Interpretation of battery diagnostic gadget

[Harry Bloomfield]

I bought this some years ago, and it is rather clever. You connect it across an engine starter battery, and it checks the condition of the battery, well enough, based on the CCA. It suggests it tests various battery types, but insists on knowing the battery CCA, with a minimum setting of 100CCA.

Not all batteries include a CCA figure, simply an aH at various rates - so how can I get an idea of the condition of one of these batteries, not designed as an engine starting battery.

This is the gadget's manual - https://mans.io/item/ancel/ba201

Testing a none engine starter battery, it will report a tested CCA, and the battery voltage, indicate if it has dead cells, etc. but what I need to know, is the aH.

 

[ericmark]

Years ago we would use a heavy load, and use our experience on how the voltage dropped, and any evidence due to gassing. These were replaced by automatic units that measured the recovery time.

However to work battery needs to be fully charged, and from experiments I found it can take two weeks to fully charge, only way around is use of a hydrometer, and many batteries one has no access to the acid.

The type of lead acid will affect both discharge and recovery. So one would need to tell the unit vehicle start, VRLA, traction, leasure etc.

I tested some 7 Ah batteries after they had been abandoned, then recharged, to power a 6 watt bulb about 12 hours, but use on a 12 watt bulb no where near 6 hours, and if we look at a lead acid it says at 10 hour rate etc.

So at best the testers are approx, unless all info entered.

 

[SUNRAY]

I use lead acid batteries for portable power, used to have ~20-25 in 40-120Ah sizes and wanted to be able to test them.
Several people highly recommended an 'ACT battery tester', so purchased one.

Simple; no settings, just clip the red and black clips on the battery and read the voltage, temperature and Ah. The instructions said to test immediately after a full charge.

My initial impression was good, even excellent. However charge a battery over night and test will show 13.5-14.5V and give an Ah a reading, leave to stand for 24 hrs and test again will show 12.5-13V and often show a 50% increase of Ah, a week later 12.5V and another modest Ah increase.

My batteries have seen better days and currently have 6 which are all at least 10 years old, they have all been used exclusively on charge/discharge and often down to 10V, so they have been abused.

2 are 95Ah car batteries, more like 20-25 years old and typically test as 30-35Ah. However testing with a 50W bulb I'll easily get 12 hours to 12V so >48Ah.
Used them at the weekend; Off charge 34.5Ah used to power radio kit with in-line power meter; 252Wh used (~21Ah) test before going back on charge 37Ah. 2nd battery: 29Ah, 181Wh(~15Ah), 32Ah.

My conclusion: Would I trust such devices? Nah.

 

[Harry Bloomfield]

The specialists, in the battery places, use a similar instrument for battery testing, and I do find it gives a fair value - if I know the CCA spec of batteries. The issue I'm struggling with, is that many of my batteries only quote an aH rating, rather than a CCA.

 

[SUNRAY]

The specialists, in the battery places, use a similar instrument for battery testing, and I do find it gives a fair value - if I know the CCA spec of batteries. The issue I'm struggling with, is that many of my batteries only quote an aH rating, rather than a CCA.

I'm finding the opposite is true, only quoting CCA

 

[bernardgreen]

For batteries that have to start internal combustion engines the CCA rating ( Cold Cranking Amps ) is relevent,

The rating refers to the number of amps a 12-volt battery can deliver at 0°F for 30 seconds while maintaining a voltage of at least 7.2 volts. The higher the CCA rating, the greater the starting power of the battery.

For batteries that have to supply current for several hours the AmpHour rating and the Charge/Discharge Hour rating are relevent.

12V 7Ah 20HR
In this instance the 7Ah is given as the 20 hour rate, at a constant discharge over 20 hours the battery will produce 0.35 amp per hour (20 hours x 0.35 = 7Ah).

 

[Rodders53]

I bought this https://www.amazon.co.uk/gp/product/B07S2LB27F/ tester for use with our mobility scooter and caravan leisure battery checking processes, simply because one could dial in the Ah capacity (and it also went down low Ah enough for my needs, not may do) as well as CCA if I ever wanted that feature.

It was some time ago now and I'd done a lot of research before purchasing; which I have completely forgotten. It's a very simple meter but a fraction of the price of the ones used by caravan service technicians and similar trades.

 

[ericmark]

I think @bernardgreen has put it in a nutshell. Many years ago, I had a problem, the sealed for life battery came out, and no longer would the hydrometer work, and to test a battery, it needs to be near fully charged, so someone would come in, and the battery shows 11.6 volts, this could be a fully charged battery with a shorted cell, or a discharged battery, if simply discharged we would not get a replacement, but would if it had a shorted cell, first was a digital voltmeter, but as time went by, more and more sophisticated testers came out, but all we were interested in was it that the battery discharged or faulty, and for the device to show it in a form where we could show the person who came in, battery is faulty or discharged.

If the latter, we would offer to charge it, then retest, but much depended on the make, Manchester batteries hardly ever refused a returned battery, so we would change it and take a chance, Oldham batteries would return at drop of hat, so very careful with them. I am going back some 30 odd years, but the more sophisticated it looked, the better, we wanted the person returning the battery to see what the machine said.

As to if the AH capacity was accurate or not, we did not care. All we wanted was if it says the battery is faulty, the manufacture would agree and replace it.

Some of the guarantees on batteries seemed odd, when fitted to a taxi only 6 months given, how were we to know if fitted to a taxi?

 

[bernardgreen]

I bought this https://www.amazon.co.uk/gp/product/B07S2LB27F/ tester

• ✔ CCA AND AH TEST MODE - Much wider test input rang(0-2000 CCA)/(0-200 AH) and more accurate than competitors. Built-in exclusive algorithm allow to complete test and analyze in seconds.

I cannot see those test leads surviving a test of a CCA at 2000 Amp

 

[Rodders53]

I cannot see those test leads surviving a test of a CCA at 2000 Amp

It's a conductance tester not a low resistance load tester, for goodness sake.

Bedtime reading https://gtc.ca/blog/how-to-use-a-battery-tester/

 

[bernardgreen]

conductance

The conductance measured using a 1 Amp test current will ( in a battery ) be different to the conductance measured with a 10 Amp test current,

 

[bernardgreen]

Bedtime reading

.Given that most users do not have access to detailed design information about a battery (aside from rated capacity, size, and cold-cranking current), you should be careful in selecting a conductance tester,

 

[Harry Bloomfield]

• ✔ CCA AND AH TEST MODE - Much wider test input rang(0-2000 CCA)/(0-200 AH) and more accurate than competitors. Built-in exclusive algorithm allow to complete test and analyze in seconds.

I cannot see those test leads surviving a test of a CCA at 2000 Amp

They don't test with a heavy current! They are much more sophisticated these days..

They test no load volts, small load volts, then work out the resistance. Resistance, indicates the likely CCA. Initial voltage, gives a clue about state of charge.

 

[ericmark]

I used one of these for years, I am sure well over 10 amp. Also dangerous, as the spark could ignite any gas, then these came along, so pressed a button after clips firmly connected, but these

have come along since, and we tend to select well known makes, with a long pedigree in the auto trade, so Durite or Ring, the others may work, but can you trust them? But some are rather expensive, this one

has a £450 price tag. This one

£185 I am sure very good, but unless in the trade, not really worth it. It was as said more down showing the customer why we were not replacing a battery under guarantee, than really testing the battery.