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Sterling B2B and Split Charge Relay


arthur49

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aandncaravan - 2018-07-10 11:06 PM

 

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

 

I believe so and Schaudt even state that only the habitation battery is charged via the solar input to the EBL.

http://www.acpasion.net/foro/archivosadjuntos/obelix/manuales/Schaudt_Electroblock_EBL208_SE_Ingles.pdf

Page 5.

 

Thanks again for the advice, Rather than send the unit back for upgrade I think I will fix up the cabling and go with your suggestion to route the output of the NDS via the pins 3 & 4 of the EBL.

What's confusing though is it appears that while there are 2 x 4mm cables on on pins 3 & 4 of the EBL they emerge from under the floor as a single 4mm cable going to a 30amp blade fuse which suggest they are spliced together somewhere under the floor. Surely this defeats the purpose of spreading the load across the 2 cables and unfortunately the same occurs on connections 1 & 2 to the habitation battery, two cables go under floor but emerge as one at the 30amp blade fuse. Confused!!

Part of the problem is I am midway through a Europe trip and home is in Australia where I have a heap of 10 and 16mm cable that would be ideal to run dedicated cables for both positive and negative connections to the starter battery. Anyways at least I have solar for now so can fix up the other issues when we return in spring next year ; )

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Wortho - 2018-07-10 3:13 PM

 

What's confusing though is it appears that while there are 2 x 4mm cables on on pins 3 & 4 of the EBL they emerge from under the floor as a single 4mm cable going to a 30amp blade fuse which suggest they are spliced together somewhere under the floor. Surely this defeats the purpose of spreading the load across the 2 cables and unfortunately the same occurs on connections 1 & 2 to the habitation battery, two cables go under floor but emerge as one at the 30amp blade fuse. Confused!!

 

Mark,

 

I have been otherwise engaged for the last 24 hours, and have been unable to consider your problem further.

 

In reply to the query raised above, it is the rating of the Electroblok connectors that is the problem. They tend to overheat at high currents. I believe that Allan of aandncaravanservices has met this problem more than once in his business role.

 

As regards your immediate course of action, it may help to consider your style of camping. If you intend to use EHU for most nights while on your European trip, the B2B function will be of little use, however if wild camping, or not using EHU, then it may be more useful. Again as you are on tour and may be on the road most of the time, is there any gain in changing the solar regulator to one that can also charge the starter battery?

 

Alan

 

 

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Alan,

Thanks again, i'm not really concerned with the solar not charging the starter battery as we tend to only stay in one place for a couple of days with no power before moving on. The main reason to upgrade is to move to a mppt regulator to increase performance as I don't know the type of regulator used in the B2B unit. We typically spend a couple of nights wild camping and then move on and so far we have only had to hook up the power twice on our trip so far. This is also without the B2B functioning properly so we would probably never need a mains hook-up if it was working properly.

 

In regards to the option of running the output of the B2B to pins 3 & 4 of the EBL I am wondering if the EBL is capable of delivering the full 30amp output of the B2B, it has a 30 amp fuse and if the EBL is really capable of delivering up to 30amps I wonder if there is any real benefit of having the B2B installed. I guess the main advantage of the B2B is the 5 different load stages during charging, but again I am assuming this still applies when charging from alternator and not just when charging from mains. The EBL has 3 stages of charging boost-charge-float but I believe this is only when charging from mains.

 

Cheers

 

Mark

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Most Schaudt Elektroblocks made after 2001 are capable of handling around 50 amps peak from the Alternator.

The EBL 208 has different connectors but should still handle about 40amps with ease.

 

Remember when the Alternator is charging the habitation battery it will only reach it's peak for a matter of minutes, slowly backing down the amps as the battery takes up the charge.

After about 20 minutes most batteries will be drawing about 3/4 of the current they did when the Alternator first started spinning.

So just because the NDS has a peak 30amp rating, I wouldn't expect it to reach that. If it does, it will be for short periods only.

However, that applies to normal running, if the batteries are wrecked (as I suspect yours are from the high currents melting the fuse) and effectively shorting out, then you may see very high currents for extended periods and that's when things go pop.

 

 

Because of the efficient design of the Schaudt Elektroblock EBL xxx installation, the voltage drop is very much reduced compared to other manufacturers.

Unless you are using AGM batteries, I don't think you will notice the difference between running with the NDS and without it.

 

 

We think installing the most efficient batteries will have a more beneficial impact than a B2B. For example Varta LFD90's charge more than twice as fast as a conventional battery and almost 3 times that of Gel.

 

A Varta LFD/Bosch L series battery is claimed to have 70% better 'electrical flow' than a conventional battery when aged a year or two.

70% is a lot. If you think of that in terms of Solar, then running two budget Lion's/Hankook's is like having 70% of the Solar panel covered with a blanket versus a Bosch/Varta Powerframe battery.

 

The B2B might give a slight improvement on Alternator charging, but the right batteries improve all charging.

 

We would say focus on the battery, not a B2B, in your vehicle.

 

 

We still suggest you upgrade both fuses we mentioned earlier.

 

 

 

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Mark,

 

I have missed the statement, but for clarification where exactly was the output of the NDS unit connected.

 

Was it connected to the EBL side of the habitation battery fuse?

 

(I understand that the input was inncorrectly connected to the habitation battery.)

 

If the above is the case you could have the situation where the NDS unit was trying to dissipate the boosted component (less than a volt?) of its output via the fuse and cables to the battery. While the voltage difference is low, so also would be the combined resistance of the fuse and cable included in the path. The resulting current passing through the fuse would be quite high. I am wondering whether this could be part of the cause of your fuse failure?

 

To be fair Allan of A and N Caravan Services has had some considerable experience of EBL units and similar, that have been damaged by faulty batteries.

 

Is it worth checkng what the mains charger in the EBL only pushes into a fully charged battery, after a few hours? I would expect it to be less than 0.5A, but Allan may have some opinion here.

 

I like Allan's suggestion of connecting the output of the NDS unit into terminals 3&4 (starter battery input) of the EBL. However I am not convinced about the need to run a negative cable back to the alternator, or in fact for the positive connection to be made at the alternator. Considering the inaccessability of some alternators, the cost/benefit ratio could be poor. However there is some history of degraded engine block earthing on post 2006 Fiat Ducato vehicles, causing poor starting and battery charging.

 

The thickness of the negative cable to the NDS unit may not be critical, as it does not appear to part of the main current path. Based on the recommendationof 1.5mm cable for my CTEK D250S, 2mm cable should be adequate.

 

As regards the solar regulator function of the NDS unit, can you not find out if it is a MPPT unit via your contact in NDS? If it is MPPT any gain in changing it would be marginal, unless there is some feature that you specifically require.

 

Overall as you have the NDS unit why not make use of it, and as Allan has suggested, use cables that are as thick as possible. In particular thicker cables on the output connections and to the habitation battery will improve voltage sensing by the chargers. I have not studied it in depth, but I cannot see any advantage in running two mains chargers unless your are supporting abnormal battery loads. At any time the charger offering the highest output will dominate. This could interfere with timed charging stages.

 

I hope that this helps you decide on your final course of action

 

Alan

 

 

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Alanb, I suspect, but don't know without more detail, that because the NDS took it's input from the habitation battery, the Alternator charge was drawn via the 'old' EBL split charge relay and then sent to the habitation battery through the habitation batteries 30a fuse, which melted when current approached 30amps.

There was no other path I can see it might have taken because both the 'In' and 'out' of the NDS were connected to the habitation battery and the only path from the Starter battery/alternator was through the EBL.

 

I can't see that the NDS did anything except raise the habitation battery voltage slightly so more current was drawn through the EBL.

 

That the unit 'worked' for several years set up like this suggests that something changed to draw extra current.

The only thing I can think of is degraded Hab batteries.

 

 

 

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Thank you again Gents for the invaluable advice. We currently have a single 100ah AGM battery as the habitation battery but I will certainly look at the Varta as a replacement option. Also good to hear that the EBL can handle loads of 40-50amps. Everything is working fine at the moment with only the solar connected at the B2B and the battery seems to be fine and has been running the fridge for a couple of days now with just the solar input. I will try and check what current it's pulling when fully charged however just to be sure.

 

Alan, The B2B output is connected direct to the habitation battery with no fuse but it was the 30amp fuse that was between the EBL and the habitation battery that was blowing when the B2B switched to alternator input. This most likely had something to do with the way it was incorrectly wired with both input and outputs to the same battery. The other contributing factor is the habitation battery was running quite low the day before the fuse melted (11.5v) but I did connect it to mains to charge before leaving the camp so both battery's were fully charged when the fuse holder finally went open circuit, but perhaps the damage had already been done as I recall running the engine for a few minutes before connecting to AC power. It appears that the fuse holder was not up to the job of delivering the high current required but it melted rather than blowing quickly. It's the standard blade fuse and they sell a 40amp fuse in the same but I don't think the holders and spade terminals can handle these high currents for longer periods.

 

I also checked on the solar regulator and it's a PWM so probably worth investing in a MPPT regulator.

 

Cheers

 

Mark

 

 

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Wortho - 2018-07-12 2:07 PM

 

We currently have a single 100ah AGM battery as the habitation battery but I will certainly look at the Varta as a replacement option. Also good to hear that the EBL can handle loads of 40-50amps. Everything is working fine at the moment with only the solar connected at the B2B and the battery seems to be fine and has been running the fridge for a couple of days now with just the solar input. I will try and check what current it's pulling when fully charged however just to be sure.

 

The other contributing factor is the habitation battery was running quite low the day before the fuse melted (11.5v) but I did connect it to mains to charge before leaving the camp so both battery's were fully charged when the fuse holder finally went open circuit, but perhaps the damage had already been done as I recall running the engine for a few minutes before connecting to AC power. It appears that the fuse holder was not up to the job of delivering the high current required but it melted rather than blowing quickly. It's the standard blade fuse and they sell a 40amp fuse in the same but I don't think the holders and spade terminals can handle these high currents for longer periods.

 

I also checked on the solar regulator and it's a PWM so probably worth investing in a MPPT regulator.

 

 

 

The EBL 208 doesn't support an AGM battery? It is designed for Wet Acid batteries but doesn't make a bad job of charging Gel's.

If you use the EBL 208 to charge up an AGM battery it is unlikely to get up to full charge even after a week on charge, if the battery has been used some.

 

Also 11.5v is an excessively discharged AGM, which will have suffered damage.

The general concensus is that AGM's are best kept above 50% Depth Of Discharge to maximise life, that is equivalent to about 12.5v.

 

That the AGM has been discharged to 11.5v plus the excessive charging current that followed leads me to stand by my original assessment that the battery is goosed and the cause of this recent problem.

 

I would suggest you reinstall the NDS if you want to continue using AGM batteries.

 

 

 

 

 

 

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aandncaravan - 2018-07-13 3:53 AM

 

The EBL 208 doesn't support an AGM battery? It is designed for Wet Acid batteries but doesn't make a bad job of charging Gel's.

 

 

There is a switch on the EBL for Battery type with following 2 options.

 

1. Lead-Gel/ AGM 1

2. Lead Acid

 

Currently option 1 is selected.

 

The habitation battery is a LEOCH LPL12-100 maintenance free sealed lead acid but has a sticker on the top 'AGM technology' so I am assuming it's a true AGM but maybe not.

 

If AGM is not supported on the EBL 208 S would this only apply when charging from mains or when charging from the alternator or solar also?

 

Thanks again.

Mark

 

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The very last version of the EBL 208, the SG model, did have the text changed to include AGM 1, just as yours, but the mains charger inside was exactly the same as that on the EBL 208 SE and earlier versions. It is designed for wet batteries, but does a fair job of charging Gels. The charger will not look after an AGM.

It might say AGM on the front, but you get a Gel charging profile.

 

All the EBL 208 chargers we have seen are 14.3v 'boost' and 13.8v Float.

Yet we have not yet seen an AGM Leisure battery that didn't want less than 14.7v, most 14.8v, and a float of no more than 13.5v. Ideally less.

 

 

When Hymer started installing AGM batteries in motorhomes they said a Gel profile was adequate. There were lots of prematurely failed AGM's and AGM's not delivering full capacity because they were not being charged fully.

 

Schaudt very quickly spent a huge amount of money revising the range of all the Hymer chargers to a proper AGM profile. They also brought out a revised Solar regulator.

 

 

The old Schaudt Solar reg was 14.2v, but the new AGM optimised version, the LRM1218, was 14.8v and 13.4v.

 

There must have been good reasons why Schaudt bothered to spend a lot of money changing their Solar reg regulator to give it a special AGM optimised profile and just about every charger from 2015 to a 14.8v output when AGM was selected?

Have a read of our AGM pages : http://www.aandncaravanservices.co.uk/agm-batteries.php

 

 

I assume that Adria fell into the same trap as Hymer?

 

 

I would guess your Alternator will be a standard 14.4v unit.

No idea what the NDS Solar regulator will be, hopefully 14.8v and 13.3v?

 

Please note that it has been recognised that AGM batteries are less happy than most Acid technologies on long term maintenance charging like Solar or EHU. Most manufacturers are now stipulating less than 13.5v Float. Victron say 13.2v.

 

Banner say on their website, don't keep their AGM batteries on float charge for more than 7 days.

 

 

It is now recognised by the industry that AGM were oversold and don't deliver, hence the switch to wet/flooded EFB technology.

For evidence of that, have a look at the Banner web site, almost all the new top range batteries are EFB's.

 

Most motorhome AGM's don't make it to 3 years, usually nearer 2.

A battery that cost twice as much as the Varta LFD90 and it's usual 4 - 5 year life, should have had a 8 - 10 year life.

 

 

I would guess that in your case the way the NDS B2B was wired might have extended an AGM's life, but it's such a strange installation, i'm not sure.

If it were me and the AGM was more than 2 years old I would ditch it before it does more damage.

 

 

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Thanks again for the information aandncaravan.

 

I found the spec sheet for the battery and you are correct as it states a charge voltage of 14.4 - 15vdc during cycling and 13.5 - 13.8vdc when on standby, so the EBL alone won't be able to provide this. I have looked for the charging voltages for the NDS B2B but they don't specify voltages but have a specific charging profile for AGM.

I think the alternator must be the standard 14.4v as the other day I went for a drive with a voltmeter attached to the starter battery and saw voltages between 14 - 14.2v at the battery post. I did this to try and determine if the van has a smart alternator as it's a Euro 6 and the NDS has another charging profile for Euro 6 with smart alternators. I determined I didn't have one or it was disabled as the voltages did not change under braking as they should if a smart alternator was active.

 

I have just checked the habitation battery and now it's been running for almost 3 days with just solar and overnight it dropped to 12.5v but has now increased to 12.7v with some morning sun hitting the panels. The battery is 20 months old but it' sounds like I will be better off with a non AGM battery or get the NDS operating fully again.

 

Cheers

 

Mark

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