Battery, alternator, or...?

Easy and free route. Stop by local auto parts store & have them run a charging system test.


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The second two are the easiest to check.

Use your multimeter to test the output of the alternator. I just did this on Saturday. Put the ground lead from your multimeter to a good ground and put the positive lead on your alternator output wire. The alternator should put out 13.4 volts.

Take the battery out of the car and go have it tested under load.

Check the ground.

Is the alternator's output wire the brown one on top?

Lane, my Odyssey, similar age, seemed to be failing so I bought a new one along with their charger.

After installing the new battery I put the charger on the old one. It looks like it may have brought the old battery back to life.

You may want to first buy the Odyssey charger, which you probably should use on a new battery anyway.

Try the charger on the old battery and them, if need be, buy the new battery.

I seem to recall I left the charger on the old battery for several days until the charger indicated it was good.

Lane Anderson posted:

Is the alternator's output wire the brown one on top?

It's the large threaded stud on top.

8 year old battery? just buy a new battery and be done with it

Robert,

A fully charged battery puts out 13.6v, and the alternator output needs to be higher than that. 14.2 v is a good number. 

Lane,

I can't speculate about your 8 Y/O battery without a load test, but as Tom suggests, a FLAPS will do it for free. I have a "toaster" load tester from Harbor Freight I think cost $10 or some such nonsense. 

But, sunce we're all just guessing, my money is on door number 3. 

I'd bet a donut it's a bad alternator. 

Stan Galat, '05 IM, 2276, Nowhere, USA posted:

Robert,

A fully charged battery puts out 13.6v, and the alternator output needs to be higher than that. 14.2 v is a good number. 

Lane,

I can't speculate about your 8 Y/O battery without a load test, but as Tom suggests, a FLAPS will do it for free. I have a "toaster" load tester from Harbor Freight I think cost $10 or some such nonsense. 

But, sunce we're all just guessing, my money is on door number 3. 

I'd bet a donut it's a bad alternator. 

Copy that. I took the number from a previous post.

MUSBJIM process of keep-it-simple....

1. Start car

2. Remove ground cable from battery

3. If engine dies, faulty alternator

4. If engine continues to run, bad cell in battery.

 

Sacto Mitch process for diagnosing any Speedster problem...

1. Look up price of first possibility (battery)

2. Look up price of second possibility (alternator)

3. More expensive part is most likely source of problem

 

That would be the battery, Mitch.

Measuring batt/alt system voltage under load is best.  Normal running is not full load, but you can get an idea about what might be the problem.  You need a DC voltmeter. with nothing on and the car having sat for a time, measure the voltage at the battery terminals.  Should be near 12 v.  If way low, then it needs to be charged.  You can apply a charger for an appropriate amt of time, and then check open circuit voltage again right after charging and then a day later.  If it comes up and stays up, then likely OK batt.  If it's hot right after charging, and then goes down without use, bad batt.  With car running at idle or a bit more, measure output at alt as described.  If either too low or too high, then alternator is the trouble.  Too low, likely worn brushes, too high likely one or more bad diodes.  I think for some alts, ,one can access brushes/diodes with alt in-situ.  My problem is too high voltage (bad diodes) and no way to access these without removal of alt. So at that prospect, I just   bought a new (and higher capacity) alternator.  The R&R remains to be done, and is scheduled for this week.

I bet on 8 year old weak batt.  Could be wrong.  Go measure some voltages and report back.

If you have a known-to-be-good battery, hook it up instead of the current one (use jumper cables if you have to) and make the voltage measurements discussed again, see if diff't.

I'll have to see if someone I know has the proper meter, cuz I sure don't.

Just go to the auto parts store!

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Lane Anderson posted:

I'll have to see if someone I know has the proper meter, cuz I sure don't.

I can't believe I ever did anything electrical without one:

http://www.homedepot.com/p/Kle...eter-MM400/206517333

Inexpensive enough and you can use it all around the house as well.

 

I guess if you're making a special trip to Home Depot to get a meter, you should get something half decent like the one Robert suggests.

But I've long felt, for our 1930s electrical systems, pretty much any simple meter will do. You really just need to check continuity, do some simple DC voltage checking ( a quarter-volt accuracy is probably good enough) and measure resistance (again, absolute accuracy isn't usually too critical).

This nine-dollar wonder from Sears has proven perfectly adequate.

 

And if you back over it with your pickup truck, you won't care.

 

Oooo...  Nine bucks, huh?

Lane Anderson posted:

Oooo...  Nine bucks, huh?

Actually it is $19.99 but it is currently on sale for $8.99 so if you don't buy it now it goes to full price.

I bought a cheap battery load tester a while back and it has come in handy a couple of times.  You may be able to recharge your battery, but that doesn't mean that it's in good shape.  Put a load tester on it and you'll know for sure.

Here's an example from Harbor Freight:  http://www.harborfreight.com/1...ad-tester-61747.html

^ that's the "toaster" I was talking about above. Use your (ubiquitous) 20% off coupon and it's pretty hard to say no to. 

 

Full disclosure: The nine-dollar wonder won't do a load test like Stan's 'toaster' (but even high-quality multimeters won't, either).

Jim's simple test will pretty much accomplish the same thing, though, with a bit less precision.

But I just use the six-year rule. Even if a battery is fine after six years, it won't be for very much longer, so why not just replace it at your convenience rather than by the side of the road on some dark and stormy night?

This way, you can put the $20 you'd lavish on the toaster towards a new battery.

If you replace a six year-old battery and your lights still flicker, you know it's either the charging system or space aliens from planet Zorba just messing with you.

 

My money is on the Zorbites.

Sacto Mitch posted:

 This way, you can put the $20 you'd lavish on the toaster towards a new battery.

... and yet, without a Chinese battery-powered toaster, how will Lane make gourmet toast for the Zorbites in his garage? No toasted Velveeta sandwiches?

It could upset the delicate balance we have so recently achieved in Charleston/ Zorbite relations. 

 

 

I think the Zorbites bring their own Velveeta with them. It's well-suited to intergalactic travel, with a sell-by date far into the next millennium.

 

Sacto Mitch posted:

 I think the Zorbites bring their own Velveeta with them. It's well-suited to intergalactic travel, with a sell-by date far into the next millennium.

Point taken.

I have one of the Craftsman multis, and can't imagine doing stuff w/out it.  Very handy.  And you don't need the toaster to load up the system to make a few preliminary measurements.  On a Speedy, about all you can do is turn on all the lights. And then maybe honk the horn . . .

Zorbites???

Keep up here, Kelly.

I'm tryin' man.  So what's the deal?  You just go buy a new battery?  I looked over the thread, hurriedly, and don't seem to find the "Ah-ha" posting, where all is revealed. 

Haven't done anything yet.  We'll see how it behaves this weekend.

10-4

UPDATE: After being no problem for a couple of weeks the battery failed to start the car this afternoon.  It was fine at one errand stop and almost totally dead at the next.  A Good Samaritan gave me a jump and the car did fine on the way home so that tells me it's a battery at end of life.  Time to get another Odyssey.

Yup,  Looks that way.

I would never use just a multimeter to diagnose a charging system.

At least expensive, you could turn on every single thing you can find in the car - headlights (hi-beam), heater blower, radio, latte-warmer, anything you can find to load the system.

THEN, with the engine running, test the voltage at the big stud on top of the alternator.  It should read at least 14.2 volts.  If it doesn't, then the alternator is questionable.  If it does, then the battery is questionable.

At least I now know how long my wicked expensive Odyssey will last.....

I think 8 or 9 years is purty good for a battery, don't you?

I've got a 9 y/o Red Top that is in the Outlaw and load tested 95%~

 

Every battery I've ever put in has lasted exactly six years.

That's when I yank them out and replace them - before needing a kind-hearted stranger with jumper cables.

I've probably missed out on making some new friends that way. But I look for drama in other parts of my life - like seeing just how many days I can squeeze out of a tube of toothpaste.

 

Blue-top Optimas have lasted me over 10 years, they better, at the cost!