Battery issues.

coopec said:
Right now I am setting up my battery bank and starting system batteries. I've just bought a Dual Battery Controller switch. Is it possible to switch from battery 1 to battery 2 and then Both in series. Wouldn't that be handy as a last resort?

Clive
Click to expand...

The both position connect both battery banks in parallel, not series.

Separate switches are better, why choose between the engine battery or the domestics ? Why not have one switch to turn the single, dedicated engine battery on/off and another for the domestics ? Add a 3rd switch for emergency starting and a split charge system. Simple, turn up, switch on, use boat, turn off, go home. None of this nonsense messing around switching from battery to battery, making sure you remember to charge both banks etc
 
Paul

Thanks for you response.

My problem is that I have
- a domestic bank of x2 135AH batteries = 24V
- my alternator is 24V
- my starter motor is 12V

I thought maybe I could have x2 engine (12v) engine batteries in series and charge them with the 24V alternator but only use one at a time to start the motor. The alternative is to put 24V through the starter motor which the experts say is not a problem.

I'll have another look at what you are suggesting too.

Clive
 
coopec said:
Paul

Thanks for you response.

My problem is that I have
- a domestic bank of x2 135AH batteries = 24V
- my alternator is 24V
- my starter motor is 12V

I thought maybe I could have x2 engine (12v) engine batteries in series and charge them with the 24V alternator but only use one at a time to start the motor. The alternative is to put 24V through the starter motor which the experts say is not a problem.

I'll have another look at what you are suggesting too.

Clive
Click to expand...

You could ;

Fit an on/off switch for the domestics and connect the alternator straight to that bank.

Fit a single 12v starter battery, with its own on/off switch.

Fit a battery to battery charger to charge the engine battery from the domestic bank.

Any additional charging sources, (mains, solar etc ) would connect to the domestic bank only.

Fit a 3rd switch to parallel one of the domestic batteries to the starter battery for emergency use.

If you fit a 1-2-B switch with your current configuration it won't work with a single battery, when you switch to the starter battery none of the domestic circuits would work. When you switch to the domestic bank the starter would be getting 24v.

If you fitted two engine batteries in series and only used one to start the engine you'd need additional switching. The 1-2-B could be used to select the engine bank, but you'd need another 1-2-B to select which battery was going to be used.
 
Crikey lots to think about, thanks all. Interesting that I've been mis-managing the battery switch. I'll give that some thought. I quite like having a simple switch, so I *may* leave that in place but add a split charge system, which should be cheap and easy to do. At least then all I need to worry about is switching the engine battery on to start and flicking to domestic as soon as we stop.

I think the alternator is probably fine, although I will check the output next time I'm at the boat. The domestic battery took a massive hammering and my Ctek charger seems to be struggling to bring it back to life - mind it is a quite a hefty battery, so it may yet live to tell the tale. But that probably explains why the voltage at the battery terminals seemed so low.

As for solar - that may well have to wait as I need to spend money in other (more vital) areas soon, but points are well noted regarding shade and the like.

Points regarding the revcounter feed also noted, thank you. The alternator needs to come off soon anyway because I want access to the heat exchanger tubes and need to get behind the alternator, so I'll combine the two jobs and ensure that all terminals on the alternator are thoroughly cleaned before refitting.

By the way, I am in Devon and have access to a battery tester which I can borrow from work, but thanks for any offers of help - much appreciated. I am trying to dredge up basic physics from school lessons half a lifetime ago, so I'll probably continue to ask completely bone questions.
 
Balbas said:
I quite like having a simple switch, so I *may* leave that in place but add a split charge system, which should be cheap and easy to do. At least then all I need to worry about is switching the engine battery on to start and flicking to domestic as soon as we stop.
Click to expand...

This thread is doing a good job of highlighting how rubbish the 1-2-B switch is in this modern age of electrics on boats. It clearly isn't the simple switch you think it is, no disrespect intended.

Normal practice is to start the engine and then switch to the domestics. If you do as you say, and you're sailing, when you arrive at your destination the engine battery will be discharged to some point, you then switch to the domestic bank and discharge that to some degree too. Will the engine start ? Will it start on the "both" setting ?

If you must keep the 1-2-B switch, fit the VSR and only use the engine battery for starting the engine, then switch to the domestic batteries.

I really do struggle to comprehend the thinking that a 1-2-B switch is a "simple switch" as opposed to a pair of on/off switches that keep both battery banks fully isolated from one another at all times by just turning them on when you arrive and off when you leave. :confused:
 
PaulRainbow said:
This thread is doing a good job of highlighting how rubbish the 1-2-B switch is in this modern age of electrics on boats. It clearly isn't the simple switch you think it is, no disrespect intended.

Normal practice is to start the engine and then switch to the domestics. If you do as you say, and you're sailing, when you arrive at your destination the engine battery will be discharged to some point, you then switch to the domestic bank and discharge that to some degree too. Will the engine start ? Will it start on the "both" setting ?

If you must keep the 1-2-B switch, fit the VSR and only use the engine battery for starting the engine, then switch to the domestic batteries.

I really do struggle to comprehend the thinking that a 1-2-B switch is a "simple switch" as opposed to a pair of on/off switches that keep both battery banks fully isolated from one another at all times by just turning them on when you arrive and off when you leave. :confused:
Click to expand...
Now I'm confused. If I fit a split charge system, my understanding (from the enforced touring caravan holidays I was subjected to as a child!) is that it will charge the primary battery first, then when that is full it will shift the charge to the secondary bank (so in touring caravan parlance, the cars alternator will charge the car battery first, then shift the charge to the caravan battery).


Thus, if I board the boat, switch to 'engine battery', flash up the motor and pootle around for a bit, the alternator will top off the engine battery and then stick some charge into the domestics. Or am I missing something?
 
Balbas said:
Now I'm confused. If I fit a split charge system, my understanding (from the enforced touring caravan holidays I was subjected to as a child!) is that it will charge the primary battery first, then when that is full it will shift the charge to the secondary bank (so in touring caravan parlance, the cars alternator will charge the car battery first, then shift the charge to the caravan battery).


Thus, if I board the boat, switch to 'engine battery', flash up the motor and pootle around for a bit, the alternator will top off the engine battery and then stick some charge into the domestics. Or am I missing something?
Click to expand...

The VSR will basically close when it senses the alternator voltage, despite the marketing claims to the contrary. So any time the engine is running all batteries will be in parallel and be getting some charge from the alternator.

But when you're sailing the alternator won't be charging, if the switch is still set to the engine battery whatever equipment you are using will be drawing power from the engine battery. Suppose you discharge the battery to the point where it won't start the engine, but it runs the electrics that are turned on, you then arrive at an anchorage and drop the hook, switching to the domestic bank. You stay there long enough to deplete the domestic bank to the point where it too won't start the engine.

What now ?

Best bet with the 1-2-B is to use the engine battery for what it says on the tin, starting the engine, then get it onto the domestic bank. Better bet, feed the switch to the fish and fit separate switches.
 
Last edited:
Right, so now I'm proper confused. Especially after a chat with a guy at work who has an adverc system fitted to his contessa.

So as I'm still thinking about adding solar at some point in the future. In which case would I be better with something like https://www.plymouthbattery.co.uk/type/marine/ctek-marine/ctek-d250s-dual-d-c-charger or would the FET system advised earlier be the best bet? I'm not in the habit of spending money unless I have to, but then again I hate spending money twice.
 
Balbas said:
Right, so now I'm proper confused. Especially after a chat with a guy at work who has an adverc system fitted to his contessa.

So as I'm still thinking about adding solar at some point in the future. In which case would I be better with something like https://www.plymouthbattery.co.uk/type/marine/ctek-marine/ctek-d250s-dual-d-c-charger or would the FET system advised earlier be the best bet? I'm not in the habit of spending money unless I have to, but then again I hate spending money twice.
Click to expand...

You are indeed confused :) Let me try to break it down for you. Firstly, forget about Adverc systems, it'll only confuse you more. You have a number if different issues, which you are mixing up.

Switching. My opinion is that the 1-2-B switch has had its day. Separate switches are the way to go and i fit a lot of them. The domestic and engine battery switches turn on the respective circuits, whilst keeping each circuit isolated from the other. Discharging the domestic battery bank will not effect the engine starting battery. In everyday use just turn the domestic switch on when you arrive at the boat, the engine switch on when you want to use the engine and turn them both off when you leave the boat to go home. You can turn the engine switch off when you have finished with the engine, or you can leave it on until you want to go home, it makes no difference either way.

The Emergency Combine switch should normally be left in the Off position. When it is turned to the On position it parallels the engine battery and the domestic bank, so they are effectively a single bank. Should the engine battery fail to start the engine this switch can be turned on, allowing the engine to be started from the domestic bank. It should be turned back off as soon as the engine has started.

Battery charging. You mention the mains charger or the FET system. It is not an either or choice. Each device serves a different purpose. If you want to charge the batteries from shore power you need a mains charger, if you want to have both batteries on charge when the engine is running you need a split charge device. There are a few ways to do both, depending on various factors. For your needs i would suggest two alternative systems.

1) Fit a Victron Cyrix 120a VSR. This will close when it senses a charging voltage at either battery, closing to parallel the batteries and ensure both get charged. You would then leave the alternator connected to the start battery, whilst connecting a single output mains charger and the solar controller to the domestic bank. No matter which device is charging the relay will close and charge all batteries.

2) Fit a Victron ArgoFET split charge device to the alternator, this makes sure both batteries get charged when the engine is running. Fit a mains charger with two outputs to keep everything charged up when in the marina. When you fit solar you need to fit a dual output controller or fit a 10w panel to keep the engine battery topped up when away from the boat and a bigger one for the domestics.

I would suggest, given the information you have provided, that option one would best suit you needs.
 
PaulRainbow said:
You are indeed confused :) Let me try to break it down for you. Firstly, forget about Adverc systems, it'll only confuse you more. You have a number if different issues, which you are mixing up.

Switching. My opinion is that the 1-2-B switch has had its day. Separate switches are the way to go and i fit a lot of them. The domestic and engine battery switches turn on the respective circuits, whilst keeping each circuit isolated from the other. Discharging the domestic battery bank will not effect the engine starting battery. In everyday use just turn the domestic switch on when you arrive at the boat, the engine switch on when you want to use the engine and turn them both off when you leave the boat to go home. You can turn the engine switch off when you have finished with the engine, or you can leave it on until you want to go home, it makes no difference either way.

The Emergency Combine switch should normally be left in the Off position. When it is turned to the On position it parallels the engine battery and the domestic bank, so they are effectively a single bank. Should the engine battery fail to start the engine this switch can be turned on, allowing the engine to be started from the domestic bank. It should be turned back off as soon as the engine has started.

Battery charging. You mention the mains charger or the FET system. It is not an either or choice. Each device serves a different purpose. If you want to charge the batteries from shore power you need a mains charger, if you want to have both batteries on charge when the engine is running you need a split charge device. There are a few ways to do both, depending on various factors. For your needs i would suggest two alternative systems.

1) Fit a Victron Cyrix 120a VSR. This will close when it senses a charging voltage at either battery, closing to parallel the batteries and ensure both get charged. You would then leave the alternator connected to the start battery, whilst connecting a single output mains charger and the solar controller to the domestic bank. No matter which device is charging the relay will close and charge all batteries.

2) Fit a Victron ArgoFET split charge device to the alternator, this makes sure both batteries get charged when the engine is running. Fit a mains charger with two outputs to keep everything charged up when in the marina. When you fit solar you need to fit a dual output controller or fit a 10w panel to keep the engine battery topped up when away from the boat and a bigger one for the domestics.

I would suggest, given the information you have provided, that option one would best suit you needs.
Click to expand...

Thanks. Couple of points

1) We're on trots, not in a Marina, so shorepower is a rare luxury
2) I understood the CTek device to not be a mains charger, but similar system to the Victron Fet, with the added benefit of a second input (solar plus alternator), have I got that wrong?
 
Balbas said:
Thanks. Couple of points

1) We're on trots, not in a Marina, so shorepower is a rare luxury
2) I understood the CTek device to not be a mains charger, but similar system to the Victron Fet, with the added benefit of a second input (solar plus alternator), have I got that wrong?
Click to expand...

Sorry, only glanced at the Ctek and thought it was a mains charger, so forget mains charging then.

It's not the same as the Victron ArgoFET, the ArgoFET takes the output from the alternator an splits it between the two battery banks, whilst keeping them separate.

So, the ArgoFET or the Cyrix VSR will both give you split charging.

Re-wording my original post :

1) Fit a Victron Cyrix 120a VSR. This will close when it senses a charging voltage at either battery, closing to parallel the batteries and ensure both get charged. You would then leave the alternator connected to the start battery, whilst connecting a solar controller to the domestic bank. No matter which device is charging the relay will close and charge all batteries.

2) Fit a Victron ArgoFET split charge device to the alternator, this makes sure both batteries get charged when the engine is running. When you fit solar you need to fit a dual output controller or fit a 10w panel to keep the engine battery topped up when away from the boat and a bigger one for the domestics.
 
Interestingly I popped down to the boat yesterday. The domestics are off for charging / bring back to life with an intelligent charger, so I just had the engine battery on. Flashed up the motor and immediately was getting 14.5v out of the alternator. So I can assume that my alternator isn't goosed and that it was my mis-management of the battery switch, combined with the domestic being completely dead, which led to the voltage at the terminals showing up as only being 12.5v.

Steps I'm taking to prevent the same re-occurring will be:

1) Fit a Victon Argo FET
2) Fit a 2nd domestic battery
3) Start on engine then immediately switch to domestic using the 1-B-2 switch
4) Fit the following on my coachroof with a suitable charge controller http://www.lensunsolar.com/Flexible-solar-panel/Black-flexible-solar-panel?product_id=209 (unless anyone tells me it's rubbish)
5) Fix the on-board Danfoss electric fridge rather than relying on an electric coolbox/fridge run off the accessory socket.
6) Replace all on-board light bulbs with LEDs (inc navigation lights)

We have minimal requirement for electricity aside from the fridge, so hopefully that will sort the issues.

Thanks for all of the help and advice.
 
Balbas said:
Interestingly I popped down to the boat yesterday. The domestics are off for charging / bring back to life with an intelligent charger, so I just had the engine battery on. Flashed up the motor and immediately was getting 14.5v out of the alternator. So I can assume that my alternator isn't goosed and that it was my mis-management of the battery switch, combined with the domestic being completely dead, which led to the voltage at the terminals showing up as only being 12.5v.

Steps I'm taking to prevent the same re-occurring will be:

1) Fit a Victon Argo FET
2) Fit a 2nd domestic battery
3) Start on engine then immediately switch to domestic using the 1-B-2 switch
4) Fit the following on my coachroof with a suitable charge controller http://www.lensunsolar.com/Flexible-solar-panel/Black-flexible-solar-panel?product_id=209 (unless anyone tells me it's rubbish)
5) Fix the on-board Danfoss electric fridge rather than relying on an electric coolbox/fridge run off the accessory socket.
6) Replace all on-board light bulbs with LEDs (inc navigation lights)

We have minimal requirement for electricity aside from the fridge, so hopefully that will sort the issues.

Thanks for all of the help and advice.
Click to expand...

All looks OK to me, apart from leaving the 1-2-B switch of course :)

Regardless, a big improvement on what you had.
 
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