Technical Battery testing how hard can it be

[koalar]

Very

Let me be clear at the start I don’t have an answer or reliable way to test a battery with a tester. The only 100% reliable test I have used so far is through substitution of a working battery

A couple of times people have taken a car to a garage and had the battery tested fine.

What we don’t know here is what was used or if the operator knew how to interpret the results

I know of one case where this has lead to an unnecessary steering column change, twice

The problem is now made worse with start stop technology and there batteries being twice as expensive. Nobody likes wasting money replacing parts unnecessary.

 

[porta]

No garages seem to carry those battery drop testers anymore

 

[koalar]

One main problem in testing a battery is it performance changes as to when you test it and type of battery


Battery temperature
Just charged
Left over night


Probably many more

 

[porta]

I will say one thing though, now being a farmer full time, our local farm machinery agents DO have a drop tester and, knowing all farmers are tight arses, are more likely to try recovering a battery than selling you a new one…I’ve changed the acid and trickle charged old batteries into new life, even some ‘so-called’ sealed for life ones…I hasten to add, not all sealed batteries can be recovered, and now you can’t buy the acid, they have to change it for you, but they have a charger that can properly de-sulphur or de-calcinate, discharge and recharge, it costs more but not as much as a big old tractor battery does!

 

[porta]

One main problem in testing a battery is it performance changes as to when you test it and type of battery


Battery temperature
Just charged
Left over night


Probably many more

Yup, lots of factors in diagnosing battery’s wehn so many external factors are in play

 

[koalar]

As few people follow links I will copy and paste a section here

If you want google will find the full text

To study the correlation between capacity and internal resistance, Cadex tested 175 aging starter batteries by measuring the CCA and capacity according to SAE J537. In this lengthy test, Cadex found that the correlation between capacity and CCA is only 0.55 (1 would be a perfect match). This led to the development of capacity estimation technology, as relying on the internal resistance, or CCA on a starter battery is unreliable.

 

[jrkitching]

(with tongue firmly located in cheek) ...

The best way to test a battery is to put it into a S/S equipped 500. If S/S works reliably, the battery's a good'un.

I know of one case where this has lead to an unnecessary steering column change, twice

There have also been unnecessary column changes resulting from failing earth connections. Always worth checking this before writing off either the column or the battery.

My own experience is that modern (ie made in the last 30 years!) batteries degrade much less gracefully than they did in days past, when you'd usually get plenty of warning before failing outright.

I've had a Panda battery go totally flat, with no prior warning, (as in unable to move the windows, much less turn the starter over) less than five minutes after a 100mile journey.

 

[vexorg]

It's subtle, but you can tell the difference with a new battery as the engine turns over better. After changing batteries, I've found a noticable difference in how it sounds turning over. That sounds obvious, but if the battery is very slowly degrading over years and you use the car every day, you dont notice the change on a daily basis.

I would still say that a battery wont affect the running of a car with health alternator unless it's really far gone. And by that point it should be obvious.

 

[koalar]

It's subtle, but you can tell the difference with a new battery as the engine turns over better. After changing batteries, I've found a noticable difference in how it sounds turning over. That sounds obvious, but if the battery is very slowly degrading over years and you use the car every day, you dont notice the change on a daily basis.

Correct

I would still say that a battery wont affect the running of a car with health alternator unless it's really far gone. And by that point it should be obvious.

Battery keeps everything tied at a nice level, Occasionally we see a battery that has plenty of cranking cause the steering to fail. We also see it the other way where a dead battery doesn’t start the car without a jump but the steering never fails

Unfortunately nobody has devised a test for this

If we knew what the Delphi is looking for it would be a trivial task to diagnose

 

[vexorg]

Battery keeps everything tied at a nice level, Occasionally we see a battery that has plenty of cranking cause the steering to fail. We also see it the other way where a dead battery doesn’t start the car without a jump but the steering never fails

So what is the cause of the difference in your view? batteries are very simple devices, and only a few key parameters.

 

[koalar]

So what is the cause of the difference in your view? batteries are very simple devices, and only a few key parameters.

No idea

I never got round to testing to find why.

I have a spare charged battery so it’s much easier to swap the battery out for me

Really does need investing as it’s probably just a simple voltage drop somewhere.

From memory there’s two power leads one for the motor and one for the logic. Two earths one for the motor one for the logic

The motor earth is definitely bolted on top of the battery negative terminal.

 

[koalar]

When I diagnose a no start after some preliminary checks I hook up Delphi (similar to multiECUscan mes ) and log engine speed and battery voltage. It’s surprising how they will still turn over fine at very low voltage
I guess if you say remove the fuel pump relay, crank the engine for a set time maybe 15 seconds while logging the battery voltage would give you similar results to a dedicated battery drop tester

You could go a stage further if you could be bothered. Test a new battery and take a photo or print out the result. Then when you next test it you can visualise the percentage capacity that’s been lost.

Use to use this until I got diagnostic software. You don’t see many now that give a range of volts

Did consider making my own at one time say 8-12V in 10 steps and plugs into the OBD port

 

[DaveMcT]

I fitted a permanent voltmeter and use it to watch the trend as I use the car. On engine start, old batteries drop the voltage more than good batteries. It's not perfect on Panda as there is no easy to find switched permanent live that's not dropped out when the starter is turning. Voltmeter on 24/7 will be a battery drain. I just used the ciggy lighter wire and accept that I can't see the voltage under starting loads.

If the battery goes flat (cold weather or more normal conditions) put it on charge and watch how long it takes to reach full charge. If its around a full day the battery is probably** usable, but if it's full in a couple of hours, there's simply no capacity and you'll need to replace it. I've had a failed battery look ok on a Halfords electronic tester. A recheck, after just two engine starts and the same machine showed it as knackered. Oh really!!!

** A really very flat battery will not accept a charge regardless of how long you try. Even worse, some (or all) cells can go reverse polarity. Really flat batteries need a 24 volt kick to get going. Give it about 15 minutes then connect a normal charger and hope. When done check the polarity or you risk frying your car.

In my experience there's little point faffing with crappy batteries. They are either very old (or very cheap) and either way are just beyond recovery. Cold weather always shows up the problems, because low temperatures reduce the usable charge capacity. Cars that live in a garage will keep their battery going far longer than those that live on the street.

 

[varesecrazy]

Regarding the threads title:

I had an issue where I worked Long days and in winter the Panda 1.1 was showing signs of poor battery


My smart charger.. would charge it.. but still no good

My multimeter had died..and my Big diesel battery wouldnt fit in the panda

I parked every day next to the Council tip..
They had a big bench with all the junk batteries on

I would 'borrow one as an experiment'..

Weve all had experience of the Alternator failing just after a battery replacement..

So I might just be lucky.. it Was November.. so a test for Batteries

Intelligent charger charged it..

still no joy on the Starter


On realising it was a New style Halfords calcium... which my diesel had done well with..

I took a trip across town to 'the teenagers'

The guy got out the tester they had..
all good he said ( I had charged it that day)

'BUT it doesnt crank a 1.1..so it might be faulty' says I

Ok .. they replaced it FOC .!!

Worked faultlessly for a few years..as did every other battery I put in it over 14 years


SO.. the shop that half of the motoring public would go to for a battery cannot tell good from bad...

They owed me from a 'Victor Meldrew.. experience'..we are just about even

 

[DaveMcT]

The battery I had taken to Halfords worked fine at home (cold weather or otherwise) it looked good. But where I worked away all week, the car was parked on a very steep hill (home was flat). My wife visited and I tried to move my car to make space - no start - dead flat. We tried to jump lead it and there was so much pull the engine wouldn't start. I disconnected my battery earth, got the car going then reconnected the earth and quickly drove down to Halfords. To be fair they pulled me out of the poo, but their testing kit is not giving them the full story.

My problem was battery plate sludge in the bottom of the cells. All is fine on the level but park on a steep hill, the sludge shifts and shorts-out the cells.

 

[porta]

Regarding the threads title:

I had an issue where I worked Long days and in winter the Panda 1.1 was showing signs of poor battery


My smart charger.. would charge it.. but still no good

My multimeter had died..and my Big diesel battery wouldnt fit in the panda

I parked every day next to the Council tip..
They had a big bench with all the junk batteries on

I would 'borrow one as an experiment'..

Weve all had experience of the Alternator failing just after a battery replacement..

So I might just be lucky.. it Was November.. so a test for Batteries

Intelligent charger charged it..

still no joy on the Starter


On realising it was a New style Halfords calcium... which my diesel had done well with..

I took a trip across town to 'the teenagers'

The guy got out the tester they had..
all good he said ( I had charged it that day)

'BUT it doesnt crank a 1.1..so it might be faulty' says I

Ok .. they replaced it FOC .!!

Worked faultlessly for a few years..as did every other battery I put in it over 14 years


SO.. the shop that half of the motoring public would go to for a battery cannot tell good from bad...

They owed me from a 'Victor Meldrew.. experience'..we are just about even

I only use Halfords wehn the local farm services can’t…I’ve tried a few motor factors but, so far three times, even with their cross-compatibility (even Halfords get this wrong), it’s been the right size but the terminal s the wrong way round and, on modern cars, there’s little excess to move the cables/clamps

 

[vexorg]

I dont like smart chargers, they can get it wrong, and dont like the voltage too low. I've got an old style charger that just pushes voltage and cuttent out regardless, always does a better job than the smart ones.

 

[porta]

I dont like smart chargers, they can get it wrong, and dont like the voltage too low. I've got an old style charger that just pushes voltage and cuttent out regardless, always does a better job than the smart ones.

Yup, cheaper end smart chargers are not really that smart…our farm services has a decent one

 

[MrMagoo]

Battery testing how hard can it be?​

It appears difficult for the Halfords and AA techs to check my weak battery in my company vehicle.
Halfords tech didn't know how to use his kit.
AA tech said I need to drive my vehicle for at least 15 minutes every time I start it. I replied I've been driving for over 30 years and I never heard anything so ridiculous; he replaced the battery.

 

[chris3234]

Battery testing how hard can it be?​

It appears difficult for the Halfords and AA techs to check my weak battery in my company vehicle.
Halfords tech didn't know how to use his kit.
AA tech said I need to drive my vehicle for at least 15 minutes every time I start it. I replied I've been driving for over 30 years and I never heard anything so ridiculous; he replaced the battery.

To be a fair he's right for larger engine's less then 10 mins driving on something like van is likely to put less back in then you have used starting especially in the cold weather


For something like a panda 5 mins so be enough to recover the used energy's