B2B / Hookup

[Marauder]

Hi All,

I decided to buy AGM leisure batts coz they can charge quicker with a B2B input.

So if i fit B2B, will it also charge batts when on hookup, or just when engine is running ?

And reading other threads, they suggest cutting the r37 resistor, but I don't even know what this means !!
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[Lenny HB]

I decided to buy AGM leisure batts

Deepest condolences, they are not very good for leisure use.

So if i fit B2B, will it also charge batts when on hookup, or just when engine is running ?

Only when the engine is running always best wired so it is triggered by the alternator D+.

And reading other threads, they suggest cutting the r37 resistor, but I don't even know what this means !!

Only applies to CBE distribution units, if you have a Burstner as in your profile you will have an Elektroblock.

 

[autorouter]

And reading other threads, they suggest cutting the r37 resistor, but I don't even know what this means !!

Cutting the R37 resistor in one particular brand of 12V distribution/fusebox will disable the split charge relay.

There are two methods of charging a leisure battery from the alternator when the engine is running. The simple method uses a relay (an electrically operated switch) that automatically connects the leisure battery to the starter battery when the engine is running, so that the alternator can charge both batteries as if it was a single big battery. That's what a split charge relay is.

The other method is to use a B2B, which is a battery charger that takes power from the alternator and provides the leisure battery with the right voltage and amps for optimum charging. The B2B is wired so that it only fires up when the engine is running, and disconnects when the engine stops.

When you fit a B2B as an upgrade from a split charge relay, you need to find a way to avoid the split charge relay from interfering with B2B charging process. Removing or disabling the split charge relay for example. Problem is, the relay is usually built into the distribution box and soldered to a circuit board, so it's not so easy.

There will be a way to get round this, but it often depends on the exact devices in your system. Cutting the R37 resistor is one example of a trick that works. What is the make/model of the distribution/fusebox in your setup?

 

[Marauder]

I have been trying to understand how to keep batteries healthy so heater will work.
Began with solar, but low sun off season in Scotland, (and I dont want to go elsewhere)
And, strangely, wind seems less useful than the dribble of PV. So I need a reliable source of power.

Most recent brainwave is make system so it will charge rapidly from mains or generator.
AGM batteries were part of this plan, but if they are poor, then I'm still struggling.

What is wrong with AGM option, and what might be a better solution ?

As Lenny suggested, I have an Electrobloc99 with AD01 nearby.

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[Lenny HB]

What is wrong with AGM option, and what might be a better solution ?

They tend to have a very short life span, although they claim to be better for high current draw and you can discharge them lower in practice they don't hold up & they are expensive.

Gels are the most reliable for leisure use and often last 10 years. You can discharge them down to 20% without shortening their life too much. They take longer to charge as they need a long absorption phase to achieve a full charge. However they are resilient to not being fully recharged whereas LA & AGM need a full charge to stop them deteriorating.

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[autorouter]

Most recent brainwave is make system so it will charge rapidly from mains or generator.

There is a limit to how fast you can charge a battery. Obviously with a generator you want them to charge as rapidly as possible to reduce the run time. The rule of thumb is to not exceed about a fifth of the battery Ah rating. So if you have 2 x 100Ah batteries, you can charge up to 200 / 5 = 40A. The mains charger in your EBL will be 18A probably, so it would be better to get a higher capacity charger.

Alternatively you could get a second charger of about 20A, and feed it into the auxiliary charger input of the EBL (labelled 'Zusatz Ladegerat'). A 2-way connector. You'd have to insert a fuse into the fuse slot labelled similarly.

If you get a higher capacity charger you could wire it directly to the leisure batteries. That would mean if you have an LCD display with battery Ah charge displayed, it won't be accurate, but you can just ignore it. If you pull out the fuse for the EBL mains charger output (labelled 'Internes Lademodul') then that will disable the output of that charger.

 

[Marauder]

Thanks for input Guys,

Lenny: So maybe I wont get the AGM's - AandN slates them too.
Autorouter: if I put in a second charger or big B2B, aiming for 40 amps(ish) would I need to worry about overloading the alternator ?

I thought I was getting there, but each time, I read something else that shakes it up again. for eg: I didnt realise that a B2B would not charge when on EHU / generator.

And now realised that Martin Bushnell / AandNcaravans is saying that uprating the original cables / Split relay will have nearly as much effect as B2B !

I just seem to be going round in circles.

Most pressing item now is still getting PV to top batteries while not driving / in storage. Spec for my panels says :

Peak power (Pmax) – 120 Wp (x2 =240)
Power tolerance range (%) – ±3
Open circuit voltage / Voc (V) – 23.4
Max. power voltage / Vmp (V) – 19.8
Short circuit current / Isc (A) – 6.42
Max. power current / Imp (A) – 6.06
Maximum system voltage (V) – 60V DC

I want to fit Votronic Duo MPPT as they seem EBL99 compatible:

Pardon our interruption...

but the votronic specs say 50v max whereas my panels seem rated at 60v -

- how significant is that 10v gap ?
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[autorouter]

but the votronic specs say 50v max whereas my panels seem rated at 60v -

- how significant is that 10v gap ?

I don't think that's a problem here. The maximum voltage the solar panel puts out is 23.4V. I imagine you are connecting the two panels in parallel (+ to +, - to -), so the max voltage of the two will still be 23.4V.

If you were stringing several panels in series, the voltage would add up, and more than two would exceed the 60V limit. But usually on MHs they are wired in parallel, so the voltage isn't a problem.

 

[Marauder]

thanks

so whats difference between power voltage and system voltage ?

 

[arthur49]

"And now realised that Martin Bushnell / AandNcaravans is saying that uprating the original cables / Split relay will have nearly as much effect as B2B"

On a previous van - Ducato base pre-smart alternator - I followed the late Allan Evan's advice (AandN) and beefed up the wiring and I installed a 120A relay I think it was.
I can't recall the exact figures but voltage at leisure batteries rose from 13.9v to 14.3v after these alterations. A huge improvement in charging for £20-30 from memory
These alterations were for LA batteries.

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[Al n Val]

There’s a Victron B2B charger and Vanbitz Battery Master in the classified’s

 

[DBK]

Beefing up the split charging system may improve leisure battery charging but does nothing about the problem of over-charging the cab battery.

After a night or two off grid the leisure batteries may be quite depleted but the cab battery could be still virtually fully charged. If you expose the leisure batteries to say 14+ volts the cab battery is going to receive the same voltage and possibly even slightly more which it doesn't want if it is fully charged.

What can also happen is the fully charged cab battery confuses the alternator and the charging voltage and current are reduced.

A B2B, which is a misleading name as the power comes from the alternator, acts like a dedicated battery charger for the leisure batteries and will charge them using a correct charging profile which a split charge system can't do.

But not many MHs have B2Bs and their owners are perfectly happy. I fitted one after a trip using aires where we only drove a short distance each day and the leisure batteries were not being recharged. It can take several hours of driving using a split charge system whereas a B2B might only need an hour or even less to replace the overnight usage.

 

[Marauder]

""A B2B, which is a misleading name as the power comes from the alternator, acts like a dedicated battery charger for the leisure batteries and will charge them using a correct charging profile which a split charge system can't do"" ( just cant get the quotes to work as expected)

So if my EBL99 is not a B2B - then it is split charger - which means it is not caring for my batteries properly ?

Is that the inference here ?

Would I be better just pulling the fuses out to disable the EBL (as Autorouter suggested ) and fitting a B2B ?

My EBL99 has AD01 associated with it - but I'm not really sure what it's function - despite reading supplied manuals for both these Schaudt products !

 

[Lenny HB]

Your EBL 99 is a 12v distribution unit which incorporates a mains charge, split charge relay & fridge relay.
The ADO1 is basically a relay box that distributes the D+ signal from the alternator so as not to overload the D+ output on the alternator.

 

[autorouter]

so whats difference between power voltage and system voltage ?

These solar panels can be used for many different applications. For example, in a solar farm, with dozens of panels wired in all kinds of series/parallel arrangements. For these particular panels you have to keep the maximum voltage to below 60V, so you can only wire two in series - three would be too many, and exceed 60V. Note that you can buy panels that can be used in arrangements up to 1000V.

The problem with wiring in series is that a slight shadow on one panel cuts the power to the whole series string. If it's a permanent installation, on a roof or in a field, you know what the shading situation will be. For a motorhome, it's constantly changing and you never know which bit might be shaded, so better to wire them in parallel. That way, shade on one doesn't affect the output of the others.

The controller will convert the panel voltage input to whatever the batteries require for charging.

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[pappajohn]

So if i fit B2B, will it also charge batts when on hookup, or just when engine is running ?

To charge starter battery on hookup you want a battery master

 

[Marauder]

So can I connect solar controller direct to starter battery, or will it have to go through EBL99 ?

who is battery master made by ?

Does the EBL 99 output 18A for both the starter and the leisure batts - do they get 18A each

 

[Lenny HB]

So can I connect solar controller direct to starter battery, or will it have to go through EBL99 ?


Does the EBL 99 output 18A for both the starter and the leisure batts - do they get 18A each

I don't think the solar connector on the EBL 99 connects to the starter battery so you have to wire direct.

No, the starter battery charge is a 2 amp trickle charge and only when on EHU.

 

[Al n Val]

Lenny HB

hi Lenny

do you know anything about the Redarc system that is fitted to our Rapido i1090 Distinction

I’ve been led to believe that it’s a B2B charger similar to the Victron Orion I had fitted which was a 12/12/30, and that it has the facility to trickle charge the engine battery from the leisure batteries like the Battery Master does

If you can confirm whether or not this is the case i’d really appreciate it please

cheers

Al

 

[Lenny HB]

Lenny HB

hi Lenny

do you know anything about the Redarc system that is fitted to our Rapido i1090 Distinction

I’ve been led to believe that it’s a B2B charger similar to the Victron Orion I had fitted which was a 12/12/30, and that it has the facility to trickle charge the engine battery from the leisure batteries like the Battery Master does

If you can confirm whether or not this is the case i’d really appreciate it please

cheers

Al

Never heard of them before just had a quick look Australian company and they do have a range of B2B's.

Battery Chargers - Dual Battery System | REDARC Electronics

Have peace of mind on the road with REDARC’s wide range of battery chargers, management systems & testers. Find your dual battery charger online now!

www.redarc.com.au

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[Al n Val]

Thanks Lennie

i’ll have a read of that later on

 

[autorouter]

who is battery master made by ?

Does the EBL 99 output 18A for both the starter and the leisure batts - do they get 18A each

There are a few different types of trickle-charger that will top up the starter battery from the leisure battery. Some only work when the leisure battery is being charged itself, by solar or EHU for example. Some work whenever the starter battery voltage is lower than the leisure battery voltage. A popular one is the Vanbitz Battery Master, which is available in the Motorhome Fun Shop which can be found here:

MotorhomeFun Shop

Official Motorhome Fun Shop

www.motorhomefun.co.uk

As Lenny HB says, the 3-way solar connector doesn't have a connection to the starter battery on the EBL99. An alternative is Pin 1 of the 5-way connector. Briefly, you get a pair of 5-way connectors and connect them together with short lengths of wire, so it is a simple pass-through connector. Then for Pin 1, instead of a short length of wire you wire in two longer lengths, long enough to reach your charging device (Battery Master, solar controller etc). Pin1 connects to the starter battery, and carries the fridge 12V heater element power when the engine is running. It is well capable of carrying the trickle-charge power when the engine is stopped.

It's a good option, often less trouble than running a new wire all the way to the starter battery. Votronic provide a connection like that as an option with their dual battery solar controllers.

 

[Figaro]

I don't think the solar connector on the EBL 99 connects to the starter battery so you have to wire direct.

No, the starter battery charge is a 2 amp trickle charge and only when on EHU.

Correct, I ran a cable from my votronic duo solar controller to a connection on the bottom of the ebl99 to charge the cab battery
Works nicely, it was probably you who told me how it was done, so many thanks.

 

[Raul]

thanks

so whats difference between power voltage and system voltage ?

Maximum power voltage, refers to max voltage at max power for that panel. System voltage, refers to the hole system and that panel is part of, as in more panels. For example you can use that panel in series up to 3 panels, and stay within 60v system. House panels are rated at 1000 and 1500v, meaning very high and good insulation. Your rating of 60v system, tells you insulation can be breached if you go higher voltage. Most small panels have a system voltage of 600v, those are accredited panels. Yours it’s probably not, since it’s only 60v. Pretty weak insulation.

 

[Marauder]

Votronic provide a connection like that as an option with their dual battery solar controllers.

Ok
sounds like it save headache with wirings etc -
- is this the

cable ?

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[autorouter]

No not that one - that 3-way is for the solar connection. Some EBLs have a starter battery feed to the centre pin. But not the EBL99, unfortunately.

The cable you want is a short 5-way-to-5-way cable, maybe 10 cm long, with two long wires going to the Pin 1s. Sorry I can't find one on the internet. If I was making one, I'd do 5 short wires, then splice another wire into the middle of the Pin1 wire, with maybe a butt connector or some other solid crimping connector.

You could get a 5-way Mate'N'Lok (MNL) connector pair, the 5-way seems to be a bit difficult to find, maybe try Ebay

Pardon our interruption...

www.ebay.co.uk

Use a crimp tool for NON-insulated terminals (not the Red/blue/yellow insulated type).

Or as Figaro says, connect to the big battery connector terminal block at the back of the EBL

 

[nicholsong]

Anybody new to MHs and their various charging systems would be tearing their hair our having read this thread and I doubt whether the OP is any the wiser.

 

[Podney]

Anybody new to MHs and their various charging systems would be tearing their hair our having read this thread and I doubt whether the OP is any the wiser.

Well I’m not new to the game,and I’m not tearing my hair out………that’s only because I haven’t got any!
I hope the OP has a better understanding of leccie than I do,I think that’s probably the case.
All I do know is that on my Rapido there is a battery charger that charges both the vehicle and leisure batteries whilst driving and when on ehu. And it can be left on hook up indefinately as it doesn’t cook the batteries. Seems to me that how they all should work…..anything else would be inadequate imo. I do not have solar. I often wonder why so many mohos seem to have complicated electrical systems that only do half a job.
But…what we do without the likes of Lenny HB and autorouter on here,who do a fantastic job of helping funsters imo.

 

[Al n Val]

.All I do know is that on my Rapido there is a battery charger that charges both the vehicle and leisure batteries whilst driving and when on ehu. And it can be left on hook up indefinately as it doesn’t cook the batteries. Seems to me that how they all should work…..anything else would be inadequate imo. I do not have solar.

May i ask, have you gitt a Redarc system on your Rapido

I’ve a 2022 i1090 and trying to establish if mine does the same

 

[Reallyretired]

May i ask, have you gitt a Redarc system on your Rapido

I’ve a 2022 i1090 and trying to establish if mine does the same

My last Rapido did all of that but was a CBE system.

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