Battery Condition.....

[jo10000_6]

Hi more technical people than me.

The attached are two battery checks - not on my motorhome but my car.

The battery is only 18m only perhaps 2 years.

With two days of each other and what look like to me as comparable readings give or take.

One : Battery Replace
One : Battery Good

Not really sure what to do.

Any comments appreciated.


Thanks
Jo

 

[pappajohn]

AGM by any chance ?.. . Load of crap.

I never had any faith in the electronic battery testers and I think this example proves they aren't accurate.

If its struggling to start, replace it.
If it isn't struggling, wait until it is then replace.

 

[jo10000_6]

I know ....its not the 1st time this has happened so their testing equipment doesn’t fill me with confidence either.

Not sure if AGM - the battery is very tightly packed away and I’m not keen to mess around with to see what make.

I just wanted to be in a stronger position to take back under warranty if there was an issue - Neither of those readings are from where I got it from.

 

[pappajohn]

Test result from mine...from an independent garage I use.

Engine Auto stop start has stopped working so had the battery tested as the dealer suggested it may be on its way out when I spoke to them.

Still have to book it in to Hyundai dealer to get their opinion.

 

[PhilandMena]

The first test is in accordance with the international standard for a starter battery and is measuring cold cranking amps, I believe. I do not have a clue about what they are measuring on the second test. You might want to enquire about this.

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[TheBig1]

both below 50% I would say that it is definitely not going to see the winter out without letting you down. if its only 18 months old it should be under warranty

 

[hilldweller]

Looks like it's basing the result on the internal resistance.

Or more likely, one is calibrated to sell more batteries.

 

[pappajohn]

The first test is in accordance with the international standard for a starter battery and is measuring cold cranking amps, I believe. I do not have a clue about what they are measuring on the second test. You might want to enquire about this.

Do you mean mine?
The EN reading?

CCA is the British standard for cranking power
SAE is the American standard
EN is the European standard (European normal)

Many battery labels have all three standards shown and all are acceptable.

 

[pappajohn]

Looks like it's basing the result on the internal resistance.

Or more likely, one is calibrated to sell more batteries.

Certainly can't base it on load like it used to be with the old bendy plate and ammeter Brian.

 

[rosalan]

Question: Why did it need testing? Was/is there a problem?
Had it in your opinion been failing?
If Yes, then the tests proved you to be right.

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[autorouter]

Both tests show very similar Cold Cranking Amps, voltage and internal resistance. Compare with @papajohn's results.
Batteries can deteriorate if left in a very low charge state for a long time, and can be damaged by a single event if it is completely discharged. If you know you never let that happen, then it's always possible that it happened on the shelf in the shop before you bought it. Or it could simply be a manufacturing fault. Either way, it looks like it's on its way out.

As the weather gets colder, the battery naturally produces less voltage and cranking amps. The engine oil thickens in the cold, and needs higher starter motor power to spin the engine. That's why starter batteries that seem good in the summer seem to fail suddenly when the weather gets colder - round about now, actually.

 

[pappajohn]

It doesn't matter where you search on the Internet there is nothing WHICH shows a formula to calculate CCA using volts and resistance, it can only be measured by a measured load (say 500amps) while cranking for a set time (say 30 seconds) without the volts dropping below a pre-determined amount, so how do these electronic testers show CCA?

 

[tonyidle]

It doesn't matter where you search on the Internet there is nothing WHICH shows a formula to calculate CCA using volts and resistance, it can only be measured by a measured load (say 500amps) while cranking for a set time (say 30 seconds) without the volts dropping below a pre-determined amount, so how do these electronic testers show CCA?

This thread prompted me to try to find some info on CCA testing. Below is what I came up with:

https://batteryuniversity.com/learn/article/how_to_measure_cca_cold_cranking_amp

 

[jo10000_6]

Hi all

I had it tested because it was showing up on one of those Bluetooth radio transmitters that is was low.

I know it’s only an indication but it was low - it had also been highlighted on its MOT in October by Halfords (they are the replace slip).

I couldn’t use my multimeter the negative terminal isn’t accessible.

I popped it on charge yesterday and and gave it a nice slow 2 amps.

I will monitor.

I just prefer it to be more straight forward - it’s either failing and is under warranty or it’s not.

Thanks for all your replies.

Jo

 

[TerryL]

Go on, if you think it's on it's way out and it's still under warranty take it back. I'll bet they'll test it and say "it's fine sir, doesn't need replacing".

Now wait until the warranty has expired by one day. Take it back, they'll test it and say " it's on the way out sir, needs replacing".

As far as I'm concerned a battery is only on the way out when it doesn't do what it's supposed to i.e. start the engine and store the power. Then I'll replace it straightaway.

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[pappajohn]

This thread prompted me to try to find some info on CCA testing. Below is what I came up with:

https://batteryuniversity.com/learn/article/how_to_measure_cca_cold_cranking_amp

Yes, I found that but it's not very helpful taking a week or more and numurous charge cycles to accertain the CCA.

 

[tonyidle]

Yes, I found that but it's not very helpful taking a week or more and numurous charge cycles to accertain the CCA.

It did mention in passing a means by which a small handheld tester could measure it though - something I, like you, wouldn't have thought possible.

 

[autorouter]

I couldn’t use my multimeter the negative terminal isn’t accessible.

You can still use a multimeter. See if you can trace where the negative battery cable is bolted to the bodywork. If not, you have to put the negative probe on a metal part of the bodywork, or the metal of the alternator or the engine. Any reading will be OK if the battery terminal clamp is clean and tight, and the bolt holding the cable to the bodywork is also. Usually they are OK, so it's worth doing this.

A 2 amp charger is going to take several hours to charge a half-charged battery. If it's a 60 Amp-hour battery that's half charged, it's going to take 30 amp-hours to charge it. At 2 amps it will take 30/2 = 15 hours. And that's assuming a constant 2 amps that doesn't taper off as the battery charges.

The battery needs to be fully charged for a proper CCA test. If it's not, you'll get a low result. Are you sure the battery was fully charged for the test?

 

[jo10000_6]

Thanks for the multimeter tip - I wasn’t aware so appreciate that.

I had the battery on for 12 hours ish - stuck her nose in the garage whilst It rained miserably -
I just thought a slow charge would be better.

When the weathers better I will try the multi meter.

 

[jo10000_6]

Yes, I found that but it's not very helpful taking a week or more and numurous charge cycles to accertain the CCA.

Read this with morning tea. Didn’t understand it all but got the gist. Thanks Pappa John.

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[PhilandMena]

Question! When doing a CCA test. What percentage figure is required to be reached for a pass and is this figure defined in the national standard for starter batteries or just left to the tester to decide. Also, what is being tested in a CCA test...............capacity?

 

[autorouter]

The most important function of a starter battery is starting the engine. Starter motors require a large current, several hundred amps, for a short time. The CCA (Cold Cranking Amps) test is designed to test how good a battery is in running a starter motor when cold.

For the CCA test, a known constant current load is applied for a defined time, and the voltage is monitored as it drops. Depending on the exact variety of the test (CCA, SAE, EN) the time and voltage limit are slightly different. If the voltage doesn't drop below the voltage limit in the defined time, the battery passes the test for that current value.

The high current capability of a battery depends on the surface area of the lead plates. Typically, the plates are thinner, there are more of them, and they are perforated to increase the surface area even more. Because of this, the battery can provide a high current for a short time in a reasonable size and weight.

The 'capacity' of a starter battery is a secondary concern. It obviously can provide low current for a long time, but because of the thin perforated plates it is more susceptible to damage when discharged to a low level. That's why they say never discharge it below about 50%. Also don't subject it to vibration (eg while driving) when it's in a low state of charge.

Leisure batteries or traction batteries are not designed to provide a high current without significant voltage drop. On the other hand, they can operate safely down to low discharge levels in a moving vehicle like a fork lift truck.

 

[Lenny HB]

Question! When doing a CCA test. What percentage figure is required to be reached for a pass and is this figure defined in the national standard for starter batteries or just left to the tester to decide.

70% is the pass level for a CCA test.
When my AGM's failed in the last van a CCA test gave 78% on one and 79% on the other so they refused to change them under warranty. The were 95 a/h Banner dual purpose batteries, in use under typical leisure conditions drawing 5-8 amps one lasted 10 a/h the other 11 a/h i.e. less than 2 hours each but the manufacturers and suppliers consider this acceptable as they pass a test that is totally irrelevant for a leisure battery even though they sell them as a dual purpose battery.

Also, what is being tested in a CCA test...............capacity?

The tester pulses the battery with a test current at 80-90 hz to simulate a cranking load, but is not cabable of giving an indication of capacity, so it can tell you it will turn the engine over but not for how long.

Some info here:

Mechanics prefer small sizes and device manufactures have developed handheld testers, which induce a momentary high-current pulse that corresponds to the entered CCA value. Ohm’s law calculates the internal resistance on hand of the induced voltage drop, and the device provides a CCA-equivalent reading. This test method is fast and convenient, but it does not estimate capacity.
The AC conductance method reads CCA by injecting a single frequency of 80–90 hertz to the battery. These non-invasive units are small and stay cool during the test, but the battery should have a SoC of 70 percent and higher. As with other resistance-based test methods, AC conductance cannot read capacity.

 

[PhilandMena]

Got It. Thanks guys.