Wiring in new Victron B2B? (2 Viewers)

Sep 29, 2019
3,073
7,097
Funster No
64,846
MH
Hymer Exsis
Exp
20 years
I currently have a Votronic 30amp wired in as the thread in my signature. It is faultless and has been great!

I am tempted by the new Victron as the rest of my kit is also Victron.

Currently it goes through the EBL as it’s only 30amps. Technically the new Victron is just within spec of the EBL at 50amps but I think I am pushing my luck and will need a complete rewire to install it. I know I can down rate the Victron, but I may as well stick with what I have if I do that?

What do the more knowledgable think?

What I have works very well and I am unsure if I can be bothered to rewire completely for an extra 20 amps and shiny new B2B, or can I? 😝
 
Jan 27, 2019
169
146
Teesside
Funster No
58,248
MH
VAN CONVERSION
Exp
Since 2016
I currently have a Votronic 30amp wired in as the thread in my signature. It is faultless and has been great!

I am tempted by the new Victron as the rest of my kit is also Victron.

Currently it goes through the EBL as it’s only 30amps. Technically the new Victron is just within spec of the EBL at 50amps but I think I am pushing my luck and will need a complete rewire to install it. I know I can down rate the Victron, but I may as well stick with what I have if I do that?

What do the more knowledgable think?

What I have works very well and I am unsure if I can be bothered to rewire completely for an extra 20 amps and shiny new B2B, or can I? 😝
Not sure which Victron B2B you are talking about but 50 amps is a heavy load on your Alternator. If it is 50 Amps then you need to follow the Victron cable size specifications to avoid heat build up. I use a Victron 30 A Orion and you can calculate the time it takes to charge.
 
Apr 3, 2018
3,722
10,318
Funster No
53,151
MH
PVC
Exp
1995-2004 & 2017》
Faster charging and integration with the rest of the kit.

You are right though, it’s a lot of money for an extra 20 amps.
Yes extra Amps seems appealing, but in the scheme of things will it really make a big differance to your usage.

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Lenny HB

LIFE MEMBER
Oct 18, 2007
53,797
151,482
On the coast in West Sussex
Funster No
658
MH
Hymer B678 DL
Exp
Since 2008 & many years tugging
If your cable run to the B2B from the starter battery is 2 m or less the 16mm sq cable Hymer fit to the EBL will be fine.

I would change the 50 amp mega blade fuse by the starter battery for a Midi fuse it needs to be 60amp anyway, blade fuses with high current are a bit of a liability.

Now days I wouldn't run any B2B through the EBL, the split charge relay contacts tend to carbon up and the output drops.

You then only need one extra cable from the B2B to the leisure battery and a fuse at the battery end.
 
Apr 9, 2022
413
398
Funster No
87,949
MH
Cathargo
Exp
Newbie
I currently have a Votronic 30amp wired in as the thread in my signature. It is faultless and has been great!

I am tempted by the new Victron as the rest of my kit is also Victron.

Currently it goes through the EBL as it’s only 30amps. Technically the new Victron is just within spec of the EBL at 50amps but I think I am pushing my luck and will need a complete rewire to install it. I know I can down rate the Victron, but I may as well stick with what I have if I do that?

What do the more knowledgable think?

What I have works very well and I am unsure if I can be bothered to rewire completely for an extra 20 amps and shiny new B2B, or can I? 😝
The reason I am putting in an XS is:
So that I can use smart networking (or DVCC ) and therefore get an accurate charge profile through shared battery voltage and temperature from the Smart Shunt
So that all the charge devices in the network will compensate accurately for voltage drop in the cables
So that I can set a 5°c low temp cut-off to ensure the Lithium batteries do not receive a charge. (I do this now using temp sense relay, but this is simpler)
I will use DVCC, so my CerboGX (Could alternatively use a raspberry PI) will control the XS as well as my two MPPT controllers to keep them all in sync, and I have a max current limit to avoid putting over a certain current into the batteries for longevity (probably unnecessary but still)
So that I can see exactly what current is coming out of my alternator (Via Connect, or VRM history) which may get a temp tab to keep an eye on its temperature (in high temp places) so if the Alt is getting hot I can set a temp limit and use a relay on the cerbo to turn it off VIA the D+ signal, just to protect the alt from premature failure (again probably not necessary but hey!)
So that I can see via VRM what the starter battery voltage is, and remove the AUX connection/fuse from the Smart Shunt (simpler)
So that I can initially tune the current on the input side, until I am fit enough to change the 8m input cable from 16mm² to whatever is needed.

Essentially because it will integrate and play nicely with the other Victron kit, and give comprehensive reporting on VRM or Connect.

I also like fiddling with this stuff
 
May 7, 2016
7,312
11,822
West Sussex
Funster No
42,951
MH
Malibu Van 640 LE K
Exp
Since 2003
I recently emailed Udo Lang at Schaudt about wiring a new B2B to a system which already had a Schaudt WA121525 Booster connected to the EBL. His advice was to run the 2 in parallel but with the new one wired directly between the batteries. This was his reply.

“Yes I agree. I would stay with the Booster WA 121525 like it is. The separate Booster you can wire directly from starter battery plus and minus to the booster and from the booster output to the leisure battery plus and minus. Maybe you use 16qmm wires for the connection. D+ the alternator signal you find at the Booster Wa 121525, in case the booster needs to have any switched signal.
With Best Regards,
i.o. Udo Lang.”
 

Lenny HB

LIFE MEMBER
Oct 18, 2007
53,797
151,482
On the coast in West Sussex
Funster No
658
MH
Hymer B678 DL
Exp
Since 2008 & many years tugging
I don't like the WA121525, it outputs a constant 14.4v even when the battery is charged relying on the BMS to cut charging not a good idea.
I think Carthago fit it as standard but they only mention a B2B on the up market models.

If one is fitted to my Compactline when I get it I may rewire it just to supply the fridge and fit a Victron XS for the batteries.
I think it is a really poor design from Schaudt.
 
Apr 9, 2022
413
398
Funster No
87,949
MH
Cathargo
Exp
Newbie
I don't like the WA121525, it outputs a constant 14.4v even when the battery is charged relying on the BMS to cut charging not a good idea.
I think Carthago fit it as standard but they only mention a B2B on the up market models.

If one is fitted to my Compactline when I get it I may rewire it just to supply the fridge and fit a Victron XS for the batteries.
I think it is a really poor design from Schaudt.
Yes Carthago fit them to all but the Iveco models, Took me ages looking in all the obvious locations until a German dealership clarified there wouldn't be one on our van.

Funnily enough I was thinking about using the old Orion as a power supply of some sort to feed the DS470 since I doubt it's worth much 2nd hand, so thanks for the good fridge idea!

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OP
OP
Googlebot
Sep 29, 2019
3,073
7,097
Funster No
64,846
MH
Hymer Exsis
Exp
20 years
I recently emailed Udo Lang at Schaudt about wiring a new B2B to a system which already had a Schaudt WA121525 Booster connected to the EBL. His advice was to run the 2 in parallel but with the new one wired directly between the batteries. This was his reply.

“Yes I agree. I would stay with the Booster WA 121525 like it is. The separate Booster you can wire directly from starter battery plus and minus to the booster and from the booster output to the leisure battery plus and minus. Maybe you use 16qmm wires for the connection. D+ the alternator signal you find at the Booster Wa 121525, in case the booster needs to have any switched signal.
With Best Regards,
i.o. Udo Lang.”
I will sell the Votronic if I go ahead. I think 80 amps will be pushing the alternator.
 
Jul 26, 2018
18
7
Scotland
Funster No
55,157
MH
Pilote P696D
Exp
Owned AutoTrail Navajo from March 2013 until replaced with current van in 2020
I also like fiddling with this stuff
Seems like a good enough reason to me :)

Nigel Ivy tells me that the 50A Victron B2B (I presume you're referring to the Orion XS 12/12-50) won't now be available until end April. One of the benefits that I was tempted by was that it's (a lot) more efficient than the previous ones. But I'm currently thinking that 50A might be too much for me (principally the cabling from the vehicle battery that I'm trying to avoid changing for now) so I'm now intending to fall back to the current 30A one. Also, I need to get all this stuff installed.

My only remaining issue is whether I want/need isolated or not.

Graham
 
OP
OP
Googlebot
Sep 29, 2019
3,073
7,097
Funster No
64,846
MH
Hymer Exsis
Exp
20 years
Just an update, I have decided to go for it. It can go in the same place and using the existing wires from the engine battery makes sense. Just need to run some new wires to the leisure batteries.

Off grid power solutions are doing a good deal so will order it.

Am I right in thinking I just need to completely disconnect the wires from the back of the EBL? Or leave the leisure battery connection in and just disconnect the starter connection with new midi fuse at 60 amp which then connect to the input on the B2B? Then I will still have fridge and engine battery charging etc.

There are mega fuses at both batteries, but they are 75 amps each collectively giving 150 amps. Do I need a 60 amp midi where I connect to the bus bar at the end of the B2B connection?
 
OP
OP
Googlebot
Sep 29, 2019
3,073
7,097
Funster No
64,846
MH
Hymer Exsis
Exp
20 years
Seems like a good enough reason to me :)

Nigel Ivy tells me that the 50A Victron B2B (I presume you're referring to the Orion XS 12/12-50) won't now be available until end April. One of the benefits that I was tempted by was that it's (a lot) more efficient than the previous ones. But I'm currently thinking that 50A might be too much for me (principally the cabling from the vehicle battery that I'm trying to avoid changing for now) so I'm now intending to fall back to the current 30A one. Also, I need to get all this stuff installed.

My only remaining issue is whether I want/need isolated or not.

Graham
Aren’t isolated only for boats? I think you can use either?
 
Mar 30, 2019
2,781
5,158
Cardiff, UK
Funster No
59,476
MH
Coachbuilt
Exp
Since 2016
Just an update, I have decided to go for it. It can go in the same place and using the existing wires from the engine battery makes sense. Just need to run some new wires to the leisure batteries.

Off grid power solutions are doing a good deal so will order it.

Am I right in thinking I just need to completely disconnect the wires from the back of the EBL? Or leave the leisure battery connection in and just disconnect the starter connection with new midi fuse at 60 amp which then connect to the input on the B2B? Then I will still have fridge and engine battery charging etc.

There are mega fuses at both batteries, but they are 75 amps each collectively giving 150 amps. Do I need a 60 amp midi where I connect to the bus bar at the end of the B2B connection?
if you definitely go ahead can I be first in line for your old one when you sell it please 👍

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OP
OP
Googlebot
Sep 29, 2019
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20 years
Of course Malcolm.

New one should arrive in about 6 weeks, will drop
you a message when it’s available. 👍
 
Sep 29, 2007
805
1,169
Wantage, UK
Funster No
475
MH
C Class
Exp
Motorhoming since 2006, 30 years tent camping in Africa
Aren’t isolated only for boats? I think you can use either?
You can use them in Motorhomes. Simply bridge the two negatives to the chassis or to one of the battery negatives (unless it’s a smart alternator in which case probably best to go to the chassis).
 

Lenny HB

LIFE MEMBER
Oct 18, 2007
53,797
151,482
On the coast in West Sussex
Funster No
658
MH
Hymer B678 DL
Exp
Since 2008 & many years tugging
Am I right in thinking I just need to completely disconnect the wires from the back of the EBL? Or leave the leisure battery connection in and just disconnect the starter connection with new midi fuse at 60 amp which then connect to the input on the B2B
That's the way to do it, just disconnect the starter battery feed to the EBL.

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Sep 22, 2023
457
369
Funster No
98,988
MH
4 berth coachbuilt
Am I right in thinking I need to leave the leisure battery connection in and just disconnect the starter connection
Yes. Our new Hymer Exsis came that way (no starter battery connection to the EBL)

The [Schaudt] B2B is wired between the two batteries. (nowhere near the EBL)
 
Sep 22, 2023
457
369
Funster No
98,988
MH
4 berth coachbuilt
I don't like the WA121525, it outputs a constant 14.4v even when the battery is charged relying on the BMS to cut charging not a good idea.
There are lots of low current wires connected to the WA 121545.

I have yet to check if any of them cut the output when the battery is charged.
 
OP
OP
Googlebot
Sep 29, 2019
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Funster No
64,846
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Off Grid have been in touch and all ordered. Thanks for everyone’s help.

Your alternator is probably 160 amp so not a problem.
Does that mean I can leave the Votronic in as well, run new cable from the starter battery to the B2B and use both?

That would mean a 50amp and a 30amp B2B.

I don’t think I will go for that. Unless it’s a good idea and I can?
 
Apr 9, 2022
413
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87,949
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Cathargo
Exp
Newbie
Out of interest what size Hab battery have you got?

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OP
OP
Googlebot
Sep 29, 2019
3,073
7,097
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64,846
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Hymer Exsis
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20 years
Out of interest what size Hab battery have you got?
200ah of lithium.

They will take 50amp of charging each. With the solar on full chat and both B2B’s that will give about 105amps. At the limit but won’t be charging for long at that rate!
 
Last edited:
Apr 9, 2022
413
398
Funster No
87,949
MH
Cathargo
Exp
Newbie
200ah of lithium.
That size battery should be able to use the 80amps, and won't need the alternator to run for hours to fill it so not much downside. I'm not familiar with the charge profile and low temp control of the old B2B so don't know how elegantly they would work together, but it'll work...
 
OP
OP
Googlebot
Sep 29, 2019
3,073
7,097
Funster No
64,846
MH
Hymer Exsis
Exp
20 years
Excellent!

Let’s give it a go.

Sorry Itsmcb, if my alternator says no, I will let you know. :)
 
May 11, 2023
190
183
Funster No
95,901
MH
Globecar Summit 540
I don't like the WA121525, it outputs a constant 14.4v even when the battery is charged relying on the BMS to cut charging not a good idea.
I think Carthago fit it as standard but they only mention a B2B on the up market models.

If one is fitted to my Compactline when I get it I may rewire it just to supply the fridge and fit a Victron XS for the batteries.
I think it is a really poor design from Schaudt.
I've set my schaudt 121525 to the lead acid setting, at least it drops down to 13.8V for absorption. I also have put an online switch in the D+ so I can disable it, I'm hoping the solar will keep things topped up most of the time.

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