Installing Victron B2B charger (1 Viewer)

[burtonwisher]

I have a couple of questions about the installation of a Victron Orion DC-2-DC / B2B charger into my motorhome.

The motorhome is a Ducato based 2010 Autotrail Apache, with a Sargent EC225 control unit and EM50 interface unit.

The reason for this is that I am installing LiFePO4 batteries. I already have a Victron MPPT solar controller and a Victron mains charger, so those charging profiles are OK for lithium, and I want to make sure that the alternator charging is also optimised for Lithium and doesn't cause any problems.

My problem though is that it seems there is no way to disconnect the existing charge to the leisure batteries from the alternator, without also disconnecting other critical connections. I spoke to Sargent who told me this. They say that the only way to disconnect their split charge relay to stop the alternator charging the leisure battery would also stop the 3-way fridge running on 12v when the engine is running, stop the step retracting, and cut off the EMC relay.

So my 2 questions are:

1) Does anybody have any knowledge or experience in disconnecting the existing alternator-leisure battery charge in this setup, without any detriment elsewhere?

2) If I install the Orion B2B but left the existing setup in place, would that cause a problem or prevent the Orion B2B from working properly?

Many thanks

 

[cmcardle75]

I have a couple of questions about the installation of a Victron Orion DC-2-DC / B2B charger into my motorhome.

The motorhome is a Ducato based 2010 Autotrail Apache, with a Sargent EC225 control unit and EM50 interface unit.

The reason for this is that I am installing LiFePO4 batteries. I already have a Victron MPPT solar controller and a Victron mains charger, so those charging profiles are OK for lithium, and I want to make sure that the alternator charging is also optimised for Lithium and doesn't cause any problems.

My problem though is that it seems there is no way to disconnect the existing charge to the leisure batteries from the alternator, without also disconnecting other critical connections. I spoke to Sargent who told me this. They say that the only way to disconnect their split charge relay to stop the alternator charging the leisure battery would also stop the 3-way fridge running on 12v when the engine is running, stop the step retracting, and cut off the EMC relay.

So my 2 questions are:

1) Does anybody have any knowledge or experience in disconnecting the existing alternator-leisure battery charge in this setup, without any detriment elsewhere?

2) If I install the Orion B2B but left the existing setup in place, would that cause a problem or prevent the Orion B2B from working properly?

Many thanks

I can't help you with the EC225 specifics (I've heard people discussing disabling the split charge without disabling step & fridge, so it might well be possible).

However, I can definitely confirm that not disabling a split charge relay will effectively disable your new charger, as you're basically shorting it out with a fat bit of cable.

 

[Insider]

Not exactly the same kit but hopefully similar enough to be useful. I bought a Stirling 60A B2B and have a Sargent EC400. I fitted a relay to disable power going from the alternator to the EC400 and this was activated by a +12V available in the EC400 from ignition on. As the B2B is supplying power to the leisure battery and the EC400 is connected to the leisure battery, essentially the EC400 and connected devices such as the fridge are power off the B2B while driving.

<Broken link removed> = link for your Sargent kit

So to answer but bear in mind I'm only learning myself so will take correction!!

1: Once you can get a circuit diagram of the EC200 hopefully a relay should be able to isolate the power coming from the alternator whilst driving. A dioded relay is a couple of quid from 12V planet

2: I would not leave the existing set in place as if the alternator is feeding directly power into the Lithium then you could damage the alternator as Lithium has low resistance and will take high charge meaning your alternator will throw everything it can at it. That might be fine on the motherway at 10°C but if you're stuck in dusty town traffic in 35°C then your alternator will overheat. I would think installing a relay would allow you to have fridge etc. As long as your EC200 is getting a substancial 12V supply into the battery then I would think all is good.

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[burtonwisher]

Thanks for the input so far.
Seems pretty clear that I do need to disconnect the existing split charge relay for things to work properly.
Just need to figure out exactly how to do this in my setup. With the above link and some other diagrams I've managed to get it's still not clear to me even where the existing split charge relay is (is it in the EM50 or in the EC225?)

 

[Diabalo]

I have the EC500 PSU and the split charging relay is on it's PCB, so it's worth looking at that at first as yours may be similar.

 

[Diabalo]

I put information about the EM50 in resources which may help

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[Wagoneer]

If the split charge relay is mounted on the PCB of the 12v control unit, it's best not to disable it. Keep it as a fallback system just incase the B2B fails for some reason.

Simplist way of checking the effect on other appliances (like fridge etc) is to:

1) Disconnect the +'ve feed from starter battery to 12v control unit. Start engine and observe whether fridge working on 12v.

2) Reconnect +'ve feed as in (1) and disconnect +'ve feed from leisure battery to 12v control unit. Start engine and observe whether fridge working on 12v.

The step sometimes retracts when you start the engine anyway or activates a warning buzzer.

Once you've observed which battery powers what, will determine on which +'ve power cable you insert a cutoff relay, triggered by a D+ signal. The 12v control unit will normally have a D+ feed which can be used to trigger the relay (my D+ wires are coloured yellow). The relay will be normally closed when the engine is not running so the step function and all the other normal stuff should not be affected.

The cutoff relay basically disables the function of the onboard split charge relay when the B2B is in operation.

This earlier thread may be of interest and gives details of the relay used:

Carthago Split Charging Unit

I'm exploring the possibility of putting a B2B charger on my Carthago, but I understand that I'll need to disable the existing split charging unit. Does anybody know where it is? Is it a separate unit, or is it built into the electronic gubbins in the boot? I can't even identify a fuse for it...

www.motorhomefun.co.uk

 

[Kannon Fodda]

In my Autotrail V-Line PVC with Sargent EC176, when fitting the Sterling B2B that had new heavier cables run between the cab (motor) battery to the B2B and then to the leisure battery. To disconnect the Sargent relay thing a fuse was pulled from a fusebox in the floor behind the driver's seat, but I believe nothing else needed to be disconnected. The electric step, 12V when driving fridge still works, and the power to everything else in the leisure area still get's cut off when the engine starts in the typical UK fashion.

There can be some wiring diagrams in the back of the Autotrail handbooks that may give you a clue on what fuse you could be looking for.

 

[burtonwisher]

Thanks Kannon Foda, I did try pulling the fuses behind the drivers seat (in the EM50 unit) but none of them stopped the alternator charging of the leisure battery, so I presume whatever does this function is in the main EC225 control unit.

If the split charge relay is on the PCB then I won't touch it. I'll keep it as a backup and will find a way to bypass it.

Wagoneer's post made me think.... in my setup I don't use the EC225 control unit for mains or solar charging... I've installed separate Victron mains and solar chargers direct to the leisure batteries (and I keep the charger switch OFF on the EC225). Then I have a Votronic standby charger that sends a couple of amps to the starter battery from whatever charge the leisure batteries get.

So I'm wondering if it could be as simple as pulling the 20A vehicle battery fuse from the EC225? If this is the connection that brings the alternator charge to the EC225 then would breaking it prevent that flowing to the leisure batteries?

I need to check next time I visit the van in storage, but any thoughts in the meantime on whether this would achieve the desired result would be welcome, as well as whether there are any other consequences of this that I haven't thought of?

If this won't work I'll keep looking into the relay option.

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[eyeball74]

I have watched quite a few videos of people just adding the B2B directly between the vehicle battery and leisure battery via an inline breaker without disconnecting anything of the original system. This what I have done an all is working fine. Not sure what, if any, damage or faults this could cause.

 

[IanRJ]

Thanks Kannon Foda, I did try pulling the fuses behind the drivers seat (in the EM50 unit) but none of them stopped the alternator charging of the leisure battery, so I presume whatever does this function is in the main EC225 control unit.

If the split charge relay is on the PCB then I won't touch it. I'll keep it as a backup and will find a way to bypass it.

Wagoneer's post made me think.... in my setup I don't use the EC225 control unit for mains or solar charging... I've installed separate Victron mains and solar chargers direct to the leisure batteries (and I keep the charger switch OFF on the EC225). Then I have a Votronic standby charger that sends a couple of amps to the starter battery from whatever charge the leisure batteries get.

So I'm wondering if it could be as simple as pulling the 20A vehicle battery fuse from the EC225? If this is the connection that brings the alternator charge to the EC225 then would breaking it prevent that flowing to the leisure batteries?

I need to check next time I visit the van in storage, but any thoughts in the meantime on whether this would achieve the desired result would be welcome, as well as whether there are any other consequences of this that I haven't thought of?

If this won't work I'll keep looking into the relay option.

I believe the 20 amp fuse in the EM40 panel behind the drivers seat (marked Vehicle Battery) is the only power connection between the Vehicle Battery and the EC225 (EC700 in my case). It's fuse No 4 in my manual.

Can I ask how you tested the alternator power reaching the EC225 panel after pulling the fuses (for my own education)?

However pulling that fuse will, I think, prevent the Sargent unit passing any power to the vehicle battery at any time (when running the B2B and when stationary) so possibly not a long term solution anyway if you want the Sargent to trickle charge the vehicle battery from solar?

The relay option does seem the most appropriate to avoid any major modifications!

 

[BillyKontiki]

I also have a decato based mh with Sargent EC600 unit.
Fitted a 100ah lithium as drop in replacement, and a victron b to b 30 amp charger everything works fine Sargent charger, and solar work as they did, and no issues with the alternator as what I am led to believe the battery via the victron charger will pull a maximum of around 30 amps from the alternator and the Sargent 20 amp max, so will not stress a 150 amp alternator.
I’m no expert but it works for me.

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[IanRJ]

I also have a decato based mh with Sargent EC600 unit.
Fitted a 100ah lithium as drop in replacement, and a victron b to b 30 amp charger everything works fine Sargent charger, and solar work as they did, and no issues with the alternator as what I am led to believe the battery via the victron charger will pull a maximum of around 30 amps from the alternator and the Sargent 20 amp max, so will not stress a 150 amp alternator.
I’m no expert but it works for me.

Did you make any voltage measurements at the engine battery with the engine running Billy? Just to see if there was an over voltage in the feedback to that battery.

 

[BillyKontiki]

Did you make any voltage measurements at the engine battery with the engine running Billy? Just to see if there was an over voltage in the feedback to that battery.

No Ian I haven’t done this and quite honestly I wouldn’t know what I should be looking for, I am handy with an amp meter and amp clamp if you let me know what I should be looking for I’ll try it out.

 

[IanRJ]

No Ian I haven’t done this and quite honestly I wouldn’t know what I should be looking for, I am handy with an amp meter and amp clamp if you let me know what I should be looking for I’ll try it out.

I'm learning too Billy - but following on from the other threads on the fitting of a relay etc. It seems the concern is that the B2B, if set to Lithium will be feeding 14.6v to the lithium battery and that will feedback through to the engine battery if no relay or other isolation made. My understanding is that 14.6v would be good for the Li but bad for the Lead Acid Battery!

So taking a volt meter I think checking the engine battery terminals when the engine is running should tell the tale. If its above 14.2v (I think - someone will be along to correct me shortly ) that might mean there is that feedback loop discussed. If the volts were high it may be possible to remove the split charge relay wire on the battery and see if the voltage at the battery drops? At least you'd know!

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[BillyKontiki]

Well put Ian I understand what you are saying I’ll test this later and post results.

 

[Tombola]

Im on the sargent ec176 on a 2019 which is quite low end psu. the charger is woeful.

I have the victron b2b linked up to 200ah of lithium and when running the alternator provides about 7 amp according to the batterys bluetooth bms, turn on the b2b and the orion 12-12-30 kicks in and the battery gets anything between 37 and 40 amps.

I did play with the relays and had issues as described with the step etc, but in the end wired it in, tested it and all seens fine.
In fact it works that well alongside my solar that I fitted the switch so I can manually switch it off if I want just alternator charge

Commonknowledge is that vans from 2019 are "smart alternators" but it isnt always the case.
Mine isnt smart, Im told some builders requested non smart from Fiat

 

[IanRJ]

Im on the sargent ec176 on a 2019 which is quite low end psu. the charger is woeful.

I have the victron b2b linked up to 200ah of lithium and when running the alternator provides about 7 amp according to the batterys bluetooth bms, turn on the b2b and the orion 12-12-30 kicks in and the battery gets anything between 37 and 40 amps.

I did play with the relays and had issues as described with the step etc, but in the end wired it in, tested it and all seens fine.
In fact it works that well alongside my solar that I fitted the switch so I can manually switch it off if I want just alternator charge

Commonknowledge is that vans from 2019 are "smart alternators" but it isnt always the case.
Mine isnt smart, Im told some builders requested non smart from Fiat

So yours is wired without the bypass relay TOMBOLA?

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[Tombola]

So yours is wired without the bypass relay TOMBOLA?

yes just wired up via b2b and i dont use the sargent for solar or 240v charger, i set up new runs, tho the old still exsist if i need to revert back

 

[EuroTrotters]

I have watched quite a few videos of people just adding the B2B directly between the vehicle battery and leisure battery via an inline breaker without disconnecting anything of the original system. This what I have done an all is working fine. Not sure what, if any, damage or faults this could cause.

May I ask what you mean by “in-line breaker “ ?

 

[BillyKontiki]

I'm learning too Billy - but following on from the other threads on the fitting of a relay etc. It seems the concern is that the B2B, if set to Lithium will be feeding 14.6v to the lithium battery and that will feedback through to the engine battery if no relay or other isolation made. My understanding is that 14.6v would be good for the Li but bad for the Lead Acid Battery!

So taking a volt meter I think checking the engine battery terminals when the engine is running should tell the tale. If its above 14.2v (I think - someone will be along to correct me shortly ) that might mean there is that feedback loop discussed. If the volts were high it may be possible to remove the split charge relay wire on the battery and see if the voltage at the battery drops? At least you'd know!

Hi Ian carried out this test engine running hab battery at 60% soc voltage at the starter battery 14.1 so I think all good.

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[IanRJ]

Hi Ian carried out this test engine running hab battery at 60% soc voltage at the starter battery 14.1 so I think all good.

That sounds perfect to me! Well done and thanks for taking the time Billy.

I'll be doing the same next week when my Lithium's arrive.

 

[Hoovie]

I have a couple of questions about the installation of a Victron Orion DC-2-DC / B2B charger into my motorhome.

The motorhome is a Ducato based 2010 Autotrail Apache, with a Sargent EC225 control unit and EM50 interface unit.

The reason for this is that I am installing LiFePO4 batteries. I already have a Victron MPPT solar controller and a Victron mains charger, so those charging profiles are OK for lithium, and I want to make sure that the alternator charging is also optimised for Lithium and doesn't cause any problems.

My problem though is that it seems there is no way to disconnect the existing charge to the leisure batteries from the alternator, without also disconnecting other critical connections. I spoke to Sargent who told me this. They say that the only way to disconnect their split charge relay to stop the alternator charging the leisure battery would also stop the 3-way fridge running on 12v when the engine is running, stop the step retracting, and cut off the EMC relay.

So my 2 questions are:

1) Does anybody have any knowledge or experience in disconnecting the existing alternator-leisure battery charge in this setup, without any detriment elsewhere?

2) If I install the Orion B2B but left the existing setup in place, would that cause a problem or prevent the Orion B2B from working properly?

Many thanks

Hi,
Thought I would add a few comments on this thread as seems to have been left a bit open-ended and no real conclusion ....

The Sargent unit has as been said a relay that gets activated when the engine runs and that is (depending on unit) not just a relay that sends alternator power (at the alternators voltage) to the Leisure battery, but can raise it, and raise it to pretty high levels.
Keeping the Sargent's split-charge circuit enabled won't stop the B2B working as such, but it won't work optimally and features like it going to float or running at its set voltage won't work correctly.
To have a B2B running on an system with a Sargent unit you really need to disable the Sargents split-charge. And especially if installing Lithium Batteries as the voltage the Sargent puts out is too high for that technology. You may setup the B2B perfectly for Li-on, but then when the batteries are closer to nearly charged the Sargent is able to whack that high voltage in.

The fuse under the floor has been mentioned. I am guessing this is the fuse #8 labelled "split charge" on the EM50? That does not seem to have any effect. When you look at the Sargent wiring diagram that is a fuse for a circuit that goes parallel to another 12V circuit that goes to the fridge (and is on fuse #9). And when I say parallel, I mean they are connected - so take out fuse #8 and the circuit is still powered by 12V via the circuit on fuse #9.
Again, going by the Sargent wiring diagram there is no way to disable the "Engine running" (D+) signal from the EM unit into the EC unit to stop the split-charge without also disabling the Fridge (and probably auto-step in function. Can't recall on that one).

The only way I have found to disable the split-charge on a Sargent (short of getting physically into the unit) was to cut the Red/Yellow wire that comes into the unit on one of the connectors. (Note, this is the Red/Yellow, and not the Yellow/Red!). By cutting this, the Sargent EC unit does not know the engine is running and the system stays in "parked up" mode - so no split-charge, but also the hab electrics stay enabled (you may like or not like that by-product. I think it is a bonus personally )
However, after doing this the Fridge still goes to 12V automatically on engine start and the step retracts by itself, so those two key functions remain.
On my own Autotrail I fitted a switch to the cut Red/Yellow so I can, if the 60A B2B fails, reenable the signal and have the built-in split-charge working as a backup. On another Autotrail I just fitted a pair of bullets so it would be very easy to reinstate that way.
It is a shame that the EM50 #8 fuse did not work as the label suggests, but it doesn't and so we are where we are looking for alternatives.

Now the above is what I have done. What anyone else does is their business and they have to be happy with the consequences (i.e. this is a disclaimer )

 

[Revolvor]

burtonwisher

Not sure if you solved your problem, but this is what I did when I installed a B2B charger.

I fitted a 30A relay in the blue/brown wire (on my Autotrail) to isolate the EC225 from charging the leisure batteries when the engine is running. It is "Normally Closed" so with the engine off, the EC225 is connected to the Leisure Batteries.

To operate the relay, I connected a wire to the "Fridge +ve" in the EM50 box which is on the floor behind the driver's seat.

I can attach a diagram showing the circuit if need by anyone.

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[autorouter]

The fuse under the floor has been mentioned. I am guessing this is the fuse #8 labelled "split charge" on the EM50? That does not seem to have any effect. When you look at the Sargent wiring diagram that is a fuse for a circuit that goes parallel to another 12V circuit that goes to the fridge (and is on fuse #9). And when I say parallel, I mean they are connected - so take out fuse #8 and the circuit is still powered by 12V via the circuit on fuse #9.
Again, going by the Sargent wiring diagram there is no way to disable the "Engine running" (D+) signal from the EM unit into the EC unit to stop the split-charge without also disabling the Fridge (and probably auto-step in function. Can't recall on that one).

Do you have a link to this wiring diagram? Which Sargent unit is it for?

 

[Hoovie]

Do you have a link to this wiring diagram? Which Sargent unit is it for?

If you have a look at this PDF - <Broken link removed> - and goto the 4th Sheet, which shows the EM50 and the EC325/225 unit cabling, you can see there are two R/Y (Red/Yellow "Engine Running") wires coming out of the EM50 on Conn M - looking at the devices and the labelling on the case of the EM50, these would seem to be protected by Fuse #9 and Fuse #10 (I think those are the two? going from memory). One goes to the EC325 and the other goes to the Fridge. But the kicker is - going by the diagram - they are linked together anyway (just above the 3-way fridge) so removing either fuse in isolation does nothing except increase the current on the other paralle circuit. This would also explain why removing the "split-charge" fuse has no effect.

 

[Tombola]

Hi,
Thought I would add a few comments on this thread as seems to have been left a bit open-ended and no real conclusion ....

The Sargent unit has as been said a relay that gets activated when the engine runs and that is (depending on unit) not just a relay that sends alternator power (at the alternators voltage) to the Leisure battery, but can raise it, and raise it to pretty high levels.
Keeping the Sargent's split-charge circuit enabled won't stop the B2B working as such, but it won't work optimally and features like it going to float or running at its set voltage won't work correctly.
To have a B2B running on an system with a Sargent unit you really need to disable the Sargents split-charge. And especially if installing Lithium Batteries as the voltage the Sargent puts out is too high for that technology. You may setup the B2B perfectly for Li-on, but then when the batteries are closer to nearly charged the Sargent is able to whack that high voltage in.

The fuse under the floor has been mentioned. I am guessing this is the fuse #8 labelled "split charge" on the EM50? That does not seem to have any effect. When you look at the Sargent wiring diagram that is a fuse for a circuit that goes parallel to another 12V circuit that goes to the fridge (and is on fuse #9). And when I say parallel, I mean they are connected - so take out fuse #8 and the circuit is still powered by 12V via the circuit on fuse #9.
Again, going by the Sargent wiring diagram there is no way to disable the "Engine running" (D+) signal from the EM unit into the EC unit to stop the split-charge without also disabling the Fridge (and probably auto-step in function. Can't recall on that one).

The only way I have found to disable the split-charge on a Sargent (short of getting physically into the unit) was to cut the Red/Yellow wire that comes into the unit on one of the connectors. (Note, this is the Red/Yellow, and not the Yellow/Red!). By cutting this, the Sargent EC unit does not know the engine is running and the system stays in "parked up" mode - so no split-charge, but also the hab electrics stay enabled (you may like or not like that by-product. I think it is a bonus personally )
However, after doing this the Fridge still goes to 12V automatically on engine start and the step retracts by itself, so those two key functions remain.
On my own Autotrail I fitted a switch to the cut Red/Yellow so I can, if the 60A B2B fails, reenable the signal and have the built-in split-charge working as a backup. On another Autotrail I just fitted a pair of bullets so it would be very easy to reinstate that way.
It is a shame that the EM50 #8 fuse did not work as the label suggests, but it doesn't and so we are where we are looking for alternatives.

Now the above is what I have done. What anyone else does is their business and they have to be happy with the consequences (i.e. this is a disclaimer )

Thanks for the detailed explaination.
I have the sergant EC176, (lowest) that has the same relay issues.
I have the b2b on a non smart alternator on a 2019 Autotraill imala 734.

Without b2b battery gets 7 a, constant.
With b2b, 39ish and seems to drop as it gets to 80%. I also have the remote switch set u to cut it off manually as Im driving.

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[autorouter]

I don't really know much about Sargent systems, but I read on another forum that some of the Sargent PSUs have a dual mains/B2B charger instead of a mains charger and a simple split charge relay. I can find zero information about this, despite searching.

I presume it's similar to the Votronic Triple Charger (mains, B2B, solar) that definitely exists. If the Sargent dual charger is in fact used, that would explain some of the unexpected results that have been reported. When the existing charging from the starter battery has not been disabled, but the new B2B works perfectly well in addition. Anybody know anything about this?

 

[Hoovie]

burtonwisher

Not sure if you solved your problem, but this is what I did when I installed a B2B charger.

I fitted a 30A relay in the blue/brown wire (on my Autotrail) to isolate the EC225 from charging the leisure batteries when the engine is running. It is "Normally Closed" so with the engine off, the EC225 is connected to the Leisure Batteries.

To operate the relay, I connected a wire to the "Fridge +ve" in the EM50 box which is on the floor behind the driver's seat.

I can attach a diagram showing the circuit if need by anyone.

That's a neat solution to it as well
out of interest where did you intercept the blue/brown wire? around where it comes into the EC unit? (as you used a wire in the EM50 box, probably fitted relay in the underfloor hatch thinking about it).

 

[Revolvor]

That's a neat solution to it as well
out of interest where did you intercept the blue/brown wire? around where it comes into the EC unit? (as you used a wire in the EM50 box, probably fitted relay in the underfloor hatch thinking about it).

I actually put the relay right by the Leisure battery.

That means the EC225 functions normally, unless the engine is running.