Electrolyte specific gravity anyone?

[nicknorman]

I know I started from 100%SOC because the previous charging tail current was less than 2% of the c20 capacity (450 Ah).

2% is 9A which is way short of 100% SoC. I get below 2A at 14.8v when the batteries are as reasonably fully charged as matters.

[Loafer]

 

>>> If you start at 100% and take out 187aH, with a light load I would expect about 12.1 volts, so your 11.67 is too low <<<

 

Big problem is that none of us knows how the cold is affecting our results (especially mine)

I might try to do something tomorrow. It means turning everything off but maybe I can do that when I walk the dog.

As Nick says an amp-hour counter can get things badly wrong and this may well have resulted in some sulphation.

(Equalisation will fix this).

 

Lets have a shot at working this out...

11.67 volts. Add 0.1 for your load effect gives 11.77. Thats about 28% charge (ouch) Add your 187aH (58%) and this suggests your batteries started out at 86% rather than 100%.

Did you say your specific gravity was just into the green? ( = 1.250? = 87% charge !!!!!!!!)

 

This is all a very rough estimate because you won't get the full 450aH with a cold battery.

 

.............Dave

 

Good words, chum. Good words. I can't fault your reasoning.

 

My counter though, for the moment, is:

 

They must have been fully charged, because of the charge tail current being less than 2% of the capacity. I can't remember the actual tail current amperage, but it would certainly have been around 7-9A because I was studying it.

 

I did an Eq charge yesterday, and had a tail current today of <5A, which is nearer to 1% of their c20. That HAS to be 100% SOC surely? Even Trojan say so in their manual! (1-3% of c20, i.e. 4.5-13.5A)

 

Temperaturewise, I don't know. My Trojans are below water level, but are inside, below the 'proper' engine room floor (no offence meant).

 

I'm guessing 4-10degC. Shouldn't be a massive factor, should it?

[Loafer]

2% is 9A which is way short of 100% SoC. I get below 2A at 14.8v when the batteries are as reasonably fully charged as matters.

 

It's funny you should say that. That is what I thought too, until I was convinced that 1-3% of c20 is 100% charged. Trojan told me that!

 

On that call, I will make an effort to to charge down to 2A next time. I reckon that's going to take all day at least!

 

This will bring forth more questions later.

 

I'm thinking that one or two of you guys ought to collaborate and become the 'New Gibbo'

 

ETcorrect stuff.

Edited February 2, 2015 by Loafer

[smileypete]

I'm guessing 4-10degC. Shouldn't be a massive factor, should it?

 

There's a table in The Battery FAQ:

 

http://jgdarden.com/batteryfaq/carfaq9.htm#temp

http://batteryfaq.org/

 

So looks like should be about 0.6V higher for batts at that temp, so 15.4V for charging, 16.1V for eq.

 

When eq charging, the batt acid should bubble quite nicely, this stops the acid stratifying and causing problems.

 

If the batts are new they'll take a fair few cycles to get to peak performance too.

 

cheers, Pete.

~smpt~

Edited February 2, 2015 by smileypete

[dmr]

The low tail current does not always mean fully charged, as in 450Ah, its just means as full as they can get in their present condition. This is why sulphation is such a bugger, the battery looks just like it is fully charged but its not.

Get that hydrometer out again, its the only real way to confirm that equalisation has got the batteries back to full capacity.

I know its all messy and a pain, and makes holes in yer clothes, but once you've got this sussed out you will need to use it less and less.

 

The SG of the Trojans should be just as high as the starter, until they are you will be digging yourself into a hole..

 

We have to get a whole lot ruder, outspoken, (and sometimes very funny) before we can take over from Gibbo.

 

............Dave

[Loafer]

Good site Pete.

 

Here's a clip from it, which supports Trojan's 100% SOC condition about tail current:

 

.2.14. Wet battery gassing usually starts at 80% of a full charge during the absorption stage. A full charge normally occurs when the charging current drops off below 2% (C/50) of the AH capacity and the battery is moderately gassing (bubbling). For example, the end current for a good 50 AH (C/20) battery is approximately 1.0 amp (1000 milliamps) or less depending on the battery type.

 

 

This suggests that 1% of c/20 is a full charge. In my case that's 4.5A.

 

Nicknorman suggests that this isn't 100%.

 

None of this really matters in the great scheme of things, but if you're a gnawing irritating old pedant like wot I am, it's important.

 

dmr: These can't be sulphated after 4 weeks, being charged to Trojan's 100% every 2 days, and never taken below my one-time 58%!!

 

Surely! There's certainly no sign of it by peering into the cells. All lead-grey and lovely.

[rogeriko]

Excellent thread I hope everyone is reading and understanding..

 

 

There's certainly no sign of it by peering into the cells. All lead-grey and lovely.

 

The plates should be alternately grey and chocolate brown with no white spots(sulphation)

Edited February 2, 2015 by rogeriko

[Loafer]

The low tail current does not always mean fully charged, as in 450Ah, its just means as full as they can get in their present condition. This is why sulphation is such a bugger, the battery looks just like it is fully charged but its not.

Get that hydrometer out again, its the only real way to confirm that equalisation has got the batteries back to full capacity.

I know its all messy and a pain, and makes holes in yer clothes, but once you've got this sussed out you will need to use it less and less.

 

The SG of the Trojans should be just as high as the starter, until they are you will be digging yourself into a hole..

 

We have to get a whole lot ruder, outspoken, (and sometimes very funny) before we can take over from Gibbo.

 

............Dave

 

I can't see how to get out of this hole. I'm doing everything by the book, and seeing strange results. At the moment, I'm taking the view that they need to get a little older before they start to man up.

 

Why did Gibbo leave? I left before he did, then I returned after he'd gone.

[Loafer]

MAJOR MISUNDERSTANDING ALERT!!,

 

You most certainly do not know your SoC from the BMV600, you only know the consumed AH.

 

You can know it with a little effort. There are many user-adjustable parameters available for twiddling. For example, I can tell the 600S not to show 'fully charged' until there has been, say, both 14.8 V AND less than x% tail current, for z minutes.

 

Crap in, crap out, I agree. But Victron seem to like their SOC, although I'm sceptical. I'm attempting to get it to say '100%SOC' only when the 105s are really at 100% SOC.

 

ETA And to show 50% SOC when I've used 225Ah.

Edited February 2, 2015 by Loafer

[dmr]

Charge to 100%, measure SG with your hydrometer, report back!!!!

 

Trojan are most likely thinking in terms of a golf cart battery that gets put on charge overnight every night for a long time.

Boating gives batteries a much harder life and some of what they might not apply.

For example,when I spoke to them (with similar problems to you) they suggested charging at 15v rather than 14.8v!

 

My rough sums suggest you are charging to less than 90% and discharging to 30%

 

Get that hydrometer out!

 

............Dave

[Loafer]

Charge to 100%, measure SG with your hydrometer, report back!!!!

 

Trojan are most likely thinking in terms of a golf cart battery that gets put on charge overnight every night for a long time.

Boating gives batteries a much harder life and some of what they might not apply.

For example,when I spoke to them (with similar problems to you) they suggested charging at 15v rather than 14.8v!

 

My rough sums suggest you are charging to less than 90% and discharging to 30%

 

Get that hydrometer out!

 

............Dave

 

It's ready Dave. SG is everything. Just a bit confused about how I can be doing things 'by the book', on quality new batteries, but still not doing it properly!

 

I'll N.B. my figures periodically and report anything noteworthy.

 

I assume that after this thread has lost it's attraction, you battery gurus will still notice a new post here, from me. Please stay tuned.

Edited February 2, 2015 by Loafer

[nicknorman]

You can know it with a little effort. There are many user-adjustable parameters available for twiddling. For example, I can tell the 600S not to show 'fully charged' until there has been, say, both 14.8 V AND less than x% tail current, for z minutes.

 

Crap in, crap out, I agree. But Victron seem to like their SOC, although I'm sceptical. I'm attempting to get it to say '100%SOC' only when the 105s are really at 100% SOC.

 

ETA And to show 50% SOC when I've used 225Ah.

Yeabut. Ok you can set it to give a better indication of fully charged. But if you take out 225AH, why do you think it should indicate 50%? Yes it will do that if the batteries really were fully charged, unsulphated and with their original capacity, but the trouble is that if they are not thus (as yours don't seem to be at present) then a reading of 50% SoC might be a much lower actual SoC. Weren't you going to get a Smartgauge as well, or am thinking of someone else?

[smileypete]

Good site Pete.

 

Here's a clip from it, which supports Trojan's 100% SOC condition about tail current:

 

.2.14. Wet battery gassing usually starts at 80% of a full charge during the absorption stage. A full charge normally occurs when the charging current drops off below 2% (C/50) of the AH capacity and the battery is moderately gassing (bubbling). For example, the end current for a good 50 AH (C/20) battery is approximately 1.0 amp (1000 milliamps) or less depending on the battery type.

 

 

This suggests that 1% of c/20 is a full charge. In my case that's 4.5A.

 

Nicknorman suggests that this isn't 100%.

 

Yeah, but it also mentions they should start to bubble moderately, if so they're probably charged enough.

 

Even if charging is less than perfect, some decent eq charging to get them bubbling nicely should make up for it.

 

Sealed flooded batts hardly bubble, but this seems to cause problems on narrowboats as they don't move much and the acid stratifies as there's not much motion to mix it up like in a car or motorhome.

 

So the big question may be, when you fully charge them, do they bubble a reasonable amount?

Even if they look OK the sulphation may be happening low down outta sight...

 

cheers, Pete.

~smpt~

Edited February 3, 2015 by smileypete

[Loafer]

 

Yeah, but it also mentions they should start to bubble moderately, if so they're probably charged enough.

 

Even if charging is less than perfect, some decent eq charging to get them bubbling nicely should make up for it.

 

Sealed flooded batts hardly bubble, but this seems to cause problems on narrowboats as they don't move much and the acid stratifies as there's not much motion to mix it up like in a car or motorhome.

 

So the big question may be, when you fully charge them, do they bubble a reasonable amount?

Even if they look OK the sulphation may be happening low down outta sight...

 

cheers, Pete.

~smpt~

Thanks Pete.

 

Yes, when 'fully charged' at 14.8V, there is 'some' gassing, which I'd say was 'not a lot', compared to an equalisation charge.

 

Ive got them up to absorption at the moment, and am going to keep them going under solar for the rest of the day. That will be at 14.6 - fixed by my Tracer Mppt controller.

 

But answer me this - how can NEW batteries be sulphated? Especially if being charged in accordance with Trojan's spec?

 

Ill do another check of SG late this afternoon and see if there's any improvement. I'm guessing there will be, since they are supposed to improve their capacity as they are cycled for the first few times. Innit.

 

Maybe my whole problem is that they are NEW, and are yet to reach their proper ability.

[nicknorman]

Thanks Pete.

 

Yes, when 'fully charged' at 14.8V, there is 'some' gassing, which I'd say was 'not a lot', compared to an equalisation charge.

 

Ive got them up to absorption at the moment, and am going to keep them going under solar for the rest of the day. That will be at 14.6 - fixed by my Tracer Mppt controller.

 

But answer me this - how can NEW batteries be sulphated? Especially if being charged in accordance with Trojan's spec?

 

Ill do another check of SG late this afternoon and see if there's any improvement. I'm guessing there will be, since they are supposed to improve their capacity as they are cycled for the first few times. Innit.

 

Maybe my whole problem is that they are NEW, and are yet to reach their proper ability.

Certainly, when I got mine they seemed quite poor for the first few cycles. However you have had yours for 4 weeks now so you would think they had got over their infancy. I am not sure at what point the acid gets added but one would presume it gets added in UK, rather than at manufacture. Anyway, I think your aim should be to get the fully charged SG up (as you are doing) and then everything will come right.

[Keith M]

Some time ago there was some mention of Trojans

Having reliability issues?

 

Keith

[Loafer]

Charging update.

 

My 105s spent the whole day on charge today, either solar up to 14.7V, or genny + Victron multiplus up to 14.9V, followed by an hour's Eq at 15.8.

 

Then back to 14.8 on the genny combo. All this has taken about 8 hrs, and I'm still going! We're down to 3A now, which simply HAS to be fully charged. It's been there for an hour or so without reducing any further.

 

There's a bit more 'green' on the hydrometer, for the first time. Some of the cells are well into the mid-green, a few are hovering just in the green on the border with white.

 

I daren't try any more Eq charge, so I'm thinking that there's nothing else to do but wait and see.

 

Another observation: the electrolyte is quite well stacked slightly above the bottom of the filler holes, i.e. rather full.

 

I'm guessing that, after a bit more gassing at 14.8V+, that the level will drop a little. Will this increase the SG of my fully charged batteries, or am I being silly?

[smileypete]

Not easy to eq charge without mains power or a programmable solar controller or combi....

 

Might be able to do something with unregulated solar panels or DC converters or both, depending on willingness to fiddle with wires.

 

It could be handy if things were set up so half the batts could be isolated and eq charged while the others supply loads as normal.

 

A long time ago I suggested having two banks, and using one while charging it to 85%ish while the other was progressively charged to 100% and eq'd, then swap over.

 

However there were howls of anguish from the 'experts' and Mr Gibbo himself, for taking the holy name of Peukert in vain.

 

Though since some inspired thinking from Nick Norman has become to Peukert what Charles Darwin was to creationism.

 

cheers, Pete.

~smpt~

Edited February 3, 2015 by smileypete

[dmr]

It sounds like the equalisation is starting to work, but if there really are significant variations from cell to cell then you need to do More. Why do you think you dare not do more?? You wont hurt them. An hour is really not enough if you have a bit of sulphation.

 

oooH your batteries are much too full so do keep an eye on them during the equalisation.

As your batteries are over-full then this will lower the SG that you measure. Not sure by how much, I keep meaning to work this out but with a bit of luck Nick will do it????

 

Another little mystery...when you top up the Trojans the capacity appears to reduce significantly for a couple of cycles!

 

................Dave

Try to avoid any temptation to take acid out of the batteries. Search for a recent thread on that topic. Just go carefully till it sorts itself out.

 

...........Dave

[Loafer]

Not easy to eq without mains power or programmable solar controller....

 

Might be able to do something with unregulated solar panels and/or DC converters, depending on willingness to fiddle with wires.

 

Could be handy if set up so half the batts could be isolated and eq charged while the others supply loads as normal.

 

cheers, Pete.

~smpt~

 

There are no problems here with an Eq charge, Pete. I'm just wary of doing it too often! What are the downsides?

 

Water loss? Not yet.

 

Temperature? They're still cold.

 

Still watching the hydrometer!

It sounds like the equalisation is starting to work, but if there really are significant variations from cell to cell then you need to do More. Why do you think you dare not do more?? You wont hurt them. An hour is really not enough if you have a bit of sulphation.

 

oooH your batteries are much too full so do keep an eye on them during the equalisation.

As your batteries are over-full then this will lower the SG that you measure. Not sure by how much, I keep meaning to work this out but with a bit of luck Nick will do it????

 

Another little mystery...when you top up the Trojans the capacity appears to reduce significantly for a couple of cycles!

 

................Dave

Try to avoid any temptation to take acid out of the batteries. Search for a recent thread on that topic. Just go carefully till it sorts itself out.

 

...........Dave

 

Agreed Dave. I wouldn't suck out any electrolyte. I'm intending to gas some off gradually. I think they're too full, too. That problem will go away soon at this rate.

 

So it's ok to Eq a bit more frequently, as long as you don't dry them out or heat them up?

[smileypete]

 

There are no problems here with an Eq charge, Pete. I'm just wary of doing it too often! What are the downsides?

 

Good for the batts, no downsides there, but long genny runs may be costly on fuel or annoy fellow moorers.

 

Some of the proper industrial chargers do a mini eq stage at the end of each overnight charge.

 

ETA: There should be info on topping up levels on the Trojan website, as it's easy to get wrong and end up batts overflowing or reduced life. There's also some general info on that Battery FAQ.

 

cheers, Pete.

~smpt~

Edited February 3, 2015 by smileypete

[Loafer]

 

Nothing for the batts, but long genny runs may get through costly fuel or be undesirable to fellow moorers.

 

Some of the proper industrial chargers do a mini eq stage at the end of each overnight charge.

 

cheers, Pete.

~smpt~

 

Ta Pete.

 

Genny fuel is authorised for this 'current' research. (We're not running it out of hours, although a neighbour on private moorings opposite is!)

 

I'm now discharging normally. Trouble is, it's shower day tomorrow, so the engine has to be run which will recharge again, plus a sunny day.

 

I won't be able to get them down much tomorrow.

 

Interesting. Thanks for your help, and to the other battery men here!

[dmr]

Yes, just keep an eye on temperature. The cheapo eBay infra-red thermometers have all sorts of uses when you live on a boat (-2 on the well deck right now)

Equalisation will most likely give a tiny reduction in battery life, but uncontrolled sulphation will certainly give a massive reduction in battery life.

 

...........Dave

[Keeping Up]

 

Though since some inspired thinking from Nick Norman has become to Peukert what Charles Darwin was to creationism.

 

[nicknorman]

ETA: There should be info on topping up levels on the Trojan website, as it's easy to get wrong and end up batts overflowing or reduced life.

~smpt~

Should be 3mm below bottom of the filler well when fully charged.

 

Trojan's instructions for equalising says to check the SG every hour, and stop the EQ when the SG stops rising, so clearly they expect it to last several hours.

Edited February 3, 2015 by nicknorman