Very few  if any load testers that we shade tree mechanics own are capable of being used as a constant load. I know mine can only be used for a few seconds on a fully charged battery or it will over heat. I don't know how many ohms the coil has but I suspect to properly load a 12v battery for a test one would want to draw at least 50 amps momentarily. Power = VxI....  12 x 50 = 600 watts. That is a lot of watts to dissipate in a small air coil. Possibly short duration loads will eventually draw the battery down.<br>. <br><div id="ymail_android_signature"><a id="ymail_android_signature_link" href="https://go.onelink.me/107872968?pid=InProduct&c=Global_Internal_YGrowth_AndroidEmailSig__AndroidUsers&af_wl=ym&af_sub1=Internal&af_sub2=Global_YGrowth&af_sub3=EmailSignature">Sent from AT&T Yahoo Mail on Android</a></div> <br> <blockquote style="margin: 0 0 20px 0;"> <div style="font-family:Roboto, sans-serif; color:#6D00F6;"> <div>On Wed, Feb 12, 2020 at 2:08 PM, szabelski@wildblue.net</div><div><szabelski@wildblue.net> wrote:</div> </div> <div style="padding: 10px 0 0 20px; margin: 10px 0 0 0; border-left: 1px solid #6D00F6;"> When connected in parallel, the current being put through the batteries will <br clear="none">split between the two, with most of the current going through the good <br clear="none">battery and the dead battery only getting a portion of the current. The dead <br clear="none">battery will have a higher internal resistance and will limit the current.<br clear="none"><br clear="none">When jumping a dead battery you are limited as to how much current your car <br clear="none">alternator will provide. Your alternator is only rated for so mush output <br clear="none">and your running car is using some of that. That’s why it sometimes help to <br clear="none">turn off all lights, radio, etc. on the running vehicle when jumping a <br clear="none">really dead battery. It’s also good the turn off all the lights, radio, etc <br clear="none">on the dead vehicle so that whatever your providing is going to go to the <br clear="none">battery and starter of the dead vehicle. Sometimes people will rev the <br clear="none">engine thinking that they’re getting significantly more lower out of the <br clear="none">alternator (double??). This is not the case, you are limited.<br clear="none"><br clear="none">When your vehicle is running, the alternator puts out about 14V after a <br clear="none">start, then, once the battery is charged back up, the output should drop to <br clear="none">12V for running whatever is turned on. At that point your battery is <br clear="none">basically in idle mode, unless the alternator can’t carry the total load, <br clear="none">then it tries to make up the difference.<br clear="none"><br clear="none">Carl<br clear="none"><br clear="none">Carl<br clear="none">----- Original Message -----<br clear="none">From: Thomas Martin <<a shape="rect" ymailto="mailto:tmartin@xtra.co.nz" href="mailto:tmartin@xtra.co.nz">tmartin@xtra.co.nz</a>><br clear="none">To: Antique Tractor Email Discussion Group <<a shape="rect" ymailto="mailto:at@lists.antique-tractor.com" href="mailto:at@lists.antique-tractor.com">at@lists.antique-tractor.com</a>><br clear="none">Sent: Wed, 12 Feb 2020 14:47:29 -0500 (EST)<br clear="none">Subject: Re: [AT] Batteries charged backwards.<br clear="none"><br clear="none">Stephen<br clear="none"><br clear="none">Well it appears you do not understand the difference between connecting in <br clear="none">series and parallel.<br clear="none"><br clear="none">When you jump start a vehicle, one connects in parallel, the current from <br clear="none">the jumper battery does<br clear="none"><br clear="none">not have any affect  on the the dead battery.<br clear="none"><br clear="none">Tom.<br clear="none"><br clear="none">> On 13 February 2020 at 07:52 Stephen Offiler <<a shape="rect" ymailto="mailto:soffiler@gmail.com" href="mailto:soffiler@gmail.com">soffiler@gmail.com</a>> wrote:<br clear="none">><br clear="none">>     I wouldn't purposely put 50 amps into a totally dead battery if I <br clear="none">> didn't have to, but then we have the example cited by others, the <br clear="none">> jump-start.  Who-knows how many amps will flow; limited only by the <br clear="none">> internal resistance of the batteries and the cables & connections.  I <br clear="none">> don't think many people appreciate that a jump-start is actually sort of a <br clear="none">> hail-Mary maneuver.  If you didn't need to get the car/truck/tractor <br clear="none">> started ASAP, the smart move is to charge the battery slowly and <br clear="none">> correctly.  People are going to chime in and say "I've been jump-starting <br clear="none">> my entire life and never had a problem!"  OK.  Me too.  But the issue here <br clear="none">> is that it's impossible to know how much you might have shortened the life <br clear="none">> of that battery by hitting it with that big uncontrolled amperage surge. <br clear="none">> In Cecil Bearden's case, he's not stuck in a field or a parking lot or <br clear="none">> whatever. He has the opportunity to do it right.  And that definitely does <br clear="none">> NOT include hitting it with a giant surge.<br clear="none">><br clear="none">>     SO<br clear="none">><br clear="none">><br clear="none">>     On Wed, Feb 12, 2020 at 1:08 PM Thomas Martin < <a shape="rect" ymailto="mailto:tmartin@xtra.co.nz" href="mailto:tmartin@xtra.co.nz">tmartin@xtra.co.nz</a> <br clear="none">> mailto:<a shape="rect" ymailto="mailto:tmartin@xtra.co.nz" href="mailto:tmartin@xtra.co.nz">tmartin@xtra.co.nz</a> > wrote:<br clear="none">><br clear="none">>         > ><br clear="none">> >         Surely US battery chargers have adjustable amperage?<br clear="none">> ><br clear="none">> >         I thought it was a given that you wouldn't put 50 amps into a <br clear="none">> > dead battery...<br clear="none">> ><br clear="none">> >         Tom<br clear="none">> ><br clear="none">> >             > > > On 13 February 2020 at 03:14 Stephen Offiler < <br clear="none">> > <a shape="rect" ymailto="mailto:soffiler@gmail.com" href="mailto:soffiler@gmail.com">soffiler@gmail.com</a> mailto:<a shape="rect" ymailto="mailto:soffiler@gmail.com" href="mailto:soffiler@gmail.com">soffiler@gmail.com</a> > wrote:<br clear="none">> > ><br clear="none">> > >             Hold on.  A completely dead 12V battery connected to a <br clear="none">> > > good 12V battery is going to cause very large current to flow into the <br clear="none">> > > dead one. This is not a good idea.<br clear="none">> > ><br clear="none">> > >             SO<br clear="none">> > ><br clear="none">> > ><br clear="none">> > >             On Wed, Feb 12, 2020 at 9:08 AM < <a shape="rect" ymailto="mailto:szabelski@wildblue.net" href="mailto:szabelski@wildblue.net">szabelski@wildblue.net</a> <br clear="none">> > > mailto:<a shape="rect" ymailto="mailto:szabelski@wildblue.net" href="mailto:szabelski@wildblue.net">szabelski@wildblue.net</a> > wrote:<br clear="none">> > ><br clear="none">> > >                 > > > > Cecil,<br clear="none">> > > ><br clear="none">> > > >                 I agree with completely discharging the batteries <br clear="none">> > > > and then putting the batteries in parallel one at a time with a good <br clear="none">> > > > 12V battery. The batteries will try to equalize when in parallel. <br clear="none">> > > > When you drain the battery, take the load off and let the battery <br clear="none">> > > > sit for a while, then put the load back on and drain some more.<br clear="none">> > > ><br clear="none">> > > >                 You should use a battery charger that has a trickle <br clear="none">> > > > charge feature. This puts a full charge into the battery at first, <br clear="none">> > > > then drops down to a small charge to top the battery off. You may <br clear="none">> > > > have to do this several times and should leave the charger on for at <br clear="none">> > > > least one full day. Don’t rush the job.<br clear="none">> > > ><br clear="none">> > > >                 You can also check that each cell is good by taking <br clear="none">> > > > a reading between each cell. A bad cell will indicate a lower charge <br clear="none">> > > > then the others. Do this with every recharge attempt and note if you’re <br clear="none">> > > > making any progress.<br clear="none">> > > ><br clear="none">> > > >                 Don’t know if you’ve ever gone on-line to look for <br clear="none">> > > > videos on bringing dead batteries back to life, but their are some <br clear="none">> > > > that show how to drain a battery, rinse it out, then refill and <br clear="none">> > > > recharge. They appear to work out quite well, but I can’t swear by <br clear="none">> > > > them since I’ve never done anything like this myself.<br clear="none">> > > ><br clear="none">> > > >                 Good luck!<br clear="none">> > > ><br clear="none">> > > >                 Carl<br clear="none">> > > >                 ----- Original Message -----<br clear="none">> > > >                 From: Thomas Martin < <a shape="rect" ymailto="mailto:tmartin@xtra.co.nz" href="mailto:tmartin@xtra.co.nz">tmartin@xtra.co.nz</a> <br clear="none">> > > > mailto:<a shape="rect" ymailto="mailto:tmartin@xtra.co.nz" href="mailto:tmartin@xtra.co.nz">tmartin@xtra.co.nz</a> ><br clear="none">> > > >                 To: Antique Tractor Email Discussion Group < <br clear="none">> > > > <a shape="rect" ymailto="mailto:at@lists.antique-tractor.com" href="mailto:at@lists.antique-tractor.com">at@lists.antique-tractor.com</a> mailto:<a shape="rect" ymailto="mailto:at@lists.antique-tractor.com" href="mailto:at@lists.antique-tractor.com">at@lists.antique-tractor.com</a> ><br clear="none">> > > >                 Sent: Wed, 12 Feb 2020 00:24:36 -0500 (EST)<br clear="none">> > > >                 Subject: Re: [AT] Batteries charged backwards.<br clear="none">> > > ><br clear="none">> > > >                 Hi Cecil<br clear="none">> > > >                 I  consulted a very good friend on the other-side of <br clear="none">> > > > the isle.<br clear="none">> > > >                 Tony is auto-electrician, of vast car, truck & <br clear="none">> > > > tractor experience.<br clear="none">> > > >                 He says you MUST discharge the batteries, separately <br clear="none">> > > > with a bulb.<br clear="none">> > > >                 They need to completely discharged. No measurable <br clear="none">> > > > voltage.<br clear="none">> > > >                 Then one battery at a time needs to be placed in <br clear="none">> > > > parallel with another<br clear="none">> > > >                 fully charged 12v battery, they then need to be <br clear="none">> > > > connected to a 12v<br clear="none">> > > >                 charger...<br clear="none">> > > ><br clear="none">> > > >                 Tom<br clear="none">> > > ><br clear="none">> > > >                 > On 12 February 2020 at 15:31 Cecil Bearden < <br clear="none">> > > > <a shape="rect" ymailto="mailto:crbearden@copper.net" href="mailto:crbearden@copper.net">crbearden@copper.net</a> mailto:<a shape="rect" ymailto="mailto:crbearden@copper.net" href="mailto:crbearden@copper.net">crbearden@copper.net</a> > wrote:<br clear="none">> > > >                 ><br clear="none">> > > >                 ><br clear="none">> > > >                 ><br clear="none">> > > >                 > > I had 2 group 31 batteries out of the tractor <br clear="none">> > > > that were completely<br clear="none">> > > >                 > > dead.  I hooked them up in series and connected <br clear="none">> > > > my 24Vcharger to them<br clear="none">> > > >                 > > as It was handy and I wanted to charge both. <br clear="none">> > > > After a couple of days I<br clear="none">> > > >                 > > checked them and found that I had hooked the <br clear="none">> > > > charger backwards.  I<br clear="none">> > > >                 > > hooked a couple of incandescent headlights to <br clear="none">> > > > drain the battery, but<br clear="none">> > > >                 > > after 3 days they won't light up the headlights, <br clear="none">> > > > but they still have a<br clear="none">> > > >                 > > lot of spark when shorted with cables..  A guy <br clear="none">> > > > at my battery shop said<br clear="none">> > > >                 > > I should hook up a 6volt light to them and use <br clear="none">> > > > that to run them<br clear="none">> > > >                 > > down....  At $100/ea, I need to try to save <br clear="none">> > > > these...<br clear="none">> > > >                 > > Cecil<br clear="none">> > > >                 > _______________________________________________<br clear="none">> > > >                 > AT mailing list<br clear="none">> > > >                 > <a shape="rect" ymailto="mailto:AT@lists.antique-tractor.com" href="mailto:AT@lists.antique-tractor.com">AT@lists.antique-tractor.com</a> <br clear="none">> > > > mailto:<a shape="rect" ymailto="mailto:AT@lists.antique-tractor.com" href="mailto:AT@lists.antique-tractor.com">AT@lists.antique-tractor.com</a><br clear="none">> > > >                 > <br clear="none">> > > > <a shape="rect" href="http://lists.antique-tractor.com/listinfo.cgi/at-antique-tractor.com" target="_blank">http://lists.antique-tractor.com/listinfo.cgi/at-antique-tractor.com</a><br clear="none">> > > >                 _______________________________________________<br clear="none">> > > >                 AT mailing list<br clear="none">> > > >                 <a shape="rect" ymailto="mailto:AT@lists.antique-tractor.com" href="mailto:AT@lists.antique-tractor.com">AT@lists.antique-tractor.com</a> <br clear="none">> > > > mailto:<a shape="rect" ymailto="mailto:AT@lists.antique-tractor.com" href="mailto:AT@lists.antique-tractor.com">AT@lists.antique-tractor.com</a><br clear="none">> > > > <br clear="none">> > > > <a shape="rect" href="http://lists.antique-tractor.com/listinfo.cgi/at-antique-tractor.com" target="_blank">http://lists.antique-tractor.com/listinfo.cgi/at-antique-tractor.com</a><br clear="none">> > > ><br clear="none">> > > >                 _______________________________________________<br clear="none">> > > >                 AT mailing list<br clear="none">> > > >                 <a shape="rect" ymailto="mailto:AT@lists.antique-tractor.com" href="mailto:AT@lists.antique-tractor.com">AT@lists.antique-tractor.com</a> <br clear="none">> > > > mailto:<a shape="rect" ymailto="mailto:AT@lists.antique-tractor.com" href="mailto:AT@lists.antique-tractor.com">AT@lists.antique-tractor.com</a><br clear="none">> > > > <br clear="none">> > > > <a shape="rect" href="http://lists.antique-tractor.com/listinfo.cgi/at-antique-tractor.com" target="_blank">http://lists.antique-tractor.com/listinfo.cgi/at-antique-tractor.com</a><br clear="none">> > > ><br clear="none">> > > >             > > > <br clear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