If you have a volt meter, you can always measure the battery voltage and note which terminal is positive according to the voltmeter. This way there is no question which terminal is which. This assumes the battery is good electrically.

From your other postings, which I neglected to read before posting the above, it looks like you do have a backwards battery and you have a legal case. Worst case is you can take it to small claims court, but I think a good manager will see the light when presented the evidence in a calm reasonable way.

Good Luck,

Jim Henderson

 

I know this for a fact - due to the chemical composition of the plates inside it you absolutely CANNOT drain the charge from a lead acid battery and then charge it up opposite to what it is intended to be charged. Its physically impossible!

So if the terminals read reversed, and the battery was installed correctly, you are owed damages that were caused by that batteries improper construction or labelling.

I bet it backflashes all the way to NAPA corporate headquarters!


NAPA: "Nearly Astronomically Priced Accessories"

 

Wolf, if the battery is completely dead (0.000 volts) you can indeed charge it in reverse. My uncle had this happen to him many many years ago (I think it was the late 60s or early 70s). He fried his radio, and some other things too.

 

I disagree, you can definitely charge a battery backwards. I teach Diesel mechanics to high school kids. As you can imagine I have seen a lot of screw ups. It is hard to keep your eyes on thirty students at a time. Anyway I can assure you an automotive battery can be charged wrong and reverse the polarity.

 

Sounds like you have a case there! Simple enough to prove in front of them with a volt meter that the battery is reversed. Let us know how it works out. They should replace whatever fried.

 

took battery to napa. manager hooked it up to tester and then looked at other batteries. definitly made backwards. i left store with a new battery, alternator, and ignition module all free of charge. i will also be getting re-embursed for labor. have to admit they might be crazy on pricing but at least this manager knows how to avoid trouble. hopefully all will turn out good soon and i will be able to laugh about this. thanks for the help guys because of your answers here i didnt sound like an idiot in the store and didnt get overly upset due to lack of knowledge.

 

Wow, that is one for the books! I hope you and the mechanic caught all that went wrong and get it up and running again. I wish we could have seen some pics of the battery. What brand was it?

On another note, I wonder if the Mercury gave the mechanic any warning signs that something was wrong before it permanently fried anything?? On one cold winter day years ago, I was in a hurry and accidentally put a battery in place backwards and the battery cables on the battery in reverse. Within a couple seconds my 97 f150 started honking and something told me right away that something was wrong. I immediately disconnected the battery and reconnected it properly and all it cost me was one blown main power fuse. I wonder if yer Mercury car would have done the same?

 

just a note guys, Napa has a "customer satisfacton " guarantee on anything they sell. If you feel that what you purchased is truly defective, and go to the store manager, you WILL get your part replaced/money refunded. This is good to know, however, some of the EDIT in the world will tend to abuse this priviledge. If you have a decent relationship with your parts guy, this should not be a problem. This might be part of the reason Napa parts are higher in some cases. I realize that in some cases, you can buy identical parts for much less at other stores, however, when the EDIT behind the counter cannot find something "because it's not in the computer" i find the extra money is not that big an issue
(former Napa manager)
rant off

 

Years ago the dealer I was working at had a Mazda come in that had the battery hooked up backwards. It had started turning over by itself and all the fun. The alternator and ignition actually survived ok, but every bulb on the car was blown.

A note on NAPA< while I generally have been ok with their parts and service, I have had trouble with them on a quality point with a idler arm, it had slop, and so did the following units as well. The manager thought that was normal, but the alignement shop was saying they couldn't align it and they showed me how much movement it had, but the manager argued with me. I even upgraded, and still same problem, so while they have the guarantee, it depends on the manager as to whether they stand by it. I commend the manager for doing what he can right up front to make it right, rather than waiting on the results before doing much. Those parts may not be failed now, and may not fail from this event, but they also may well be failed, but he gave the parts without knowing absolute. That's service.

 

have made the switch outs and mechanic just called to say the radio got fried also but everything else electrical wise is good. his labor charge for all was 110 that napa will have to eat and with parts might total about 500. sucks that a 50 battery turned into that much but hey coulda been worse i will have car back tonight sometime. fyi since the problem was solved so fast they just earned my business in the future except when i can get over to my buddies advanced where i get his employee discount. you should seen his face when i brought him back the brand new battery and alternator just bought yesterday.

 

I agree to disagree.

But if you can show proof of that - i would find it highly interesting.

To zero the plates usually results in cells shorting out from the deposits between plates.

From what i have personally witnessed, batteries are worthless thereafter.

I spent at least a year of my service career running both a lead acid and nicad battery shop on the USS NIMITZ. If we could bring batteries back from the dead - we did.

All based on basic physics and chemistry.

 

I would agree with you if I had not seen it. It was not just a surface charge either. After the students blew all of the fuses in my Cummins ISB trainer, we hooked up the battery with reversed polarity backwards and used it to start the engine while it was charged backwards. It was fascinating. sometimes the scwew ups are the best teaching tools. If I still had it I would send you some pictures of a voltmeter hooked to it but I thought it was a little dangerous to keep that particular battery around.

 

It should have been completely neutralised, by all the natural laws I know of....

 

I am thinking about the chemistry of what happens when a battery discharges. In a fully charged battery the pos plates contain lead peroxide and the neg plates are just lead submerged in sulfuric acid H2SO4. As the battery discharges the O2 in the pos plate combines with the H2 in the sulfuric acid to form additional water. The lead in both plates combine with O2 and sulfur S to form PbSO4 or lead sulfate. This lead sulfate coats both Pos and Neg plates while the electrolyte becomes plain water. (the reason a dead battery will freeze) If this is so, if you charge the battery backwards why would the lead peroxide not be deposited on the negative plate and reverse the polarity. I know this could develop into a huge chemistry debate that I am not prepared to get into, but I have also seen it happen. If the battery stays discharged for a long period of time the lead sulfate will harden and the chemical reaction to charge the battery will not be able to take place. This is called a sulfated battery.


All based on physics and chemestry.