Lithium battery with Sargent split Charge??

[iain26]

Our Lead Acid batteries have given up the ghost so 2 new lithiums are on order.
Our electric system is all Sargent as fitted in the Autotrail’s.
The PX300 battery charger is being left in place for now as we are hoping we will not need a lot of plugging in.
The original 100w solar panel is set up to charge the engine battery only.
The 2 x 120w retrofitted panels go through an Epever MPPT controller direct to the leisure batteries and will be set with a Lithium profile.
There is no B2B or Battery Master etc fitted however the Sargent controller has a split charge system that charges both Engine battery and Leisure batteries when the engine is running. I don’t believe this is modern enough for it to be a smart alternator. (2014 model)

The question is does anyone have any experience of dropping in Lithium is place of LA as far as the split charger is concerned - will it work or cause issues if it isn’t disabled?

I know the mains charger is not ideal but that will get changed at a later date if we find we need to.

Thanks
Iain

 

[MichaelT]

We just dropped one in our last van, changed solar to lithium profile and charger to gel. All worked fine as we didn't have smart alternator.

Lots will be on here soon saying you need a B2B (which is a good idea) and there's no such thing as a drop in but can only tell you what I did.

 

[Insider]

I also have a Sargent control unit, EC400 I think and the PX300. I put in a relay to turn off the split relay when ignition on and fitted a B2B. If you're interested I can dig out the wiring diagram

 

[iain26]

I also have a Sargent control unit, EC400 I think and the PX300. I put in a relay to turn off the split relay when ignition on and fitted a B2B. If you're interested I can dig out the wiring diagram

Can I ask why?
Did you expect the split relay to not work or you needed a B2B to cover when your motorhome is in storage or not being used?
Certainly interested in the wiring if you can find it.

 

[MichaelT]

Can I ask why?
Did you expect the split relay to not work or you needed a B2B to cover when your motorhome is in storage or not being used?
Certainly interested in the wiring if you can find it.

B2B only works when engine running.

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[iain26]

B2B only works when engine running.

Can I ask which B2B?

 

[Just smiffy]

Can I ask why?
Did you expect the split relay to not work or you needed a B2B to cover when your motorhome is in storage or not being used?
Certainly interested in the wiring if you can find it.

You mean battery master..?

 

[MichaelT]

Can I ask which B2B?

On new van orion xs 50a, didn't have one on old van.

 

[Cush]

If your lithium battery stops accepting charge because it hits the cell full voltage, the alternator can be affected although your lead acid starter battery may be able to deal with the instant surge of power that is no longer going to you leisure batteries. A b2b will charge on the popular lithium profile and protect your alternator. Do you know what charge your alternator can put out? I have an autotrail and for the amount of charge I get (5 amps / hour) it may be as well disabling it and letting solar do its business.

 

[iain26]

Does anyone know how to disable the leisure battery side of the Split relay while still allowing it to charge the starter battery?
Is that a sensible compromise?

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[autorouter]

Does anyone know how to disable the leisure battery side of the Split relay while still allowing it to charge the starter battery?
Is that a sensible compromise?

The split charge relay has no effect on the starter battery charging. The starter battery is permanently connected to the alternator, and is never disconnected from it, so the alternator can always charge the starter battery when the engine is running.

The split charge relay connects the starter battery and the leisure battery together when the engine is running, so that the alternator can charge both the starter and leisure batteries. When the engine stops the split charge relay disconnects the leisure battery from the starter battery. The starter battery remains connected to the alternator.

So the split charge relay never allows the leisure battery to charge the starter battery.

A device called a battery maintainer, of which the BatteryMaster is a good example, can be permanently connected between the leisure battery and the starter battery. It will allow a small trickle charge from the leisure battery to the starter battery if the starter battery voltage drops to about half a volt below the leisure battery voltage. So if for example the leisure battery is being charged by the solar panels, its voltage will rise to 14V or more, and the battery maintainer will send a trickle charge to the starter battery.

 

[iain26]

So my thinking so far.
There is a risk that when the engine is running that the Lithium gets fully charged and so charging is stopped. This could result in a spike that the starter battery will need to absorb. But the alternator is not a smart alternator so this could be minimal and not actually cause any issues?
Disconnecting the Leisure side of the split charge relay would prevent this issue and would still allow the engine to charge the starter battery.
Fitting something like a Orion XS seems a little overkill and seems primarily aimed at Smart alternators.

Fitting a Battery maintainer is probably not a good idea as these work when the engine is not running and I have 2 seperate solar systems, one on the engine battery and one for the leisure batteries. A maintainer may possibly get confused with this as will the solar controllers.

I should add we are FT so the van is never in storage or unattended for any length of time.

Happy to be educated .
And thanks for the ideas so far.

Iain

 

[autorouter]

There is a risk that when the engine is running that the Lithium gets fully charged and so charging is stopped. This could result in a spike that the starter battery will need to absorb. But the alternator is not a smart alternator so this could be minimal and not actually cause any issues?

I'm not convinced this is an issue at all. When the alternator is running, things get switched on and off all the time and it doesn't cause any problems. The lights, wipers, fans etc for a start. With a battery what usually happens is the amps gradually reduces as the battery gets near its fully charged voltage, so the switching transient when it becomes full is minimal. Provided the starter battery remains connected across the alternator, it is fine for absorbing the occasional transient spike.

 

[Insider]

Can I ask why?
Did you expect the split relay to not work or you needed a B2B to cover when your motorhome is in storage or not being used?
Certainly interested in the wiring if you can find it.

A B2B only works when the engine is running. I think you are referencing a Battery Master which trickle charges the vehicle battery typically from excess solar while the vehicle is not being used.

From my understadning there are a couple of reasons to use a B2B when you have a split relay and are considering Lithium

1: Lithium batteries have very little internal resistance and so will take as much charge as your alternator can throw at it and thus you risk damaging your alternator.

2: A split relay sees both batteries as a single battery from a charging point of view and is certainly not smart in turns of charging. While this might be acceptable when both batteries are lead acid it is not great when you have different battery chemistry. A lithium requires specific charging voltages when a B2B is speced to provide.

3: The wiring in the majority of vans with split charge relays is not great resulting in a significant voltage drop at the leisure battery. Fitting a B2B is typically done in conjunction with fitting new cabling to allow for more efficient charging of the leisure.

If you do decide to fit a B2B then the split charge relay should be disabled while the B2B is active thus avoiding competition between them. How ever to permanetnly disable the split charge relay may cause issues when the vechile is turned off. It certainly did in my van with the EC400. Thus I fitted a relay which allows the split charge relay to act normally and only be disconnected when the engine is running. Diagram below should explain.

 

[Boxerman]

I also have a Sargent control unit, EC400 I think and the PX300. I put in a relay to turn off the split relay when ignition on and fitted a B2B. If you're interested I can dig out the wiring diagram

Hi there, I would be very interested in your wiring diagram if you don't mind. I have the Sargent ec400 fitted and I'm currently fitting a b2b charger for my new lithium batteries. I would like to disable the split charge without causing any further problems.
Many thanks...Allan

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[Insider]

Allan - see my last post in this thread - #14. That shows you where to break into the EC400. I can send you on pics etc if you contact me directly. I downloaded the circuit diagram of the ec400 from the Sargent website and used that in conjunction with the above diagram to install the B2B.

 

[Boxerman]

Relay: 12V 40A Change Over Diode Relay With Moulded Bracket

12V 40 A Change Over Diode Relay With Moulded Bracket Type: 5 Pin Changeover Mini Relay with Diode Protection Voltage: 12V Load: Continuous - 40A Peak - 40A Bracket Type: None Terminals Sizes: 5 x 6.3mm

www.splitcharge.co.uk

Insider....

Would this be a suitable relay to fit that would allow me to disable the split charge whilst driving?

 

[Insider]

Relay: 12V 40A Change Over Diode Relay With Moulded Bracket

12V 40 A Change Over Diode Relay With Moulded Bracket Type: 5 Pin Changeover Mini Relay with Diode Protection Voltage: 12V Load: Continuous - 40A Peak - 40A Bracket Type: None Terminals Sizes: 5 x 6.3mm

www.splitcharge.co.uk

Insider....

Would this be a suitable relay to fit that would allow me to disable the split charge whilst driving?

I would think so.

This is what I used

Mini Change Over Relay - 12V 30/40A - With Diode

Durite 12V 30/40A standard/mini changeover relay with diode and 6.3mm blade terminals in type B configuration. Includes detachable metal bracket.

www.12voltplanet.co.uk

For some reason Sargent fed both the positive and negative in on 2 cables each so I also had to use a spade connector of the type below

6.3mm Blade Terminal Splice Connectors | 12 Volt Planet

Blade Terminal Splice Connectors from 12 Volt Planet. Splice connectors featuring 6.3mm blade terminals encased in a PVC cover- various configuratons. Suitable for automotive & marine wiring applications

www.12voltplanet.co.uk

 

[Boxerman]

I would think so.

This is what I used

Mini Change Over Relay - 12V 30/40A - With Diode

Durite 12V 30/40A standard/mini changeover relay with diode and 6.3mm blade terminals in type B configuration. Includes detachable metal bracket.

www.12voltplanet.co.uk

For some reason Sargent fed both the positive and negative in on 2 cables each so I also had to use a spade connector of the type below

6.3mm Blade Terminal Splice Connectors | 12 Volt Planet

Blade Terminal Splice Connectors from 12 Volt Planet. Splice connectors featuring 6.3mm blade terminals encased in a PVC cover- various configuratons. Suitable for automotive & marine wiring applications

www.12voltplanet.co.uk

Thanks for that, I'll order one now. So if I read your diagram correctly it's 30 to the starter battery or permanent live, 85 to common earth, 86 is the blue/white ignition feed from P15 which I've found today and 87a is the positive from P1 which I'm assuming is the starter battery as opposed to P2 which is leisure battery?
If that's incorrect I would appreciate your input. Many thanks again.
Allan

 

[Fazerstorm]

A B2B only works when the engine is running. I think you are referencing a Battery Master which trickle charges the vehicle battery typically from excess solar while the vehicle is not being used.

From my understadning there are a couple of reasons to use a B2B when you have a split relay and are considering Lithium

1: Lithium batteries have very little internal resistance and so will take as much charge as your alternator can throw at it and thus you risk damaging your alternator.

2: A split relay sees both batteries as a single battery from a charging point of view and is certainly not smart in turns of charging. While this might be acceptable when both batteries are lead acid it is not great when you have different battery chemistry. A lithium requires specific charging voltages when a B2B is speced to provide.

3: The wiring in the majority of vans with split charge relays is not great resulting in a significant voltage drop at the leisure battery. Fitting a B2B is typically done in conjunction with fitting new cabling to allow for more efficient charging of the leisure.

If you do decide to fit a B2B then the split charge relay should be disabled while the B2B is active thus avoiding competition between them. How ever to permanetnly disable the split charge relay may cause issues when the vechile is turned off. It certainly did in my van with the EC400. Thus I fitted a relay which allows the split charge relay to act normally and only be disconnected when the engine is running. Diagram below should explain.

View attachment 986568

I used your diagram to isolate our split charge relay... thanks.... I did however put a switch in to leave it connected if required. This is because the fridge takes about 10amps when driving, meaning the victron 30amp charger was only charging the ks lithium battery at 20amps. With the split relay charging connected, it gives out 32amps in total. So if the battery is really low, I leave both connected. I then turn off the split charge at around 90% and allow the victron, or solar to fully charge at the correct lithium profile.

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[Roadman]

Hi, below is a diagram I got from Sargent a while ago when I was considering upgrading to lithium, hope this helps.

 

[Insider]

Thanks for that, I'll order one now. So if I read your diagram correctly it's 30 to the starter battery or permanent live, 85 to common earth, 86 is the blue/white ignition feed from P15 which I've found today and 87a is the positive from P1 which I'm assuming is the starter battery as opposed to P2 which is leisure battery?
If that's incorrect I would appreciate your input. Many thanks again.
Allan

Allan,

All looks good. Being pedantic 87A is the postive TO P1 rather than FROM

When the vehicle is off power flows from the vehicle battery to the EC400 and is used for step retraction and fridge control(not powering) but goes not further due to the "split charge relay". When the vehicle is turend on the power goes to the EC400 and charges the leisure battery. The relay you're installing allow power thru when the vehicle is powered off and stops it when vehicle is powered on allowing the B2B to provide power to the leisure battery which in turn feeds back into the EC400 allowing anything "allowed" to run. P2 is the leisure battery. Circuit diagrams are a bit funny - they don't have to be connected where you see the connection.

Below is a diagram of the relay I used explaning it a bit better than I would.

 

[Insider]

I used your diagram to isolate our split charge relay... thanks.... I did however put a switch in to leave it connected if required. This is because the fridge takes about 10amps when driving, meaning the victron 30amp charger was only charging the ks lithium battery at 20amps. With the split relay charging connected, it gives out 32amps in total. So if the battery is really low, I leave both connected. I then turn off the split charge at around 90% and allow the victron, or solar to fully charge at the correct lithium profile.

Interesting. I have a 60A B2B and only just left lead acid and gone over to Lithium. I was actually throttling my B2B due to the C5 rule and never really going anywhere near the potential of the B2B. Now I have Lithium that should change but with 60A B2B I can spare 10A for the fridge. I just hope my alternator is up to the job!!!
Thanks
Rory

 

[Bradders65]

Our Lead Acid batteries have given up the ghost so 2 new lithiums are on order.
Our electric system is all Sargent as fitted in the Autotrail’s.
The PX300 battery charger is being left in place for now as we are hoping we will not need a lot of plugging in.
The original 100w solar panel is set up to charge the engine battery only.
The 2 x 120w retrofitted panels go through an Epever MPPT controller direct to the leisure batteries and will be set with a Lithium profile.
There is no B2B or Battery Master etc fitted however the Sargent controller has a split charge system that charges both Engine battery and Leisure batteries when the engine is running. I don’t believe this is modern enough for it to be a smart alternator. (2014 model)

The question is does anyone have any experience of dropping in Lithium is place of LA as far as the split charger is concerned - will it work or cause issues if it isn’t disabled?

I know the mains charger is not ideal but that will get changed at a later date if we find we need to.

Thanks
Iain

I can only say that Dropped a Fogstar battery in my van with the Sargent split charge system ( not a smart alternator) and it works fine. I did change the spare controller for one that has a lithium profile and also trickle charges the the engine battery but I fitted an inline switch between the controller and the panel. It may not be the absolute optimum set up but it works well and if I lose a few charge cycles on the battery it is still far better and will last far longer than the lead acid one I removed.

 

[fred_jb]

If you do decide to fit a B2B then the split charge relay should be disabled while the B2B is active thus avoiding competition between them. How ever to permanetnly disable the split charge relay may cause issues when the vechile is turned off. It certainly did in my van with the EC400. Thus I fitted a relay which allows the split charge relay to act normally and only be disconnected when the engine is running. Diagram below should explain.

View attachment 986568

I am not familiar with Sargeant kit so forgive me if this a silly question. I can understand disconnecting it when the engine is running so that the B2B can be used instead, but why do you need to arrange for the direct input from the starter battery to be reconnected when the engine is not running?

Surely under those conditions, that is engine off, the split charge relay does not operate anyway nor does a fridge normally connect to the starter battery unless the engine is running, so this connection seems to have no purpose when the engine is off, and its function is replaced by the B2B when the engine is running.

If that is true then why not just leave it disconnected and thereby permanently disabled, which is what I have done with what I think is the equivalent connection on my Schaudt Electroblock?

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[Insider]

I am not familiar with Sargeant kit so forgive me if this a silly question. I can understand disconnecting it when the engine is running so that the B2B can be used instead, but why do you need to arrange for the direct input from the starter battery to be reconnected when the engine is not running?

Surely under those conditions, that is engine off, the split charge relay does not operate anyway nor does a fridge normally connect to the starter battery unless the engine is running, so this connection seems to have no purpose when the engine is off, and its function is replaced by the B2B when the engine is running.

If that is true then why not just leave it disconnected and thereby permanently disabled, which is what I have done with what I think is the equivalent connection on my Schaudt Electroblock?

When I was investigating this I did just that and the Sargent siphons off power for the step and the fridge control panel from the vehicle battery so leaving it disconnected was not an option - would have been much easier.

 

[fred_jb]

When I was investigating this I did just that and the Sargent siphons off power for the step and the fridge control panel from the vehicle battery so leaving it disconnected was not an option - would have been much easier.

That explains it then! Not a problem with the Electroblock as the split charge relay in that has a dedicated input which does not power anything else. There is a separate 20A fused feed from the starter battery to the Electroblock, though that only powers the fridge when the engine is running, not permanently.

I wonder why your step and fridge control panel are powered from the starter battery? Taking power from the starter battery for these when you have a leisure battery available seems an odd thing to do, and could potentially run down the starter battery.

I would think converters would avoid permanently powering anything in the habitation side from the starter battery as that would mean the vehicle manufacturer can use that as an excuse should a fault develop which caused the starter battery to go flat. I had exactly this problem on a previous vehicle, and even when I completely disconnected the habitation side they still refused to believe the fault was with the base vehicle. I ended up replacing the vehicle's main 12V control unit myself, which fixed the problem.

 

[Insider]

That explains it then! Not a problem with the Electroblock as the split charge relay in that has a dedicated input which does not power anything else. There is a separate 20A fused feed from the starter battery to the Electroblock, though that only powers the fridge when the engine is running, not permanently.

I wonder why your step and fridge control panel are powered from the starter battery? Taking power from the starter battery for these when you have a leisure battery available seems an odd thing to do, and could potentially run down the starter battery.

I would think converters would avoid permanently powering anything in the habitation side from the starter battery as that would mean the vehicle manufacturer can use that as an excuse should a fault develop which caused the starter battery to go flat. I had exactly this problem on a previous vehicle, and even when I completely disconnected the habitation side they still refused to believe the fault was with the base vehicle. I ended up replacing the vehicle's main 12V control unit myself, which fixed the problem.

I can potentially see a reason for the step being powered off the vehicle battery as you need to be able to retract it the morning after and if your hab battery died during the night then that presents a problem. I have no idea why the fridge is included in this set up and yes a seperate connection would have been better but that would have involved some extra wire and therefore less profit!! Likewise what is the reasoning for disabling most hab equipment with ignition on? Anyways it gives us something to do on a dark winter's evening

 

[fred_jb]

Maybe it's a UK converters thing? My Etrusco, with Etrusco being part of the German Hymer group, does not disable the habitation electrics while driving, nor does it permanently power any habitation stuff off of the starter battery.