# Sterling B2B Major Disapointment



## gromett (May 9, 2005)

I bought one off ebay a couple of months ago and got round to installing it today. I am not sure if it is faulty or what but it is only putting 4-6Amps into the 440AH battery bank.

There is 14.6V at the input side when the engine is running. I left it for 5 minutes then revved it to 2,000rpm which is what it is at when doing 60mph. The output voltage didn't rise at all.

The batteries were in desperate need of a boost as they were down to 11.8V (40% according to my nasa BM-1)

Does anyone have any suggestions please? Or do I need to call sterling on Tuesday?

The Top LED shows up RED and the low voltage out led lights up.
The constant current charge LED lights up also.

I have just driven for 3 hours to test it out and get some charge into the battery and it didn't make any difference. 

Karl


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## erneboy (Feb 8, 2007)

Talk to Sterling about it Karl, they are very helpful. Mine works as it should, Alan.


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## Roger7webster (Oct 10, 2006)

There are a number of possibles with this problem. Is the battery bank is on its way out if you are only showing 11.8 v at the start of the trial and the low voltage led is indicating. Can you check each cell with a hydometer? 
Just a thought, my b2b works ok


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## gromett (May 9, 2005)

Battery bank is fine. This is the first time they have been discharged below 90%. I have had them on a hookup charger (25amp) and they have taken on 15% charge no problem over 2.5Hours (ish). They lasted me a week running everything. Definitely not a battery problem......


Karl


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## coppo (May 27, 2009)

Hi
I bought one new about 18 months ago, only just had it fitted a few weeks ago.
Regarding the top LED mine shows red, is this correct, according to the booklet(as i read it) this LED is a tri coloured one and red indicates AGM batteries, i have flooded ones, so the top LED shows red and two down from this is a green one, is that correct.

Have not had the chance yet to test with discharged batteries due to the sun shining and plenty of solar keeping them charged,

Paul.


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## Jean-Luc (Jul 21, 2005)

Low voltage light on :?: . Can you check the voltage on the output terminal with a meter, it should be somewhere between 13 and 14.8 depending on the charging phase the unit is in.
Try disconnecting the input this could reset something that's gone haywire, the unit only 'sleeps' so the only way to 'power it down' completely is by disconnecting the input.
Try connecting the unit to a different battery to check if it performs as it should.

As the unit can draw up to 50 amps from the chassis battery, depending on the distance quite heavy cable is needed to avoid voltage drop when on load.

Your scenario of asking it to hit a 440 amp battery bank which is down to 11.8 volts would have had the unit running at its max for quite a time, it may have 'tripped out' due to low input voltage if the cable from the chassis battery wasn't up to the job and not reset.

Here is a useful CALCULATOR to determine the correct cable size.

Otherwise it's a call to Stirling after the hols.


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## gromett (May 9, 2005)

Thanks guys,

The cables are well over specced. I can't remember the size but it was rated for 170Amp. The auto electrician who installed it offered me the correct size but I went up by two sizes just to be certain. It is bigger than the cable that comes out of the alternator 

I will try disconnecting the input to reset it. However I am not hopeful as it is putting out 6.4Amps.

Karl


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## Jean-Luc (Jul 21, 2005)

gromett said:


> Thanks guys,
> 
> The cables are well over specced. I can't remember the size but it was rated for 170Amp. The auto electrician who installed it offered me the correct size but I went up by two sizes just to be certain. It is bigger than the cable that comes out of the alternator Karl


The length of the cable run has a significant bearing on the size required to minimise voltage drop, the alternator - battery run is quite short.

My run was over 5 meters and the cable size I needed was more than twice that of the alternator - battery one.


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## gromett (May 9, 2005)

The run from the vehicle battery to the unit is just over 1.5mtrs. The run from the unit to the leisure batteries is about .5Mtrs. Very short.
The cable is well over specced. You will have to take my word that I do know what I am doing on that front  (electrical engineer by original trade)

I tried disconnecting it and reconnecting. This has had no effect.

The output voltage is .1V higher with the unit connected (about 11.9V compared to 11.8V) This is where the 6.4Amp charge is coming from.

I am not fairly certain that the unit is faulty now.... As I bought it off ebay second hand more that two months ago I am thinking it is lost money now. However at least the wiring is in place for when I buy a (new) replacement for it. I will give Sterling a ring on Tuesday but I am not holding out much hope.

I have managed to get a hookup today and the 25Amp charger is working its nuts off to put over 250AH back into the battery. I think it will take two days as I have to disconnect it at 8pm.......

All good fun


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## C7KEN (May 27, 2005)

Hi Karl
There are two fuses above the main terminals. check they are OK. Mine played funny a couple of months ago and I found a fuse blown
The attachment for them is not so impressive . Does the fan come on when the unit is running?


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## gromett (May 9, 2005)

The fuses have been checked and are fine. If they were blown I wouldn't even get the 6.4Amps 

No the fans don't start which is another thing pointing to a fault.

Karl


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## Jean-Luc (Jul 21, 2005)

gromett said:


> The fuses have been checked and are fine. If they were blown I wouldn't even get the 6.4Amps
> 
> No the fans don't start which is another thing pointing to a fault.
> 
> Karl


Fans only run if high ambient temp (don't know the temp) and/or if output is over 30 amps,a 6.4 amp output by itself wouldn't have the fans running.


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## C7KEN (May 27, 2005)

The fans on mine run most of the time, its when they stopped i checked the fuses and one was blown. I also have a Masa unit and even if showing full charged batts when the B2B is on the fans run. I know I live in a warm place but the B2B is not getting hot. However it all works fine so I dont worry.Karl I believe you have a self build so I guess this is taking the place of a split charge relay? Make sure to let us know the outcome of this because I wonder how many are not giving out their max and I wonder what Sterling will advise.


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## JockandRita (Jun 1, 2005)

Hi Karl,

Sorry to hear of your woes with the purchased unit.

Ours works a treat, and will come into it's own tomorrow morning, when we fire up after four days of camping. Like Ken's, our fan runs most of the time, even after unplugging from mains at home before setting off, ie, within minutes of starting the engine.

*FAO Coppo*. Paul, have you set the switches correctly on your B2B for FLA batteries, before installation? The charging rates are different.

Cheers,

Jock.


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## weldted (May 1, 2005)

*b2b output*

pardon the obvious but have you linked the negative lead from the engine battery and the negative lead from the leisure battery to the common terminal on the b2b unit, ours will start the fans about five mins after the engine had been started, we also route our Solar panels through ours by putting the Solar + to the terminal from the engine battery, have seen the voltage to the leisure batteries go up to 15 volts (have 340 watts of panels) (three 110 amp batteries) double check that the engine and leisure +'s are the correct way around , bottom terminal both negatives, middle terminal input from engine batt, top terminal output to leisure battery. good luck


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## gromett (May 9, 2005)

It is wired up correctly. Both me an an auto electrician checked the wiring.

The common ground is linked to the chassis and then to the negative on the leisure battery.

I am at a total loss on this and am now pretty sure that it is a faulty unit.

Karl


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## artona (Jan 19, 2006)

Its going to be something really simple or a duff piece of equipment. I assume you checked the earthing points?


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## Jean-Luc (Jul 21, 2005)

Just saw these pieces of info in the user manual which look like they might be relevant to your issue. Hope they might help

[/I]
The current lights are flashing with the low input voltage light in the information section also flashing. Unlike the above
warning, this could be no problem at all , it simply means that the input voltage to the unit is unable to keep up with the
performance demand of the unit and the units performance is being limited because the input power source ( alternator )
cannot keep the input terminal voltage above 13 volts. This is to protect the starter battery from dropping too low and
causing a failed engine start. There are a few possibilities for this, such as the input cable being too thin, or the run to
long. (Remember, it is best to fit the unit close to the input battery to reduce voltage drop.) It could also simply be that at
engine tick-over or low r.p.m. the alternator feeding the starter battery cannot produce enough surplus power to keep up
with the unit's charging demand, and we are simply reducing the unit's performance to prevent draining the starter battery.
Neither of the above are safety issues but simply information to make it easier for you to maximise the performance of the
unit either by increasing cable thickness or upgrading your alternator to a bigger one_
Also_
BATTERY INPUT LOW VOLTS: This is simply saying that there is a low voltage at the main battery bank and has no active function. For information only, this usually indicates a defective alternator or very high demand at low r.p.m._
And
_Fans on at 50 deg C
Fans on over 35 amps


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## C7KEN (May 27, 2005)

I think Karl was saying that the output voltage was the problem and input voltage was fine, Karl please ask Sterling about the fans, as clearly the unit does not need 50deg and 35amps to trigger the fans. 
I'm sure Jock n Rita's unit will never see 50deg in a UK winter but similar to mine the fans do run.


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## JockandRita (Jun 1, 2005)

C7KEN said:


> I'm sure Jock n Rita's unit will never see 50deg in a UK winter but similar to mine the fans do run.


I wish Ken. :lol:

Started up this morning, jumped out and put the ramp away, and by the time I jumped back into the cab, (seconds away) the fans were running, but no reading on the ammeter yet, as the starter battery gets the first three minutes of charge, I do believe. It has done this from day one.

Cheers,

Jock.


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## gromett (May 9, 2005)

Jean Luc, It was the output voltage low indicator that was on not the input. the indicator was correct as the voltage was 11.9V.

I will be calling Sterling tomorrow.

Thanks guys.

Karl


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## C7KEN (May 27, 2005)

*Sterling B2B Charger*

I wonder what was the outcome of Karl's problem with his B2B . I was waiting for a post to tell us. However I was thinking what could be the problem assuming there is no fault with the unit itself and I thought it would be a faulty battery. So Karl let us know what happened after your last post on this. Did you contact Sterling? were they helpfull? What was the problem?


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## nicholsong (May 26, 2009)

I am also interested in the outcome.

Karl, please tell, even if it an embarassing self-induced error - we have all done it, and more than once!

Geoff


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## oldosc (Sep 20, 2010)

*sterling btob (or not to b)*

Old osc
sorry about the joke, but too good to repeat inni't

I was hoping for a reply from Carol also, at the time I had just bought a B to BE from sterling , having had good results from my (His) alternator machine. I waqs told that due to EMS on the new Hymer I could not interfere with any of the wiring as faults would show up due to the strict monitoring now in force. This was borne out by a neighbour fitting a tow bar to his new transit, and hacking the loom to fit the lights..total confusion, had to resort to a friend with the equipment to sort it out, and install a prop interface.
(My neighbour is a chief electrician working on Nuclear Sub maintenance)
Any how, went ahead and installed Sterling, taking the pos lead from the designated point behind seat (there is another clean take off under bonnet used for jump-start leads) On the little journeys so far it works as promised..30 amp measured into leisures until full

I need this thing, as I have just bought a Torqeedo outboard for my catamaran..and with the semi electric bikes solar don't give enough amps. Am thinking of a fuel cell, lovely quiet .....about 2 grand
but what the hell..how long do you live after 75


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## oldosc (Sep 20, 2010)

old osc
sorry about the Carol instead of Karl..it was the spell checker wot dun it..honest
My step son is Carl
Osc


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