6 * 1.7v = 10.2v, there's your minimum. 6 * 2.35 = 14.1v to 6 * 2.40 = 14.4v while running/charging. That's your numbers. Source - 34 years working in the battery industry.
This is not really a situation to do a load test; if you see a 0.6V drop from full in a few minutes with the car off, then there is either a problem with significant drain on the battery, or the battery is rapidly self-discharging. What you *should* have done is first disconnect the negative lead and check amperage flowing out of the battery with car off. It should be *very* low, I've never measured it but I'd expect less than 200mA. And if it is high, like 1A, then I would expect there is a problem. But more likely, you would see a reasonable number, and all you should do then is leave the battery disconnected and see if it is self -draining. That is common in older lead-acid batteries, as the plates will sulfate and drop that sulfate to the bottom, where it builds up and eventually shorts a cell. If the battery is good, it will barely drop in voltage. Even with a little load on it, you should see it drop to 13.2V, which is the steady state for a full battery (2.2V per cell), before it finally drops and stays at 12V. But if a cell is bad, it will continue to drop, possibly down to 10V (5 times 2V) if one cell is bad, and even lower if the problem is across cells. Also, not sure I would call what you did a "Load Test", but labels may differ across the Atlantic. Here in the USA, a Load Test is putting a measured heavy load on the battery and looking at the current it supplies as well as the voltage the battery can hold up.
Thanks for the very comprehensive comment! I did check the amperage “drain” and it was negligible. I don’t really think it matters what order you do these tests in, it’s more of a process of elimination, usually starting with the most likely and I had a feeling the battery wasn’t holding charge. Maybe I should have included it but I was trying to stay focussed on the load test in this video. My battery is 14 months old and has never been left in a discharged state, so I knew the problem wasn’t sulphate. I’m aware of method for a Full load test using a known heavy load but most people don’t have one of these at home and it’s harder to get to a shop for it to be done if your car is having starting problems. I’ve used this method of using the starter motor as the load many times and have always gotten really good results. Maybe give it a try next time you have a battery issue and see how the tests compare? Thanks, Phil
Thanks! Sorry about the link, totally forgot. I haven't done a video yet on this but there's a channel that I like to watch called "Eric the car guy". He did a good video on this, here's the link! ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-KF1gijj03_0.html Cheers, Phil
My voltage is displayed on my dash on my bike. When I first power up, before cranking, the V sometimes shows it's as low as 6-7v but rapidly rising until it slowly creeps up to 12.2 where I crank it. If I try to start it too soon it dies momentarily and the bike does a factory reset. Usually the 2nd crank it starts up fine.
@@ReviveMyRide I think there's a big load on it, just as I power it on. It has automatic suspension control which I think it tests as well as a servo motor on the exhaust valve, ABS pump, all kinds of diagnostics I don't even understand. There's a whirring noise which doesn't seem to go away either. I just bought the Topdon BT20 load tester so maybe that will reveal some of what's going on with my starting issues, as sometimes it is a bit iffy at cranking.
Batteries especially lead acid don’t have much of a gradual decline in CCA capacity. It’s common to go from starting your vehicle to almost junk when you go for the next start. Simply put end of life is abrupt. It’s just time to replace it. For piece of mind the auto parts store has a load tester to verify the battery. Just personal preference but if you can swing it a AGM style battery is better in every way to a lead acid. With all of that said verify all connections are tight and making proper contact. A weak connection can act like a bad battery or starter ect.
Hi, does charged 1347 mean 13.47 volts? Yes, I would expect the battery to have pretty much the same charge in the morning if disconnected and left overnight. If it has dropped a lot, then yes, that wouldn’t be good news for the battery. However, if it stays the same, doesn’t mean the battery is good, hence doing load tests etc to test the battery. Cheers, Phil
Agree! You mean the second crank right? First one sounded ok and a lot of people only do one load test. I’ve learned to do two because if you do a short journey, the alternator doesn’t have much time to charge the battery and you can get stranded! Cheer, Phil
Spent 40 years fix German dumpsters , always problems with power drains, spilt drinks,water ingress?? A living nightmare. I’m retired and drive a Tesla mod3 ,never been sooooo happy 😉
I had a Merc CLK for 12yrs, and a BMW Z4 for a similar amount of time, never any issues but the newer cars? Now that’s a different story. I’m glad you are enjoying your Tesla, I’ve been in one, fantastic machines but not my cup of tea 🫖 cheers, Phil
