Trojan batteries

[sailaboutvic]

sorry, didn't notice that on my mobile before Vic.
YES, when I do set for a MANUAL equalise, and obviously do that when the panels are capable of giving some Amps to the batteries, for that hour voltage is 32.something. So yes, it does work, hope you're not trying to do that in the evening!

V.

No I been bring the batteries to abs then manually switching over to equalise, three time I have tried this each time I let it work for several hours Iredell the panels I. Serial for this and had voltage 80v from panels , it's never passed 14.7 v at the batteries . fu@k knows what's going on

 

[GHA]

Once Bulk charge reach 14.6v it goes into abs , at that point the Voltages start to drop but the current keep poking into the batteries until the batteries accept 3 Amps or less at that point it goes in float charge the voltage at that point is around 13.3/13.4v
Now am I correct if all these factor are reach the battieres must had reach float charge and are fully charge ?
If not why not please

No, the battery will continue to accept charge at 14.6v, just less and less at it gets charged, the voltage will stay there until the regulator decides to go to float voltage. Commonly solar regulators do this move to float far too early and the batteries never get fully charged, hardly anything goes into the batts at float voltage. Just cos your regulator has gone to float does *not* automatically mean the batts are actually fully charged, good change they aren't. Takes prob at the very least 4 hours at absorption voltage to get up near fully charged.

 

[noelex]

Once Bulk charge reach 14.6v it goes into abs , at that point the Voltages start to drop but the current keep poking into the batteries until the batteries accept 3 Amps or less at that point it goes in float charge the voltage at that point is around 13.3/13.4v
Now am I correct if all these factor are reach the battieres must had reach float charge and are fully charge ?
If not why not please

During the absorption phase, providing the solar panels can deliver enough energy, the voltage should remain constant at your 14.75 v setting (plus/minus the temperature adjustment). As the battery state of charge increases, the current will gradually decrease while the solar controller maintains the same voltage.

Ideally when the current (@ 14.75 v) has dropped back to 1% (I think from memory you had a 400 Ahr battery bank so this would be 4 A), the charger will switch to float. This indicates the absorption/float transition is occurring at the correct time.

If the battery is still accepting a higher current than 4A (@ 14.75 v) when the switch to float occurs then the transition to float is occuring to early and the batteries are being undercharged. The absorption time should be increased. If the current is under 4A then the absorption time should be reduced. (1% is good but slightly agressive compromise for most batteries, but you are better to check your battery specifications. The manufacturers nominate from 0.5% to around 2%. In practice the tail current drops off rapidly so the difference absorption time is not great despite these wide % limits).

Once the controller has switched to float the current will immedatetly drop much further at this lower voltage, but at this stage the batteries should be 100% charged (technically they are not quite 100% but for our purposes they are generally regarded as 100% SOC).

 

[lw395]

No, the battery will continue to accept charge at 14.6v, just less and less at it gets charged, the voltage will stay there until the regulator decides to go to float voltage. Commonly solar regulators do this move to float far too early and the batteries never get fully charged, hardly anything goes into the batts at float voltage. Just cos your regulator has gone to float does *not* automatically mean the batts are actually fully charged, good change they aren't. Takes prob at the very least 4 hours at absorption voltage to get up near fully charged.

Might be worth stepping back a little and defining what 'bulk' and 'absorption' phases actually are.
Definitions do vary a tad, but in charger manufacturer speak, 'bulk' is when the charger is current limited, i.e. the charger is giving out either its controlled charge, or the max it can wring out of the sun.
When the volts rise to the 'absorption' level, you are then in the constant voltage absorption phase.

The effect of this is that how 'charged' the battery is when it goes from bulk to abs will depend on the current limit in relation to the size of the battery.
A big battery taking 10A at the end of 'bulk' is more charged than a smaller one taking 10A, because the volts/state of charge graphs are pretty much governed by the current in or out in terms of amps/amphr capacity.
So unless you know the bulk current has been a known fraction of the capacity in Ah, you can't say how long the absorption phase needs to be.
With a solar controller, the bulk charge current will vary with how sunny it is.
With a system with loads, the bulk charge is reduced by what the loads are using.
In the limit, you can overcharge a battery without it ever reach the absorption voltage, just by having the 'bulk' current too low!

Bear in mind also that these Victron controllers are actually designed around a different application, where the loads are connected to the 'Load' terminals.

 

[sailaboutvic]

No, the battery will continue to accept charge at 14.6v, just less and less at it gets charged, the voltage will stay there until the regulator decides to go to float voltage. Commonly solar regulators do this move to float far too early and the batteries never get fully charged, hardly anything goes into the batts at float voltage. Just cos your regulator has gone to float does *not* automatically mean the batts are actually fully charged, good change they aren't. Takes prob at the very least 4 hours at absorption voltage to get up near fully charged.

P...
I never seen the abs time last 4 hours it's usually around 1.5 hours even tho the max abs time as been set at 4 hours .
I have now rise it to 6 hours but I can't see what different that's going to make when it only reaches 1.5 h set at 4 hour max .
The abs voltage set at 14.75 and the float at 13.5v was taken off Trojan data sheet it also came from a few on here when I ask the question some years back .
So what's gone wrong , it seen the setting where correct as far Trojan says .

 

[sailaboutvic]

During the absorption phase, providing the solar panels can deliver enough energy, the voltage should remain constant at your 14.75 v setting (plus/minus the temperature adjustment). As the battery state of charge increases, the current will gradually decrease while the solar controller maintains the same voltage.

Ideally when the current (@ 14.75 v) has dropped back to 1% (I think from memory you had a 400 Ahr battery bank so this would be 4 A), the charger will switch to float. This indicates the absorption/float transition is occurring at the correct time.

If the battery is still accepting a higher current than 4A (@ 14.75 v) when the switch to float occurs then the transition to float is occuring to early and the batteries are being undercharged. The absorption time should be increased. If the current is under 4A then the absorption time should be reduced. (1% is good but slightly agressive compromise for most batteries, but you are better to check your battery specifications. The manufacturers nominate from 0.5% to around 2%. In practice the tail current drops off rapidly so the difference absorption time is not great despite these wide % limits).

Once the controller has switched to float the current will immedatetly drop much further at this lower voltage, but at this stage the batteries should be 100% charged (technically they are not quite 100% but for our purposes they are generally regarded as 100% SOC).

J..
I wish I knew this while we was in lock down mode it would had been easier to check then when we moving .
So what your saying is once it reaches Abs the voltage stays at 14.7 v or there about until the current drop to 4A for my 400ah bank ?
(Only problem it's no longer 400ah more like 200ah.)
At that point once it only excepting 1% of the batteries back the voltage will drop to 13.5 v and only at that point it switches into Float .correct .

Taken that the case , and mine haven't been getting a full charge .
How am I going to correct it?
Taken into account .
Abs max time 6 hours
Abs voltage 12.75 v
Float voltage 15v

 

[noelex]

(Only problem it's no longer 400ah more like 200ah.)

Batteries are considered at the end of their life when the capacity drops to around 80%, so if your estimation is correct these batteries are very dead. Sometimes very aggressive charging (a few equalisation cycles) will restore some capacity, but the exact charging specifications while important to keep the batteries in good health are not very critical at this terminal stage.

It is not clear why your batteries died at such a young age. The depth of discharge was very gentle. Your charging parameters look reasonable. The important voltage set points were correct. It is not clear if your absorption time was ideal, but it was at least in the right ball park.

These batteries do benefit from correct periodic equalisation and I suspect from your posts (but perhaps I have misunderstood) that the high voltages required were never fully achieved. Nevertheless, the batteries should have lasted longer.

One intriguing detail is the very low 1.02v battery voltage reported by the software. This is probably accidentally turning off the battery supply to the regulator. This is easy to do but ideally should not be done without turning off the solar supply first. As you do not remember doing this it could also could be a sign of some intermittent poor connection or short circuit. I think this is probably a red herring, but before fitting new batteries I would at least watch for this again and try and find the cause as this seems to be the only significant anomaly.

The most likely explanation is at least one of your batteries was defective. This can prematurely destroy the whole bank.

 

[PaulRainbow]

Taken that the case , and mine haven't been getting a full charge .
How am I going to correct it?
Taken into account .
Abs max time 6 hours
Abs voltage 12.75 v
Float voltage 15v

Your Abs max time was set to 3 hours, see the pic of settings you posted in post #27

 

[miyagimoon]

Vic,
I know what I about to say is not associated with solar panels or their associated MPPT but many years ago I used my Charger / Inverter to equalised my Lead Acid batteries. When they eventually died I used it on the new batteries but the voltage would no longer get above 14.7v. I contacted the charger/inverter manufacturer who told me it was due to the internal resistance in the batteries. Again some time later I replaced those batteries with another make. Low and behold when in equalisation mode the voltage went above 14.7. So maybe you cannot get higher than 14.7v in equalisation mode due to internal resistance of your batteries.

 

[GHA]

So what's gone wrong , it seen the setting where correct as far Trojan says .

Diagnosis by forum will always be tending towards guesswork but this...

I never seen the abs time last 4 hours it's usually around 1.5 hours...

looks like a possible smoking gun...very likely just not enough time for the batteries to get up to full charge, if day in/ day out the regulator was dropping the voltage to float after 1.5h then likely the bateries won't be happy for very long.

 

[noelex]

The ideal absorption time is very variable with the system. This is why using the default absorption time is rarely close.

On our system, our typical absorption time is around 30 mins, on our previous boat around half of this time was needed. On the other hand, an absorption time of a few hours can be correct for some systems.

A couple of things to note:

1. The Victron MPPT controllers count the absorption time correctly, but it is not reported correctly on the app. This is a legacy from the earlier software versions. In the early versions the Victron counted the absorption time in a very unusual way. This has been corrected on later software versions but the app has never been updated.

So the absorption time reported by the app is not the actual absorption time, sometimes it can be very significantly wrong.

2. On the Victron controllers you set the maximum absorption time. This will only be used if the batteries are very flat (or the controller is fooled into thinking the batteries are very flat).

 

[lw395]

P...
I never seen the abs time last 4 hours it's usually around 1.5 hours even tho the max abs time as been set at 4 hours .
I have now rise it to 6 hours but I can't see what different that's going to make when it only reaches 1.5 h set at 4 hour max .
The abs voltage set at 14.75 and the float at 13.5v was taken off Trojan data sheet it also came from a few on here when I ask the question some years back .
So what's gone wrong , it seen the setting where correct as far Trojan says .

If you read all the blurb from Trojan, it's based on charging at 13% of the 20-hour capacity in the bulk phase.
That means 29A into each T105.
You're charge limit is 30A into two strings, if you've got full sunlight (400W /14.4V= 27A less losses), less anything your loads use.
When your fridge is taking 8A, there's at best about 10A left for each Trojan. Roughly a third of what Mr Trojan bases his advice on.
So your setup does not really remotely resemble Trojan's preferred regime.
Therefore, expecting the absorption time to be the same is just hopeless.

You are charging the batteries more slowly, therefore they are at a higher state of charge when they hit the voltage limit.
Therefore they don't need so much absorption time.

I suspect your capacity test is equally not really valid and your batteries may well be in much better health than you imagine.

 

[sailaboutvic]

Your Abs max time was set to 3 hours, see the pic of settings you posted in post #27

It was Paul until I download new app , but even so considering the starting min battieres voltages shown on the MPPT the lowest it's been is 12.2 v according to Victron 12.2 to 12.6v the setting is 2 hours well within my 3 hour setting I had it set to .
There was a couple of lower voltage but then there appeared while I been playing around with it .turning it off and on .

 

[sailaboutvic]

Diagnosis by forum will always be tending towards guesswork but this...

looks like a possible smoking gun...very likely just not enough time for the batteries to get up to full charge, if day in/ day out the regulator was dropping the voltage to float after 1.5h then likely the bateries won't be happy for very long.

Not wishing to disagree with you P as you know much more then me re these batteries. Suggest that the abs is too low and should be more like 4 hours according to Victron that for batteries with a starting voltage of 11.6v to 12.2 v mine when I not playing and doing test it's never been lower then 12.2v and thennormally some thing on like the fridge or freezer have come on , so really its a lot more higher, which mean the abs time of 2 hours when mine was set for 3 hours is about right .

 

[lw395]

Vic,
I know what I about to say is not associated with solar panels or their associated MPPT but many years ago I used my Charger / Inverter to equalised my Lead Acid batteries. When they eventually died I used it on the new batteries but the voltage would no longer get above 14.7v. I contacted the charger/inverter manufacturer who told me it was due to the internal resistance in the batteries. Again some time later I replaced those batteries with another make. Low and behold when in equalisation mode the voltage went above 14.7. So maybe you cannot get higher than 14.7v in equalisation mode due to internal resistance of your batteries.

Nonsense.
Higher internal resistance would make it easier to raise the terminal voltage.
If you can't get > 14.7V in equalisation, it's probably either a faulty cell or the battery needs longer to equalise.
Or the equalisation current is inadequate for the size of battery.

 

[sailaboutvic]

Batteries are considered at the end of their life when the capacity drops to around 80%, so if your estimation is correct these batteries are very dead. Sometimes very aggressive charging (a few equalisation cycles) will restore some capacity, but the exact charging specifications while important to keep the batteries in good health are not very critical at this terminal stage.

It is not clear why your batteries died at such a young age. The depth of discharge was very gentle. Your charging parameters look reasonable. The important voltage set points were correct. It is not clear if your absorption time was ideal, but it was at least in the right ball park.

These batteries do benefit from correct periodic equalisation and I suspect from your posts (but perhaps I have misunderstood) that the high voltages required were never fully achieved. Nevertheless, the batteries should have lasted longer.

One intriguing detail is the very low 1.02v battery voltage reported by the software. This is probably accidentally turning off the battery supply to the regulator. This is easy to do but ideally should not be done without turning off the solar supply first. As you do not remember doing this it could also could be a sign of some intermittent poor connection or short circuit. I think this is probably a red herring, but before fitting new batteries I would at least watch for this again and try and find the cause as this seems to be the only significant anomaly.

The most likely explanation is at least one of your batteries was defective. This can prematurely destroy the whole bank.

John the 1.02 v appeared after I turned them all off to change them from parallel to serial to get more voltage to equalise them , which never happened .
I going to have to replaces these batteries sooner or later and I just trying to work out if it's worth spending another 800€ on some thing that seen so temp hard to set up and look after other wise they only last a few years or do what I was doing for 30 odd years and buy cheaply batteries at a third of the cost and just plug them in and forget them ,
Lasting just as long .
There just no point to buy trojan again unless I find what gone wrong this time and make sure i don't have the same problem again.
Which is what I'm doing with my posting .
And thanks everyone with your input .

 

[sailaboutvic]

Nonsense.
Higher internal resistance would make it easier to raise the terminal voltage.
If you can't get > 14.7V in equalisation, it's probably either a faulty cell or the battery needs longer to equalise.
Or the equalisation current is inadequate for the size of battery.

Just to say , it can't be a faulty cell as they all above the gravity reading , can't be voltage as all day it had a voltage of 80v .
And it can't be the time it was on equalise as there where on for most of the day and never pass 14.7 v

 

[geem]

Trojan data sheet doesnt get much more specific than voltages. They do recommend equalisation for 2-4 hrs.
I suspect you will have difficulty equalising your batteries on solar. Before I upgraded to my current 720w of solar I was using 340w of solar. I found with this little solar I couldnt maintian the batteries at an equalisation voltage.

 

[sailaboutvic]

Trojan data sheet doesnt get much more specific than voltages. They do recommend equalisation for 2-4 hrs.
I suspect you will have difficulty equalising your batteries on solar. Before I upgraded to my current 720w of solar I was using 340w of solar. I found with this little solar I couldnt maintian the batteries at an equalisation voltage.

They also say the equalise then if the cell show low reading an indication of u der charging and unbalanced cells mine do not show low reading , so even if I did manage to equalise them I doubt they be any better.

 

[vas]

OK, all this discussion is interesting, v. interesting (and I personally would like to thank the contributors!), but not going to draw any definite conclusions...
If we try to summarise we have:

Looks like each day your batteries under load (not open circuit) don't go down much something like 70-75% SOC, which is not bad.
Why do you keep on saying you have to replace them? I don't get it. Do they not serve their purpose at this time? OK, maybe you bought more useable Amps than you have now, but looks like they are OK for your usage, no?

Also it seems that your solar power is not enough to drive the equalisation stage. FWIW, my 600W solar on 225Ah@24V bank is happy to do it, your 400W solar on 450Ah bank is not, maybe not that surprising?
Can you use your mains charger to do this equalisation stage? I do wonder if normal main chargers can do that, have to check my Victron multiplus3000VA.

Being liveaboard, I'd try for a nice sunny day to be on shore power disconnect in the morning the trojans from the various loads you have (seem to be many!) and do
a careful recording of how solar fills up the batteries, how long is the bulk/absorption stage, what temps/Voltages are registered and go on from there (I wonder if you can do that, are your fridges/freezers also 230V?)
You may even be lucky and manage to run the equalisation with no other loads!

Then I'd go on from there, adding (SOME) loads the next day, record and follow how things perform and regulate abs times till you reach the point that hopefully everything works.

another black art we have to manage/master...
good luck!

V.