Trojan T105 Dead

[dmr]

My batteries are not doing as well as they should and investigation revealed that one of my Trojans T105's is totally dead, one of its cells has completely run out of those specific gravity thingies!  I noted that the other cells in the pair all read quite high. These two old Trojans have been using a LOT of water for a while now so this failure was not a big surprise.

 

I purchased and fitted these batteries in October 2011 so they have just failed to last a full seven years. With the exception of a holiday in Cornwall each year, and a week or two on shore power in Liverpool, these batteries have been in use every day and cycled to varying degrees most days. 

 

Two new T125's will hopefully arrive on Tuesday to supplement the existing 4 T105s.

 

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

[nicknorman]

When is the funeral?

 

Any idea what the failure mode is? Excessive plate shedding perhaps?

 

Still, 7 years constant use is pretty good. Do you have any gadgets that count full cycle equivalents? (Like my Mastershunt does).

Edited August 26, 2018 by nicknorman

[Dr Bob]

21 minutes ago, dmr said:

has completely run out of those specific gravity thingies!

You cant run out of specific gravity thingies. The specific gravity is eider one thing or another. You can run out of water. You can run out of beer (if Mrs Bob does not put enough bottles in the trolley) but you cant run out of specific gravity.?

Have a greenie for making them last 7 years.

[MtB]

3 minutes ago, Dr Bob said:

You cant run out of specific gravity thingies. The specific gravity is eider one thing or another. You can run out of water. You can run out of beer (if Mrs Bob does not put enough bottles in the trolley) but you cant run out of specific gravity.?

Have a greenie for making them last 7 years.

 

Yes I was wondering about that too. I can't even see how the SG can have subsided to 1.000. 

 

I suspect the cell has boiled itself dry so there is no electrolyte showing to slurp up into the measury thing.

[dmr]

25 minutes ago, nicknorman said:

When is the funeral?

 

Any idea what the failure mode is? Excessive plate shedding perhaps?

 

Still, 7 years constant use is pretty good. Do you have any gadgets that count full cycle equivalents? (Like my Mastershunt does).

I still only have the Smartgage, so not even a basic amp-hour counter. I did start to make one last winter based on an Arduino but other projects got in the way. I might have another go this winter. Revised plan is to use one of these dirt cheap Hall effect current transformers that are all over eBay and to fix any shortcomings in software.

 

I might do a bit of diagnostics when I get the batteries out of the battery box (to estimate capacity on the non failed battery) . The other cells had high SGs so I am suspecting a shorted cell which has caused the others to get a sort of constant mega equalisation. The acid was looking a bit mucky in one of the other cells.

 

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

[dmr]

14 minutes ago, Mike the Boilerman said:

 

Yes I was wondering about that too. I can't even see how the SG can have subsided to 1.000. 

 

I suspect the cell has boiled itself dry so there is no electrolyte showing to slurp up into the measury thing.

 

I have been putting a lot of water in for the last year, some cells more than others, though I don't think the failed cell was one of the really thirsty ones.

I have adopted the Ditchcrawler approach of checking batteries at the same time that I do the oil change so every 200 hours, and even so the plates have been a bit exposed once or twice.

 

I suspect a shorted cell will cause a 100% discharge of that cell which I estimate would give an SG of about 1.05. You might remember that when we did our big hydrometer comparison that mine did over read a bit so nothing I measure is very accurate ?!  I could send you a"sample" in the post ?.

 

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

[Detling]

I note you say the new batteries are to supplement your current batteries. It is a bad idea to mix old and new in one bank as the old limit the performance of the new batteries and can even damage them.

[MtB]

11 minutes ago, Detling said:

I note you say the new batteries are to supplement your current batteries. It is a bad idea to mix old and new in one bank as the old limit the performance of the new batteries and can even damage them.

 

 

There was a long thread about this a few years back and Gibbo's view was that it was OK to mix up old and new. 

 

In what way does an old battery in a bank limit the 'performance' of the newer ones please? (Assuming it isn't 'broken'.)

[dmr]

1 hour ago, Detling said:

I note you say the new batteries are to supplement your current batteries. It is a bad idea to mix old and new in one bank as the old limit the performance of the new batteries and can even damage them.

This is an untruth that is sadly propagated by this forum. It is only when batteries are wired in series that the new one is "pulled down" to the same capacity as the old one, and that is why I am replacing two Trojans rather than just the one that has failed.

 

The reason not to mix old and new is that there is an increasing risk of failure as the batteries age, especially the shorted cell as I experienced, and an unobservant owner might fail to spot that a battery has failed which could lead to damage, though most likely won't. If you are paying somebody else to supply and fit the batteries then they may well refuse to mix old and new because it is not in their financial interest, and they may well get the blame for a failure even if it is the old battery that failed. So "the pros" say you can't mix old and new!

 

The myth that batteries are permanently damaged the instant they drop below 50% is also.....a myth.

 

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

[MtB]

18 minutes ago, dmr said:

The myth that batteries are permanently damaged the instant they drop below 50% is also.....a myth.

 

 

Those batts I bought when out with you last year are totally and utterly goosed now. I'm wondering about reverting to the old way discussed earlier. i.e. running batt down to 0.1% SoC then charging to about 60%. Seem to work ok for us 40 years ago. Batteries still lasted a year or two. 

[dmr]

14 minutes ago, Mike the Boilerman said:

 

Those batts I bought when out with you last year are totally and utterly goosed now. I'm wondering about reverting to the old way discussed earlier. i.e. running batt down to 0.1% SoC then charging to about 60%. Seem to work ok for us 40 years ago. Batteries still lasted a year or two. 

I am not surprised, though as its only a part time boat they should have lasted a bit longer. I suppose once they are "dead" you could squeeze a bit more life out of them by cycling them down to 20% or even less.

 

We travelled up the Rochdale with a young woman with a "project boat"  and she took her batteries down to zero% (9volts or less) on a couple of occasions (domestics and starter connected together.) We charged them off our Travelpower and they came back to life and did a good job of starting her BMC, and that BMC took a LOT of cranking.

 

I think you need to get one of your Smartgages calibrated and fitted, and an ammeter to monitor charging. There are some cheopo units on eBay that use a current transformer so no need to fit a shunt, but not sure how good they are at low currents.

 

You are a bit limited as you don't have the height to fit Trojans unless you can do something the other side of that lovely engine. I just wonder if this could be a case to try out a Lithium? Can you get Lithiums the same height (or less) than a standard battery??? 

 

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

[MtB]

8 minutes ago, dmr said:

I am not surprised, though as its only a part time boat they should have lasted a bit longer. I suppose once they are "dead" you could squeeze a bit more life out of them by cycling them down to 20% or even less.

 

We travelled up the Rochdale with a young woman with a "project boat"  and she took her batteries down to zero% (9volts or less) on a couple of occasions (domestics and starter connected together.) We charged them off our Travelpower and they came back to life and did a good job of starting her BMC, and that BMC took a LOT of cranking.

 

I think you need to get one of your Smartgages calibrated and fitted, and an ammeter to monitor charging. There are some cheopo units on eBay that use a current transformer so no need to fit a shunt, but not sure how good they are at low currents.

 

You are a bit limited as you don't have the height to fit Trojans unless you can do something the other side of that lovely engine. I just wonder if this could be a case to try out a Lithium? Can you get Lithiums the same height (or less) than a standard battery??? 

 

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

 

 

Well yes, lithiums are very much at the front of my mind here. I'm not ready to shell out £3k for a Victron system yet so bare cells plus DIY monitoring and charging will have to be the way, hence my interest in Tom and Bex posts. His links to australain monitoring electronics seem unnecessarily complex though. Gobbledygook to me in fact. 

 

Bare cells can be laid on their side to fit that space under the floor of the hobby boat, although I'd probably put them on a nice shelf at hip level so fully accessible for fiddling with. Tucking batts away out of the way in awkward spaces with poor or no access always strikes me as insane. 

 

Edited August 27, 2018 by Mike the Boilerman

[dmr]

26 minutes ago, Mike the Boilerman said:

 

 

Well yes, lithiums are very much at the front of my mind here. I'm not ready to shell out £3k for a Victron system yet so bare cells plus DIY monitoring and charging will have to be the way, hence my interest in Tom and Bex posts. His links to australain monitoring electronics seem unnecessarily complex though. Gobbledygook to me in fact. 

 

Bare cells can be laid on their side to fit that space under the floor of the hobby boat, although I'd probably put them on a nice shelf at hip level so fully accessible for fiddling with. Tucking batts away out of the way in awkward spaces with poor or no access always strikes me as insane. 

 

But Lithiums really are (or should be) 100% maintenance free so as long as you make the electrical connections well then you really can safely tuck them away. What about next to the prop shaft under the back cabin floor? 

I would be tempted by "fit and forget" types with built in electronics, I suspect there are some a bit less costly than the Victrons. If you make a DIY system it will likely end up costing just as much, especially if you have a total failure or two, but if you do decide to go the DIY route then I will be very interested ?

 

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

[MtB]

1 hour ago, dmr said:

But Lithiums really are (or should be) 100% maintenance free so as long as you make the electrical connections well then you really can safely tuck them away. What about next to the prop shaft under the back cabin floor? 

I would be tempted by "fit and forget" types with built in electronics, I suspect there are some a bit less costly than the Victrons. If you make a DIY system it will likely end up costing just as much, especially if you have a total failure or two, but if you do decide to go the DIY route then I will be very interested ?

 

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

 

Well yes, but there are fault conditions when the get very VERY hot and I'd rather they did that on a shelf where I can see them, not under the floor. At least until I'm happy my DIY controls work reliably. 

 

I too am tempted by a proprietary idiot-proof offering but the only one that uses large four large cells is Victron, AFAIK. Both the others use hundreds of tiny cells which I find fundamentally problematic. From the videos I've seen cell balancing has to be crude, at best. 

 

 

Edited August 27, 2018 by Mike the Boilerman

[nicknorman]

17 minutes ago, Mike the Boilerman said:

 

Well yes, but there are fault conditions when the get very VERY hot and I'd rather they did that on a shelf where I can see them, not under the floor. At least until I'm happy my DIY controls work reliably. 

 

I too am tempted by a proprietary idiot-proof offering but the only one that uses large four large cells is Victron, AFAIK. Both the others use hundreds of tiny cells which I find fundamentally problematic. From the videos I've seen cell balancing has to be crude, at best. 

 

 

I’m not sure it matters (hundreds of cells and balancing) - cells in parallel with each other can’t be manually balanced, they are intrinsically balanced because their voltages are identical. It is only cells in series that have to be balanced. For a 12v battery there will be 4 cells or groups of cells in series, each cell or parallel group of cells has to be balanced so I can’t see how it makes any difference whether we are talking about 4 x large cells in series or 4 x groups of paralleled small cells in series. Same amount of balancing!

[MtB]

8 hours ago, dmr said:

I am not surprised, though as its only a part time boat they should have lasted a bit longer. I suppose once they are "dead" you could squeeze a bit more life out of them by cycling them down to 20% or even less.

 

Ok arrived at the boat late this afternoon, SG reading 100%. Battery flat in my cordless grinder so plugged in the 300w maplins inverter, plugged flat 4ah grinder

 battery into charger and turned it all on.  No other power being drawn, and a leetle bit of solar charge coming from the panel. 

 

4ah battery fully charged 90 mins later, SG reading down to 72%. So ignoring charger and inverter losses (probably roughly the same as the solar input) that pair of 110ah batteries now has a total capacity of 14ah by my arithmetic!! 

 

 

[dmr]

So much for our observation/theory that sulphated batteries get down to about 50% capacity then sort of stay there (or was it 25%?).

 

Assuming you have the lovely Makita cordless grinder then that's 18volts so that 4Ah battery corresponds to 6Ah at 12 volts,but that's getting a bit pedantic.

 

At this level of knackerdness the Smartgage will likely be totally confused.

 

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

[Detling]

9 hours ago, dmr said:

This is an untruth that is sadly propagated by this forum. It is only when batteries are wired in series that the new one is "pulled down" to the same capacity as the old one, and that is why I am replacing two Trojans rather than just the one that has failed.

 

The reason not to mix old and new is that there is an increasing risk of failure as the batteries age, especially the shorted cell as I experienced, and an unobservant owner might fail to spot that a battery has failed which could lead to damage, though most likely won't. If you are paying somebody else to supply and fit the batteries then they may well refuse to mix old and new because it is not in their financial interest, and they may well get the blame for a failure even if it is the old battery that failed. So "the pros" say you can't mix old and new!

 

The myth that batteries are permanently damaged the instant they drop below 50% is also.....a myth.

 

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

As the internal resistance of the old battery will be higher (smaller clean plate area) than the new one it takes less current on charge than the new one and delivers fewer amps on discharge. This means the new one is working harder, yes the voltages will be the same so the SOC is also the same but the amps will differ. I extreemis this could mean with a 200 amp load  the new battery supplying 150 amps and the old 50 amps, what current causes plate buckling?  If you can be sure there is no sulphation on the old and no oxide deposits at the bottom, then there is no problem, but on a 7 year old battery?

[MtB]

11 minutes ago, dmr said:

So much for our observation/theory that sulphated batteries get down to about 50% capacity then sort of stay there (or was it 25%?).

 

I think we should revise that to 5%! 

 

No my grinder is Ryobi, but still 18v and just as nice as makita.  

 

 

[WotEver]

4 minutes ago, Detling said:

I extreemis this could mean with a 200 amp load  the new battery supplying 150 amps and the old 50 amps...

As opposed to not keeping the old Batteries and supplying the entire 200A from the new one!  

 

How is that ‘damaging the new batteries’? How is that ‘limiting their performance’?

10 hours ago, Detling said:

It is a bad idea to mix old and new in one bank as the old limit the performance of the new batteries and can even damage them.

 

 

[mrsmelly]

8 hours ago, dmr said:

I am not surprised, though as its only a part time boat they should have lasted a bit longer. I suppose once they are "dead" you could squeeze a bit more life out of them by cycling them down to 20% or even less.

 

We travelled up the Rochdale with a young woman with a "project boat"  and she took her batteries down to zero% (9volts or less) on a couple of occasions (domestics and starter connected together.) We charged them off our Travelpower and they came back to life and did a good job of starting her BMC, and that BMC took a LOT of cranking.

 

I think you need to get one of your Smartgages calibrated and fitted, and an ammeter to monitor charging. There are some cheopo units on eBay that use a current transformer so no need to fit a shunt, but not sure how good they are at low currents.

 

You are a bit limited as you don't have the height to fit Trojans unless you can do something the other side of that lovely engine. I just wonder if this could be a case to try out a Lithium? Can you get Lithiums the same height (or less) than a standard battery??? 

 

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

Dave

just a quick hi jack question. Not thought of it before but when we cruise and switch travel power on why does the battery charging figures Ie voltage and amps change a bit from the figures when the engine alt only is on?

[WotEver]

4 minutes ago, mrsmelly said:

Dave

just a quick hi jack question. Not thought of it before but when we cruise and switch travel power on why does the battery charging figures Ie voltage and amps change a bit from the figures when the engine alt only is on?

Because the battery charger voltage is higher than the alternator voltage

 

[mrsmelly]

7 minutes ago, WotEver said:

Because the battery charger voltage is higher than the alternator voltage

 

Ah thanks and yes that makes complete sense so I will need to address that then if I change battery types, Nowts ever easy innitt.

[dmr]

10 minutes ago, WotEver said:

Because the battery charger voltage is higher than the alternator voltage

 

If there is a battery charger connected then yes, when the TP is turned on the charger might join in with the alternators, actually I spent a bit of time this afternoon trying to make this happen, its not straightforward.

 

But also, if you have a big load, like immersion heater or washing machine, then turning on the TP causes the engine speed to fall a little and so the current available from the alternator will also fall a little bit.

 

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

[dmr]

28 minutes ago, Detling said:

As the internal resistance of the old battery will be higher (smaller clean plate area) than the new one it takes less current on charge than the new one and delivers fewer amps on discharge. This means the new one is working harder, yes the voltages will be the same so the SOC is also the same but the amps will differ. I extreemis this could mean with a 200 amp load  the new battery supplying 150 amps and the old 50 amps, what current causes plate buckling?  If you can be sure there is no sulphation on the old and no oxide deposits at the bottom, then there is no problem, but on a 7 year old battery?

Batteries are one of those things that just automatically share fairly and correctly, so we don't even need to think about internal resistance and the like, the stronger battery will just do a bit more than the weaker battery (as you said) and all will be well. Its good. If the older battery with a reduced capacity did the same work as a new one then it would over discharge itself. Batteries really do just sort themselves out.

 

The seven year old pair will now be replaced with a brand new pair (hopefully delivered to the boat tomorrow) and these will work with the current 4 batteries from March 2015 so 3-1/3 years old. This all came about because one of the original Trojans had a "premature" bad cell failure after 3-1/2 years and I didn't want to throw the them all away, so kept two good ones and got 4 new ones.  

 

I have always said that mixing old and new batteries can be done with a bit care so I have put my money where my mouth is!!! They are wired as a semi split bank (two isolator switches) so if and when a battery fails (as has just happened) I can switch that bank off and continue with the other.  This is a bit over the top as its pretty quick to take a cable off,but I did plan to investigate split bank equalisation....but have lost interest in that project. 

 

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