What is wrong with this battery?

[KenK]

Hi All

 

I have a Numax 110 Amp Marine Starting and Deep Cycle battery, it is approximately two years old, its not been used much and has been kept charged. At the moment it is on my workbench connected to the charger. It appears according to all the tests to be in full working order, 12.71 V across the terminals, surface charge removed, (measured with a calibrated Fluke x 2), all the cells read the same on the hydrometer around 1.270, the battery is probably at ambient temperature around 20oC as its been in here for a week..

It has been equalized several times and charged several times over the week, using two different intelligent chargers, all the cells bubble happily during charging.

 

However put a load on it and it does not work, for example a small 12 V motor used to start model aircraft engines will spin but can be stopped by hand pressure, normally this motor runs from a 4 amp battery and would take the skin off if you tried to stop it. It will turn the boat engine over but only for a few seconds and too slowly for it to start; any other battery starts it at once. Measure the voltage on load and it drops to 11.6 V however it recovers fairly quickly to 12.5 V once the load is removed without further charging. Clearly this is one dead battery but does anyone know what is actually wrong with it?

 

Ken

[chris w]

It sounds like the battery has a very high internal resistance. has it ever been left discharged for an extended period because any sulphation would have hardened and will be pretty impossible to reverse.

 

It's analogous to a lock on a canal. The lock (the battery) is full (fully charged). However if the sluice gate is jammed almost shut (equivalent to a high resistance to flow) then you can't get the water out of the lock quickly (ie: low current flow).

[Gibbo]

Hi All

 

I have a Numax 110 Amp Marine Starting and Deep Cycle battery, it is approximately two years old, its not been used much and has been kept charged. At the moment it is on my workbench connected to the charger. It appears according to all the tests to be in full working order, 12.71 V across the terminals, surface charge removed, (measured with a calibrated Fluke x 2), all the cells read the same on the hydrometer around 1.270, the battery is probably at ambient temperature around 20oC as its been in here for a week..

It has been equalized several times and charged several times over the week, using two different intelligent chargers, all the cells bubble happily during charging.

 

However put a load on it and it does not work, for example a small 12 V motor used to start model aircraft engines will spin but can be stopped by hand pressure, normally this motor runs from a 4 amp battery and would take the skin off if you tried to stop it. It will turn the boat engine over but only for a few seconds and too slowly for it to start; any other battery starts it at once. Measure the voltage on load and it drops to 11.6 V however it recovers fairly quickly to 12.5 V once the load is removed without further charging. Clearly this is one dead battery but does anyone know what is actually wrong with it?

 

Ken

 

If the SGs are similar at around 1.27 then it isn't sulphated up as if it was the SG would be much lower.

 

It could have been topped up with tap water (or something worse) which could cause this.

 

It could be that one of the internal conductors has corroded.

 

I can't think of anything else that could cause it. Either way, as it isn't sulphated up there's nowt you can do about it.

 

Gibbo

[smileypete]

Clearly this is one dead battery but does anyone know what is actually wrong with it?

 

If you're connecting to it via battery clamps it might be worth checking they have a bright metal to metal contact with the battery posts.

 

I would also try discharging it about halfway to 12.2V and then recharging it, to see if that helps.

 

cheers,

Pete.

Edited March 14, 2008 by smileypete

[steelaway]

If you're connecting to it via battery clamps it might be worth checking they have a bright metal to metal contact with the battery posts.

 

I would also try discharging it about halfway to 12.2V and then recharging it, to see if that helps.

 

cheers,

Pete.

 

 

Just out of interest.

Has any one tried the Battery Conditioner pills you can buy from car spares?

How are they supposed to work?

 

Alex

[chris w]

They are apparently a specially formulated blend of acidic salts of rare earth metals designed specifically to extend the life of, and replenish, failing or poorly performing lead acid batteries by removing insoluble sulphate deposits from the plates, effectively raising the electrolyte level and thus restoring the ability to recharge the battery more fully.

 

Whether they do this effectively or not, I have no idea as I've never tried them.

 

Chris

 

PS: Aspirin is also rumoured to have the same effect although, again, I have no proof either way on this. Aspirin is made from neutralized salicylic acid created by buffering it with sodium (sodium salicylate) and acetyl chloride, creating acetylsalicylic acid. Presumably, this attacks the lead sulphate on the battery plates, if indeed it works.

 

Maybe the battery pills you can buy are just aspirin tablets!!!

Edited March 14, 2008 by chris w

[Dylan]

If the SGs are similar at around 1.27 then it isn't sulphated up as if it was the SG would be much lower.

 

It could have been topped up with tap water (or something worse) which could cause this.

 

It could be that one of the internal conductors has corroded.

 

I can't think of anything else that could cause it. Either way, as it isn't sulphated up there's nowt you can do about it.

 

Gibbo

Reminds me of a Morris Minor I had with similar problems. A good thump on the battery terminal with a hammer would make the battery work for a while

[sueanddaren]

Reminds me of a Morris Minor I had with similar problems. A good thump on the battery terminal with a hammer would make the battery work for a while

 

 

Definatly a loss of contact issue. Could be:-

Dry intercell weld or bad burn.

 

Could be same with original question but that could also be:-

Active material loose

Corrosion of pos grid wires

Or 3 or 4 other things

 

Does the label say anything about a calcium alloy?

If yes, probably Antimony in neg group bars causing corrosion.

 

PS Don't waste your money on the pills they won't fix any contact issues.

 

Daren

[Dylan]

Definatly a loss of contact issue. Could be:-

Dry intercell weld or bad burn.

 

Could be same with original question but that could also be:-

Active material loose

Corrosion of pos grid wires

Or 3 or 4 other things

 

Does the label say anything about a calcium alloy?

If yes, probably Antimony in neg group bars causing corrosion.

 

PS Don't waste your money on the pills they won't fix any contact issues.

 

Daren

Daren, do battery pills fix any battery issues in your opinion?

Edited March 15, 2008 by Dylan

[NB Willawaw]

Hi Daren,

 

You sound like you know your batteries.

 

In what way are you connected with them ?? (excuse the pun )

[sueanddaren]

Daren, do battery pills fix any battery issues in your opinion?

None you can't fix with pure water and a good charge.Daren

Hi Daren,You sound like you know your batteries.In what way are you connected with them ?? (excuse the pun )

Ive heard all the puns before.Too many years (28) working for a battery company. 15 years just designing batteries (all types).Daren

[Dylan]

None you can't fix with pure water and a good charge.DarenIve heard all the puns before.Too many years (28) working for a battery company. 15 years just designing batteries (all types).Daren

As in a desulphating charge?

[PaulG]

It's the wrong type of battery for leisure use.

 

To quote from Sterling's FAQ's:

 

"...for starting you have a large surface area of thin plates, for traction you have a small surface area of thicker plates. One is black and one is white, there is no grey area. So, if you are purchasing a battery and it has a cold cranking rating and the salesman says it is a deep cycle battery, but will also start your engine; then it is in fact a starter battery."

 

http://www.sterling-power.com/support-faq-2.htm

[KenK]

It's the wrong type of battery for leisure use.

 

To quote from Sterling's FAQ's:

 

"...for starting you have a large surface area of thin plates, for traction you have a small surface area of thicker plates. One is black and one is white, there is no grey area. So, if you are purchasing a battery and it has a cold cranking rating and the salesman says it is a deep cycle battery, but will also start your engine; then it is in fact a starter battery."

 

http://www.sterling-power.com/support-faq-2.htm

There is always a grey area it's called cost.

I have seven of these batteries, six leisure and one starter. I only found the problem when by chance I picked that battery as the starter battery. They are Numax "Starting and Deep Cycle Batteries", like all compromises they are probably not the best for either purpose, but that's what was fitted when I bought the boat, when they die I'll look at obtaining something more suitable, the replacement will be a starter battery.

 

Someone with far more knowledge of battery manufacturing than I, Darren, might be able to tell us how likely this kind of fault is, the normal tests i.e. measuring with an accurate meter or with a hydrometer don't show any problem. Equally if it was still in the domestic bank I'd be none the wiser, it only fails under a heavy load, cranking the engine.

 

Ken

[PaulG]

it only fails under a heavy load, cranking the engine.

Ken

 

Kinda proves my point, then, if it won't do both?

 

Seriously, I'd consider replacing it with a decent starter battey. BTW, I've never understood why such large capacity starter batteries are fitted in narrowboats. I use a good quality 50AH wet battery with loads of cold cranking amps, and it works fine. If a similar battery starts the 2-litre turbodiesel engine in my car, why should I need a bigger capacity for a 1300 cc narrowboat engine?

 

(Puts on steel helmet and waits for incoming)

[KenK]

Kinda proves my point, then, if it won't do both?

 

Seriously, I'd consider replacing it with a decent starter battey. BTW, I've never understood why such large capacity starter batteries are fitted in narrowboats. I use a good quality 50AH wet battery with loads of cold cranking amps, and it works fine. If a similar battery starts the 2-litre turbodiesel engine in my car, why should I need a bigger capacity for a 1300 cc narrowboat engine?

 

(Puts on steel helmet and waits for incoming)

 

To be fair the other six all start the engine without problems, the boatbuilder probably was probably more concerned with cost than quality. Also the general advice on here seems to be buy cheap batteries as it is just as easy to wreck expensive ones. I'm just glad I found it before we took the boat out.

 

 

Ken

[Timleech]

Kinda proves my point, then, if it won't do both?

 

Seriously, I'd consider replacing it with a decent starter battey. BTW, I've never understood why such large capacity starter batteries are fitted in narrowboats. I use a good quality 50AH wet battery with loads of cold cranking amps, and it works fine. If a similar battery starts the 2-litre turbodiesel engine in my car, why should I need a bigger capacity for a 1300 cc narrowboat engine?

 

(Puts on steel helmet and waits for incoming)

 

I just bought a new battery for my car (also 2l turbodiesel), as well as a boat starting battery. Same maker, same supplier, same discount. The car battery is much smaller than the boat battery, it was also significantly more expensive and a much higher price in 'pounds per Ah'. The cold cranking amps per Ah are much higher for the smaller battery, more 'concentrated power', if you like.

 

Tim

[Orca]

Kinda proves my point, then, if it won't do both?

 

Seriously, I'd consider replacing it with a decent starter battey. BTW, I've never understood why such large capacity starter batteries are fitted in narrowboats. I use a good quality 50AH wet battery with loads of cold cranking amps, and it works fine. If a similar battery starts the 2-litre turbodiesel engine in my car, why should I need a bigger capacity for a 1300 cc narrowboat engine?

 

(Puts on steel helmet and waits for incoming)

 

 

Agreed fully - I use a Ford Transit battery for starting (650CCA) and never even bother with any 'stamped' AH ratings on thin plate starter batteries (what's the point??). The only leisure batteries I entertain are 6 volters in series (tall with thick plates), though very expensive I know, they do last and are worth it long-term..

[chris w]

Agreed fully - I use a Ford Transit battery for starting (650CCA) and never even bother with any 'stamped' AH ratings on thin plate starter batteries (what's the point??).

 

You're correct, for a starting battery AH rating is irrelevant.

 

Chris

[Orca]

You're correct, for a starting battery AH rating is irrelevant.

 

Chris

 

These are what I use for any type of leisure use (T125's): http://www.tayna.co.uk/catalog/1188/0/Troj...Volt-page1.html

[chris w]

Are they sealed or wet types?

 

Note that the Reserve Capacity they quote follows exactly Peukert's Law. From the data they give (25A for 488 minutes and 75A for 132 minutes) one can calculate the Peukert exponent, which works out to be 1.21.

 

Chris

Edited March 18, 2008 by chris w

[sueanddaren]

As in a desulphating charge?

 

 

Yes, one of the old ways of recovering a sulphated battery was to tip out the acid, replace with pure water, charge slowly for about 2 weeks in a warm area (it takes a long time for the sulphite crystals to disolve) then discharge, recharge and adjust the acid to the correct sg. Then finaly do a test discharge. If all the crud at the bottom hasn't caused a short when you tip the acid and everything else is OK (contact wise ) off you go again.

 

Daren

[Orca]

Are they sealed or wet types?

 

Note that the Reserve Capacity they quote follows exactly Peukert's Law. From the data they give (25A for 488 minutes and 75A for 132 minutes) one can calculate the Peukert exponent, which works out to be 1.21.

 

Chris

 

Your being a little too esoteric - but from what I understand of Peukert's Law an exponent of between 1.1 and 1.3 is in keeping with the stated AH rating (though A is ever much a coeffcient or variable?) Your obviously more clued up than me in terms of the mathematical data, though in general terms the chap on the clapham bus never really adheres to this...

 

Edited to say: I was actually surprised to find these were not (are not??) used more extensively in Narrowboats - due to price?? My second hand boat came with 4 of these (each one a 3 cell wet type, 6 volt monobloc) wired in series..plus two more for the Eperspacher heating boiler.

Edited March 18, 2008 by copernicus

[chris w]

Your being a little too esoteric - but from what I understand of Peukert's Law an exponent of between 1.1 and 1.3 is in keeping with the stated AH rating (though A is ever much a coeffcient or variable?) Your obviously more clued up than me in terms of the mathematical data, though in general terms the chap on the clapham bus never really adheres to this...

 

 

If the man on the Clapham bus were more clued up on this, there would be far fewer cases of failing/failed batteries and the generally pervading unrealistic expectation of actual battery life vs current. The maths may be esoteric, but the conclusions are not. They ought to be known to everyone with domestic batteries. Your own implied (and incorrect) belief that even the results are esoteric is typical of probably 99% of boaters.

 

Note, that for the batteries cited, trebling the current on their data sheet (from 25A to 75A) reduced the battery life by almost a factor of 4 and not 3. These batteries have a Peukert factor better than most wet cells (1.2 vs 1.3); for many cells the degradation in time vs current would be even more marked.

 

The man on the Clapham bus would say, "Ah a 240AH battery. If I draw 100A from it and don't want to run it down below 50% capacity, it will last 120/100 hours = 72 minutes."

 

In reality, (taking the esoteric maths into account), the true figure would be 47 minutes; less than 2/3rds what one might expect.

 

For a more typical wet cell, (with a Peukert factor of 1.3), the time would be reduced to virtually half the expected time (as given by Clapham maths) and would be 38 minutes and not 72 minutes.

 

Chris

[Orca]

If the man on the Clapham bus were more clued up on this, there would be far fewer cases of failing/failed batteries and the generally pervading unrealistic expectation of actual battery life vs current. The maths may be esoteric, but the conclusions are not. They ought to be known to everyone with domestic batteries. Your own implied (and incorrect) belief that even the results are esoteric is typical of probably 99% of boaters.

 

No I agree, but my use of the word 'esoteric' was referring purely to Peukert's Formulae and NOT the given statistics; though the former has of course enlightened me to the root of the conclusions - which I will file for future use! My apologies if my choice of wording caused offence..