Testing Batteries: It's More Than Volts!!

[@garbleduser]

I use a Cadex C7400ER-C battery analyzer for most batteries. Also, It is amazing how much information can be gleaned from using just a multimeter and a variable psu for lead acid batteries once you learn their language.

[@BjornV78]

7:22 The 4 wires are Kelvin 4 wire measuring method to rule out the resistance of the testleads themself. Almost all of those little battery testers are for automotive use, they only do some calculation that fully depends on the parameters you have set, like voltage, Ah and Cold Crank Amps (CCA) . Some use the SAE or DIN numbers that are printed on the battery. With any type of battery, you can go back to basics for calculating the internal resistance. You can do a load test, but then you drain the battery, and need a Clamp meter. But there is a another way without loading or draining the battery. Here for you need a signal generator, a analog multimeter, and a 100uF (or higher) bi-polair capacitor. Set the signal generator to a 1V peak to peak 100Khz square wave, place the 100uF in series with the analog multimeter (set in mA range) and connect the signal generator to the battery. The capacitor will block the DC from the battery, but will pass the AC signal from the signal generator. With 100Khz , a 100uF looks like a dead short (0,016 Ohm). Measure now the current, and use Ohm's law to calculate the internal resistance of the battery. Why a analog multimeter ? Because many DMM can't measure current above 1Khz, a analog multimeter doesn't care. To get a very accurate measuring, you can do this test without the battery, so only the signal generator in series with the capacitor, and measure the current. This gives you the resistance of the capacitor itself, this value needs to be abstracted from the value you calculated with the battery connected. This 100Khz square wave signal is what many high end battery testers use to calculate the internal resistance, and this is also used in ESR meters.

[@gg-gn3re]

I'd use YR1035 / TR1035 over all these or even RC3563

[@PM-wt3ye]

But there is a coincidence between Vorlage and General condition, isnt it? if a 12v Car Batterie has been charged and it keeps voltage of ~12,8v its in good condition. If it only keeps 12,0V its probably gonna „die“ soon.

[@BetterBiomedChannel]

Voltage only tells you the difference of potential. The amp capacity of the battery depends on the quality of the plates.

[@mattn2151]

Just because the battery is discharged, doesn’t tell you anything about the amps that will be produced once it’s charged. If they sit at low voltage, the plates will start to get sulfur crystal buildups that will hinder amp output. There is no way to check this except with a load test when fully charged

[@PM-wt3ye]

Im not talking about being discharged. Im talking about KEEPING the charge.@@mattn2151

[@PM-wt3ye]

Thx. But if you have, lets say a 5 year old battery and you dont have the equipement u used, the voltage AFTER charging is a good indicator in my opinion. If it drops down quickly near 12v, not so good. If it stays at ~12,8V for 12 hours, battery probably is very fine. @@BetterBiomedChannel