Battery health testing

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UsInWorld

Active Member
Posts
97
Location
Scotland
Hi

My Defender 300TDI wouldn't start after been sat for days due to low battery.
Got the battery tested at local car shop. They used a Durite battery tester and it said replace batter as state of health is 39%. Battery is 10 years old so bought new, fitted it and it starts again.

Looked at Battery Analyzers online and bought a Topdon BT20 for under £20. Charged the old battery indoors and tested it with the BT20 and result said state of health 87%

Thats a big difference and wondering why. Is it because battery is room temp + full charged or is the Topdon not precise?
Reviews online says they are good quality. Could it the the shops Durite meter thats rubbish? Just had another thought could it be the difference of CCA and EN settings in the tester? Think shop said 740 CCA and when battery was out I seen its 740 EN.

Does anyone on here have experience with battery analyzers?
 
How long did you leave the battery after charging before testing?
I bet when it is loaded up it will read low SOH again.

I have an ebay cheapy I use at work, pretty accurate.
 
lynall said:
How long did you leave the battery after charging before testing?
I bet when it is loaded up it will read low SOH again.

I have an ebay cheapy I use at work, pretty accurate.
Click to expand...
About a day from fully charged to the battery tester arrived and did the test.
Guess the battery in knackrd as the fully charged voltage is 12.60. To stress the battery I ran the test 3 or 4 times and the results were v similar, resting voltage dropped to 12.57
Still feel the SOH is too high

Know a scrappy so might take meter there and test known faulty batteries and compare
 
UsInWorld said:
About a day from fully charged to the battery tester arrived and did the test.
Guess the battery in knackrd as the fully charged voltage is 12.60. To stress the battery I ran the test 3 or 4 times and the results were v similar, resting voltage dropped to 12.57
Still feel the SOH is too high

Know a scrappy so might take meter there and test known faulty batteries and compare
Click to expand...
Them modern testers do not stress the battery like the old style drop testers.

You could always chuck it back on the car for a day or two, with the new one in the boot just in case.
 
lynall said:
Them modern testers do not stress the battery like the old style drop testers.

You could always chuck it back on the car for a day or two, with the new one in the boot just in case.
Click to expand...
Tested the Battery tester with a Clamp meter and the peak current draw is 45 Amp.
Could you do the same test as would be interesting to compare old vs new type of battery test meter
 
kermit_rr said:
Do you mean you measured the amps while doing a drop test? 45a seems very low
Click to expand...
Yes a clamp meter on the positive wire with max setting activated.
I agree that 45A seems low, would think it should be near a engine cranking amperage.
I been searching online and youtube and lots of "reviews" thou none actually testing the current. Surely thats the point of stressing the battery to obtain the health status. When knowinng this figure could then compare to other tester meters and buy one with most precise test

Wonder what the manufacturer says, maybe my BT20 meter is faulty
 
UsInWorld said:
Tested the Battery tester with a Clamp meter and the peak current draw is 45 Amp.
Could you do the same test as would be interesting to compare old vs new type of battery test meter
Click to expand...
The only old ones I have used were the ones you push onto the battery terminals themselves whilst looking into the cells, voltage over 10 and no bubbling in the cells meant it would take a charge and go again.
Like this

Screenshot 2024-12-11 at 19.44.41.png


At work we were testing my 20 quid cheapy against the bosses brand new 70 quid Durite tester, the results were different but not enough to make a duff battery appear good and vice versa.
These were with 1150A batteries.

Screenshot 2024-12-11 at 19.44.59.png
 
Topdon does a decent digital tester at around £40. BT200 i think.
My drop tester is an old taskmaster with big thick jumper cables. It's let down by the scale on the voltage read out. Just not enough detail
 
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