windlass battery

[Storyline]

We have 3 x 105ah sealed batteries for our domestic supply. Not true deep discharge but quite good quality Delco Freedom type. A heavy duty truck type battery is used for engine starting.

I have wired our windlass (Lewmar 1000w) to the engine start battery and when operating it I make sure the battery selector switch is switched to battery 1 (engine).

I have noticed that when the windlass is under heavy load, for example when the Rocna is fully buried, the chart plotter switches itself off. I presume the windlass is pushing the battery capacity to the max. I do try to minimise the strain by using the boat to pull out the anchor.

Would I be better to move the windlass off the engine battery to the house bank or would the load be too much for them ?

 

[pvb]

It would be much better to run the windlass off the domestic bank, which should normally be under charge from the engine when you're using the windlass anyway.

Interesting that your plotter is run from the start battery - most people have the engine battery dedicated to starting only.

 

[omega2]

Start your engine first and use the engine/boat to assist always a good idea, the "toys" can be switched on later. Our set up switches everything off, when starting let alone winching.

 

[Cloven]

It would be much better to run the windlass off the domestic bank, which should normally be under charge from the engine when you're using the windlass anyway.

Interesting that your plotter is run from the start battery - most people have the engine battery dedicated to starting only.

Agree with this or alternatively have a small dedicated windlass battery such as a Red Flash close to the windlass and then all you need is lightweight wiring to charge it

 

[nigelmercier]

... I have wired our windlass (Lewmar 1000w) to the engine start battery ... I have noticed that when the windlass is under heavy load ... the chart plotter switches itself off...

So your instruments are wired to the start battery? Why?

 

[Storyline]

.....

Interesting that your plotter is run from the start battery - most people have the engine battery dedicated to starting only.

I have always assumed that the battery selector switch just switches the engine charging. When battery 1 is selected all the electrics on the boat still work.

nb
1. I inherited the wiring from the previous owner (apart from the windlass which I installed myself).
2. I have no detailed knowledge of electrical wiring - I know the basics but am a classic case of a little knowledge is a dangerous thing
E dit - this has got me thinking. I can see that the plotter should not be affected by the windlass if the windlass is wired to battery 1. Maybe I have forgotten and the windlass is connected to battery 2 in which case this thread is pointless. Damm, I am intrigued now and the boat is 250 miles away - how frustrating !

 

[awol]

If you have a 1/2/Both switch I would recommend running the engine and using the"Both" position for the anchor windlass.

 

[JumbleDuck]

I have always assumed that the battery selector switch just switches the engine charging. When battery 1 is selected all the electrics on the boat still work.

Normally the 1-2-Both Switch connects whichever you choose to everything ie. 1 charges and supplies, 2 charges and supplies or both charge and supply. Yours might be wired differently, of course. Do your electrics work when the switch is in the off position?

 

[Storyline]

Just for clarification - in a 'normal' setup should all the electrics on the boat work with the battery selector switch in position 1 (engine battery) ?

 

[Storyline]

Normally the 1-2-Both Switch connects whichever you choose to everything ie. 1 charges and supplies, 2 ch charges and supplies or both charge and supply. Yours might be wired differently, of course. Do your electrics work when the switch is in the off position?

No, the electrics do not work when the battery switch is set to off. I still cannot grasp why Pete said the plotter should not be affected when operating the windlass when switch 1 is selected and I am using the windlass. The plotter works when I am on battery 1. I am probably missing something so simple and obvious - age, early morning a slight hangover !

 

[prv]

No, the electrics do not work when the battery switch is set to off.

In that case it would seem that you have a conventional 1-2-both setup and so the idea of anything being wired to a particular battery is nonsense. Everything (both the charging and the consumption) applies to whichever battery you've selected, and the other is idle.

Pete

 

[nigelmercier]

In that case it would seem that you have a conventional 1-2-both setup and so the idea of anything being wired to a particular battery is nonsense.

That's me told off then

Sorry, I keep forgetting that a 0-1-2-B switch is a master switch. But surely if the engine is running, as I assume it would be when using the windlass, then you should be on 2?

 

[pvb]

Sorry, I keep forgetting that a 0-1-2-B switch is a master switch. But surely if the engine is running, as I assume it would be when using the windlass, then you should be on 2?

And people keep challenging me when I say that 1-2-Both switches are confusing and that there are much simpler solutions!

 

[prv]

Sorry, I keep forgetting that a 0-1-2-B switch is a master switch. But surely if the engine is running, as I assume it would be when using the windlass, then you should be on 2?

Depends entirely on what is wired where - on many boats 2 is the domestic bank. But in any case, the conventional approach is to select Both as soon as the engine is running, to charge both batteries (although some people have other habits).

Pete

 

[William_H]

With 3 batteries for demestic and a separate truck battery for starting I presume that the engine start battery is on one position ie 1 or2 and the 3 domestic batteries are on the other position. The switch is use to isolate all power off when you leave the boat. As said we would expect all electrics to be connected to the switch ie engine start charging and domestic loads. These are then switched to either 1 or 2 ie engine start battery or domestic battery. if as you say the winch is connected to the engine battery this may be a mistake and the winch would norally be connected to the switch for connection to either battery. If you go to both position then all batteries are in parallel.
Firstly you do need to investigate and understand just what is connected to what.
I would suggest that a better system might be to throw away the switch. Connect the truck battery to the engine charge and start circuits and winch via an isolation switch.
Put all other loads instrrument and domestic on the 3 batteries via an isolation switch. Fit a Voltage Sensing Relay to connect both battery sytems together when engine is charging or fit another high current switch between the 2 batteries for charging. (and emergency start)
With a VSR with engine running the domestic battery with plotter operating from it will be on charge. With the winch on the engine battery the great load when winching will partially be supported by the alternator but if the voltage drops then the VSR will disconnect so that instruments are isoalted from the big volt drop as they are running purely on domestic battery (which is not being charged.) good luck olewill

 

[Storyline]

Thanks olewill a clear explanation

 

[KellysEye]

The battery should a cranking one and be dedicated to the winch as close to the winch as possible or you will need heavy duty cable to stop current drop. Ours was in a box under the forward berth 75 CCAs .

 

[Storyline]

The battery should a cranking one and be dedicated to the winch as close to the winch as possible or you will need heavy duty cable to stop current drop. Ours was in a box under the forward berth 75 CCAs .

Thanks KE. The windlass is already installed and it is connected with very heavy cable back to the battery compartment. I plan to move the connection from the engine start battery over to the house supply as there are a lot more ah's there and the batteries are not true deep discharge so should take the load.

 

[Talulah]

Just to add to the confusion here is our set up.
Two banks.
The normal engine bank comprises of 2 105Ah batteries wired in parallel.
The domestic bank comprises of 3 deep cycle AGM 105Ah batteries wired in parallel.

The 1-2-Both-Off switch is purely used to decide which battery bank starts the engine. Nothing else.
Normally bank 1 (the engine battery) is used but if it fails the domestic bank can be used.
The only time bank 1 knows about bank 2 is if the switch is in the both position.

Bank 1 is also used for Windlass and Bow Thruster. These requiring large amounts of CCA'a but not for long periods.
Bank 2 has everything else. Lights, Electronics, Fridge etc.

Charging
Domestic bank can be charged by shore power charger or alternator.
Engine bank can only be charged by alternator.
Now in our case we have 2 alternators. One for each bank.
If we only had 1 alternator I would use a VSR to charge the domestics off the main engine battery alternator.

The main concerns I have are people switching the 1/2/Both/Off switch to off when the engine is running and blowing the alternator diodes. In the above setup it doesn't matter if the switch is turned to off as the switch does not cut off the output from the alternators. (As stated above it is only relevant for engine starting.)

The other concern I have is how much output the Alternator would chuck out if it only senses the engine battery voltage.
In most setups the engine battery is nearly always fully charged. If the alternator is sensing a high engine battery voltage it is not going to be chucking out much to recharge a depleted domestic bank.

I understand the way in which we are using the 1/2/Both/Off switch is more commonly found in American boats and not that common this side of the pond where the 1/2/Both/Off is also relevant for charging.

 

[BabaYaga]

The other concern I have is how much output the Alternator would chuck out if it only senses the engine battery voltage.
In most setups the engine battery is nearly always fully charged. If the alternator is sensing a high engine battery voltage it is not going to be chucking out much to recharge a depleted domestic bank.

I might well be wrong, but this is my view: If the fully charged engine battery is paralleled with a depleted domestic bank, by VSR or switch, the alternator sensing wire at the engine battery will sense a much lower voltage than if the domestic bank had been isolated from the charging circuit. So as long av the banks are paralleled the alternator will not be held back (until the point where the domestic bank reaches absorption voltage).