Sterling inverter problem ?

[Danica]

Hi all. Having a bit of a nightmare at the moment. Was due to go out for the week but after filling up with diesel, I noticed that once the engine was turned off, the voltage indicator on my invertor dropped quickly and steadliy, then the inverter cut out and displayed 'Uut' (Battery under voltage trip). After a few minutes, there wasn't even enough power to light up the 12v led lighting. I've had the batteries tested and they appear to be fine, the alternators seem fine too and appear to be charging the batteries through the invertor when the engine runs or is plugged into the shoreline. I know that's not much to go on but any ideas would be appreciated. Thanks

Edited March 30, 2013 by Danica

[Chris Pink]

The symptom is that of knackered batteries. And "had the batteries tested" - testing batteries is by no means an easy task so I'm still suspecting them until shown otherwise.

 

The only other thing that would cause this problem is a dodgy connection or wiring between the inverter and the batteries.

 

That is easy to test.

 

With the load switched on measure the voltage at the batteries with a multimeter and then at the inverter terminals. If it is this fault the readings will be different.

 

What is the load on the inverter?

[Alan de Enfield]

..........and appear to be charging the batteries through the invertor when the engine runs or is plugged into the shoreline.

 

Maybe you can describe in a little more detail your 'system'

 

Inverters do not charge the battery (they are not battery chargers),all they do is take 12v out of your battery and convert it to 220v.

 

What do you have running on 220v (via your inverter)?

How were your batteries tested ?

How was your alternator tested ?

Edited March 30, 2013 by Alan de Enfield

[Danica]

The symptom is that of knackered batteries. And "had the batteries tested" - testing batteries is by no means an easy task so I'm still suspecting them until shown otherwise.

 

The only other thing that would cause this problem is a dodgy connection or wiring between the inverter and the batteries.

 

That is easy to test.

 

With the load switched on measure the voltage at the batteries with a multimeter and then at the inverter terminals. If it is this fault the readings will be different.

 

What is the load on the inverter?

 

I'm sorry, really need to get to grips with how everything works on here, everything's been fine for a year and as soon as there's a problem, I have to call somebody out as I can't eliminate anything myself, I don't have a multimeter but will add that to my list of things I need.

Edited March 30, 2013 by Danica

[Chris Pink]

I have just thought of one other possibility. This is a Sterling combi, no?

 

Are you sure the battery charger is not taking power from the inverter?

 

(This question applies whether or not the answer to the combi question is 'yes')

[Danica]

Maybe you can describe in a little more detail your 'system'

 

Inverters do not charge the battery (they are not battery chargers),all they do is take 12v out of your battery and convert it to 220v.

 

What do you have running on 220v (via your inverter)?

How were your batteries tested ?

How was your alternator tested ?

 

 

Sorry, I'm new to all this it's a combined invertor/battery charger. When I'm connected to shore power, the indicator shows that the batteried are being charged (well that's what I've been told)

I only run a small TV, phone and kindle chargers and a lap top on 220

Not sure really, the batteries were disconnected individually and tested with a large meter with leads similar to car battery jump leads (best I can describe)

I think he tested that with a smaller multi meter.

 

Maybe you can describe in a little more detail your 'system'

 

Inverters do not charge the battery (they are not battery chargers),all they do is take 12v out of your battery and convert it to 220v.

 

What do you have running on 220v (via your inverter)?

How were your batteries tested ?

How was your alternator tested ?

 

 

Sorry, I'm new to all this it's a combined invertor/battery charger. When I'm connected to shore power, the indicator shows that the batteried are being charged (well that's what I've been told)

I only run a small TV, phone and kindle chargers and a lap top on 220

Not sure really, the batteries were disconnected individually and tested with a large meter with leads similar to car battery jump leads (best I can describe)

I think he tested that with a smaller multi meter.

[Guest]

All of the above plus; Is there a large isolator in the circuit between the batteries and the inverter? These have been known to cause problems.

[Danica]

I have just thought of one other possibility. This is a Sterling combi, no?

 

Are you sure the battery charger is not taking power from the inverter?

 

(This question applies whether or not the answer to the combi question is 'yes')

 

Yes it's a Sterling combi, I wouldn't know where to start to find out if it's taking power from the invertor.

 

All of the above plus; Is there a large isolator in the circuit between the batteries and the inverter? These have been known to cause problems.

 

I think there is one. Is it possible that the batteries are charged but somewhere along the line, the 'power' isn't being allowed out ? (Please excuise my terminology)

[Chris Pink]

Yes it's a Sterling combi, I wouldn't know where to start to find out if it's taking power from the invertor.

 

 

Is the battery charger light on?

 

Reading the above, either;

 

you are trying to charge your batteries with the inverter - easy way to find out, unplug the mains plug from the combi

 

or

 

your batteries are knackered. It sounds like the engineer did a drop test and although this will tell you how much power your batteries can deliver it won't tell you how much capacity they have. How old are they?

 

 

What means do you have of measuring voltage?

[Danica]

Is the battery charger light on?

 

Reading the above, either;

 

you are trying to charge your batteries with the inverter - easy way to find out, unplug the mains plug from the combi

 

or

 

your batteries are knackered. It sounds like the engineer did a drop test and although this will tell you how much power your batteries can deliver it won't tell you how much capacity they have. How old are they?

 

 

What means do you have of measuring voltage?

 

 

No, just realised that the charger lights are out and I'm sure that they are usually lit up.

 

I have no means of measuring voltage at all, I think that I can buy/borrow a multi meter today though.

[Guest]

No, just realised that the charger lights are out and I'm sure that they are usually lit up.

 

I have no means of measuring voltage at all, I think that I can buy/borrow a multi meter today though.

Half decent multimeters are buttons now. Don't be talked into paying silly money for one that has all kinds of bells and whistles that you will never use. I got one for under 20 quid from Maplins and it is as accurate as my expensive meter at the 12 volt DC range.

[Chris Pink]

No, just realised that the charger lights are out and I'm sure that they are usually lit up.

 

I have no means of measuring voltage at all, I think that I can buy/borrow a multi meter today though.

 

It's looking like the batteries at fault, even a wiring or connector fault wouldn't cause the change in voltage you are seeing.

[by'eck]

No, just realised that the charger lights are out and I'm sure that they are usually lit up.

 

I have no means of measuring voltage at all, I think that I can buy/borrow a multi meter today though.

 

Your Sterling Combi is a combined charger and inverter. When AC (shore) power is supplied to it the charger part automatically charges the batteries and the inverter is off. AC power also feeds through the unit to supply the AC distribution system if you have one.

 

When the shore power is removed the inverter automatically switches on and takes power from the batteries to supply AC through the same distribution system.

 

There is a three way centre off control switch. This may be remote from the unit. With this you can select on or on with power saver. There are various LED indicator lights on the Combi which indicate which mode its in when switched on.

 

In either on position and with AC shore power present the charger should be on with the yellow constant current/voltage light on solid or flashing or the green float light on, depending on the charge mode its in. If neither of these are on either the unit is faulty, or you don't have AC power going to it, or its switched off.

 

As the inverter automatically switches on with shore power removed, the only means you have of switching it off is via the single Combi control switch. There is a green indicator light to tell you its on. If this shows its on before you get the low volts fault light and the batteries have previously been fully charged, it suggests they are knackered, but a voltage test at the batteries would confirm this.

 

The engine alternator(s) provide a second entirely separate means of charging the batteries directly when the engine is running.

Edited March 30, 2013 by by'eck

[Richard10002]

Yes it's a Sterling combi, I wouldn't know where to start to find out if it's taking power from the invertor.

 

 

 

If it's a Sterling combi, it will be charging the batteries when on shore power, and drawing power from the batteries as an inverter when not on shore power. Unless it's fitted in an incredibly weird and convoluted way, the inverter side of things will not be able to charge the batteries.

[Chris Pink]

If it's a Sterling combi, it will be charging the batteries when on shore power, and drawing power from the batteries as an inverter when not on shore power. Unless it's fitted in an incredibly weird and convoluted way, the inverter side of things will not be able to charge the batteries.

 

It might be weird but it's not convoluted. Unless there is a transfer switch that's exactly what will happen if the combi is plugged into the same 240V wiring it's supplying.

 

It has no way of telling the difference and it is something that i think the OP, with his lack of experience, should check rather than your dismissive "oh it couldn't happen"

[Richard10002]

It might be weird but it's not convoluted. Unless there is a transfer switch that's exactly what will happen if the combi is plugged into the same 240V wiring it's supplying.

 

It has no way of telling the difference and it is something that i think the OP, with his lack of experience, should check rather than your dismissive "oh it couldn't happen"

 

I didn't say it couldn't happen. I suggested it would be strange if it could, if it's a Sterling combi. I didn't say don't check it, I said it would be weird and convoluted.

 

On my Sterling combi, the mains comes into the combi, and out to a consumer unit. It also has an out to the batteries. The unit senses whether mains is connected and does the right thing.

 

To do what you are suggesting, the mains would come into a consumer unit, then to the Inverter charger, then back to the same consumer unit. I would call that weird and convoluted. I would also guess it would have caused a problem before now because every time the inverter was on without shore power being on, it would be charging the batteries from the batteries. In addition, with shore power connected there would be potentially 2 sources of mains into one consumer unit.

[by'eck]

It might be weird but it's not convoluted. Unless there is a transfer switch that's exactly what will happen if the combi is plugged into the same 240V wiring it's supplying.

 

It has no way of telling the difference and it is something that i think the OP, with his lack of experience, should check rather than your dismissive "oh it couldn't happen"

 

I didn't say it couldn't happen. I suggested it would be strange if it could, if it's a Sterling combi. I didn't say don't check it, I said it would be weird and convoluted.

 

On my Sterling combi, the mains comes into the combi, and out to a consumer unit. It also has an out to the batteries. The unit senses whether mains is connected and does the right thing.

 

To do what you are suggesting, the mains would come into a consumer unit, then to the Inverter charger, then back to the same consumer unit. I would call that weird and convoluted. I would also guess it would have caused a problem before now because every time the inverter was on without shore power being on, it would be charging the batteries from the batteries. In addition, with shore power connected there would be potentially 2 sources of mains into one consumer unit.

 

Sorry Chris and Richard but the scenario's you each suggest cannot happen and are doubtless confusing to the OP.

 

The Sterling Combi's cannot have the inverter and charger running simultaneously no matter how they are wired. As soon as AC is sensed on the Combi's input, the inverter is cut so it could not feed itself, and rightly so from a safety point of view should shore power still be connected.

[Richard10002]

Sorry Chris and Richard but the scenario's you each suggest cannot happen and are doubtless confusing to the OP.

 

The Sterling Combi's cannot have the inverter and charger running simultaneously no matter how they are wired. As soon as AC is sensed on the Combi's input, the inverter is cut so it could not feed itself, and rightly so from a safety point of view should shore power still be connected.

 

Hence "convoluted"

[by'eck]

Hence "convoluted"

 

No impossible

[Chris Pink]

Sorry Chris and Richard but the scenario's you each suggest cannot happen and are doubtless confusing to the OP.

 

The Sterling Combi's cannot have the inverter and charger running simultaneously no matter how they are wired. As soon as AC is sensed on the Combi's input, the inverter is cut so it could not feed itself, and rightly so from a safety point of view should shore power still be connected.

 

OK. I did wonder after I posted. Apologies to the OP.

[coventrylad]

Sorry Chris and Richard but the scenario's you each suggest cannot happen and are doubtless confusing to the OP.

 

The Sterling Combi's cannot have the inverter and charger running simultaneously no matter how they are wired. As soon as AC is sensed on the Combi's input, the inverter is cut so it could not feed itself, and rightly so from a safety point of view should shore power still be connected.

Hi, I also have a stirling pro combi, wired exactly as you have said. When my generator is running (2,5 kw honda)the combi goes on to shore power and battery charge mode auotomatically. Today a pluged a 1500watt hoover 240 volt in to one of the sockets, and then put a clamp meter around the poitive dc from the inverter to battery bank and it was showing an increase in amps, so does this mean the combi was putting in more juice to the batterys or were the batterys suppling juice to the inverter? I now have four 110ah batts connected in series parraell to give 24 volt. when i did this last week with only two 100 amp old batterys, the amperage shot up to 50 amps, im sure today it only showed about 4 amps. If you can follow all that i would be even more impresed with you than I am now.

[by'eck]

Hi, I also have a stirling pro combi, wired exactly as you have said. When my generator is running (2,5 kw honda)the combi goes on to shore power and battery charge mode auotomatically. Today a pluged a 1500watt hoover 240 volt in to one of the sockets, and then put a clamp meter around the poitive dc from the inverter to battery bank and it was showing an increase in amps, so does this mean the combi was putting in more juice to the batterys or were the batterys suppling juice to the inverter? I now have four 110ah batts connected in series parraell to give 24 volt. when i did this last week with only two 100 amp old batterys, the amperage shot up to 50 amps, im sure today it only showed about 4 amps. If you can follow all that i would be even more impresed with you than I am now.

 

Your generator was supplying the AC power the vacuum was taking so there should theoretically be no instantaneous change in the charge current from the Combi's charger. There would however be a considerable extra load on the generator which you would have heard. If this is a variable speed inverter/generator its possible it over compensated for the extra load and its output volts rose enough to increase the chargers output by a small amount.

 

The only other reason for a sudden increase in current supplied by the Combi's charger, would be an extra DC load such as a fridge compressor cutting in.

 

If the generator wasn't running of course, the Combi's inverter would supply AC power to your vac and draw a considerable current from the batteries in so doing. I doubt your clamp on meter will show which direction the measured current is flowing though.

 

As an aside, note that when a multi-stage charger jumps from absorption to float mode (a drop of one volt or more in maintained voltage) the charger will produce zero current for a while until the batteries catch up. Any load on the batteries at that time will show up as a temporary drain on the batteries by a shunt type current meter until they settle to the lower charge voltage.

[coventrylad]

Your generator was supplying the AC power the vacuum was taking so there should theoretically be no instantaneous change in the charge current from the Combi's charger. There would however be a considerable extra load on the generator which you would have heard. If this is a variable speed inverter/generator its possible it over compensated for the extra load and its output volts rose enough to increase the chargers output by a small amount.

 

The only other reason for a sudden increase in current supplied by the Combi's charger, would be an extra DC load such as a fridge compressor cutting in.

 

If the generator wasn't running of course, the Combi's inverter would supply AC power to your vac and draw a considerable current from the batteries in so doing. I doubt your clamp on meter will show which direction the measured current is flowing though.

 

As an aside, note that when a multi-stage charger jumps from absorption to float mode (a drop of one volt or more in maintained voltage) the charger will produce zero current for a while until the batteries catch up. Any load on the batteries at that time will show up as a temporary drain on the batteries by a shunt type current meter until they settle to the lower charge voltage.

Thank you once again for your help I really do appreaciate the time you put in to answer peoples queries and or wories. Been on the boat again today with meter in hand ! the alternator is putting in 28 volts at about 10 amps, load the inveter the volts drop for a few seconds then go back to 28 volts and 50 plus amps. switch the engine off, start the generator 2500watts suppling 233 vots to the pro combi clamp meter on 1 amp being supplied at 26 volts ! reading on the batteries prior to this 12.8 volts I have used 95mm2 cable from dc alternator to battery bank approx 12 inch, and also 95mm2 cable from combi to batterie bank aprox 3 foot. measured voltatage at combi and at batterie bank no voltage drop at all. So why only 26 volts at fast charge rate and 1 amp when the dc alternator is giving 28 at 10 amps ? I have emailed Mr Sterling and am awaiting a reply, I am not a happy bunny at the moment. And your thoughts would as ever be greatly appreacited. Oh the genny is not a inveter genny just a 2.5 kva 50 hert jobby. thanks again.

[Chris Pink]

You wouldn't expect your charger to do much at all after the engine alternator has been charging it. The charger will 'see' a high voltage and probably drop into float (26.4V)

 

If you try the charger on the generator when your batteries are flat(ter) you will see a more realistic picture.

 

You are being a little cruel to Mr Sterling at the moment.

 

His combi is cleverer than your alternator

 

Incidentally this is completely unrelated to the OP who seems to have gone a little quiet.

Edited April 1, 2013 by Chris Pink

[coventrylad]

Hi Chris. the combie was tried first. 1 amp 26volt, then the engine/dc alternator, straight away the dc alternator was giving 28 at 10 amp. the batteries as said were only showing 12. 8 volts, the combi was not on float charge, it was on fast charge mode. I really hope the combi does not have a problem, been over the moon with it till i started measuring amps and vots out put. perhaps its a case of a little knowledge being dangerous