dual battery solar charging and 1 2 both switch

[VicS]

The BEP switches mentioned - are these the ones? https://www.furneauxriddall.com/aca...th-Two-Dedicated-Battery-Banks-BEP_715_H.html They certainly seem the correct ones, already wired up, horizontal or vertical bank available. (a bit cheaper elsewhere)

Yes that is a pre"wired" cluster consisting of two isolators and an emergency paralleling switch

See the BEP catalogue for for the full range http://www.delzer.com/powerproducts/BEP_CAT_003/12/

There is a possible snag if these clusters are wired as shown is as much as the paralleling switch parallels the batteries rather than the circuits which means that a duff battery cannot be left isolated and everything run from the good one Easily wired though so that the circuits are paralleled rather than the batteries ( although they can be if both isolators are closed )

 

[FairweatherDave]

Okay, I have been getting my head around VSRs as I am going for the second option, ie keeping the 1 2 both and just using the solar charge controller on the domestic. The VSR allows solar charging of the engine battery once the domestic battery is full. I can do 40 quid inc postage for the Victron Energy Cyrix-ct 12/24V-120A intelligent battery combiner.

Back to how to use the beloved 1 2 both switch....This is obviously a basic question .......So leaving the switch on BOTH is a bad thing. So if I start the engine on 1, and run for a while before going to 2 is it harmful to swiftly pass through the Both setting? My understanding is you never pass through OFF while the engine is running as it knackers the alternator. I am guessing the answer is it not harmful to pass through Both as
1. prior to installing my solar it was a legitimate option for short term use
2. installing the solar charge on the domestic battery only means that is not an issue

The reason for asking is that obviously the 1 2 both could get accidentally to the Both position (it can get knocked), as well as you need to pass through Both to get from 1 to 2. Said it was a basic question

 

[RupertW]

Okay, I have been getting my head around VSRs as I am going for the second option, ie keeping the 1 2 both and just using the solar charge controller on the domestic. The VSR allows solar charging of the engine battery once the starter battery is full. I can do 40 quid inc postage for the Victron Energy Cyrix-ct 12/24V-120A intelligent battery combiner.

Back to how to use the beloved 1 2 both switch....This is obviously a basic question .......So leaving the switch on BOTH is a bad thing. So if I start the engine on 1, and run for a while before going to 2 is it harmful to swiftly pass through the Both setting? My understanding is you never pass through OFF while the engine is running as it knackers the alternator. I am guessing the answer is it not harmful to pass through Both as
1. prior to installing my solar it was a legitimate option for short term use
2. installing the solar charge on the domestic battery only means that is not an issue

The reason for asking is that obviously the 1 2 both could get accidentally to the Both position (it can get knocked), as well as you need to pass through Both to get from 1 to 2. Said it was a basic question

The Both position is designed to be passed through so you are fine. In fact if both batteries are similar type, age and charge level they can be left on Both whilst charging (but not discharging as you risk losing the ability to start the engine again). But there's a lot of manual judgement in using a 1:2:Both which can be avoided using the other options.

 

[BabaYaga]

Okay, I have been getting my head around VSRs as I am going for the second option, ie keeping the 1 2 both and just using the solar charge controller on the domestic. The VSR allows solar charging of the engine battery once the starter battery is full. I can do 40 quid inc postage for the Victron Energy Cyrix-ct 12/24V-120A intelligent battery combiner.

Assuming that you meant "once the domestic battery is full".... but this is still a misconception in my view. The VSR will close long before the domestic battery is full. I don't know exactly the set point for the Victron, but somewhere around 13.2 - 13.5V is common I think.
But if you are OK with slower solar charge in winter you will be fine.

 

[FairweatherDave]

Thanks both. Baba Yaga I've now edited my post and point taken about the speed of charging in the winter and VSRs. The reality is there will be long gaps over the winter between sails and I can imagine if I do "sail" over winter that it might involve a fair bit of motoring.......

 

[lw395]

Normal use of a 1B2 switch is to designate one battery as 'engine' and the other as 'house'. You may chop and change which is which.
When the engine is stopped the switch is set to 'house'.
To start the engine, you switch to 'engine' and start.
Then you switch to both while the engine is running, to charge both.
When you stop the engine, you switch to 'house'.

'Off' when you leave the boat
'Both' when the motor isn't keen to start on 'engine'.

It's a simple discipline that people lived with in ye olde days, like turning the gas off when you're not using it.

It isn't perfect, but no system is.


So you can carry on doing all that with a dual solar controller added, provided the controller is not damaged by connecting the two outputs together in the 'both' position. I would be checking this with the supplier if I were you.
Alternatively you can spend some more money to have a different system.
But If I were spending more money, I'd first be looking at more house bank capacity, if I didn't spend all my cash on sails and stuff like that.....
I would suggest lashing out a few beer tokens on a voltmeter or two if you don't have one?

 

[halcyon]

Assuming that you meant "once the domestic battery is full".... but this is still a misconception in my view. The VSR will close long before the domestic battery is full. I don't know exactly the set point for the Victron, but somewhere around 13.2 - 13.5V is common I think.
But if you are OK with slower solar charge in winter you will be fine.

Remember the VSR goes back to the days of 13.6 volt alternator regulation, so 13.5/13.55 was the highest voltage you were going to see on charge. The relay closes, maximizing the spread between cut in and drop out reduces the change of relay chatter. Drop voltage should be around 12.9 volt, which represents a flat battery re-charge voltage, below this you are not charging the battery.

It can be more complicated, but that's the basic.

Brian

 

[Poey50]

Thanks both. Baba Yaga I've now edited my post and point taken about the speed of charging in the winter and VSRs. The reality is there will be long gaps over the winter between sails and I can imagine if I do "sail" over winter that it might involve a fair bit of motoring.......

Assuming you have a mains charger, the occasional visit to a marina where you can charge batteries fully might be a good idea.

 

[RupertW]

Assuming that you meant "once the domestic battery is full".... but this is still a misconception in my view. The VSR will close long before the domestic battery is full. I don't know exactly the set point for the Victron, but somewhere around 13.2 - 13.5V is common I think.
But if you are OK with slower solar charge in winter you will be fine.

I'm in danger of learning something here - my alternator never seems to go above 13.3 volts - but (doh!) I have just realised as my monitor is based on the domestic bank and the VSR controls how the domestic bank chargers after (the almost instant) charging of the always full engine battery then the VSR could be the reason. Must look at my model to see what the settings and possible controls are.

 

[halcyon]

I'm in danger of learning something here - my alternator never seems to go above 13.3 volts - but (doh!) I have just realised as my monitor is based on the domestic bank and the VSR controls how the domestic bank chargers after (the almost instant) charging of the always full engine battery then the VSR could be the reason. Must look at my model to see what the settings and possible controls are.

!3.3 volt is to low, you need 13.6 minimum, check voltage at alternator output pins.

The VSR setting will not effect the voltage you see, this is a function of battery level and alternator.

Brian

 

[RupertW]

!3.3 volt is to low, you need 13.6 minimum, check voltage at alternator output pins.

The VSR setting will not effect the voltage you see, this is a function of battery level and alternator.

Brian

That was what I had thought until I read Baba Yaga's post above where he says that the VSR will close the domestic battery long before it is full - at 13.2-13.5V - which is exactly what I am seeing and had until then assumed I should be looking at the alternator and it's settings.

 

[halcyon]

That was what I had thought until I read Baba Yaga's post above where he says that the VSR will close the domestic battery long before it is full - at 13.2-13.5V - which is exactly what I am seeing and had until then assumed I should be looking at the alternator and it's settings.

The battery has three voltage levels for any capacity level, off load, on charge, or discharge. For example 50% no load ( settled ) is around 12.35v, on charge ( 10 hour rate ) 13.6v , on nominally 5% load 12 volt.

You start engine, voltage rises to say 13.6 volt, relay cuts in, now lets say service battery is 30%, voltage drops to around 13.2/13.3 v. This is set by service battery, engine battery is now below it's charge voltage, but above it's discharge voltage, so sits and does nothing. Service battery takes charge, voltage rises to 13.6 volts, engine battery now starts to take a charge as well. Both banks now take a charge depending on charge level, acting as one big battery bank.

Simple as that.

Brian

 

[RupertW]

The battery has three voltage levels for any capacity level, off load, on charge, or discharge. For example 50% no load ( settled ) is around 12.35v, on charge ( 10 hour rate ) 13.6v , on nominally 5% load 12 volt.

You start engine, voltage rises to say 13.6 volt, relay cuts in, now lets say service battery is 30%, voltage drops to around 13.2/13.3 v. This is set by service battery, engine battery is now below it's charge voltage, but above it's discharge voltage, so sits and does nothing. Service battery takes charge, voltage rises to 13.6 volts, engine battery now starts to take a charge as well. Both banks now take a charge depending on charge level, acting as one big battery bank.

Simple as that.

Brian

Again, that's exactly how I had seen it until Baba Yaga's post, so nothing to stop both batteries continuing to rise above 13.6 volts if that's what the alternator is set to put out. Hence my surprise reading that the domestic battery will not be able to rise above 13.2-13.5v due to the VSR. After the last two confirmations then normal knowledge is restored and I will go back to looking my alternator and (lack of) smart regulator requirements to get a fuller charge more quickly and start seeing up to 14.4v across the domestic bank as I do on mains charge.

 

[halcyon]

That was what I had thought until I read Baba Yaga's post above where he says that the VSR will close the domestic battery long before it is full - at 13.2-13.5V - which is exactly what I am seeing and had until then assumed I should be looking at the alternator and it's settings.

Should add 13.2-13.5 volt is no where near full, to fully charge a flooded lead acid battery you need 15.4/15.6 volt.

Once an alternator starts to regulate the voltage, say 13.6 volt, charge current will fall to a very low amperage, and will not recharge the battery any further.

Brian

 

[BabaYaga]

That was what I had thought until I read Baba Yaga's post above where he says that the VSR will close the domestic battery long before it is full - at 13.2-13.5V - which is exactly what I am seeing and had until then assumed I should be looking at the alternator and it's settings.

I think you might have misunderstood. What I meant to point out was that the VSR will close (close as in connect) the two banks together long before the first bank or battery is fully charged.
In the OP's case the first battery would be the domestic battery, as this is where the solar would be wired. If charging by alternator, the first battery in line is most often the engine battery (which as you say most likely already is fully charged).
I did not intend to say that the VSR would close the domestic battery off from the charging circuit.

 

[PaulRainbow]

Okay, I have been getting my head around VSRs as I am going for the second option, ie keeping the 1 2 both and just using the solar charge controller on the domestic. The VSR allows solar charging of the engine battery once the domestic battery is full. I can do 40 quid inc postage for the Victron Energy Cyrix-ct 12/24V-120A intelligent battery combiner.

Back to how to use the beloved 1 2 both switch....This is obviously a basic question .......So leaving the switch on BOTH is a bad thing. So if I start the engine on 1, and run for a while before going to 2 is it harmful to swiftly pass through the Both setting? My understanding is you never pass through OFF while the engine is running as it knackers the alternator. I am guessing the answer is it not harmful to pass through Both as
1. prior to installing my solar it was a legitimate option for short term use
2. installing the solar charge on the domestic battery only means that is not an issue

The reason for asking is that obviously the 1 2 both could get accidentally to the Both position (it can get knocked), as well as you need to pass through Both to get from 1 to 2. Said it was a basic question

You missed a key point in one of my previous posts Dave, glad you're going with the VSR, it'll be a better system than you have now.

key point/s..... the VSR will allow all batteries to be charged by the solar controller and the alternator. So no need to fiddle with the switch, all batteries will get charged whether the switch is on 1, 2 or Both. Please ignore anyone that says it's OK to leave the switch on "both", other than for an emergency start. It is not OK, certain conditions or battery failures can leave you with all of the batteries flat.

So, with the VSR fitted there are two very simple options for using the lovely 1-2-B switch :

1) Turn to 1, start engine, turn to 2. No need to wait on 1 for the engine battery to charge, it gets charged on 1,2, or B :encouragement:

2) Designate 1 as emergency engine start, but never use it. You select 2 and leave it there. Engine starting and all domestic function work from the "domestic bank", which should probably be mentally designated as "everyday use bank" or some such meaningful name So you use 2 all of the while, whilst 1 is sitting there, fully charge, just in case.

Those two options assume 1 is the engine battery, feel free to swap 1 and 2. Try both options and see which you prefer ?

 

[FairweatherDave]

Just sizing the cable for installing the Victron Energy Cyrix-ct 12/24V-120A intelligent battery combiner.
My alternator is rated for 40amps which I believe is what you base it on. The cable runs would be pretty short so I am thinking 6 or 8 AWG, which is 13.3 or 8.37 mm squared. The third little wire to the starter negative I'm not sure how to determine but in one post somewhere I read 1 mm squared (AWG 17). Feel free to confirm anyone?

 

[FairweatherDave]

You missed a key point in one of my previous posts Dave, glad you're going with the VSR, it'll be a better system than you have now.

key point/s..... the VSR will allow all batteries to be charged by the solar controller and the alternator. So no need to fiddle with the switch, all batteries will get charged whether the switch is on 1, 2 or Both. Please ignore anyone that says it's OK to leave the switch on "both", other than for an emergency start. It is not OK, certain conditions or battery failures can leave you with all of the batteries flat.

So, with the VSR fitted there are two very simple options for using the lovely 1-2-B switch :

1) Turn to 1, start engine, turn to 2. No need to wait on 1 for the engine battery to charge, it gets charged on 1,2, or B :encouragement:

2) Designate 1 as emergency engine start, but never use it. You select 2 and leave it there. Engine starting and all domestic function work from the "domestic bank", which should probably be mentally designated as "everyday use bank" or some such meaningful name So you use 2 all of the while, whilst 1 is sitting there, fully charge, just in case.

Those two options assume 1 is the engine battery, feel free to swap 1 and 2. Try both options and see which you prefer ?

Cheers Paul, I've got it. What I was exploring was if it accidentally got set on both. I was considering glueing an obstruction on the both setting but that would mean twiddling the knob via the off position to get from 1 to 2 which is not desirable. I often store stuff under the nav table/ on the floor in front of the quarter berth and the switch is vulnerable to being knocked.

 

[RupertW]

I think you might have misunderstood. What I meant to point out was that the VSR will close (close as in connect) the two banks together long before the first bank or battery is fully charged.
In the OP's case the first battery would be the domestic battery, as this is where the solar would be wired. If charging by alternator, the first battery in line is most often the engine battery (which as you say most likely already is fully charged).
I did not intend to say that the VSR would close the domestic battery off from the charging circuit.

I did misunderstand and have been soundly corrected by the others. Rereading your post that's the only thing that "close" could have meant, sorry.

 

[RupertW]

Should add 13.2-13.5 volt is no where near full, to fully charge a flooded lead acid battery you need 15.4/15.6 volt.

Once an alternator starts to regulate the voltage, say 13.6 volt, charge current will fall to a very low amperage, and will not recharge the battery any further.

Brian

Exactly my long term issue. I have capacity for all my needs and make enough through involuntary engine use but if I had a few days in a row where I was able to sail all day then the hour or so in and out of harbour would not be enough at the 1 or 2 amps I'm getting in at 13.3 volts.