Sterling 1260 B2B info needed

[Jaws]

Sterling B2B install has +ve going to cab battery, +ve going to hab battery(s) and common negative
it does not have a feed from the alternator... So HOW can it boost charge hab battery, as the alternator output will 'see' the cab battery as normal

 

[andy63]

You have lost me.. ?
The altenator feeds the cab battery directly and therefore it feeds the the battery to battery charger..

it does not have a feed from the alternator

Or have I misunderstood ..

HOW can it boost charge hab battery, as the alternator output will 'see' the cab battery as normal

It takes an incoming voltage from the alternator when the engine is running or hab battery and supplies the habitation batteries with a voltage depending on the selected type of battery.. Ie a bulk ..absorption and trickle charge voltage..
Just like any modern smart charger..

 

[Jaws]

You have lost me.. ?
The altenator feeds the cab battery directly and therefore it feeds the the battery to battery charger..



Or have I misunderstood ..


It takes an incoming voltage from the alternator when the engine is running or hab battery and supplies the habitation batteries with a voltage depending on the selected type of battery.. Ie a bulk ..absorption and trickle charge voltage..
Just like any modern smart charger..

There is no connection for a feed from the alternator, only the batteries
So the alternator is still connected to the cab battery as normal
As I see it ( which MUST be a flawed view ) when the cab battery is charged the alternator will 'see' the voltage of the cab battery and reduce the charge level ...
I would have expected an input to the unit from the alternator which is then fed tp the hab and cab batteries as needed

 

[andy63]

No..the battery to battery is designed to take an incoming voltage and supply an outgoing charging voltage to the hab batteries..
Your alternator voltage has to be above whatever the threshold voltage is for the battery to battery charger... Something like 13.3 v but it will continue to function even if the alternator voltage drops below that ..that function is timed .. If the low voltage continues beyond that time the battery to battery will switch off until it see's the voltage rise again..

There is no connection for a feed from the alternator, only the batteries

But the alternator is connected directly to the positive of the cab battery and therefore to the battery to battery charger via that link.. It then sees the alternator or cab battery voltage on that connection....

 

[G7UXG]

Think of the B2B as an electrical load on the vehicle, just like switching the headlights on, or any other electrical circuit that draws a current. It'll draw off the cab battery, and that will recharge from the alternator. That's my understanding of it.

I've just fitted a Votronic triple charger, which includes a B2B. It seems to work fine.

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[Jaws]

No..the battery to battery is designed to take an incoming voltage and supply an outgoing charging voltage to the hab batteries..
Your alternator voltage has to be above whatever the threshold voltage is for the battery to battery charger... Something like 13.3 v but it will continue to function even if the alternator voltage drops below that ..that function is timed .. If the low voltage continues beyond that time the battery to battery will switch off until it see's the voltage rise again..



But the alternator is connected directly to the positive of the cab battery and therefore to the battery to battery charger via that link.. It then sees the alternator or cab battery voltage on that connection....

Ok Andy.. I am still a bit at sea as to my mind the alternator will still be chucking it all at the cab battery, but I get what your saying

 

[Stealaway]

The alternator will stop charging the cab battery when it reaches 13+ volts but the B2B convinces it to keep charging until the hab batteries are also full.

 

[andy63]

Ok Andy.. I am still a bit at sea as to my mind the alternator will still be chucking it all at the cab battery, but I get what your saying

I think g7uxg has explained it in far better terms than me...?
I've not long fitted one and until I got it and read the instructions I had no idea what a battery to battery was actually capable of and how many programming options you had..

 

[AXO66]

I think g7uxg has explained it in far better terms than me...?
I've not long fitted one and until I got it and read the instructions I had no idea what a battery to battery was actually capable of and how many programming options you had..

Where did you fit it to the hab +ve. ? Directly to the terminal on the battery or somewhere else?

 

[hilldweller]

The alternator will stop charging the cab battery when it reaches 13+ volts but the B2B convinces it to keep charging until the hab batteries are also full.

but the B2B convinces it to keep charging.................. by drawing enough current to keep it below 13V+

B2B drags alternator and cab down to say 12.5V, pumps it up to 13.6V and feeds that to the hab battery.

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[andy63]

Where did you fit it to the hab +ve. ? Directly to the terminal on the battery or somewhere else?

Mine is fitted to the battery positive terminals of start and hab batteries... And I've linked the negative terminals of hab and start batteries to the negative of the battery to battery charger rathervthan rely on the common chassis link..

 

[andy63]

but the B2B convinces it to keep charging.................. by drawing enough current to keep it below 13V+

B2B drags alternator and cab down to say 12.5V, pumps it up to 13.6V and feeds that to the hab battery.

I don't think it does that Brian...
The battery to battery operates at whatever the alternator voltage is.. And that voltage varies quite a bit with smart alternators ..
The voltage fed to the hab bank depends on battery type selected and what bit of the charge cyclecis in operation.. Ie. Bulk..absorption or trickle/ float..

 

[hilldweller]

I don't think it does that Brian...

OK. Somewhere I was sure I had read that some such device fooled the smart alternator into providing maximum output.

 

[68c]

Think of it as two water tanks, the alternater is a pump supplying water to the 'cab tank'. Once it is full the pump stops pumping the water, imagine a ballcock is controlling the level as in your toilet cistern. When you use water the cock opens and the pump refills the tank. If the 'hab tank' is taller and connected by a one way valve to the cab tank the hab tank will fill to the same level as the cab tank. Now if we add a second pump which can draw water from the the cab tank it can fill the hab tank to a higher level.
The B2B is the second pump. The alternator is designed to only charge the cab battery to a certain level, not really a full charge but at a level that can be be continuously supplied without the battery gassing and loosing water. The B2B can boost the alternate9r output to a full charge voltage so your hab battery has maximum charge, it only supplies this higher charge until the hab battery is fully charged then reverts to a lower voltage as with the cab battery. As the B2B is supplying the hab battery it draws power from the cab battery which is immediately topped up by the alternater.

 

[DBK]

I think B2B makers could sell more if they could explain how they work. As has been said it wasn't until I fitted mine I realised what they do. Which is to place a load on the vehicle electrics, driving down the alternator voltage and boosting the voltage to charge the leisure batteries.
Just don't expect any battery monitor you might have to give a reliable indication.
And of course you need to disable any split charge system you might have otherwise the B2B will do nothing and just becomes an expensive set of flashing led lights. The same applies to Elektroblok systems but you will need to ask some else about them.
The instructions which come with Sterling B2Bs mention none of these things.

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[andy63]

driving down the alternator voltage and boosting the voltage to charge the leisure batteries.

But that's not always what is happening..there has to be more to what goes on in a battery to battery charger..
At times the alternator can be putting out close to 15v.. The battery to battery may only be charging at 13. Odd volts..

 

[DBK]

But that's not always what is happening..there has to be more to what goes on in a battery to battery charger..
At times the alternator can be putting out close to 15v.. The battery to battery may only be charging at 13. Odd volts..

You have to look at the power, not just the voltages, although there is a link, amps times volts equals power.
I'm not sure how better to explain other than a B2B can put the majority of the alternator output directly into the leisure batteries without frying the cab battery.

 

[andy63]

Just don't expect any battery monitor you might have to give a reliable indication.

What do you mean by reliable indication..
My battery monitor shows voltage on start and hab banks and the net current flow through a shunt either in to or out of the hab batteries..I have no reason not to trust those readings.. What may not be reliable any more is the battery capacity readout if you have installed lithium as its based on a led acid algorithm .

 

[hilldweller]

At times the alternator can be putting out close to 15v.. The battery to battery may only be charging at 13. Odd volts..

This is exactly what happens with a good solar charger. The input can be 8V to 20V. Stage one uses a buck-boost regulator to generate a stable 14V or so stable voltage then a charger circuit feeds the appropriate voltage/current to battery.

 

[andy63]

This is exactly what happens with a good solar charger. The input can be 8V to 20V. Stage one uses a buck-boost regulator to generate a stable 14V or so stable voltage then a charger circuit feeds the appropriate voltage/current to battery.

Believe it or not Brian I was thinking of comparing a battery to battery to a good mppt controller as it does function a bit like that to my mind..
Ie.. Takes an incoming voltage source and then supplies a correct charging regime to its output side..

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[hilldweller]

comparing a battery to battery to a good mppt controller

We are now on the same wavelength.

I am surprised at Jaws, he knows a thing or two about electronics but the high life of Benidorm must have got to him.

 

[DBK]

What do you mean by reliable indication..
My battery monitor shows voltage on start and hab banks and the net current flow through a shunt either in to or out of the hab batteries..I have no reason not to trust those readings.. What may not be reliable any more is the battery capacity readout if you have installed lithium as its based on a led acid algorithm .

If you wired it as Sterling recommend it bypasses the shunt so the monitor has no idea what current the B2B is putting in. However, my experience is the battery monitor recognises something has happened and adjust the % charge figure accordingly. It probably does this based on battery voltage profile against time after the engine has been turned off.

 

[Jaws]

Ok... took some time, read the blurb, and took on board what has been said, and NOW have it right in my head ....

Appreciate every ones time and effort in this thread

 

[andy63]

If you wired it as Sterling recommend it bypasses the shunt so the monitor has no idea what current the B2B is putting in. However, my experience is the battery monitor recognises something has happened and adjust the % charge figure accordingly. It probably does this based on battery voltage profile against time after the engine has been turned off.

I may be missing your point john..
If you have a shunt installed then that effectively becomes the new battery terminal and any connection has to be made to the correct side of the shunt..if that is done and no other connections are made to the battery terminal bypassing the shunt then surley the current ( volt drop ) it measures is the current flow of that battery..
I'm trying to think if it makes any difference as to which terminal the shunt is installed in but can't see that.. The one I have currently fitted is in the negative side of the battery but I've had a sterling unit where I installed it in the positive side..I think it stated it could be installed in either.... But most indicate negative for some reason I don't follow...
So even though the installation diag shows direct connections to the battery if a shunt is installed its just an extension of a battery terminal and you connect to that..
Is that thinking flawed.. I can't see how you wouldn't record the net current flow if installed that way..

 

[Robert Clark]

Sterling B2B install has +ve going to cab battery, +ve going to hab battery(s) and common negative
it does not have a feed from the alternator... So HOW can it boost charge hab battery, as the alternator output will 'see' the cab battery as normal

View attachment 370618

I wouldn’t recommend the Stirling B2B

Ours packed up on our last trip.
Looks like the fuse holder on the input side had melted. Spoke to Stirling and they said ‘that can happen as the b2B can pull more power than the fuse holder can take” . They suggested removing the damaged fuse holder and soldering a piece of wire across it.

Bad design cured with a bodge me thinks

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[andy63]

Looks like the fuse holder on the input side had melted.

Hi Robert. Just so I'm sure what fuse we are talking about...do you mean the main fuses they recommend in both positive battery connections... They don't come supplied and are for the installer to fit..

Which amperage ie 60 or 30 unit did you have , and what was the rated fuse holder that failed..

 

[Robert Clark]

Hi Robert. Just so I'm sure what fuse we are talking about...do you mean the main fuses they recommend in both positive battery connections... They don't come supplied and are for the installer to fit..

Which amperage ie 60 or 30 unit did you have , and what was the rated fuse holder that failed..

No I’m talking about the units inbuilt fuse. It’s the one just to the left of the input live.

We’ve got the 60a unit

 

[andy63]

No I’m talking about the units inbuilt fuse. It’s the one just to the left of the input live.

We’ve got the 60a unit

View attachment 370686

Hmm..I've got the 60amp unit and don't recall any inbuilt visible fuse ..I'll check again , but wondering if they have changed that..
Cheers

 

[Robert Clark]

Hmm..I've got the 60amp unit and don't recall any inbuilt visible fuse ..I'll check again , but wondering if they have changed that..
Cheers

There are two infact
One on the input and one on the output
They’re shown on the wiring diagram

 

[andy63]

There are two infact
One on the input and one on the output
They’re shown on the wiring diagram

They must have changed the design or I have a different model..
I've had a look.. The only external fuse on mine is a small blade fuse in the negative side..
And the only fuses shown on the wiring schematic are the fuses in each positive battery connection.. Which are not supplied but fitted by the installer..

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