[AT] Batteries charged backwards.

[Stephen Offiler]

Hold on.  A completely dead 12V battery connected to a good 12V battery is
going to cause very large current to flow into the dead one. This is not a
good idea.

SO


On Wed, Feb 12, 2020 at 9:08 AM <szabelski at wildblue.net> wrote:

> Cecil,
>
> I agree with completely discharging the batteries and then putting the
> batteries in parallel one at a time with a good 12V battery. The batteries
> will try to equalize when in parallel.  When you drain the battery, take
> the load off and let the battery sit for a while, then put the load back on
> and drain some more.
>
> You should use a battery charger that has a trickle charge feature. This
> puts a full charge into the battery at first, then drops down to a small
> charge to top the battery off. You may have to do this several times and
> should leave the charger on for at least one full day. Don’t rush the job.
>
> You can also check that each cell is good by taking a reading between each
> cell. A bad cell will indicate a lower charge then the others. Do this with
> every recharge attempt and note if you’re making any progress.
>
> Don’t know if you’ve ever gone on-line to look for videos on bringing dead
> batteries back to life, but their are some that show how to drain a
> battery, rinse it out, then refill and recharge. They appear to work out
> quite well, but I can’t swear by them since I’ve never done anything like
> this myself.
>
> Good luck!
>
> Carl
> ----- Original Message -----
> From: Thomas Martin <tmartin at xtra.co.nz>
> To: Antique Tractor Email Discussion Group <at at lists.antique-tractor.com>
> Sent: Wed, 12 Feb 2020 00:24:36 -0500 (EST)
> Subject: Re: [AT] Batteries charged backwards.
>
> Hi Cecil
> I  consulted a very good friend on the other-side of the isle.
> Tony is auto-electrician, of vast car, truck & tractor experience.
> He says you MUST discharge the batteries, separately with a bulb.
> They need to completely discharged. No measurable voltage.
> Then one battery at a time needs to be placed in parallel with another
> fully charged 12v battery, they then need to be connected to a 12v
> charger...
>
> Tom
>
> > On 12 February 2020 at 15:31 Cecil Bearden <crbearden at copper.net> wrote:
> >
> >
> >
> > > I had 2 group 31 batteries out of the tractor that were completely
> > > dead.  I hooked them up in series and connected my 24Vcharger to them
> > > as It was handy and I wanted to charge both.  After a couple of days I
> > > checked them and found that I had hooked the charger backwards.  I
> > > hooked a couple of incandescent headlights to drain the battery, but
> > > after 3 days they won't light up the headlights, but they still have a
> > > lot of spark when shorted with cables..  A guy at my battery shop said
> > > I should hook up a 6volt light to them and use that to run them
> > > down....  At $100/ea, I need to try to save these...
> > > Cecil
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