Reverse Polarity Battery

[Moo.]

Have a rather weird situation. Bike has been sat unused for a couple months in a shed. Over this time the battery has discharged and reversed polarity, I hooked it up to a charger, but it won't accept charge, but reversing the poles it will. Multimeter shows up a minus charge too.

Thought it was the battery, so replaced with a spare I had and all was fine. Left the bike a few more months (at uni) and again, the same has happened, battery has discharged and has reversed its polarity. What is causing this to happen? Don't want to buy a new battery for it to turn again

Can any electrickery wizards help?
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A2 Passed 18/6/10

[RhynoCZ]

Well, do not leave a battery sit for that long without charging?

Are you sure the polarity is reversed? I have never heard of this before and my mate says it's impossible.
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'87 Honda XBR 500, '96 Kawasaki ZX7R P1, '90 Honda CB-1, '88 Kawasaki GPz550, MZ 150 ETZ
'95 Mercedes-Benz w202 C200 CGI, '98 Mercedes-Benz w210 E200 Kompressor

[Nobby the Bastard]

Lead acid?

I'm pretty sure that you can't turn lead oxide to pure lead just by leaving it alone. If anything it will react with more oxygen.

Suggesting that the battery has swapped polarity is akin to stating that you have a car that runs on tapwater....
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trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[Moo.]

Ones a Yuasa sealed battery, the other is a Motobatt sealed battery. Neither will charge on a trickle charger or a car battery charger but both will charge on opposite poles
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A2 Passed 18/6/10

[Just_James]

It's not difficult to reverse polarity of a battery but it won't have done it on its own - it technically can happen but only in extremely rare circumstances and even then it would only be a very small charge.

In the real world, it happens when a completely discharged battery is then hooked up to a charge incorrectly (wrong way round).

If you accidentally got your leads on the wrong way round when you tried to charge it from flat then it will reverse polarity and battery is goosed. If you're certain you didn't accidentally get the leads wrong, maybe your charger is faulty.
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Current Bikes / Projects: 1999 Rieju RS1 50
Previous bikes - 1986 DT125R (field bike), 1989 KX250, 1980 KX420 (with 500cc big bore), 1992 YZ250, 1988 KX500, 1989 XR250R, 1988 VFR400R NC24, 1999 Cagiva Mito 125, 2008 Rieju RS2 50 , 1993 Honda NSR 125

[Aff]

The only way this can happen is if you completely discharge the battery, then charge it up reversed.

It doesn't just happen by itself.
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Current Bikes:Honda 929RR Fireblade, Honda CD200 Benly (Project), Stomp Z2 140
Electric Bike Project

[Moo.]

Yeah, couldn't see how it would happen without a charge going in to reverse it. I'll borrow another charger and just leave it on charge overnight and see if it holds it. Don't these sealed units get dodgy when discharged? I wonder if it just goosed because it got too low (which means something is discharging it?)
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A2 Passed 18/6/10

[Rogerborg]

Your bike has fully discharged the battery and then somehow pulled energy from the æther in order to build up a negative potential.

Congratulations, you have created an infinite energy machine. You should patent it immediately, then prepare yourself for Nobel prizes, untold riches and all the hot bitches you can eat.
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Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike

[kramdra]

Do not leave a dodgy battery on charge over night unsupervised

What charger are you using? Are you certain you are connecting it correctly?

What happens during charge? Does it instantly hit cut off voltage? is the cut off too high? Does the charger not cut off?


I recommend RC hobby chargers (Imax B8), automotive ones are shite. Ive rescued several old Pb's that were left flat for 6 months, now work like new, good load test.

[Moo.]

[kramdra]

Halfords car chargers do not have a cut off or regulation, or even a display to show the current rate or state of charge. Your essentially connecting battery to a unregulated transformer with a couple of diodes to make it DC.

The voltage is too high, as the battery can not charge at a suitable rate to load the transformer. It will not hold a charge.

So instead of buying the second battery, you should have got a suitable charger. Optimates are also shit.

[Polarbear]

[jjdugen]

Agreed, you can only have a reverse charged battery if it has actually been reversed charged.
If it is in reasonable condition (yours might not be), discharge the battery fully with something like a headlight bulb wired across the terminals. Once fully flattened, get a fully charged battery and hook it up for a few seconds, (Pos to Pos, Neg to Neg!). That usually gets the plates cleaned up enough to start accepting a charge. Ghetto, I know but this has worked on many supposedly dead batteries I have regenerated. They seem to last pretty well too.
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The CBR900RR has been sold. Aprilia Falco worms its way into my heart.
Try Soi 23 on Amazon for a good read.... Self promotion? Moi?

[stinkwheel]

[andyscooter]

don't use a car charger

it run at too high an ampage to charge a bike battery safely

if the battery is that flat it needs replacing

and instead of keep letting it go flat remove it from the bike and keep somewere warm
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gilera runner vxr200 (chavped)
if its spelt wrong its my fat fingers and daft auto correct on my tablet

[monkeybiker]

Are you sure someone has not sneeked in an turned your battery 180 degrees when you were not looking

[stinkwheel]

[Rogerborg]

Probably doesn't go without saying that if it's a wet cell, don't do anything until you've checked and topped up the level of electrolyte in the cells with distilled water.
____________________
Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike

[Islander]

[Islander]

[Nobby the Bastard]

[Islander]

[FriendlyEllis]