Sterling 60amp B2b and split charge

[Poutie]

Hi I’m after some advice. I recently fitted a sterling B2b, all went well with the installation and I think it’s working ok however reading other threads on here I’m worried that I have not disconnected my split charge as others have and it’s working overtime. Any advice would be gratefully received. My specs are as follows

Laika kreos 5009 (2016)

CBE electrics

CBE pc320 control panel

CBE 520 charger

In the may issue of MMM they say it’s a relatively easy process of removing the wire from J87 on the relay but I’ve looked everywhere for the relay and can’t find its location below is the wiring diagram from the pc320 manual

 

[aandncaravan]

What model of fuseboard do you have, a DS300?

 

What makes you think it is working overtime?

 

 

 

[Poutie]

Hi there, I was hoping you would come back to me as I’ve viewed your web pages with interest, I can’t find the DS300 anywhere my distribution box is RB550. The reason I think it’s working overtime is the fan is going quite often whilst I’m driving but looking at the control panel in the van it does seem to be doing the right thing battery does go upto 14.4v.

Reading other posts people do say to disconnect the split charge however are they talking about older vans and should I just leave well alone and let it do it’s thing

[aandncaravan]

Nobody I have asked has been able to give any thing solid and I can see no bad reason for removing it but I can see good ones for leaving it.

But if I just say that, then several people will come on here and disagree and give 'back feed' as an issue.

 

 

So if we start by looking at a typical CBE system and it's issues and work through from there.

 

 

The CBE systems we have worked on have an Negative/Earth feed into the DS unit, a single Starter Battery/Alternator positive feed, and a Habitation positive supply.

 

There is no direct, independent feed from the Alternator/Starter battery for the Fridge.

 

The Fridge take off is picked up just after the Starter battery supply Stud point on the PCB and not far from where the feed to the Split charge relay is taken. And that is the key problem as the heavy load of the Fridge creates a big voltage drop at exactly the point where the power is taken to charge the habitation battery, which then only gets 13.9v (typically).

 

When we have given the Fridge it's own supply from the Alternator, charging has been transformed.

 

Now if you wire a B2B into the circuit it will supply 14.4v at the habitation battery terminals. There is a good chance that 14.4v will flow against the 'old' 13.9v back to the DS300 PCB.

This is good as the Fridge will also get a decent voltage as everything is 'linked' together by the old Split charger.

 

Now, so the 'expert' argument goes, the 14.4v from the B2B will carry on back down the Starter battery feed cable, double back into the B2B, create a tragic circle of Doom and explode, etc.

 

Except it can't.

 

The minute you remove the load (Fridge and charging) from the Starter Battery feed at the DS300, the voltage drop will disappear and strong 14.4v will appear back at that point.

 

The 'backfeed' voltage from the B2B will have been so heavily loaded by charging the habitation batteries and feeding the Fridge, it won't be at 14.4v anymore, more like 14.1v.

Therefore won't be able to track back down to the Starter battery/Alternator.

 

If your CBE Alternator charge/Fridge circuit was only passing 0.25amps, then the voltage would be up near 14.4v. It is only the load on the cabling/PCB that drops it down.

 

The RB550 may operate slightly differently but all the above principals still apply.

 

 

I suspect what you are seeing with the B2B fan running all the time, assuming the batteries are perfect, is the B2B supplying the Fridge with a really decent voltage, and about 15amps, that gives a better functioning Fridge that should be noticeably more efficient when driving on 12v.

 

Leaving the old mechanism in place also gives you an automatic standby system when the B2B fails.

 

 

You could have achieved the same end result without a B2B, just powering the Fridge from the Alternator direct, it has a much bigger impact than even we expected.

 

 

[veletron]

Hi

 

Cant help with the CBE side, mine was Nordelettronica, and their man francozille@nordelettronica.it told me which resistor to de-solder from the PCB in order to disable only the split charge, and leave the fridge feed intact.

 

My B2B is the same as yours BTW, and I had issues with it and the smart alternator fitted to the van. Rather than leaving it on auto-sense [link in place] (which led to inadequate charging), I used the remote terminal to manually activate the B2B. I also changed the cut-off voltage to the lower one as per the manual (Mode 3). There was a warning in the manual that this would mean that the B2B could drop the van battery to as low as 11.5v before the cutout operated, but as The B2B comes on (off the fridge D+ feed) via the remote sense wire and as the alternator would be running, this will never happen.

 

I see about 52A as a maximum after a nights heavy use, the B2B fan runs continuously until the SoC rises to around 80% and the current gradually falls off. You'll never actually see 60A at the leisure batteries BTW, only at the van battery. The B2B steps up the voltage, barring losses of maybe 3% (heat!), the wattage is the same, but as the voltage is higher, the current will be lower to the LB's.

 

For reference, I have a couple of Exide 140AH batteries which have been doing sterling service for three years over about 230nights away in total. I would consider myself a heavy 12V user having a van full of gadgets, and running both a kettle and toaster off a 1KW inverter without issues. There is also 200W of solar on the roof.

 

To keep an eye on the state of the LB's, and the current being passed to them, I recommend the NASA BM1! https://photos.veletron.com/picture.php?/168/category/222

 

Nigel

 

 

 

Nigel

[Poutie]

Sorry I’m a little late replying to you I’m currently in Norway and the signal is a bit sporadic,Thanks for giving the assistance I required, the fridge does indeed seem colder running on the battery than before so I’m going to leave all alone

[Derek Uzzell]

A couple of follow-up points

 

1: The CBE RB550-LK ’switchboard’ was mentioned in the "PC770-LK GETS NEW FUNCTIONS” section of this 2012 press kit

 

http://www.cbe.it/pro/wp-content/uploads/2012/09/CBE_PRESSKIT_2012_EN_PM_FINAL.pdf

 

but I can’t find any other useful information about it. (Andrew’s 2016 Laika Kreos has a CBE PC320 control-panel, not the PC770-LK panel.)

 

2: The MMM article (May 2019 Page 172) Andrew refers to related to an enquiry about fitting a Votronic B2B charger to a 2011 Rapido motorhome that had 340W of solar panels and two 125Ah lithium batteries. However, although the (probably correctly) assumption was made that the Rapido would have CBE-made electrical equipment, the advice that the existing engine-charging arrangement needed to be disconnected from the leisure-battery set-up included a diagram with separate relays as shown here

 

http://www.motts.org/SPLIT%20CHARGING%20SYSTEM.htm

 

rather than the equivalent components that are an integrated part of a CBE distribution box. It might well be practicable to disable the coupler/separator that (I assume) is on a RB550’s PCB (as Veletron did with the Nordelettronica unit) but it would not be as simple a task as disconnecting a wire from a traditional separate relay.

[Steve928]

veletron - 2019-05-14 10:01 PM

 

Hi

 

Cant help with the CBE side, mine was Nordelettronica, and their man francozille@nordelettronica.it told me which resistor to de-solder from the PCB in order to disable only the split charge, and leave the fridge feed intact.

 

 

Nigel

 

Nigel

 

Hi Nigel,

I wondered if you still had the information from Nordelletronica on this modification to save me pestering them in these troubled times?

We've just brought home a new Eura Mobil Profila with Nordelletronica systems (NE287 charger, NE274 control panel and NE196 fusebox) and I have my Sterling B2B from the old van to fit and this is exactly the modification that I need to make.

Thanks, Steve

 

[veletron]

Hi

 

You'll need a nice small soldering iron as its an SMD part that needs removing. I replaced mine with a standard resistor and a toggle switch so that if I wanted to sell the van without the Sterling B2B, a simple flick of the switch would re-enable the old charging scheme, also good as a backup if the B2B dies. NB: I cant remember resistor value, you'll have to measure the SMD part with a multimeter.

 

Aye, indeed, I reckon franco has more important things on his mind!!

 

See pic for what needs removing.

 

[Steve928]

Excellent, thanks very much. I have the required small soldering iron but whether or not I can stop my hand from shaking using it on a 5 day old van is another question..

 

The supplying dealer replaced the standard fit 80Ah gel hab battery with a 100Ah NDS GreenPower AGM (which despite reservations about AGM technology seems to be a good battery) so I need to get charging in place at the voltages that suit the AGM.

 

[Derek Uzzell]

I’m guessing you are already aware of this, but I notice that a Nordelettronica NE287 battery charger has a couple of dip-switches that allow selection of three different IUoU charging regimens - AGM, or gel, or ‘Pb flooded’.

[Steve928]

Indeed, plus a 4th. setting marked 'DES' which I guess might me for desulphation.

The charger instructions don't state what the difference in voltages/timings are between these regimes though. I've emailed Delta Conversions (essentially Nordelletronica UK) requesting this data but have not yet had a reply.

The fitment of the AGM has left me with an incompatability charge-wise between lead-acid starter battery and AGM hab battery. As we don't often use EHU this isn't a big problem as long as the NE287's settings don't damage either which, at a measured 14.4v boost and 13.6v float in AGM setting, it shouldn't.

 

It does make it imperative that I get proper charging for the AGM in place though.

My Sterling B2B can be set to 14.8v/13.6v and my Votronic solar controller to 14.7v/13.5v, both of which should be perfect for the NDS AGM for which voltages should be between 14.4-14.9 cyclic and 13.5-13.8 float according to its spec. sheet.

 

[spirou]

I wouldn't worry about NE charger settings too much if you're mostly relying on solar and alternator charge which obviously can be set to whatever you need.

[xsilvergs]

Just found this thread, I see its been quiet for a few months but wonder if anyone else has tried veletron's removal tip?

 

If so any comments on how the NE196 performs, does relay RE1 still function when when external EHU is connected?

[Alanb]

When I installed the more basic and smaller CTEK B2B in conjunction with a CBE DS520, I opted to place an additional relay for the fridge in series the B1 (starter battery) connection to the DS520. This relay is controlled by the simulated D+ output of the DS520, which is not modified from standard. My reasoning was similar to Velotron's in respect to emergency restoration.

 

I did not, and cannot accept the deceased Allan Evans reasoning for leaving the split charge relay functional. When the split charge relay operates, it forms a short circuit between the input and output of the B2B, The B2B will try to maintain its boosting voltage difference, by circulating current through the split charge relay. This could result in overheating of the B2B and wiring.

 

Alan

[xsilvergs]

Alanb - 2020-08-28 8:19 PM

 

When the split charge relay operates, it forms a short circuit between the input and output of the B2B, The B2B will try to maintain its boosting voltage difference, by circulating current through the split charge relay.

Alan

 

My thoughts too.

 

Hence I wish to disable relay RE1 in the NE196. I wonder what effect removing the resistor has, does it disable the relay completely or only when IGN is ON and allow it to function normally when on EHU.

 

Hopefully veletron or some one else who has carried out this modification.