[AT] Batteries charged backwards.
deanvp at att.net
deanvp at att.net
Fri Feb 14 23:40:57 PST 2020
Cecil, let me try to explain why going to the 6v light helps discharge the battery faster. I think your statement of “…. would not discharge the battery” should really be phrased as it takes too long to discharge the battery. Lets assume that the 12V lamp and the 6 V lamp are designed to produce 60 Watts. The 12V lamp then uses 5 Amps but the 6V lamp uses 10 Amps to produce the same power. So the resistance of the 6V lamp will be half of the 12V lamp. Or looking at it another way, the resistance of the 12V lamp is 2.5 ohms and the 6V lamp is 1.25 ohms. Now lets assume the 12 V battery has been discharged to 1.25 volts and needs to be pulled down further. The 12 V lamp will only draw a ½ Amp and slowly draw less but the 6V lamp will draw 1 Amp initially and slowly get less. The 6 Volt lamp will discharge the battery twice as fast at this lower voltage which one could not do at the 12V starting voltage because it would burn out the 6V lamp. As the battery discharges a lower resistance is needed to keep the discharge rate at a reasonable rate. As the battery voltage drops the discharge rate drops with it unless the attached resistance is lower. A 12 V lamp would take much longer to fully discharge the battery. That is why the 6V lamp is used after the battery has dropped below 6V. Just plain old math. It takes a really long time to get to a true “0” V. It just takes longer with a 12V Lamp vs a 6V lamp.
Dean VP
Apache Junction, AZ
From: AT <at-bounces at lists.antique-tractor.com> On Behalf Of Cecil Bearden
Sent: Thursday, February 13, 2020 7:37 AM
To: at at lists.antique-tractor.com
Subject: Re: [AT] Batteries charged backwards.
The problem I cannot understand is why, when I connected 2 incandescent headlights in parallel to the battery it would not discharge the battery completely. My battery supplier told me to then use a 6 volt light. I have seriously thought about just hooking both in series and then using them as power for arc welding. A welding rod would discharge them quickly and completely. Welding can be done using batteries as power...
I charge my batteries outside for safety. These are sealed batteries.
Cecil
On 2/13/2020 8:28 AM, Stephen Offiler wrote:
I do not have ADD, although I am starting to wonder what personal issues you might have, Thomas. And no, the point of this exercise is not to reverse the polarity, The point is to make the best possible attempt to recover two batteries that have been accidentally reverse-charged. That involves much more than reversing the polarity. There's a right way and a lot of wrong ways to tackle each of the steps. Discharge. Repolarize. Recharge.
SO
On Thu, Feb 13, 2020 at 9:08 AM Thomas Martin <tmartin at xtra.co.nz <mailto:tmartin at xtra.co.nz> > wrote:
Do you have ADD? The point of this exercise is to reverse the polarity of a battery.
On 13 February 2020 at 23:15 Stephen Offiler <soffiler at gmail.com <mailto:soffiler at gmail.com> > wrote:
For some actual information on lead-acid charging, try this:
https://batteryuniversity.com/learn/article/charging_the_lead_acid_battery
On Thu, Feb 13, 2020 at 3:49 AM Thomas Martin < tmartin at xtra.co.nz <mailto:tmartin at xtra.co.nz> > wrote:
Hi Dean
After the dead battery is connected to the charged 12v battery in parallel, a battery charger is connected, (the charged battery
is there only to dictate the polarity), and charging can commence.
Tom
On 13 February 2020 at 20:41 deanvp at att.net <mailto:deanvp at att.net> wrote:
Tom,
Could you explain this a little further. If the current from the jumper battery does not have any effect(affect) on the dead battery how does it charge it up?
Dean VP
Apache Junction, AZ
From: AT <at-bounces at lists.antique-tractor.com <mailto:at-bounces at lists.antique-tractor.com> > On Behalf Of Thomas Martin
Sent: Wednesday, February 12, 2020 12:47 PM
To: Antique Tractor Email Discussion Group <at at lists.antique-tractor.com <mailto:at at lists.antique-tractor.com> >
Subject: Re: [AT] Batteries charged backwards.
Stephen
Well it appears you do not understand the difference between connecting in series and parallel.
When you jump start a vehicle, one connects in parallel, the current from the jumper battery does
not have any affect on the the dead battery.
Tom.
On 13 February 2020 at 07:52 Stephen Offiler <soffiler at gmail.com <mailto:soffiler at gmail.com> > wrote:
I wouldn't purposely put 50 amps into a totally dead battery if I didn't have to, but then we have the example cited by others, the jump-start. Who-knows how many amps will flow; limited only by the internal resistance of the batteries and the cables & connections. I don't think many people appreciate that a jump-start is actually sort of a hail-Mary maneuver. If you didn't need to get the car/truck/tractor started ASAP, the smart move is to charge the battery slowly and correctly. People are going to chime in and say "I've been jump-starting my entire life and never had a problem!" OK. Me too. But the issue here is that it's impossible to know how much you might have shortened the life of that battery by hitting it with that big uncontrolled amperage surge. In Cecil Bearden's case, he's not stuck in a field or a parking lot or whatever. He has the opportunity to do it right. And that definitely does NOT include hitting it with a giant surge.
SO
On Wed, Feb 12, 2020 at 1:08 PM Thomas Martin < tmartin at xtra.co.nz <mailto:tmartin at xtra.co.nz> > wrote:
Surely US battery chargers have adjustable amperage?
I thought it was a given that you wouldn't put 50 amps into a dead battery...
Tom
On 13 February 2020 at 03:14 Stephen Offiler < soffiler at gmail.com <mailto:soffiler at gmail.com> > wrote:
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 <mailto: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 <mailto:tmartin at xtra.co.nz> >
To: Antique Tractor Email Discussion Group < at at lists.antique-tractor.com <mailto: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 <mailto: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
> _______________________________________________
> AT mailing list
> AT at lists.antique-tractor.com <mailto:AT at lists.antique-tractor.com>
> http://lists.antique-tractor.com/listinfo.cgi/at-antique-tractor.com
_______________________________________________
AT mailing list
AT at lists.antique-tractor.com <mailto:AT at lists.antique-tractor.com>
http://lists.antique-tractor.com/listinfo.cgi/at-antique-tractor.com
_______________________________________________
AT mailing list
AT at lists.antique-tractor.com <mailto:AT at lists.antique-tractor.com>
http://lists.antique-tractor.com/listinfo.cgi/at-antique-tractor.com
_______________________________________________
AT mailing list
AT at lists.antique-tractor.com <mailto:AT at lists.antique-tractor.com>
http://lists.antique-tractor.com/listinfo.cgi/at-antique-tractor.com
_______________________________________________
AT mailing list
AT at lists.antique-tractor.com <mailto:AT at lists.antique-tractor.com>
http://lists.antique-tractor.com/listinfo.cgi/at-antique-tractor.com
_______________________________________________
AT mailing list
AT at lists.antique-tractor.com <mailto:AT at lists.antique-tractor.com>
http://lists.antique-tractor.com/listinfo.cgi/at-antique-tractor.com
_______________________________________________
AT mailing list
AT at lists.antique-tractor.com <mailto:AT at lists.antique-tractor.com>
http://lists.antique-tractor.com/listinfo.cgi/at-antique-tractor.com
_______________________________________________
AT mailing list
AT at lists.antique-tractor.com <mailto:AT at lists.antique-tractor.com>
http://lists.antique-tractor.com/listinfo.cgi/at-antique-tractor.com
_______________________________________________
AT mailing list
AT at lists.antique-tractor.com <mailto:AT at lists.antique-tractor.com>
http://lists.antique-tractor.com/listinfo.cgi/at-antique-tractor.com
_______________________________________________
AT mailing list
AT at lists.antique-tractor.com <mailto:AT at lists.antique-tractor.com>
http://lists.antique-tractor.com/listinfo.cgi/at-antique-tractor.com
_______________________________________________
AT mailing list
AT at lists.antique-tractor.com <mailto:AT at lists.antique-tractor.com>
http://lists.antique-tractor.com/listinfo.cgi/at-antique-tractor.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.antique-tractor.com/pipermail/at-antique-tractor.com/attachments/20200215/42318dbe/attachment.htm>
More information about the AT
mailing list