Hi all

Boat has typical start and house battery set up.

4 position BEP battery switch and AVR.

Yesterday we had two flat batteries.

We took the house battery out but now with only the starting battery we still have house power when switch on house position.

Is it an incorrect switch wiring or something else?

I thought the point of the four position switch was to ensure the start battery can be isolated but that doesn't appear to be happening.

It seems we are always running off start battery.

Any corrections to my logic or understanding?

Do you have any power when switch is in the Starter battery position? If not, it may just be that house and starter cables were accidentally swapped at the switch connection.

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Bushdog said..
Do you have any power when switch is in the Starter battery position? If not, it may just be that house and starter cables were accidentally swapped at the switch connection.

Thanks Bushdog..no we defs have power to the starter when switch is in start position. Power to appliances when switch is in house position and house battery removed.

Rough sketch based on today's investigations.


Working on a neater sketch btw!

Updated pic

Not an expert with electrics (or refrigeration especially) but I would looking a fault in the engine switch (or left on) or the VSR.
No other way to get a circuit.
Shaggy the God will be long shortly.

Thanks Lydia.
Seems wiring is roughly right so yes mist be a fault?
The fridge is not functional btw.

I'm not sure whats typical about this system. If you need a keyed engine isolation switch it should be after the 4 position switch.

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Ramona said..
I'm not sure whats typical about this system. If you need a keyed engine isolation switch it should be after the 4 position switch.

Typical in the sense that it has a house and starting battery.

Not even sure we need the keyed engine isolator. Pic of similar isolator added for clarity.

This is the four position switch and keyed isolator in the boat btw.




Thanks!

I thought this was a good simple example
newwiremarine.com/how-to/wiring-a-boat/

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sparau said..
I thought this was a good simple example
newwiremarine.com/how-to/wiring-a-boat/

That is spot on. Even uses the same switch as I do. The start isolation switch is OK if you think you need some sort of security, I use a switch near the quarter berth that shuts off power to the starter button in the cockpit. It has to be wired in after the 4 position switch though. If I leave it on it does not make any difference when I leave the boat as the power from the batteries is off.
Having a key in a switch is handy if you remove it after sailing and hang it on the engine cooling seacock!

I suppose my main question is how do l have power to my house 'appliances' when the house battery is removed?

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Madmouse said..
I suppose my main question is how do l have power to my house 'appliances' when the house battery is removed?

I use a two battery system. Both batteries are actually start and house batteries. I just use them on alternate days. Both are on separate full time solar set ups. I can of course use both batteries at once using the rotary switch and I can remove any battery at any time.

I also have a completely separate third battery system just for the automatic bilge system. Solar panel ahead of the mast, controller below and a battery under the forward bunk, Water Witch switch and an 800gph pump on a fuse, no switch. This is carefully installed so there are no stray currents.

Sounds good Ramona..what sort of batteries are you using?

Sealed lead acid.

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Madmouse said..
I suppose my main question is how do l have power to my house 'appliances' when the house battery is removed?

From your drawing it appears that if you have your battery select switch to start it would make a circuit to the house positive leads?
Else if you have a multi meter or simply 2 wires and a 12v globe or a car elec test light with the stabby bit you could check the functionality of the unit, I seem to recall having a multi pole switch fail internally, once, long ago.

Yeah l with defs check that and maybe try removing the vsr and test it.

Hi Mad,
I remember Jode saying to toss VSRs as they are more for sensing low voltage. He had a dodgy VSR chew up his house batteries IIRC.
Just swap it out for an ACR, Use bus bars if pathways look likely to get messy.
Cheers!

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shaggybaxter said..
Hi Mad,
I remember Jode saying to toss VSRs as they are more for sensing low voltage. He had a dodgy VSR chew up his house batteries IIRC.
Just swap it out for an ACR, Use bus bars if pathways look likely to get messy.
Cheers!

Wow thanks Shaggy.

Since l have acquired a lithium house battery would you agree a dcdc charger would be the way to go?

In which case would it just replace the acr in the wiring diagram above?

If you have a lithium battery just select that setting on the solar controller. I'm not selling anything and I don't think there is any need for any of the extras. Start with a quality rotary switch and keep it simple. My race car had a lithium battery and it charged from an ordinary automotive alternator. I replaced it with an Odyssey AGM dry battery after the positive terminal broke free. It's fixed now and I use it as a jump start battery. I charge it with a $5 charger from a garage sale.

Ramona what l have been reading about lithium says they 'sort of' charge off an alternator but not to the full extent.

Hard to sort the truth from the sales pitch out there l agree!

A mppt solar charger dcdc charger seems like a good investment tho.

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Madmouse said..
Ramona what l have been reading about lithium says they 'sort of' charge off an alternator but not to the full extent.

Hard to sort the truth from the sales pitch out there l agree!

A mppt solar charger dcdc charger seems like a good investment tho.

Gday Mad,
yep, dc-dc charger would fit lithium and lead acid perfectly.
cheers!

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Madmouse said..
Wow thanks Shaggy.

Since l have acquired a lithium house battery would you agree a dcdc charger would be the way to go?

In which case would it just replace the acr in the wiring diagram above?

Definitely go with the DC-DC charger - well worth the investment & your batteries will thank you for it!!

I went with one that I can run my solar panels through as well as the two battery banks. The peace of mind knowing my batteries are safe & getting the absolute maximum charge is sooooo goooood!!!

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Definitely go with the DC-DC charger - well worth the investment & your batteries will thank you for it!!

I went with one that I can run my solar panels through as well as the two battery banks. The peace of mind knowing my batteries are safe & getting the absolute maximum charge is sooooo goooood!!!

Agree! Bought one today complete with an mppt solar input so can't see how that is bad.

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Madmouse said..

Definitely go with the DC-DC charger - well worth the investment & your batteries will thank you for it!!

I went with one that I can run my solar panels through as well as the two battery banks. The peace of mind knowing my batteries are safe & getting the absolute maximum charge is sooooo goooood!!!

Agree! Bought one today complete with an mppt solar input so can't see how that is bad.

I agree dc- dc charger, save the stooging about. And if you have a 24v start and a 12v house it's makes it so easy