Dead Battery

I recently purchased a used '96 Miata with 61K. Love the car. I've put about 1000 miles on it during the past few weeks and everything has been perfect, until Saturday night...

I stopped at a local tavern with a friend to get a bite to eat. A couple hours latee, we're getting ready to leave and the battery is dead. No hint in advance whatsoever. The condition was similar to what you would see if a connector on the battery had become badly corroded, but that was not the case. We push-started it and drove about 10 miles, ran great, all electrical worked fine (including all idiot lights), which would appear to rule out an alternator problem.

Got home, turned it off, not enough power to crank the starter, not even a groan. I slap the charger on it and it doesn't want to charge because the battery reads 12.75 volts. There's enough power to run the radio, but turn on anything that draws amps and it's no-go.

I put a meter between the battery positive and the battery cable and it seems to be drawing 6 milliamps cold, which I understand is within specs since I don't have an alarm system. That appears to rule out a short.

I tried to jump-start it with a '95 Accord and couldn't quite get it started, the starter would turn a bit but I think the resistance of the jumper cables was too much to get enough amps from the Accord. Running the jump car for a while did not appear to charge the Miata battery at all (no surprise there given the driving experience).

The battery appears to be a Mazda replacement acid unit (it's got vent hoses and there's a warning on the top about acid) but maybe I'm wrong about that. I haven't spoken to the previous owner. I'm left to conclude that it is a simple battery problem. Given the fact that I have to push- start it and can't turn restart it if I turn it off, I need to do something and replacing the battery is the quickest and least-expensive "fix."

Any ideas? Thanks.

dm

Reply to
Dave Molta
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Reply to
chuckk

Dave,

You may need a new battery, but before you spend the money to replace it you might check the connections at the terminals. With the car running you should have at least 14 volts across the terminals. If you don't have 14 volts, the alternator charging current is not getting back to the battery. Next, remove the wires from the terminals. Clean the connections with a wire brush or sand paper. Use a little grease on the connectors before reinstallation. Charging the battery over night with a 1 ampere trickle charger might bring it back to full operation.

The Panasonic AGM battery originally supplied on the Miata is often good for

10 years or more. the Westco replacement battery is usually the best choice if the battery needs replacement.

Reply to
Larry Gadbois

Dave:

I'll just add to the good advice that you've been given, that my '96 needed a new battery in 2003. I remember reading (probably in this group) that later model Miata's (like ours) didn't get the 10 year battery service that lots of the earlier ones got--mine was the aforementioned Panasonic, however.

The replacement battery arrived quickly from Westco (don't know how your UK experience will be), and other than the UPS man literally throwing it over my fence (landed on concrete!), it is a nice, stock-like, replacement. My Panasonic wasn't dead but wouldn't hold a charge over 2 weeks (the car sits sometimes)...not an issue with the replacement.

Happy motoring,

M
Reply to
Mouse

Vaseline, they used to tell me.

Leon

Reply to
Leon van Dommelen

Reply to
Larry Gadbois

I wanted to follow up and thank those of you who replied.

I brought the old battery to my local Autozone and they put it on their load-tester. A couple minutes later, it responded with a "Battery is Bad." I've never known whether to really believe those tests, but since this was the answer I was hoping for (easier/cheaper to replace the battery than to bring it to the dealer for analysis), I belived it. The tech also noted that there was a date-seal on the old Mazda lead-acid battery that indicated it was installed in 2001. Based on what I've read,

3 years isn't an unreasonable life span.

Anyhow, the surprising element of this was the fact that Autozone had an "original fit" replacement in stock for $80. It is part of their Duralast Gold prduct line (model 8AMU1R) that comes with an 8-year warranty, 3 years free replacement. I'm guessing that's better than Mazda offers and it was a few dollars cheaper.

Since the car was undriveable and it was a beautiful day to drive, I let my desire to fix it get in the way of ordering a replacement from WestCo. It seems like most folks view that as the best solution, but for those who are less patient, or simply prefer lead-acid, the Autozone option seems to be a pretty good one in light of the warantee.

dm

Dave Molta wrote in news:Xns951D5F3024B6Adjmoltasyredu@24.24.2.166:

Reply to
Dave Molta

For an conventional lead acid.

I do not know why people would prefer "lead-acid" if a Westco AGM cannot release corrosive or explosive acids and their fumes, hence is very safe in the trunk for both car and driver, frees up a bit of trunk space, is light, requires zero maintenance, and lasts ten years barring mistreatment.

Not only does the long life of the AGM mean the cost per year is *much* lower, also you do not have to go through the hassle (and possible inconveniences) of dealing with a bad battery every three years.

I guess to each his/her own.

Leon and Bozo, make mine an AGM

Reply to
Leon van Dommelen

Less charitably - it's sad to see what we can do with our ability to rationalize.

Reply to
Frank Berger

Give me a break on the preaching, guys.

I explained my reasoning for not wanting to wait a week for a Westco battery. I posted my experience back to the group, after thanking everyone for input, because I suspect there are many others out there who, faced with a car that will not run, would prefer to fix the problem immediately rather than wait a week to mail order a part. Further, while I acknowledged that AGM batteries are technically superior to lead-acid, a high-quality lead-acid battery, properly vented as this one is, is quite serviceable on this car. And as you know, there are certain situations where an AGM unit can be prematurely killed. Yes, I understand the issues and how to avoid it, but what if my wife has the car, accidentally leaves the lights on, kills the battery, and calls AAA for a jump? Perhaps you feel I should educate her on the unique characteristics of AGM units. For the same price as the Westco, I have a battery with an

8-year warranty and I was back on the road the same day. It's doubtful that I will still own the same car in 8 years, or even 3, which is the full-replacement warantee period. I read all the posts on Miata.net and nobody ever mentioned the Autozone battery, so I thought I would share the information.

If my battery ever starts to gradually fade away and I have enough time to order a WestCo, I will certainly consider it.

dm

"Frank Berger" wrote in news: snipped-for-privacy@news.teranews.com:

Reply to
Dave Molta

Huh? No. ;)

Actually, the car can be jumped normally as long as the battery is not completely rock-bottom flat. See the FAQ at miata.net.

In the unlikely case it is really completely gone, the FAQ lists all sorts of weird stuff that I forgot. However, I would think you could take the terminals off the battery to jump it.

I do not know how much current the alternator gives off; if it is not too much, you could put the leads back on after the other battery has been disconnected. Otherwise, maybe you could drive it home with the battery leads detached. Anybody?

No, I feel that you should install a light buzzer so that you save your wife from the self-reproach, hassle, time loss, and expense of this happening. A loving husband should do no less.

Good, but people have put in wet cell since times immemorial. Nowadays, that is what you get from the Mazda dealer.

I would like you to jump to it.

Leon

Reply to
Leon van Dommelen

Never, ever disconnect the battery while the engine is running. On any car with an alternator. It is good practice to charge a completely discharged battery using a charger set to 2 amps. After 1/2 hour use jumper cables to start.

Chas Hurst

Reply to
Chas Hurst

----- Original Message ----- From: "Frank Berger" Newsgroups: rec.autos.makers.mazda.miata Sent: 07 July, 2004 11:25 AM Subject: Re: Dead Battery

I bought my 1990 Miata more than six years ago, and I have never had occasion to buy a new battery since then. It still works fine. The battery is a Mazda one, and I find it remarkable that it should last in this way. Perhaps it has something to do with the battery being in the trunk, and away from the heat of the engine.

Reply to
Kenneth S.

What is the problem?

I was thinking for something to use in the field.

Leon

Reply to
Leon van Dommelen

The problem is the alternator will self-destruct.

Well neccessity can be a mother. From what I have read on Miata.net, jump starting a dead OEM Miata battery can damge it. From my own experience, jump starting a dead battery can damage the alternator because when the jumpers are removed the battery is effectively absent-same as disconnecting the battery while the engine is running.

Chas Hurst

Reply to
Chas Hurst
[and then, after some bashing]

Don't worry about it, Dave. You bought the same battery WestCo sells, just with a different label and a better warranty. Both are apparently OEMed from East Penn / Deka.

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Reply to
David Higgins

It seems clear upon thought that the alternator must be giving out tens of ohms or we would be in trouble. So leave it off.

Leon

Reply to
Leon van Dommelen

Those of us with true foresight keep a couple of spare kilohms in the glovebox. In the face of today's many temptations, one wouldn't want one's resistance to falter.

Back when cars had carburetors with chokes, I always kept a few extra henrys around as well. Very handy in cold weather.

However, it is a myth that storing a farad or two in the Miata's trunk will increase its capacity.

Reply to
Lanny Chambers

That should of course have been "tens of Ahs".

Leon

Reply to
Leon van Dommelen

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