Timeline for How to measure the car battery charge with good precision
Current License: CC BY-SA 3.0
13 events
| when toggle format | what | by | license | comment | |
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| Nov 18, 2012 at 20:50 | vote | accept | fceconel | ||
| Nov 18, 2012 at 3:57 | answer | added | Nick Alexeev | timeline score: 3 | |
| Nov 17, 2012 at 21:25 | comment | added | fceconel | @NickAlexeev my answer to dean also answers some of the points you asked, for the others: yes, I want to measure the standard car battery; and no, I'm doing nothing more than is regularly done (i.e. supply the engine electric system, power the car lights, the car stereo, etc.). | |
| Nov 17, 2012 at 21:23 | comment | added | fceconel | @DeanB SOC is more important, but it'd be nice if I could have both. Mainly, I want to detect two situations: (1) when the battery is approaching a too low charge while the car engine is off (for whatever reason - sitting idle for too long in the garage or the headlights were left on) and (2) when the battery is not recharging correctly with the engine on (if the alternator isn't working perfectly or the battery is old/defective) preferably before the battery gets too much discharged, so the driver could be warned in advance. | |
| Nov 17, 2012 at 19:01 | history | tweeted | twitter.com/#!/StackElectronix/status/269878160072515584 | ||
| Nov 17, 2012 at 3:19 | comment | added | D.A.S. | Most accurate lead acid battery SoC testers do an Interrogate and Response load test. This is related to the worst case cell in series and it's specific gravity and then scaling by the number of cells and capacity of each cell. | |
| Nov 17, 2012 at 3:15 | history | edited | Nick Alexeev |
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| Nov 17, 2012 at 3:14 | comment | added | Nick Alexeev | @fceconel Do you want to measure the battery, which starts the motor in the car? If so, why do you need to know its SOC precisely? Are you doing anything else with this battery, outside of normal car operation? | |
| Nov 17, 2012 at 2:33 | comment | added | HikeOnPast | That presumes a linear or near-linear relationship between SOC and terminal voltage, which you may find lacking when monitoring Pb-acid batteries. (en.wikipedia.org/wiki/Peukert%27s_law) What is of more interest to you: voltage or SOC? | |
| Nov 17, 2012 at 0:42 | comment | added | fceconel | It's SOC, but the reading'll be fed to a uC, so I can do the translation there - If I just have the voltage with 3-digit precision it'll be fine. | |
| Nov 17, 2012 at 0:19 | comment | added | HikeOnPast | Are you trying to measure battery state of charge (SOC), or just measure terminal voltage in a different way? | |
| Nov 16, 2012 at 23:50 | history | edited | fceconel | CC BY-SA 3.0 |
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| Nov 16, 2012 at 23:28 | history | asked | fceconel | CC BY-SA 3.0 |