamburking

I never change the battery switch with the engine running (charging)...ever! Argue all you like, but I won't be blowing any diodes. Its a simple rule to remember and follow.

.

You won't blow diodes by switching 'through', only by switching 'off'. Many battery controllers actually have marked 'do not turn off when operating' or something similar. I havn't read anyone suggesting to turn 'off' when the engine running.

[jongleur]

Originally Posted by Rustic Charm

You won't blow diodes by switching 'through', only by switching 'off'.

Unless you have a "break before make"
switch.

[darylat8750]

Originally Posted by jongleur

Here's my answer:

1/BOTH/2/OFF Switches Thoughts & Musings | SailboatOwners.com Forums

What he said! +1

[Sunsetrider]

Originally Posted by Rustic Charm

Can you perhaps explain what your advising here a little more, you have confused me a bit

Why don't you use an on-off switch with an ACR? How do you turn everything off without an on-off switch? How do you select your heavy duty starter battery to start up without a switch? ( I know there is an optional wiring system to do this with my Blueseas but I've not chosen that option).

No wonder you are confused: I typed "of" instead of "if". So sorry!

And I should clarify as well that I refer to an on-of switch to distinguish it from a 1-2-both switch which is prone to human error unlike the ACR/on-off setup.

I made the switch to the Bluesea system and it improved my peace of mind greatly. Before that I never really knew which battery needed charging more. Now I don't even think about it.

[NewMoon]

Originally Posted by Sunsetrider

In my opinion of you don't use an ACR with an on-off switch you are just guessing as to the charging of the batteries and taking an unnecessary risk. The variety of opinions here on which position to use and when is an indication of the guesswork going on.

We might be guessing as to how long it takes to fully recharge our start bank (typically no more than 10-15 minutes, just like a car), except that we also have a Link 2000 battery monitor. So we know the state of both of starting and house battery banks.

[Rustic Charm]

Originally Posted by jongleur

Here's my answer:

1/BOTH/2/OFF Switches Thoughts & Musings | SailboatOwners.com Forums

this is what I used when I designed my system too. My switch doesn't determine which bank is being charged.

But last year I had an auto electrican criticise me for 'starting' on my house bank and since then I start on my 'starter' and then switch 'through' to my house bank as soon as it's started. My Blueseas ACR takes care of charging both banks.

[jongleur]

Originally Posted by Rustic Charm

... an auto electrican criticise me for 'starting' on my house bank...

What was the electrician's reasoning?

[Rustic Charm]

Originally Posted by jongleur

What was the electrician's reasoning?

He looked at my AGM's that make up my 480 amps (I think?) of house and said there not built solidly enough to continually start your engine. My starter on the other hand is a high crank battery designed for that purpose.

[Stu Jackson]

Originally Posted by Rustic Charm

He looked at my AGM's that make up my 480 amps (I think?) of house and said there not built solidly enough to continually start your engine. My starter on the other hand is a high crank battery designed for that purpose.

Here's another link to Maine Sail's discussion on this issue.

Engine Starting Loads - Amp Draw Data (by Maine Sail)

Engine Starting Video / Real World Amp Load Data | SailboatOwners.com Forums

[Scott Berg]

While understand like MainSail's approach I've always preferred a binary approach. That is, every battery bank is switched (ON/OFF) and, if needed, a bridge (ON/OFF) switch is between the systems. So the engine has a starter battery that does just that, starts the engine. That battery has switch. The House Bank also has a switch. In normal operation all charging sources charge the house bank (alternator, solar, wind, etc). The starter battery is kept up with either a voltage follower (think EchoCharge or Duo Charge) or, if the engine has a high DC running load like some Cummins, an ACR rated at 100a or so.

I also fit an extra ON/OFF switch between the B+ wires from Starter and House. This is a BINARY combine switch that can be used in emergencies. Simple, easy to understand, and flexible. In normal operation no switches to ever move...

[Rustic Charm]

Originally Posted by Stu Jackson

Here's another link to Maine Sail's discussion on this issue.

Engine Starting Loads - Amp Draw Data (by Maine Sail)

Engine Starting Video / Real World Amp Load Data | SailboatOwners.com Forums

Yeah I think I'll go back to doing what I designed it to do without the need for switching. He's meant to be a well known 'auto' electrician that does lots of work on boats, but I guess that's not necessarily a 'marine electrician'.

[Stu Jackson]

Scott, that's one of basically three ways to do it. Here are the wiring diagrams for all of them.

Basic Battery Wiring Diagrams This is a very good basic primer for boat system wiring: Basic Battery Wiring Diagrams

This is another very good basic primer for boat system wiring: The 1-2-B Switch by Maine Sail (brings together a lot of what this subject is all about)
1/BOTH/2/OFF Switches Thoughts & Musings | SailboatOwners.com Forums

[Rustic Charm]

Originally Posted by Scott Berg

While understand like MainSail's approach I've always preferred a binary approach. That is, every battery bank is switched (ON/OFF) and, if needed, a bridge (ON/OFF) switch is between the systems. So the engine has a starter battery that does just that, starts the engine. That battery has switch. The House Bank also has a switch. In normal operation all charging sources charge the house bank (alternator, solar, wind, etc). The starter battery is kept up with either a voltage follower (think EchoCharge or Duo Charge) or, if the engine has a high DC running load like some Cummins, an ACR rated at 100a or so.

I also fit an extra ON/OFF switch between the B+ wires from Starter and House. This is a BINARY combine switch that can be used in emergencies. Simple, easy to understand, and flexible. In normal operation no switches to ever move...

That sounds all complicated to me

[Golden Echo]

Originally Posted by Chuck Hawley

When I worked at West Marine, we had a lot of customers who would have a two battery system, but would still end up with one of the following problems:

1. Both batteries dead; can't start engine.
2. Damaged alternator.

I would argue that the primary problem is one of having to switch the battery switch at almost any time in the boat's existence. It's too easy to forget and leave the switch in the Both position, and too easy to turn it one click too far and leave the alternator open-circuited.

The answer, I believe, is to use a voltage controlled relay like the Blue Sea ACR (Automatic Charging Relay) or the variety of other products from BEP or Mastervolt that accomplish the same thing. High voltage? Batteries are paralleled. Low voltage? Batteries are isolated.

On a "simple" boat (one engine, two battery banks, no generator, etc.) this is best accomplished with the Dual Circuit battery switch, which allows the engine battery to be connected to the engine/starter, and the house battery to be connected to the house loads, but with no interconnection. Use the ACR to charge both banks when there is a charger (alternator, inverter/charger, solar, shorepower) in the circuit.

I know the purists will worry that you shouldn't charge batteries in parallel, but in the real world, on boats that are common in harbors around the U.S., this system really works.

Cheers, and smooth seas,

Chuck Hawley

I have the 2 bank system Mr Hawley has described and it works perfectly. The only difference is that I have my start battery connected to my house bank with a Xantrex Echo Charger. This limits the current my start battery is receiving and allows more current to go to my house batteries when charging. Changed over to this system shortly after I bought the boat in 2008 (replacing the diode type combiner) and just this year had to replace my 11 year old start battery. Never have to touch the switch and always have plenty of power. Also if you have your alternator connected directly to your house bank and then combined when charging there's no chance of shorting the alternator.