Car Battery Load Test With Multimeter | EASY DIY

Learn how to perform a QUICK and ACCURATE load test of a 12-volt car battery using a multi meter with and without a Min/Max Function!

[lgude]

Yes, excellent video. Easy to follow exactly. The second load test with the min way down was an eye opener. I've certainly heard exactly that kind of weak battery and had enough experience to know it was probably time to replace it. But now I can know for sure. I've got a Fluke similar to yours.

[bearpuf]

A really nice video. You have a a very fine easy to understand verbal delivery that makes using a multimeter easy for a novice to find out if the battery is good or bad through a load test. Thanks. Good teachers like yourself are worth their weight in gold.

[wiretamer]

I’ve been using a sulphated battery in my Sprinter Van for the past six months. I did so by fitting a cut off switch to the positive terminal of the battery. I keep the battery isolated whenever I know I won't be driving for more than 10 minutes. This also gives me a bit of extra security on the vehicle. The battery has trouble starting the Van if it is left connected for more than 4 hours.

The morning start is the hardest. If I can't get it going, I use an emergency jump starter which is cheaper than a new battery in the morning. What I tend to find however is a couple of start attempts, warms up the battery enough to get the car started.

After that, normal use of the Van, and continuing to isolate the battery as much as possible, means I don't have any trouble for the rest of the day. All this on a battery I should have replaced six months ago.

Next time I buy a new battery I will continue to isolate it and see how long it lasts. For a tiny bit more trouble than normal battery use, I expect a new battery will last at least five years before I have real difficulty.

[nlimchua]

I enjoyed your presentation esp. your accent and enunciation!

[I.Liveoldcars.prospecting]

This was very helpful. And easy to understand. Thank you

[Malc]

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.

[susanhenderson]

Take battery to a parts store, they will perform a proper load test using the correct tester, your crank till it starts is insufficient time at the minimum disable ignition system and crank for thee recommended time to simulate a longer crank before start.

[BionicRusty]

Another very helpful video.
Thank you for posting. 👍

[montanadan]

100% Montana Dan endorsement.
The internet contains a lot of misinformation relating to electronics. That is not the case with this video and I strongly agree with the diagnostic approach and the battery voltages specified for lead acid, high output, cranking batteries.
Commenters qualifications:
I hold a BSEE (Electronics) and have lifelong experience in the mechanical and electronic/electrical fields. My hobbies include a self contained 1989 IP35 sailboat (600w solar 400 Ah AGM, no invertor) and a 2003 Roadtrek camper van (high output self regulated alternator, Victron FET isolator, lead acid start and deep cycle 100AH house, no inverter).

[Milkybar]

Cold temperatures will also affect the performance

[jonathanwebb]

Probably just wants topping up with water. Some of the Varta batteries you can peal off the label and unscrew the caps to top them up. I can see circular outlines on the label so maybe that's the case here. I managed to get a fair few extra years out of mine by topping it up. Unfortunately many if not most are physically sealed to stop owners topping them up.

[tonytully]

Great video. Correct information presented perfectly 👍👍

[leonardodavinci]

Nice overview. You didn't put the other promised link in the description.

[ArcanePath]

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.

[rosemcbirney]

My battery is saying charged 1345 on the bench should it still read that number in the morning if it’s drops down is telling me the battery is failing

[seeyouintheeighties]

mine reads 12.6 and 10.5 during cranking (but not turning over) as my immobiliser seems to keep forgetting key transponder codes and stopping it from turning over and I can't work out why

[geoffhanbury]

Apologies for a possibly dumb comment but does removing a lead form a modern car battery (my car is a Skoda Octavia 1.5tsi 2019) cause problems with the car "recognising" the battery when you reconnect?

[hapn]

I have a upgraded car stereo with amp and if I turn off the engine and leave the light on with radio it will drain my battery with in 5-10 minutes.

[LarryB-inFL]

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.

[simeunovicm]

You have volt meter on mercedes dash menu in case there is no multimeter around