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| Lead Acid Battery Analyzers. Working principle? |
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| rvalente:
Hello Mates, does anyone carry any papers or knows about how these Lead Acid Battery Analyzer working principles? They measure internal resistance, Cold Crank Amps (in various standards). Have small gauge cables for this much current and appears to use Kelvin probes. Cheapo Aliexpress stuff: Hioki BT3554 Fluke 500 are similar... |
| ogden:
--- Quote from: rvalente on November 27, 2017, 02:50:35 pm --- does anyone carry any papers or knows about how these Lead Acid Battery Analyzer working principles? They measure internal resistance, Cold Crank Amps (in various standards). Have small gauge cables for this much current and appears to use Kelvin probes. --- End quote --- Usually most of them do just voltage and internal resistance. Maybe those aimed at car battery testing, do cold crank amps- dunno. Hioki BT3554 specs briefly describes how internal resistance measurement is done: Testing source frequency: 1 kHz ±30 Hz, With function for avoiding noise frequency enabled: 1 kHz ±80 Hz, Testing current: 160 mA (3m/30 m\$\Omega\$ range), 16 mA (300 m\$\Omega\$ range), 1.6 mA (3 \$\Omega\$ range), Open-circuit Voltage: 5 V peak |
| G7PSK:
I would not rely on one of those as the only sure way to know if the battery is good or not is a heavy load. I had a suspect car battery and they used something like one of those and pronounced the battery good, when it kept not wanting to start the car after the side lights had been left on a couple of hours, the garage wanted to replace the alternator then decided a new starter was in order so I went to anothe place where they had one of the old style testers, basicly a dead short with a volt meter across it, that showed the battery as being poor and in need of replacement. |
| CJay:
I *think* it's a Motorola App not that gives a nice run down on how to test a battery, you can measure and calculate a lot of data about a cell by applying an AC signal to it (bit like, if not identical to, the capacitor ESR testers) but as G7PSK says, while it measures the cell resistance, capacity and charge state, it doesn't load the battery and you can have a battery that shows good but won't reliably crank an engine. Some of the better ones will apply a small load and measure recovery time as well, the older units applied a load of a few tens or even more amps but they're not a little scary to use when they can draw ~100 amps. |
| ogden:
--- Quote from: CJay on November 27, 2017, 03:47:57 pm ---you can have a battery that shows good but won't reliably crank an engine. --- End quote --- You can have battery that shows nominal voltage, nominal ESR but does not provide nominal current? Is this some kind of fisherman's story? :D Whatever. That's why there's car battery chargers, car battery testers and then there's industrial devices - inverters and UPS'es, testers as well. Original Post does not tell what kind of batteries shall be tested. Only Aliexpress "el cheapo" seemingly is aimed at car battery testing. Both Hioki and Fluke testers are aimed at industrial use - they indeed measure all you want to know about UPS lead acid batteries, without "cold crank" or load test. |
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