Victron 12/40

[sailaboutvic]

Following on from my last thread .
We now in the Marina so more test .

Victron 12/40 centaur charger
Three set of batteries 100 AH each . One starter battery 75AH all sealed LA
Batteries 1 year old .

As soon as the battery charge is turned on , it charge around 35A but within a very short time it drops to 5A to 7A
Batteries voltage at this point 12.3
Four / five hours on and the batteries reach 12.6/12.7 at rest .
Is this correct ?
Why is the current dropping so low when the batteries are not reach float .
Is there a way I can charge at an higher current to charge the batteries quicker ?

The charger as an DIP switch for LA , GEL,AGM wouldn't moving it on a different setting help to charge quicker ? Which setting ?

Any other suggestion

Thanks .

 

[RichardS]

Hi Vic

I have the same charger and mine is set to AGM. Do you have AGM batteries?

When you say the batteries reach 12.7V at rest, do you mean that you've disconnected/turned off the charger and left the batteries with no current drain for a few hours? If so, that's about right ..... but if they batteries are still connected to the charger and there is no drain from the fridge then they should read 13.8 to 14.4V depending upon which part of the charge cycle they are on.

If you never see 13.8 - 14.4V then there is something wrong or the charger is on the wrong setting.

Just a thought ..... are the house batteries are connected to a different output to the starter battery at the charger? Might not make any difference but obviously best to use the charger as it was intended.

Richard

 

[sailaboutvic]

Hi Vic

I have the same charger and mine is set to AGM. Do you have AGM batteries?

When you say the batteries reach 12.7V at rest, do you mean that you've disconnected/turned off the charger and left the batteries with no current drain for a few hours? If so, that's about right ..... but if they batteries are still connected to the charger and there is no drain from the fridge then they should read 13.8 to 14.4V depending upon which part of the charge cycle they are on.

If you never see 13.8 - 14.4V then there is something wrong or the charger is on the wrong setting.

Just a thought ..... are the house batteries are connected to a different output to the starter battery at the charger? Might not make any difference but obviously best to use the charger as it was intended.

Richard

Hi Richard
Hope all ok your end .
My batteries are all Seal Lead Acid .
As you know we on board all the time so we can't really turn every thing off for hours .

So I rest them for 15 20 mins everything off other then the LED dash lights on and the reading I getting is as said 12.7
Last night , first night on shore power , we left the charge on all night , fridge was also left on but still in the morning the batteries was around 12.9v if I rested the batteries say 20 mins
Am I wrong in saying that they should had been up to 13.5 v ?

also they seen to be taken a long time to charge , surly the charger amps shouldn't drop so quickly .

Ok best to ask some question and do more test .

At what Volts would the charger go from bulk charge to Float ?

Isn't float around 13v and if that's the case , shouldn't the charge charge more the 5/ 7 amps

 

[RichardS]

Hi Richard
Hope all ok your end .
My batteries are all Seal Lead Acid .
As you know we on board all the time so we can't really turn every thing off for hours .

So I rest them for 15 20 mins everything off other then the LED dash lights on and the reading I getting is as said 12.7
Last night , first night on shore power , we left the charge on all night , fridge was also left on but still in the morning the batteries was around 12.9v if I rested the batteries say 20 mins
Am I wrong in saying that they should had been up to 13.5 v ?

also they seen to be taken a long time to charge , surly the charger amps shouldn't drop so quickly .

Ok best to ask some question and do more test .

At what Volts would the charger go from bulk charge to Float ?

All good here Vic .... but freezing outside .... literally!

If your batteries are sealed but not AGM then I think that you should have the charger on the normal Lead Acid setting.

If you connect them to the charger and they are not fully charged the current should go right up to 35A as you say. Now measure the voltage across the batteries whilst the current is at it's highest. You should see something between 14.4V and 14.8V bulk/absorption and this should hold until you see the current start to drop. The voltage should now come down to around 13.8V float and hold steady at that as long as the current stays low.

If you're not seeing this then something is not right.

Richard

 

[sailaboutvic]

All good here Vic .... but freezing outside .... literally!

If your batteries are sealed but not AGM then I think that you should have the charger on the normal Lead Acid setting.

If you connect them to the charger and they are not fully charged the current should go right up to 35A as you say. Now measure the voltage across the batteries whilst the current is at it's highest. You should see something between 14.4V and 14.8V bulk/absorption and this should hold until you see the current start to drop. The voltage should now come down to around 13.8V float and hold steady at that as long as the current stays low.

If you're not seeing this then something is not right.

Richard

Thank richard .
Have to wait till tomorrow to test what you say as the batteries at this moment as saying 13.3 , amps going in are 0.03 and we have quite a lot on , i.e. Fridge , lights and iPad charging . So more coming out then in ,
At this rate the batteries are not going to reach full charge .
More test to morrow when battery's are lower .

 

[ex-Gladys]

The settings on most of my kit has been Gel/sealed/flooded. Sealed/AGM are often referred to as VRLA (Vapour regulated lead acid) and I've had new AGM's for motorcycles (that are installed horizontally) arrive with an acid pack that saturates the glass mat (AGM=absorbed glass mat). I'd set your charger to AGM to see what happens over one cycle.

My upgraded solar panels and MPPT controller (set at sealed) are floating my batteries at 13.7-13.8V...

 

[PaulRainbow]

Thank richard .
Have to wait till tomorrow to test what you say as the batteries at this moment as saying 13.3 , amps going in are 0.03 and we have quite a lot on , i.e. Fridge , lights and iPad charging . So more coming out then in ,
At this rate the batteries are not going to reach full charge .
More test to morrow when battery's are lower .

Are the 13.3v and 0.03a readings coming from the BM ?

If so, i doubt there is anything wrong there. If the charger is in float mode and putting out 13.4v you will see slightly less at the batteries due to the load, so 13.3v is about right. 0.03a will be the net amps going into the batteries. Say you have a 10a load, the charger could be outputting those 10a plus a tiny bit for the batteries, if they are charged already.

 

[sailaboutvic]

Are the 13.3v and 0.03a readings coming from the BM ?

If so, i doubt there is anything wrong there. If the charger is in float mode and putting out 13.4v you will see slightly less at the batteries due to the load, so 13.3v is about right. 0.03a will be the net amps going into the batteries. Say you have a 10a load, the charger could be outputting those 10a plus a tiny bit for the batteries, if they are charged already.

Looking into it a bit more my LA batteries on that charger should stay on bulk charge (14.5) till SOC 80% , then go into Absorption Chargeat a rate of about13.5 v until it nearly fully charge about 96% at which it goes in float 13.1 v

What I think I am finding is it dropping from bulk charge to Absorption a lot sooner then what I expected , in which case it taking much longer to get the batteries to 100% , off cause my figure are all coming from my BM .

Taken reading and doing test , over next few days , once I got more to work with I report back for more suggestion .

 

[sailaboutvic]

Here we go first test
No Load isolated battery
100ah after a few hours at rest it read 13.0 v , I take it it's fully charge and if not almost fully charge .
I put an 3.9A draw on for 2.30 mins , Volts 12.2 .
after after a rest of 1 hours it recover to 12.42v that around 80% half an hour later is was about the same .
The question is what happen to the other 12% ?
Then I place it on charge the charge read 14.5v 35A within 10 mins the Ampe drop to 4A and a while later to 2A
So the question is
If I used 20% of the the 100AH = to 20amps why is the charger only replace at a rate of 2A after a short time on charge ?
At 20% lost would'nt it still be at bulk charge and putting in a lot more AMPS .

Keep it simple

 

[RichardS]

Here we go first test
No Load isolated battery
100ah after a few hours at rest it read 13.0 v , I take it it's fully charge and if not almost fully charge .
I put an 3.9A draw on for 2.30 mins , Volts 12.2 .
after after a rest of 1 hours it recover to 12.42v that around 80% half an hour later is was about the same .
The question is what happen to the other 12% ?
Then I place it on charge the charge read 14.5v 35A within 10 mins the Ampe drop to 4A and a while later to 2A
So the question is
If I used 20% of the the 100AH = to 20amps why is the charger only replace at a rate of 2A after a short time on charge ?
At 20% lost would'nt it still be at bulk charge and putting in a lot more AMPS .

Keep it simple

Firstly, I would suggest that a battery which has been regularly used for a year will have dropped capacity slightly, and that's assuming that the original 100Ah was correct when it was new and that it is correct at the ambient temperature. You might be looking at 90 or 95 Ah rather than 100.

The 4A draw for 2.5 hours = 10 Ah. If the battery was now at, say, 80 or 85 capacity, that would suggest a voltage of 12.2 to 12.3V under load which you seem to be achieving.

That should recover to around 12.6V when rested, which makes me think that it needs to be rested for longer to get a true reading.

On top of all of this is the question of how accurate are the voltage measurements?

Perhaps look again at your re-charging conclusions because if the charger steps down the bulk current at 80% charge then it's probably not going to take long for a 100Ah battery with 35A going into it to hit 80%.

Richard

 

[sailaboutvic]

Firstly, I would suggest that a battery which has been regularly used for a year will have dropped capacity slightly, and that's assuming that the original 100Ah was correct when it was new and that it is correct at the ambient temperature. You might be looking at 90 or 95 Ah rather than 100.

The 4A draw for 2.5 hours = 10 Ah. If the battery was now at, say, 80 or 85 capacity, that would suggest a voltage of 12.2 to 12.3V under load which you seem to be achieving.

That should recover to around 12.6V when rested, which makes me think that it needs to be rested for longer to get a true reading.

On top of all of this is the question of how accurate are the voltage measurements?

Perhaps look again at your re-charging conclusions because if the charger steps down the bulk current at 80% charge then it's probably not going to take long for a 100Ah battery with 35A going into it to hit 80%.

Richard

Thank for bearing with me richard .
I using two meters both saying the same , so I reckon the reading pretty good .
I removed the BM for now .
The Amps reading are coming from the battery charge , no sooner I turn it on it goes to 35A but very quickly drops to 2 or 3 Amps I doubt if it's put a couple of amps in that time .
Looking at victron chart for the 12/40 charger it says float charge is 13.5v so I am guess 14.5 would still be bulk or at less Absorption and at that state of charge wouldn't I be seeing more the 2A ?
This is where I getting confused .

 

[RichardS]

Thank for bearing with me richard .
I using two meters both saying the same , so I reckon the reading pretty good .
I removed the BM for now .
The Amps reading are coming from the battery charge , no sooner I turn it on it goes to 35A but very quickly drops to 2 or 3 Amps I doubt if it's put a couple of amps in that time .
Looking at victron chart for the 12/40 charger it says float charge is 13.5v so I am guess 14.5 would still be bulk or at less Absorption and at that state of charge wouldn't I be seeing more the 2A ?
This is where I getting confused .

No problem Vic. The ammeter on the front on my 12/40 goes up to 50A and when I turn it on when my batteries are really down, like around 50%, the needle goes hard over to the end stop which is actually beyond 50A. I think it starts to come down in an few hours (I've never really checked it) but that's connected to a very old 600 Ah (ignoring the two engine batteries which will be fully charged already). Assuming my total capacity is down to 400 Ah and I'm starting at 200Ah and 80% charged is 360Ah then I need to put in 160Ah which would be 3 or 4 hours at 50A+.

I'm not sure whether this 3 or 4 hours is right but it feels about right. What I am sure about because I can see the voltmeter on the panel (the charger ammeter is hidden in a locker) is that the voltage stays steady at 14.4V (mine are AGMs) until it suddenly drops to 13.4V at which point the batteries are fully charged. If I look at the charger now it will be showing less than 5A but I've always got stuff running, of course.

Richard

 

[sailaboutvic]

No problem Vic. The ammeter on the front on my 12/40 goes up to 50A and when I turn it on when my batteries are really down, like around 50%, the needle goes hard over to the end stop which is actually beyond 50A. I think it starts to come down in an few hours (I've never really checked it) but that's connected to a very old 600 Ah (ignoring the two engine batteries which will be fully charged already). Assuming my total capacity is down to 400 Ah and I'm starting at 200Ah and 80% charged is 360Ah then I need to put in 160Ah which would be 3 or 4 hours at 50A+.

I'm not sure whether this 3 or 4 hours is right but it feels about right. What I am sure about because I can see the voltmeter on the panel (the charger ammeter is hidden in a locker) is that the voltage stays steady at 14.4V (mine are AGMs) until it suddenly drops to 13.4V at which point the batteries are fully charged. If I look at the charger now it will be showing less than 5A but I've always got stuff running, of course.

Richard

Sorry your right , mind also goes to 50A .
The battery has now been on chRge for over three hours , Volts has stayed reading 14.6v and it's been on 2A nearly all that time .
So by what you said it's not fully charge yet , , plain to leave it until we go to bed to see if the Volts drop to 13.5 this is what victron say float charge is for LA batteries .
By which time it would had been on for 6 hours ,
If it don't drop , that's going to be another puzzle .

 

[crisjones]

Sorry your right , mind also goes to 50A .
The battery has now been on chRge for over three hours , Volts has stayed reading 14.6v and it's been on 2A nearly all that time .
So by what you said it's not fully charge yet , , plain to leave it until we go to bed to see if the Volts drop to 13.5 this is what victron say float charge is for LA batteries .
By which time it would had been on for 6 hours ,
If it don't drop , that's going to be another puzzle .

Hi Again Vic!!

From what you and Richard are saying I guess the Victron charger has an analogue meter on the front panel (i looked on line and yes it does!!) These meters are usually difficult to read accurately especially near zero and they are not generally the most accurate of things. However they should give at least a fair indication of charging currents and when the current is down at around 2A it should mean the battery is pretty close to 100% SOC.
Richard is right when he says your batteries may not actually have 100AH capacity especially if they have not been fully charged for weeks/months on end - that is a sure way to reduce actual capacity by sulphation. Basically some of the lead sulphate on the plates hardens if a battery is not fully charged for a length of time, after that charging does not convert the lead sulphate back to acid so you end up losing capacity over time.
At 14V the charger will certainly still be in bulk or more likely absorbtion mode and I would expect the battery to be taking a bit more charge than you are seeing.

Richard's general idea is correct but he has missed out charging efficiency in his example - to put 160AH into his batteries the charger would need to output around 190AH because the charge efficiency is around 80-85% - his AGM's should be at the top end of this.
Also if you remember back to my post in the other thread charging the last 10% into lead acid batteries will take a long time, maybe as long as 4-6hrs to be absolutely sure they are 100% SOC.
Also some of your figures are relying on the accuracy of your Nasa BM and that is not going to be helping you trying to sort things out!!
I would suggest charging your batteries for a full 24hrs or more and during that time turn the charger on and off a few times, this will cause the charger to start the charge programme again from bulk and should ensure the batteries get absolutely fully charged. After that apply a steady load of 5A for 10 hrs, this should get the battery down to 50%. Let the battery rest for a couple of hours or longer and then check the voltage to estimate the actual SOC%. This will give you a far better idea of the actual capacity of your battery. No need to worry too much if this test actually takes the battery down to 40%SOC or even 30% SOC since you will be immediately charging it up again, a one off test like this will not have much impact on overall battery life.

 

[sailaboutvic]

Chris and Richard , thank for your input .
Well this is what I found is happening after two days of messing around .

I flatten a battery down enough 12.1 to get the charger to start from the begin .
The battery isn't connected to the boat .

The charger started charging at 13.5v at this rate it putting in 42 amps ,
Over some time the Amps drop until it's only putting in a few amps still charging at 13.5 v , then slowly the voltage start to go up until it reach 14.5v and stay like this for about 4 hours , all this time only putting in a very small amount of Amps , 2 or 3 . ( that's the bit I couldn't understand )
then after four hours it seen slowly drop again until 13.5v still only putting in a few amps if any .

It seen at bulk charge the voltage is kept low 13.5 but the Amps are high and only when the battery can't except any more amps that it start to charge at an higher voltage rate , 14.5v Which I expect is Absorption , this Seen to go on four four hours at which time I expect the batteries are almost full and the volts drop to 13.5 and it carry on .

Where I was getting confused is , I expected the charging voltage and current from the charger to behave like an alternator, high charging voltage high current , has the amps reduces so does the voltage.

In other words I looking at Absorption stage and seeing Volts 14.5v and expecting to see high current going in , instead there only 3a amps .

This has now cause me another problem , within the winter months and early spring when we not getting enough day sun on our panels to keep the batteries up pass the bulk stage , it mean I will have to run the generator for at less Four hours to get the charger pass the Absorption stage and nearly fully charge ,
Or find a way to push more amps into the batteries at a shorter time without messing up the batteries.
Can't add more batteries as we have no more room .

I expect the answer is more panels and more batteries.


Or except that my batteries aren't going to get a full charge .

 

[crisjones]

Hi Vic,

It sounds like your charger is doing exactly what it is supposed to do!! The Victron datasheet here https://www.victronenergy.com/upload/documents/Datasheet-Centaur-Charger-EN.pdf says it will bulk charge until current drops to 70% of rated output and then changes to absorbtion for a fixed 4hr time before changing to float charge.
As you are finding it will take all of that 4hr period to get to 100% SOC, more solar is the best answer to your problems.

 

[sailaboutvic]

Hi Vic,

It sounds like your charger is doing exactly what it is supposed to do!! The Victron datasheet here https://www.victronenergy.com/upload/documents/Datasheet-Centaur-Charger-EN.pdf says it will bulk charge until current drops to 70% of rated output and then changes to absorbtion for a fixed 4hr time before changing to float charge.
As you are finding it will take all of that 4hr period to get to 100% SOC, more solar is the best answer to your problems.

Morning Chris
Yes it is going what it should , what was confusing me was I happened to be checking it at Absorption stage when the Volts where hight but hardly any amps being replace even if there a large discharge at that time , and couldn't understand why not ,
comparing to an alternator where if I was discharging the Amps would increase to make up for what's taken out .

Still confused tho , as an over night charger when hardly nothing being discharge I can see how it bring the batteries back up to 100 SOC .
BUT let's say says in that Absorption 4 period it just putting two or three amps , and I have discharge the batteries by say 8 APH i used 32A and the batteries charger only placed 8 Amps so it ended up going back to Absorption stage after 4 hour , so I can't see how the batteries will have reach full charge unless nothing it taken out of the battery until it goes through a full cycle.
As on the other boat where I had a quick make of charge ,not the victron make , any current was being used , it was replace at the same rate and a bit more to what ever the battery will accept .

Yes more Panels , but where to put them .

 

[crisjones]

Hi Vic,

Our Victron charger (Multi-Plus Inverter Charger) seems to put the max current the batteries will accept when in Absorbtion mode, regardless of other loads. So if I have 20A of loads switched on and the batteries will take 20A then the charger will output 40A so the batteries get charged regardless of other system loads.

Not sure what your Centaur charger does but I would have expected it to compensate for other loads so the battery should still get charged at the same rate as it would without other loads switched on.

It would be worth emailing Victron to see what they say, I think they are pretty good at responding to such enquiries and at least you will get an accurate answer.

 

[sailaboutvic]

Hi Vic,

Our Victron charger (Multi-Plus Inverter Charger) seems to put the max current the batteries will accept when in Absorbtion mode, regardless of other loads. So if I have 20A of loads switched on and the batteries will take 20A then the charger will output 40A so the batteries get charged regardless of other system loads.

Not sure what your Centaur charger does but I would have expected it to compensate for other loads so the battery should still get charged at the same rate as it would without other loads switched on.

It would be worth emailing Victron to see what they say, I think they are pretty good at responding to such enquiries and at least you will get an accurate answer.

Did that last night Chris , still awaiting on A reply Like you I would had through any current used would be replaced ,
i just working on the second battery now and getting the same as I got with the first battery ,
One good bit , the first battery been standing for 22 hours now and not lost any thing .

 

[PaulRainbow]

My Sterling charger works the same. If the batteries need 5a the charger outputs 5a plus whatever the load is. My solar controller does the same.