Sterling B2B and Split Charge Relay

[arthur49]

I had B2B professionally installed in 2014 in our then new van. I have been looking to uninstall the B2B to put in next van.

 

One of the considerations was to reinstate the Sargent EC155 split charge relay since it was - or I thought it was - disconnected when B2B was installed. My understanding is that was a requirement otherwise there would be conflict between the B2B and standard alternator charging through the EC155. So disable the latter is, or should be, standard good practice.

 

So I e mailed professional I used in 2014 to ask how to reinstate split charge relay charging to be told he "may well have left it as it was on the basis that the B2B would simply override it".

 

That somewhat alarmed me. I had the B2B professionally installed precisely because I was not sure how to disable the split charge relay!

 

Am I being concerned over nothing?

 

 

 

[Alanb]

Having installed a CTEK D250S B2B charger in association with a CBE PC200 system, I think that you are right to be concerned.

 

If all the original connections were left in place, the split charge relay would effectively short the output of the B2B to its input, rendering it usless.

 

I am not sure what effect this would have on the B2B, but in my own case I took particular care to avoid any possible damage to expensive piece of kit. As I wished to retain the mains maintenance charge of the starter battery, I ended up with several extra relays and an electronic driver for one of them.

 

Have you observed any increase in habitation battery charging rate, after the B2B was fitted? In my own case with a slightly discharged habitation battery I read 20A at tickover immediately after starting. This soon settles back to a more moderate level.

 

 

 

Alan

 

 

[arthur49]

Alanb - 2017-09-26 6:14 PM

...........................

 

If all the original connections were left in place, the split charge relay would effectively short the output of the B2B to its input, rendering it usless.

......................................

 

Have you observed any increase in habitation battery charging rate, after the B2B was fitted? In my own case with a slightly discharged habitation battery I read 20A at tickover immediately after starting. This soon settles back to a more moderate level.

 

 

 

Thank you Alan. I suspect the split charge HAS been disconnected since on start up of engine after an overnight off EHU, the B2B does kick in with a high initial charge rate (max I've seen is 27A) then, as does yours, it settles back quickly to a more moderate level.

But even if the split charge relay has been disconnected it is still concerning that a professional would believe its OK to leave it in place.

[keninpalamos]

I have an older Sterling B2B 12 12 50 on my van (Hymer '98) for 10 years now and it has never given any problems and works as you describe above. I will admit it can be a little enthusiastic for the first 2-5 mins when starting up after a night without EHU. So I turn it off for that first 10 mins. via the remote control unit. This can save excessive strain on Alternator and drive belt. Iv'e not had a problem with the 'vans own electrics as far as charging goes but if you are unsure give Junior Sterling a call on 01905 771771. a very amiable chap whom I have met, or you may be fortunate enough to talk to Charles Stirling Senior, who pops in from time to time, a real character but be prepared to duck if he doesn't rate your question :D I have just purchased their latest Pro Battery Ultra B2B charger which I intended to fit but am holding on to it as I may change my 'van in the not to distant future.

[arthur49]

Update: We are in process of changing vans. The B2B is uninstalled and on Fleabay!

 

In new van I intend to adopt Veletron's (Nigel) suggestion some time ago with a Voltage sensitive Relay and 25sq mm cabling to see how well that works. And of course disable the split charge relay which is also within an EC155.

 

I have found the split charge relay in old van had been disabled but I struggled to find how that had been done. Initially I thought the 'engine run' wire had simply been cut but its complete. Now I've found a relay tucked out of sight in the wiring loom. I need to investigate further but I suspect its a 'normally closed' relay and he's driven it from the engine run signal, to cut the charge from the EC155 to leisure battery whilst driving.

[Alanb]

Arthur,

 

I think that Allan of aandncaravanservices had some problems with a voltage sensitive relay.

 

It may be wise to investigate further before purchasing one.

 

Alan

 

 

 

[aandncaravan]

Arthur, a Voltage Sensitive Relay will work but can give unpredictable and unwanted results, as the voltage at the Starter battery can rise above 13.2v for several reasons, not just when the Alternator is spinning.

 

Imagine you have intelligent mains charging in the Motorhomes power controller/charger for the Starter battery that limits the Starter battery voltage to 13.5v (on the assumption this will almost always be fully charged when the Habitation battery is being given a big charge).

If you install a VSR it will 'see' the Starter battery rise above 13.2v and join both batteries together so that the Starter battery gets the same voltage as the habitation.

 

Same might happen with Solar charging of the Starter battery.

Etc.

 

 

An additional problem is that these devices have not kept pace with battery technology, they almost all assume the battery will have a fully charged resting voltage of a conventional batteries 12.6v. Yet AGM's, Gel's and Varta Powerframe sit near or even above 13v.

 

Imagine your VSR assumes the Starter battery is fully charged at 12.6v so waits until the voltage rises above 13.0v before it joins the batteries together. It then disconnects the batteries when the voltage drops to 12.9v.

 

You can see that because a quality Starter battery may sit above 13v for some time after charging, it could be days before it breaks the connection. Starting the engine soon after a short stop will have the two batteries joined together so BOTH can take part in supplying power to the Starter Motor, which is not a good idea for many reasons!!

 

 

Similarly, if the Starter battery is 'conventional' but the habitation battery is a healthy Gel sitting at about 13.1v, the VSR will continue to 'see' 13.1v at the starter battery and keep things connected. Why?

Because the batteries are joined together, so the VSR will have no idea that the Starter batteries real voltage is actually 12.6v, it will only see the higher 13.1v of the Habitation battery to which it is now connected. Therefore disconnection by the VSR may not occur until the habitation battery has become quite discharged.

The minute the Starter battery and Habitation battery are joined as one large bank, the voltage of the 'highest charged battery' is what will appear at both battery terminals so that is what the VSR will base it's activity on.

 

Obviously different VSR makes will have different voltage ranges AND different tolerances. We have seen some that activate at 13v and don't disconnect until 12.7v. A 10% manufacturing tolerance is normal on a quality unit, but makes a heck of difference in reality when the batteries are not the usual Car Starter batteries they are basing the design on.

 

Expect any tolerance to change as the units age. One very poor one we saw triggered as late as 14v but didn't disconnect unit 12.7v.

Definitely avoid the Durite versions.

 

 

VSR's discharge the Starter battery. ALL VSR's constantly sample the Starter battery power looking for a rise in voltage. That draws power from the Starter battery.

It won't be much during one day, but over 4 weeks...............

Again this will vary dependent on make and quality.

 

 

Lastly, they are also expensive, when a decent 'Fat Contact' 100amp 'manual' style relay can be found for less than £10, it does it make sense to pay a lot more to get worse functionality?

 

 

See the type of relay we recommend and why here : http://www.aandncaravanservices.co.uk/add-a-second-battery.php.

http://www.aandncaravanservices.co.uk/add-a-second-battery.php

 

There are very good reasons why all the major Motorhome electronics manufactures avoid using voltage sensing triggers and a good reason to ignore any kit that does.

.

 

 

 

 

[arthur49]

Alanb - 2018-02-01 2:24 PM

 

Arthur,

 

I think that Allan of aandncaravanservices had some problems with a voltage sensitive relay.

 

It may be wise to investigate further before purchasing one.

 

Alan

 

 

Thank you Alan

[arthur49]

aandncaravan - 2018-02-01 2:50 PM

 

Arthur, a Voltage Sensitive Relay will work but can give unpredictable and unwanted results, as the voltage at the Starter battery can raise above 13.2v for several reasons, not just when the Alternator is spinning.

 

Imagine you have intelligent mains charging in the Motorhomes power controller/charger for the Starter battery that limits the Starter battery voltage to 13.5v (on the assumption this will almost always be fully charged when the Habitation battery is being given a big charge).

If you install a VSR it will 'see' the Starter battery rise above 13.2v and join both batteries together so that the Starter battery gets the same voltage as the habitation.

 

Same might happen with Solar charging of the Starter battery.

Etc.

 

 

An additional problem is that these devices have not kept pace with battery technology, they almost all assume the battery will have a fully charged resting voltage of a conventional batteries 12.6v. Yet AGM's, Gel's and Varta Powerframe sit near or even above 13v.

 

Imagine your VSR assumes the Starter battery is fully charged at 12.6v so waits until the voltage rises above 13.2v before it joins the batteries together. It then disconnects the batteries when the voltage drops to 12.9v.

 

You can see that because a quality Starter battery may sit above 13v for some time after charging, it could be days before it breaks the connection. Starting the engine soon after a short stop will have the two batteries joined together so BOTH can take part in supplying power to the Starter Motor, which is not a good idea for many reasons!!

 

 

Similarly, if the Starter battery is 'conventional' but the habitation battery is a healthy Gel sitting at about 13.1v, when charging stops, the VSR will continue to 'see' 13.1v at the starter battery and keep things connected. Why?

Because the batteries are joined together, so the VSR will have no idea that the Starter batteries real voltage is actually 12.6v, it will only see the higher 13.1v of the Habitation battery to which it is now connected. Therefore disconnection by the VSR may not occur until the habitation battery has become quite discharged.

The minute the Starter battery and Habitation battery are joined as one large bank, the voltage of the 'highest charged battery' is what will appear at both battery terminals so that is what the VSR will base it's activity on.

 

Obviously different VSR makes will have different voltage ranges AND different tolerances. We have seen some that activate at 13v and don't, disconnect until 12.7v. A 10% manufacturing tolerance is normal on a quality make, but makes a heck of difference in reality.

Expect any tolerance to change as the units age. One very poor one we saw triggered at 14v but didn't disconnect unit 12.7v.

Definitely avoid the Durite versions.

 

 

VSR's discharge the Starter battery. ALL VSR's constantly sample the Starter battery power looking for a rise in voltage. That draws power from the Starter battery.

It won't be much during one day, but over 4 weeks...............

 

Lastly, they are also expensive, when a decent 'Fat Contact' 100amp 'manual' style relay can be found for less than £10, it doesn't make sense to pay a lot more to get worse functionality.

 

 

See the type of relay we recommend and why here : http://www.aandncaravanservices.co.uk/add-a-second-battery.php.

http://www.aandncaravanservices.co.uk/add-a-second-battery.php

 

 

Thank you Allan. Since posting earlier today I had a good look at the relay I found. It is 'normally closed' so I unplugged the coil + and - and I had charging back whilst driving! Tidied up the wiring and put it back together. I did consider taking out the relay but I left it in place.

 

I found the EC155 split charge relay PCB mounted so the only way I could see to disable that inside the box would be to cut the solder track to relay coil or completely demount the relay. So I've learned how to disable the EC155 split charge on new van ...... when I get it.

 

And I'll use the split charge relay or similar, you suggest. On researching VSR relays I found the norm cut out at 12.8v but some have been changed to cut out at 12.65v because of the introduction of smart alternators.

[Alanb]

arthur49 - 2018-02-01 3:18 PM

 

Thank you Allan. Since posting earlier today I had a good look at the relay I found. It is 'normally closed' so I unplugged the coil + and - and I had charging back whilst driving! Tidied up the wiring and put it back together. I did consider taking out the relay but I left it in place.

 

.

 

Arthur,

 

I would feel duty bound to remove the additional relay from the habitation battery charging circuit.

 

The normally closed contacts of a relay typically have a lower current rating than normally open contacts, and the contact resistance will affect the habitation battery charging.

 

Leaving an undocumented, non functional relay concealed in the wiring could create expensive problems for a future owner.

 

Alan

[arthur49]

Alanb - 2018-02-03 9:11 AM

 

arthur49 - 2018-02-01 3:18 PM

 

Thank you Allan. Since posting earlier today I had a good look at the relay I found. It is 'normally closed' so I unplugged the coil + and - and I had charging back whilst driving! Tidied up the wiring and put it back together. I did consider taking out the relay but I left it in place.

 

.

 

Arthur,

 

I would feel duty bound to remove the additional relay from the habitation battery charging circuit.

 

The normally closed contacts of a relay typically have a lower current rating than normally open contacts, and the contact resistance will affect the habitation battery charging.

 

Leaving an undocumented, non functional relay concealed in the wiring could create expensive problems for a future owner.

 

Alan

 

Thank you Alan. I'll do that

[arthur49]

Update

Well new van has arrived and in process of installing Allan's suggested improved charging. But an issue has arisen. The Control Unit etc is Sargent EC155. The engine run is located at pin 7 of 9 pin connector - a red wire.

 

On Autotrail V-line 635SE its not! There is no connection to pin 7 and no trace of red wire working back the harness - but not to alternator. So where is the engine run signal located since pin 7 is blank?

 

Pin 1 is the Fridge 12v output. Could this be utilised as an engine run signal? (I suppose I could cut the wire to see the voltage with engine on and engine off but if someone knows it would be useful)

[sshortcircuit]

When I installed a Ctek B2B I simply pulled the fuse between the alternator and the Sergent. located beside the split charge relay, in my Kontiki.

[aandncaravan]

Hello Arthur, if you are looking for a 'driver' circuit for a chunky 100/200 amp relay then the relay coil may overload an Alternators D+ circuit, especially if D+ is already driving other items, like retracting the step, Satellite dish, etc?

 

We normally suggest using the existing Split charge relay to drive the new higher power relay, but this isn't always easy to do, but use it if you can.

 

The Fridge 12v Heating Element output is likely to have spare current for a big relay, so might be a good option.

 

 

Suggest a 2amp fuse in the feed to the relay coil.

 

 

 

 

[arthur49]

sshortcircuit - 2018-03-12 1:54 PM

 

When I installed a Ctek B2B I simply pulled the fuse between the alternator and the Sergent. located beside the split charge relay, in my Kontiki.

 

Thanks Hamish

[arthur49]

aandncaravan - 2018-03-12 8:18 PM

 

Hello Arthur, if you are looking for a 'driver' circuit for a chunky 100/200 amp relay then the relay coil may overload an Alternators D+ circuit, especially if D+ is already driving other items, like retracting the step, Satellite dish, etc?

 

We normally suggest using the existing Split charge relay to drive the new higher power relay, but this isn't always easy to do, but use it if you can.

 

The Fridge 12v Heating Element output is likely to have spare current for a big relay, so might be a good option.

 

Suggest a 2amp fuse in the feed to the relay coil.

 

 

Thank you Allan. I think I'll go for Fridge 12v ..... thats easy to identify! Failing that off to a professional

[Wortho]

Our 2016 Adria Twin was a few months old when we purchased in Germany and there was a Ladebooster fitted which Sounds like what is reffered to as a B2B. There is also a Electroblock EBL 208 S fitted and it appeared to me that both were doing the same job however in our case the solar panel was connected to the B2B. I was curious how it all worked but as the Circuit diagram in the manual only showed the EBL etc I just trusted that whoever installed the B2B knew what they were doing so left it at that.

 

So after travelling for two seasons without any issues we notice a burning smell but initially put it down to brakes as we were in the Pyranees and lots of downhill braking, then the EBL started to alarm so I pulled over and found that a 30amp fuse between the EBL and habitation battery had completely melted in its holder. I removed the holder and connected a new 30amp fuse direct to the spade terminals to try and get the fridge back on but it blew, then I tried to disconnect the feed to the B2B which was supposed to come from the starter battery and that stopped the fuse blowing but the B2B was disabled so no solar but strangely enough both batteries still charged when driving and also when plugged into mains which meant that both the B2B and EBL were charging both batteries at the same time : ( I got home a week or so later and after tracing wire etc I find the the input to the B2B was actually connected to the habitation battery and not the starter battery as it should have been, I'm confused how it went almost 2 years without becoming an issue but now I'm wondering what to do as if I correct the cabling so that the input to the B2B is from the starter battery I still have the issue of both units trying to charge the same battery which can't be good. I guess I could isolate the feed from the starter battery to the EBL but then I would lose the float charge to the start battery when I store the van and there are other connections on the EBL that seem to rely on the starter battery as well that could be disrupted. I'm thinking I should just remove the B2B and buy a solar regulator that plugs directly to the EBL, it seems all I will be missing out on is the extra charging amps that the B2B provided (or should have if wired properly) Has anyone come across a similar issue and maybe found a way for both charging methods to operate independently without loss of functionality of existing EBL.

Cheers

Mark

 

 

 

[Alanb]

Mark,

 

Whilst the thread is relevant to your problem, I thik that perhaps it would have been better to start a new thread.

 

That being said, may I say that your problem is of interest to me as I have a similar system with a CTEK D250S, and a CBE DS520 distribution board.

 

Your problem is somewhat simplified by the fact that diagams showing the connections inside the EBL 208, while the CBE and Sargent units are the black boxes. I had to deduce the internal connections of my CBE unit.

 

If you scan back in this (Arthur.s ) thread you will find that he had a normally closed relay inserted in the starter battery connection. However I do not think that even this will be necessary in you case.

 

I am not familiar with the EBL 208 but if you look at the published diagrm on page 12 of the Schaudt manual you will see the 30A fuse for the starter battery +ve connecting at pins 3&4 about a third of the way down the page. This only connects to the "Battery cut-off relay", which is in fact the split charge relay, as it is operated by the D+ connection from pin 16.

 

Looking closer to bottom of the page you will finf a 15A "Starter battery for refridgerator" fuse. It is via this second fuse that mains charging is given to the starter battery.

 

From the above, if you remove the 30A starter battery fuse, you should still have the mains charging facility for the starter battery, however a word of caution as I cannot see where the maintained 12V supply for fridge is taken from.

 

You mention loss of solar charging with the B2B disconnected. Is the solar panel connected to the B2B, and not into the EBL via a regulator. The CTEK D250S has a MPPT regulator included and can charge the starter battery after the habitation battery is charged,

 

I have often speculated as to the effect of shorting the output to the input of a B2B via a split charge relay. I think that what will happen is that the B2B will try to circulate current through the split charge relay. While the voltage difference is quite low, the currents could be up to the output limit of the B2B. Not good, so perhaps it would be wise to examine your EBL connections for any signs of overheating.

 

Alan

 

 

[Wortho]

Alan,

 

Many thanks for your detailed reply. I will try pulling the 30amp fuse and then check the starter battery when connected to mains to ensure the float charge is still present.

The B2B is an NDS power service Gold 30 and yes the unregulated feed from the solar panel goes straight to the unit but I am considering purchasing a MPPT regulator and going straight to the EBL instead as I am unsure of the type of regulator used in the NDS unit.

I will also check the fridge once I remove the 30amp starter fuse but I'm unsure why the fridge would connect to the starter battery and would prefer it to only have access to the habitation battery in any case. It's a 12v only fridge not an AES.

 

Cheers

 

Mark

[Wortho]

 

Update. I just found the install schematic for the NDS unit and it seems that Existing connections from EBL to habitation battery via connectors 1&2 should be redirected via pin 5 of the NDS B2B. I assume this method prevents charge from the EBL to habitation battery but allows power to flow in reverse to provide power to the EBL, maybe they use a blocking diode between pin 5&6 to restrict flow to one direction. In this case maybe I don't need to disable the starter battery feed to the EBL.

At the moment there is no cable connected to pin 5 of NDS so it seems whoever installed it really stuffed up the installation.

https://www.ndsenergy.it/prodotto/power-service/?lang=en

Cheers

 

Mark

[Alanb]

Mark,

 

The problem is that you are dealing with a black box, without even a block diagram of the internals.

I am not against blocking diodes in low current circuits, and have used them several times. However even with a Schottky diode the forward voltage drop would be at least 0.4V, and more like 0.6V or more under load. Not a good idea.

 

I would favour a normally closed relay between terminals 3 & 6 of the NDS unit, with the coil energised via the split charge relay via terminal 5. PURE SPECULATION, but in my opinion a relay contact would be more efficient than a blocking diode.

 

Is the starter battery input at the NDS Gold terminal 3, a sensing input, or the main charging current path? The NDS "Installation Scheme" diagram is very basic, with no guidance on cable sizing or fusing.

 

I am tempted to wonder if the NDS expects the loads to be taken directly from the service (habitation) battery.

 

Possibly using the diode test facility on a multimeter between NDS 5&6 in both directions may give a clue.

 

Sorry to pose more problems than answers.

 

Alan

 

It may be possible to try

 

 

 

 

 

[aandncaravan]

Wortho, the way to wire an Elektroblock EBL 208 using a B2B is to wire the B2B's output into the EBL's Starter battery port, not wire the NDS to the habitation battery direct.

 

Remove the Starter battery connectors from the EBL 208 Pins 3 and 4 and insulate them carefully. These are the existing Alternator charging paths. We are removing them as we want to break the existing Alternator charge path.

 

Then take two cables from the NDS Pin 6 and route them to EBL Pins 3 and 4. You must use two cables and both pins 3 and 4 as one on it's own will not carry the current.

 

 

The 'input' end of the NDS, can be routed to the Starter battery and this is the way most diagrams depict it should be done, however, this does not take account of the poor quality 'Earths' that most Motorhome chassis are known to suffer from after a few years use.

 

Therefore, ideally, run the NDS pin 3 to the Alternator B+.

Run NDS pin 4 to the Alternator D+ terminal, or pick up the D+ signal from the EBL's pin 22

Run the NDS pin 1 and 2 to the Alternator body and the Starter battery earth/negative clamp respectively.

 

I don't understand what NDS pin 5 is for as the 'old' split charge relay seems to be redundant as the diagram indicates it should be 'broken'? It seems to be functioning as a second D+ trigger in that NDS Pin 5 gets 12v+ when D+ triggers the old relay?

I would leave this unconnected.

 

 

Use cable sufficient to carry 60 amps. Although it is only actually carrying 30 amps, we want fatter cable for reduced voltage drop. Mount the NDS as close to the EBL as possible for the same reason.

 

I would bin the Solar capability and fit a proper motorhome specific Votronic MPPT dual battery regulator.

Mouting it next to the EBL will give you 'hooks' into both habitation and Starter battery wiring.

 

 

By routing the output from the B2B into the EBL you maintain all existing functionality, any current display capability the EBL had, will be maintained.

Instead of the EBL getting 14.4v direct from the Alternator, it now gets a B2B boosted voltage appropriate to the batteries installed. E.g, if the AGM battery option is selected, it will supply 14.8v to the EBL, etc.

 

The EBL208's split charge relay also isolates the B2B from the habitation battery, reducing battery drain in long term storage. It is often forgotten that a B2B will sometimes draw power from the batteries it is connected to. A relay doesn't.

 

 

Note 1 : Your original 'fault' of the overheated habitation battery fuse is indicative of an exceptional Alternator charging current being applied to the habitation batteries. Either because the battery bank is too big, too tired or both.

Suggest you replace the existing fuse holder with a Maxi, if it isn't already, and increase the fuse to 40a which is the more normal size for a Schaudt EBL set-up.

 

 

Note 2 : The lower spec NDS units claim to fast charge a battery at twice the speed of a none B2B setup. However their charge curve graph shows this is versus a 13.5v Alternator, not the more usual 14.4v unit that gets installed in all motorhomes.

So as per most B2B's claims, take them with a pinch of Salt unless the motorhome standard installation is appallingly bad.

 

 

 

 

[Wortho]

Thank you Alan and aandncaravan for your input and detailed responses.

 

I have been communicating with an Engineer from NDS and just this morning he has responded again and advised I could have the wrong version of their B2B : ( it seems they now have an 'M' version that presumably means motorhome and to confirm the Engineer asked me to check if I had continuity between pin 5 & 6 on the NDS when pin 4 was at 0 volts (Engine off), I checked and no continuity and hence why the EBL has no power when connected as per their install diagram.

It seems I now need to send the unit back to Italy for an upgrade to the M version. At this stage I'm considering just sticking with the EBL arrangement for charging and go with your recommendation to install a MPPT regulator direct to the EBL.

It appears that they have made changes to the M version and used what was a Aux output on pin 5 to provide a power source back to the EBL after breaking the existing connections between 1&2 and the habitation battery. I found the instructions for the M version here. https://www.roadpro.co.uk/userfiles/PDFs/product%20information/NDS/PWS%20GOLD%20manual.pdf Cheers Mark

[Wortho]

Just re-reading your post if I do end up getting the NDS upgraded I guess the recommendation is to still route the NDS output 6 through the EBL 3&4 after breaking the existing connections, with this approach hopefully a float charge can still be provided to the start battery when the van is stored as per Alan's earlier comments "15A "Starter battery for refridgerator" fuse. It is via this second fuse that mains charging is given to the starter battery"

Actually thinking about it with the above approach do I need to even bother getting the unit upgraded as I won't need to provide power back to the EBL via pin 5 on the NDS. I have to pay shipping both ways to Italy so would rather not send it back if I can avoid it.

 

Also just checked and D+ at pin 16 already connected to pin 4 of NDS.

Pin 3 of NDS should go direct to start battery and provides both alternator charge and power to the NDS as I tried to disconnect it to stop the 30amp habitation batt fuse blowing which it did but also lost solar input. I got around this by leaving pin 3 on NDS connected but removing D+ Wire so the unit stays with solar input even when engine running. I am assuming this approach is ok until I get a new solar regulator but means both the alternator (via EBL) and solar panel are charging the habitation battery at same time for the time being.

 

So to sum up.

 

*NDS B2B incorrectly wired with both input and outputs connected to same habitation battery.

* Incorrect cabling used - positive cables only 2.5mm and negative 1.5mm. NDS recommend cable with cross section greater than or equivalent to 10mm

* NDS B2B model fitted not correct model for motorhomes fitted with existing power controllers when using their recommended installation method.

 

Scary as it appears this German Adria dealer is fitting or getting someone to fit these B2B units to all the campers they sell.

 

Cheers

 

Mark

 

[aandncaravan]

"Wortho - 2018-07-10 11:35 AM

 

Just re-reading your post if I do end up getting the NDS upgraded I guess the recommendation is to still route the NDS output 6 through the EBL 3&4 after breaking the existing connections, with this approach hopefully a float charge can still be provided to the start battery when the van is stored as per Alan's earlier comments "15A "Starter battery for refridgerator" fuse. It is via this second fuse that mains charging is given to the starter battery"

Actually thinking about it with the above approach do I need to even bother getting the unit upgraded as I won't need to provide power back to the EBL via pin 5 on the NDS. I have to pay shipping both ways to Italy so would rather not send it back if I can avoid it".

 

 

Yes I would still suggest you use pins 3 & 4 and the mains Starter battery charge will take place down 'in reverse' to the Starter battery feed to the Fridge. Yes I agree that the upgrade would not be necessary and would be surprised if a dedicated Habitation and starter battery Solar charger were not a major improvement.

I would guess that even if the NDS Solar regulator is any good, it is just to the habitation battery, not the Starter battery?

 

 

 

 

"Also just checked and D+ at pin 16 already connected to pin 4 of NDS.

Pin 3 of NDS should go direct to start battery and provides both alternator charge and power to the NDS as I tried to disconnect it to stop the 30amp habitation batt fuse blowing which it did but also lost solar input. I got around this by leaving pin 3 on NDS connected but removing D+ Wire so the unit stays with solar input even when engine running. I am assuming this approach is ok until I get a new solar regulator but means both the alternator (via EBL) and solar panel are charging the habitation battery at same time for the time being".

 

 

Yes agree with that, by taking out D+ you have effectively disabled the NDS Alternator boost.

 

 

On the subject of cabling, you could use the removed 'Starter battery feed cables' to EBL 208 pins 3 and 4 to supply the NDS. That will connect the NDS input to the Starter battery.

It won't overcome any loss of voltage through poor Earths or issues resulting from the Alternator being mounted onto an Alloy casting which is then bolted using Steel Bolts to an Alloy Head/Engine Block which may or may not have a good Earth to the chassis, etc.

 

However, you could address this later by fitting a separate cable from the Alternator body to the Starter battery negative, if you wish.

That should make it all quite easy to wire up.

 

 

When you fit your Solar Regulator, use the Fridge Starter battery feed to access the Starter battery, Pin 7, not the main Alternator charge cable. Upgrade the fuse to 20amp, 15 amp is too near the 13amp most Fridges draw.

Use the Solar regulator 3 pin port to access the habitation battery.

 

If you get a Votronic MPPT, then ask for the 'EBL cable' which plugs straight into the Solar port.