Combined for starting, or in need of a better system design?

[Ryban]

We're looking for a better solution on how to wire our starter battery so that only the starter battery is used during starting, but it's still possible to to use the house bank if needed. Let me try to elaborate:

On our boat, the big-picture wiring looks as shown in the diagram below.



The two 6V batteries are our house bank, and the 12V is a dedicated starter battery. The starter for the engine is wired to the output from the main switch. In this way, the batteries can be combined (if needed) for starting. Our engine is only a 14HP, so it can start off the house bank in a pinch without trouble.

The ACR is a BlueSea Systems PN:7600 (http://assets.bluesea.com/files/reso...tions/6330.pdf). It combines the batteries when they're being charged, and disconnects them after the voltage drops below 12.7. So we normally leave our battery switch in the "house bank" position. But it doesn't have a starter-disconnect feature like the newer ones do.

In any case, we'd prefer to use only the starter battery for actual starting under normal circumstances. I think the first step would be to tie the engine connection to the "2" position on main switch. This way the house bank is employed if the switch is turned to the "combined" position. However, during the day, the batteries will be combined regardless, because of the ACR. The ACR can have a manual-operation switch connected to it, which we could then use to isolate the two banks during starting. But this procedure would involve first turning the main switch to the "2" position, then flipping the manual ACR switch, and then starting the engine, and that just seems all a bit unnecessary.

Which makes me think I'm overlooking a simpler, better, more fool-proof solution to my dilemma. So here I am!

[smac999]

Buy the blue seas dual circuit switch. 5511e

Or full manual control buy a 2nd 1.2. All switch. One to feed panel and one to feed engine. Then you can choose to power either from either battery.

[Uncle Bob]

Originally Posted by smac999

Buy the blue seas dual circuit switch. 5511e

Or full manual control buy a 2nd 1.2. All switch. One to feed panel and one to feed engine. Then you can choose to power either from either battery.

This is the way that I chose to go, with the addition of a VSR between the batteries that only connects when the engine is running.

[Reefmagnet]

You can buy an ACR with a manual momentary push button override. You don't need to connect the start battery to the Bank #2 position at all, you just wire the start battery to the engine and press the override switch on the ACR to combine if needed. All other boat electrical circuits run off the house bank.


I had a Vega once upon a time and wired mine up this way.

[smac999]

Originally Posted by Reefmagnet

You can buy an ACR with a manual momentary push button override. You don't need to connect the start battery to the Bank #2 position at all, you just wire the start battery to the engine and press the override switch on the ACR to combine if needed. All other boat electrical circuits run off the house bank.

.

you are required to have a battery switch on engine battery.

if the house battery dies, how do you use the VHF and nav lights for emg use?

momentary parallel does not work for this.

[Reefmagnet]

Originally Posted by smac999

you are required to have a battery switch on engine battery.

if the house battery dies, how do you use the VHF and nav lights for emg use?

momentary parallel does not work for this.

Who requires it, exactly? I'd suggest in your scenario starting your engine with the starter battery that didn't discharge because it's now impossible to leave paralleled with the housebank. The ACR will then kick in and power both your VHF, nav lights etc with the added benefit of also charging your discharged housebank.

[smac999]

Originally Posted by Reefmagnet

Who requires it, exactly? I'd suggest in your scenario starting your engine with the starter battery that didn't discharge because it's now impossible to leave paralleled with the housebank. The ACR will then kick in and power both your VHF, nav lights etc with the added benefit of also charging your discharged housebank.

acr doesn't kick in under 9v.

north america requires the switch. but anyone would be dumb not too. I have seen starter motors fail and stay on. engine wiring caught on fire. owner had no way to shut power off to starter. he now has a battery switch as required.

[Reefmagnet]

Originally Posted by smac999

acr doesn't kick in under 9v.

north america requires the switch. but anyone would be dumb not too. I have seen starter motors fail and stay on. engine wiring caught on fire. owner had no way to shut power off to starter. he now has a battery switch as required.

So you can be fined in Panama for not having a battery switch, or what?

But I would agree a battery switch is a good idea. At the same time, adding the starter battery to a 1-2-both switch is a dumber idea that defeats the purpose of having a starter battery.

The ACR will most certainly kick in if the starter battery is charged. By default the alternator output connects to the starter battery.

[Stu Jackson]

OEM 1-2-B Switch Wiring History Alternator/Batteries & "The Basic" 1-2-B Switch BEST Wiring Diagrams

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)
http://forums.catalina.sailboatowner...d.php?t=137615

This is a newer primer for boat system wiring design with a thorough digram: Building a Good Foundation (October 2016)
http://forums.sailboatowners.com/ind.../#post-1332240

The Short Version of the 1-2-B Switch Stuff: Electrical Systems 101 This is a link to the Electrical Systems 101 Topic, reply #2

What are ACRs, Combiners & Echo Chargers? (by Maine Sail) [scroll to the top]
http://forums.catalina.sailboatowner...d.php?p=742417 and Battery isolator / voltage regulator / batteries

Making Sense of Automatic Charging Relays (2019)
https://marinehowto.com/automatic-charging-relays/


AGM Battery Issues and the Blue Seas Dual Circuit Switch (from Maine Sail) "DARN AGM Batteries"
https://forums.sailboatowners.com/in...teries.133773/

[rbk]

I went with the blue seas 8686 dual bank panel. I know some will argue you can’t isolate a single bank but in the event the need comes up it is quite simple for me to manually switch cables on my banks and isolate either or. Outside that scenario both circuits are separated so no dimming of lights or having to power down electronics when starting.
Guess I should add the following: x4 6v /x1 12v flooded; pro nautic 12/40 shore; Balmar 120 w/mc regulator;balmar duo to start & 150w solar all wired proper.

[Q Xopa]

Originally Posted by Ryban

We're looking for a better solution on how to wire our starter battery so that only the starter battery is used during starting, but it's still possible to to use the house bank if needed. Let me try to elaborate:

On our boat, the big-picture wiring looks as shown in the diagram below.



The two 6V batteries are our house bank, and the 12V is a dedicated starter battery. The starter for the engine is wired to the output from the main switch. In this way, the batteries can be combined (if needed) for starting. Our engine is only a 14HP, so it can start off the house bank in a pinch without trouble.

The ACR is a BlueSea Systems PN:7600 (http://assets.bluesea.com/files/reso...tions/6330.pdf). It combines the batteries when they're being charged, and disconnects them after the voltage drops below 12.7. So we normally leave our battery switch in the "house bank" position. But it doesn't have a starter-disconnect feature like the newer ones do.

In any case, we'd prefer to use only the starter battery for actual starting under normal circumstances. I think the first step would be to tie the engine connection to the "2" position on main switch. This way the house bank is employed if the switch is turned to the "combined" position. However, during the day, the batteries will be combined regardless, because of the ACR. The ACR can have a manual-operation switch connected to it, which we could then use to isolate the two banks during starting. But this procedure would involve first turning the main switch to the "2" position, then flipping the manual ACR switch, and then starting the engine, and that just seems all a bit unnecessary.

Which makes me think I'm overlooking a simpler, better, more fool-proof solution to my dilemma. So here I am!

ACR is fine for the Charging side of the circuit.
But IMHO better to have both/all batteries seperately switched to the loads, ie house and starter etc.
I would not 'parallel'/ 'both' a good battery to a bad battery as the bad batt will pull the good one down.
If you have the seperate switch you can switch OFF the bad batt and switch on the good one.

[donradcliffe]

I'd have a look at the Blue Sea 6011
http://assets.bluesea.com/files/reso...eb_version.pdf

[Q Xopa]

Originally Posted by donradcliffe

I'd have a look at the Blue Sea 6011
http://assets.bluesea.com/files/reso...eb_version.pdf

I know a lot of systems are done this way. But Im not conviced
when you have a low starter batt it is the best idea to 'combine' it to a house bank. If your house bank is better, but only marginally better. By combining the good to the bad you will drag the good one down. Its true that you will lift, or atleast try, the bad one.
Why not switch off bad one, then switch on good one.
That 6011 looks like it will do that, ie break before make on the which is fine. But I dont like the 'Combine' position.
I have remote BlueSea swiches but, a switch is a only a means of making or breaking a battery connection, so which ones dosent matter too much. Assuming of course they are adequate ratings.
The important thing in my opinion is being able to switch them on and off to the load side independantly, only one on at a time.
From the charge side combining is fine, usually done with an ACR, VSR or FET Isolator. Go by many names do mostly the same thing although by slightly different means. I have a BlueSea ACR, but the Victron Isolators look good too. Some people like the BlueSeas for their substantial 10mm terminal posts. Others like the Victrons for the FET surge protection.

[john61ct]

http://forums.sailboatowners.com/ind...0#post-1346247

http://forums.sailboatowners.com/ind...-2#post-891581

[Ryban]

Thank you all for your replies. I've followed the majority of the links offered here, until my weak internet got fussy with me.

From the info gathered here, I think the ideal layout is the 3 on/off switch approach, that allows full control over the load pathways, defaults the engine on the starter battery, and retains the option for an emergency parallel. But I'm not going to come by 3 on/off switches here, without putting in an order from the states, and patiently waiting. It would also greatly clutter the already small electrical panel.

A lot of the other advice offered in the links seems to be predicated on the assumption that the house bank is sufficient for starting the engine by itself, and that the starter/reserve is there mostly as a back-up. This isn't necessarily the case for our setup.

I do not know the CCA rating of our two 6V batteries (in series of course), but I do know that the engine struggles to crank off this bank by itself, unless loads are turned off, or there is a charge source present (like the sun). We've been in situations where we've had to start our engine quickly in the middle of the night to avoid dangerous situations, so that isn't ideal. For reference, our Beta 14 uses an 800W starter.

At this time, buying a different ACR, or a different switch configuration isn't really possible, so maybe my question should be more focused on what ill-effects do we face by starting in the "combined" position, other than the potential for human error (not switching back to the primary bank, or somehow switching to the OFF position).