I want to install a car battery backwards (and reverse the poles). Will it work?
 

A discussion came up on another board I am on. I told a story about my father discovering that my grandfather was running his car battery backwards. I've heard this story a few times over the past 30 years and have no reason to doubt what my father, the ex-airplane mechanic, told me. Several people are telling me that it is impossible to do so of course I want to try it. My idea is to take an old car battery, completely drain it of power, drain it of acid, flush with dist water, add acid (or rather some Alum Sulfate or something cheaper than acid from Autozone), and recharge the battery with the poles reversed (probably start with a small trickle charge). If I can get meter 12V out of it I'll hook up an old radiator fan and see if it will turn it. If I can get the fan to run I'll slap the thing in a vehicle and attempt to start it.

So, any reason why this won't work? Anything you can think of that will help/hinder the experiment?

Motors spin direction is determined via polarity.

Motor does not equal engine.

Im pretty sure the anode and cathodes are of a different material, even in a lead acid battery. So Im not sure if it would work, or it it does work it probably wont work very well.

EDIT:
Upon googling it looks like the anode and cathode plates are both lead, so maybe it would work. I say go for it, hopefully the discharging doesnt ruin it.

Since I work at an automotive battery manufacturer, I can tell you that this will work. There have been many occurrences when a battery was sent to the activation room where it was hooked up to leads incorrently and formation occurred in reverse. The battery will still perform how it should, but lifespan will be short.
I'm not going to explain it as I'm on my phone right now, but when I get home, if you're interested in knowing more, I'll type more detail from my PC.

I would only use the motor to put a load on the battery to see if it actually had enough amps to drive something. If it can't spin the fan there would be no reason to try to turn the engine over.

Fantastic! This is exactly what I wanted to hear!

Yes, teach me something about batteries when you get the time...

I should be back on here around midnight..it's 9:30 now.

My god, I expected to open this thread and find the worlds most idiotic noob, or some jackass trolling.

Interesting stuff. I would like to see more info from thirdgen if he gets a chance.

No rush (for me), gotta get ready for bed. 12 hour shift tomorrow...

Don't get disappointed yet. Plenty of time for that...

Last time I did it by accident it blew some fuses.

No one has ever completely discharged a battery, drained the acid, refilled, and charged backwards by accident.

Why would you go to the effort of this. Makes no sense.

So, you don't want to reverse the leads, you want to make a positive charge come out of the negative pole, and vise versa? I feel like the thread title is misleading.

This sums it up the best...there is no sense of doing this as all you are doing is trashing a battery.

I think Opti meant that he hooked his battery up backwards in a car and bad stuff happened.

This may have worked in an old school no fancy electronics systems like on plain old mechanical air planes where the only electronic thing is the spark plug but in our cars with fancy ecus and shit. as said reversing the polarity will pop few fuses. Hopefully nothing else.

Why does the acid have to be drained?

I just got home from the lead mine, it's beer:30 and I'm tired. I'll give you the quick version.
Cut the top off an old 12 volt car battery with a sawzall. Inside the battery you will find that there are 6 cells. Each cell contains the same exact thing, lead plates, vinyl looking paper thin material, and across the top of the lead plates there are thick lead bars. Here's what you're looking at...
Casting process:
Lead is poured though a mold to create a grid. The grid is similar to a piece of screen from a household screen door, except it's made of lead. There are 2 types of plates, positive and negative, they differ in grid design and thickness. After the grids are moulded, they get pasted.
Pasting:
The pasting process is like if you spread peanut butter onto a screen door. The paste is made from acid/ water/ and oxide. The paste is also what separates the chemical designation of polarity for a plate. After the plates are pasted they go into a curing oven where they are exposed to different cycles of humidity. After the curing process they go to Enveloping/ COS (Cast on Strap)...
Enveloping:
The enveloper machine is like a card sorting machine, kind of. It'll take a stack of negative plates and a stack of positive plates, and it'll sort them P then N the P then N, or vise versa. However, it'll wrap (in this case we'll say the positive plate) in plastic material that resembles an envelope with the end cut off. This is so when the positive plates get stacked with the negative plates, there is no metal to metal contact...thus keeping the polarities separate. The machine will stack the plates into group with a certain plate count. Let's say 15 in this case. 8 negatives and 7 enveloped positives.
COS (cast on strap)...or as my department calls it...(cast on scrap):
Once the enveloper machine stacks 6 groups (this happens in seconds). The groups enter a jig box that clamps them and aligns the lugs that are on top of each plate. Then they get dipped into a mould that lead pours into at about 800* Fahrenheit. Then all 6 groups get inserted in a battery case. At this point you will see a battery with no top on it, and if you look inside, you will see 6 groups. Each group now has 2 straps cast onto it. A strap for the negative lugs, and a strap for the positive lugs. The outer 2 groups will also have a tall post. 1 negative post, and 1 positive. After this step they then to go my department.
Assembly:
Now you have a battery with 6 cells...assembly's first step is to weld the cells together to complete the circuit. Then we heatseal a cover onto the top of the battery. After heatseal comes post burning. An operator puts a round mould on top of the cover, melts lead with a torch and fills the mould with liquid lead poured from a ladle.
From assembly, the batteries get filled with acid and sent to Forming.
Formation: This is what determines the polarity.
A formation operator connects clip jumpers to the designated battery terminal. The battery goes through a series of charges and discharges. When this step is complete after a few days, the batteries get cleaned and stickered and sent out into the world.

There are many many strict tests I left out in this process...I just wanted to give the short version. Ask me a question and I'll answer it.
a 12 volt battery has 6cells, 2 volts per cell. It's always 2 volts per cell...I don't know why. 6 volt batteries have 3 cells, 8 volt military batteries have 4 cells...you get it.
There are different group sizes, different acid gravities, different enveloping materials, etc. The plate count in a group constitutes the life span and CCA (cold cranking amps) of a battery.
Back to the main question.
Positive plates are designed to hold a positive charge and negative plates are designed to hold a negative charge. If you hook a negative cable to the positive post and a positive cable to a negative post at the start of formation, you will form (form is the term for the electrical chemical reaction that occurs inside the battery at it's first charge) the battery in reverse. If a battery is formed reverse, and you take a multimeter at the end of formation and touch the positive lead to the the positive battery terminal and the negative lead to the negative terminal, your meter should read -12.**v. BUT, if you hook it up in your car incorrectly (negative cable to the positive post and positive cable to a negative post)...Your car will fire right up. The problem is, now you have negative plates that were designed to hold a negative charge, but they're holding a positive charge...and vise verse with the positive plates. This most likely will cut the batteries life span in 1/2 and also affect CCA. Pretty much, it defeats every performance aspect that the battery was designed to provide.
Fun Facts!!!!
It takes about 15 seconds for a COS machine to take 6 groups, pour the strap onto it, and insert all 6 groups in a battery case.
It takes my assembly department only 1 8 hour shift to produce about 20,000 batteries.
Just from my department, on all 3 shifts, in ONLY my building (there are 5 automotive divisions, mine is the largest), we produce over 250,000 batteries in 1 40 hour work week. That's a million car batteries in 1 month just from 1 assembly department in 1 building.
I'd still rather be brewing beer though...

Because someone told me it couldn't be done.