Quick Question

"zeontestpilot" (zeontestpilot)
11/07/2016 at 13:43 • Filed to: Question

A friend of mine has a ‘01 Montana, that keeps killing the battery. I put a multimeter to the battery, and it had 5 volts. This is the third battery this has happened to (low voltage I mean). Might this be an indicator that the alternator is bad?

If it is, is there a way to verify that it is indeed the alternator that’s bad? What other culprits might there be?

Thanks in advance!

DISCUSSION (23)

If only EssExTee could be so grossly incandescent > zeontestpilot
11/07/2016 at 13:48

Solution: get rid of that hateful vehicle.

functionoverfashion > zeontestpilot
11/07/2016 at 13:51

What is the voltage while the engine is running? Should be 14...

TheD0k_2many toys 2little time > zeontestpilot
11/07/2016 at 13:53

Alt voltage is 14volts when the vehicle is running

zeontestpilot > functionoverfashion
11/07/2016 at 13:53

Didn’t check, I was passing his house when I inquired what he was doing. Will have to check for him. It died while leaving the driveway.

E90M3 > If only EssExTee could be so grossly incandescent
11/07/2016 at 13:53

My mom had a 2001 Silhouette, I hated that vile thing.

Tekamul > zeontestpilot
11/07/2016 at 13:53

It’s possible the alternator is bad, but more info is needed.

Are these batteries just getting pitched with no attempts to recharge, or have they actually been tested and shown to be bad?

How long has this been going on? Are they in quick succession, or is it over years?

Has anybody checked for a large current draw on the system? Maybe something else has failed and the alternator can’t keep up.

The quickest test for an alternator is to start the car with a good battery in it, then check the voltage of the system, it should be ~14V. Too low, the altenator isn’t charging the battery effectively. Too high, the acid in the battery will cook off.

Tristan > zeontestpilot
11/07/2016 at 13:53

Eric the Car Guy can help!

vicali > zeontestpilot
11/07/2016 at 13:55

Could be a few things, the obvious one would be a drain. I’m a fan of these little guys;

Kinja'd!!!

They are an easy way to isolate your battery if you have a weird drain in a pinch.

Otherwise you are going to have to put your multimeter to work;

Nibby > zeontestpilot
11/07/2016 at 13:56

show your friend this video

zeontestpilot > Tekamul
11/07/2016 at 13:57

The batteries are getting returned, and it’s been happening since they got the car last year. Not sure how quick they go though.

When he gets home I’ll see if he has a battery charger. We can see if the battery can be charged, then we can try the voltage on the alternator.

zeontestpilot > TheD0k_2many toys 2little time
11/07/2016 at 13:58

That’s what I’m finding out here. Will have to check it for him.

Spoon II > zeontestpilot
11/07/2016 at 14:00

Might be a short somewhere that’s draining it while it’s parked too. Some exposed wire somewhere on the vehicle.

jimz > zeontestpilot
11/07/2016 at 14:15

yeah, if the voltage lifts to about 14 volts while the engine is running, the alternator is OK. if it doesn’t, then you’ve got your culprit.

but if the battery is being drained down to 5 volts, I’d suspect a sizable parasitic draw somewhere. The car will quit running at about 9.6 volts. something else has to be draining it down to 5; and running a lead-acid battery that flat will kill it dead; the plates build up enough sulfate where no charger can revive it.

zeontestpilot > Tristan
11/07/2016 at 14:16

I’m liking Eric, :)

Stapleface > zeontestpilot
11/07/2016 at 14:19

I too would suspect the alternator. Unless there’s some type of parasitic loss that slowly drains the battery.

zeontestpilot > Nibby
11/07/2016 at 14:21

I’d imagine all mini vans would be in a similar boat honestly.

zeontestpilot > jimz
11/07/2016 at 14:25

Well it died last week...or two weeks ago...

Continuous draw?

VonBootWilly - Likes Toyota, but it's still complicated. > zeontestpilot
11/07/2016 at 14:26

My father has a similar U-Body Venture. Just recently his light switch started turning the lights on and off randomly while parked, which he didn’t know was happening until he caught it. Probably not the issue, but happened to him just last week.

I drive a U-body Uplander as a DD once in a while, they generally self disintegrate pretty well without any help, so this is pretty normal.

duurtlang > zeontestpilot
11/07/2016 at 14:35

Depends on the continent. Here’s a 1997-2002 minivan by Renault, a mk3 Espace, tested in 1999.

edit: same year (1999) but now the (rebadged euro version of the) Montana by euroncap. Similar results as the American test.

Compare and contrast (same year vehicles):

Kinja'd!!!

zeontestpilot > Stapleface
11/07/2016 at 14:38

I’m telling him we need to see if there is a draw somewhere, it’s the best bet.

Stapleface > zeontestpilot
11/07/2016 at 14:41

Seeing how it’s a minivan and they seem to have a million lights on the interior, double check to be sure one isn’t on. It would probably be one that isn’t easily seen, like down low in the cargo area.

Rico > zeontestpilot
11/07/2016 at 14:54

Newer minivans are significantly better. Old cars are fine except when their lack of crash safety puts an entire family at risk of dying in an accident.

Full of the sound of the Gran Fury, signifying nothing. > zeontestpilot
12/14/2016 at 22:57

Back in high school I had a nearly new Rabbit GTI. After the third alternator and third battery, my shop finally replaced the entire engine compartment wiring harness and the electrical problems went away. This was on a 2 year old car with a one year warranty. They just don’t make ‘em like they used to (thankfully).

I went on to buy two more VWs having not learned my lesson, but the Vanagon was OK except for the headgaskets (1st gen wasserboxer) and the Rabbit Pickup was actually a pretty reliable vehicle.