Opinions on Midtronics battery test gizmo?

What you need to test a battery and a charging system is a voltmeter and a dummy load and some brains. The Midtronics tester provides the voltmeter and a (very small) dummy load along with some computer-driven displays.

There is no substitute for brains.

There are also plenty of intermittent alternator issues, starting with brush problems. It can test fine and then five minutes later be bad and then clean up by the time you find the meter.

This is why cars should come with voltmeters and ammeters on the dash.

--scott

As I see it, no matter what he does, "the test" that really counts is at his auto club. If they choose to be obstinant and ignorant, they still hold the reins.

I agree with Scott in his statements above.

Maybe OP needs to change autoclubs.

What I'm wondering is if it's possible they use a particular test gizmo because it's prone to showing their battery as good when an actual auto shop shows it as not good. Though I have reservations about auto repair places as well, I would think an (honest) professional, certified mechanic is going to be more on top of things than some guy who got company training on how to push some buttons and interpret the display on a particular gizmo. I'm not aware these battery service guys are required to have any background in automotive tech.

"pongespob" wrote in What I'm wondering is if it's possible they use a particular test gizmo because it's prone to showing their battery as good when an actual auto shop shows it as not good. Though I have reservations about auto repair places as well, I would think an (honest) professional, certified mechanic is going to be more on top of things than some guy who got company training on how to push some buttons and interpret the display on a particular gizmo. I'm not aware these battery service guys are required to have any background in automotive tech.

********* It is very possible that their equipment is not capable of evaluating a battery effectively, OR that the personnel do not know what they are doing.

Some years back, I nearly went broke having a service station come and jump start my car during cold weather. Each time they took the car to the station and "tested" it. They told me the battery was fine, alternator fine, just needed a charge. Finally I got tired of this and bought a new battery....and found that this had been the problem all along.

It is not that you CANT test a battery....it is just that untrained or disinterested personnel sometimes DONT do it correctly.

Well, of course.

If they didn't have the test gizmo, they wouldn't be able to test anything and therefore wouldn't be able to sell you a battery.

The test gizmo may have as many false negatives as it has false positives, but even if it were 100% accurate it would still allow them to sell something they couldn't otherwise.

And you can always demand your money and old battery back afterward.

--scott

Charging systems are not always easy to diagnose. The best way to diagnose it would be to leave the car with the mechanic for a week and let him drive it back and forth to work every day. Since that is not realistic the mech has to use his best guess based on available data. My batteries last me 3 years or less. I get them from Wal-Mart because there are Wal-Marts everywhere.

You pretty much have to test batteries under a load but who the heck has a dummy load for a car battery? What do you think of turning on the AC fan for a load? Anyway, I just use a voltmeter. Hopefully, you'll see around 13.4 volts when running and a lower than normal battery voltage when the engine is off.

I think you're right about this but that might be expecting a little too much. I'd opt for a voltmeter. My old Barracuda came with an on-dash vacuum gauge. That was that bomb. It was good because it taught the driver to maximize engine vacuum when driving.

Snap-On. Also ATD sells a nice one for about $50. It'll drop a 100A load on the battery for a second or so.

The Midtronics does something similar but for a shorter amount of time.

That's hardly any load. You want to know what happens to the battery when it's unloaded, when it has a moderate load (say, the headlights), and then when it's cranking.

Plenty of batteries with sulfation issues will be fine with a moderate load but won't crank.

The good testers will put a cranking-grade load on the battery.

The voltmeter tells you most of what you need to know, but the ammeter tells you when you're charging and when you're discharging the battery. Not essential, but I'd pick it over a vacuum gauge (or a fake "turbo boost" gauge that displays a useless derived value).

--scott

replying to Scott Dorsey, Murray wrote: The midtronics tester tests loaded and unloaded battery charging as well as craking amps on the starter motor and gives you bad cell info or if battery internals are good and current draw. If performed correctly Source: motorist club technician (me).

Its ultimately upto the technician to relay such info.