My battery's neg terminal post is disolving!

Re: My battery's neg terminal post is disolving!

feeds@yuku.com (kmpres) — Thu, 19 Mar 2009 07:23:29 GMT

Thank you, gentlemen, that looks like just the thing I need! I like both circuits, but the 741 battery monitor circuit is especially simple and the parts count is minimal. Thanks for the hysteresis suggestion, too. I wondered how that was going to play out as a battery's voltage tends to bounce back a bit once the load is removed. I shall be making my Digikey order forthwith for version 2 of the magic desulfator.

Re: My battery's neg terminal post is disolving!

feeds@yuku.com (NavyTrained) — Thu, 19 Mar 2009 00:24:58 GMT

Yes, and there you see the versatility made possible by knowledge of how the circuitry works!

You may tailor its characteristics to whatever you desire.

Please let us all know what your final circuit modification consists of and how well it works for you.

Both of you, that is!

Re: My battery's neg terminal post is disolving!

feeds@yuku.com (Laurentiu) — Wed, 18 Mar 2009 03:08:51 GMT

The Battery Monitor circuit can be upgraded to add a little hysteresis (a 30k-50k resistor from pin6 of the 741 to pin3). This way, when the output from 741 goes up, the input on pin3 rises a little, getting rid of the annoying flip-flop.

Re: My battery's neg terminal post is disolving!

feeds@yuku.com (emsvitil) — Wed, 18 Mar 2009 00:18:09 GMT

I used the fan-control as a start point because of the built-in feed-back.

With a straight above/below control the pulser circuit would turn off, then turn right back on because the load of the pulser was removed the battery. Then voltage would rise, turning the pulser on, which would of course lower the voltage turning the pulser off, etc.,etc........

The on again, off again might cause some really funky pulser results as it's continually cuts in and cuts out at the...

Re: My battery's neg terminal post is disolving!

feeds@yuku.com (NavyTrained) — Wed, 18 Mar 2009 00:06:27 GMT

emsvitil,

Very good link!

Figure 14 Battery Monitor is the circuit. When the battery voltage falls below a pre-determined level the 741 output (pin 6) will go LOW (LED on). When the battery voltage is above the pre-determined minimum the output will be HIGH (LED off).

To allow the Battery Monitor circuit to control the Ingraham Desulfator, disconnect the 555 Reset pin from the +12 Volt supply and connect it to the 741 output pin 6. This output pin, when...

Re: My battery's neg terminal post is disolving!

feeds@yuku.com (emsvitil) — Tue, 17 Mar 2009 00:58:21 GMT

A variation of the 'auto-fan' circuit between fig 13 and 14 should be able to handle the turn on/off:

Towards bottom of this page:

http://www.uoguelph.ca/~antoon/gadgets/741/741.html

I haven't made one yet, but threw something together on a project bread-board and had something that turned off at 12.4 once it was on (had to be above 12.6 to start)..... Lost my notes, but it was rather easy to do. I used 2 5.1 zeners in place of the thermisitor, and Q1...

Re: My battery's neg terminal post is disolving!

feeds@yuku.com (NavyTrained) — Mon, 16 Mar 2009 19:32:53 GMT

Nice work on the battery post repair!

Yes, the enhancements you desire to incorporate into your desulfator are possible.

The 'Reset' pin on the very versatile 555 allows external control, particularly with the Ingraham configuration.

The circuit you've linked to is more complicated than what you really need.

A CMOS Comparator 'programmed' to monitor battery voltage and to 'turn off' the 555 when it's too low will do the...

Re: My battery's neg terminal post is disolving!

feeds@yuku.com (kmpres) — Sun, 15 Mar 2009 01:21:16 GMT

I think I have a cure for the dissolving battery post problem I had at the top of this thread. My negative post had developed a deep scar near the bottom where the post exits the case (see picture above). A small amount of electrolyte was wicking up a crack and out this scar and corroding the negative clip to my charger. Well, chalk up another use for JB Weld! I used the Quick variety and stuffed some into the scar and some completely around the bottom of the post. Before it cured I...

Re: My battery's neg terminal post is disolving!

feeds@yuku.com (kmpres) — Sun, 15 Mar 2009 00:51:22 GMT

Hi Guys,

Well, it's been several weeks since I built my desulfator and I'm happy to report that it seems to be working well. Initially, however, I thought I had a problem where my battery would charge to steadily increasing voltage levels (now well past 14V) but it would drop gradually to about 12.6V after a few days, even with the charer left on. I found that this was caused by my charger as it apparently has no real trickle setting and gradually drops the charging...

Re: My battery's neg terminal post is disolving!

feeds@yuku.com (desulfator2) — Sat, 28 Feb 2009 20:30:11 GMT

While pulse conditioning with a trickle charger and desulfators, it is quite common to see battery voltage drop.

It can be because of one of two reasons.

1. You have overheated a cell(s)

2. The battery is beginning to recover. It has exposed cleaned plate area and the dioxide coating is being rebuilt (charged). This is common on severely sulfated batts as they are recovering.

The normal course of events with severely sulfated batts is to see an...

Re: My battery's neg terminal post is disolving!

feeds@yuku.com (kmpres) — Sat, 28 Feb 2009 07:53:51 GMT

Thank you for these comments, NavyTrained. I have reduced my corrosion problem with a judicious cleaning and an application of a bit of vaseline jelly, and the corrosion of the post seems to have been arrested, but the negative battery clip is still picking up grayish gunk deposits. I'm not a chemist but it looks like some kind of galvanic corrosion is taking place as the clip's copper coating is being eaten away. Not sure yet if the steel underneath is also being eaten away. For...

Re: My battery's neg terminal post is disolving!

feeds@yuku.com (NavyTrained) — Sat, 21 Feb 2009 00:28:12 GMT

To test for acid creep up the post through the seals, drip a solution of baking soda and water onto the post. As the baking soda solution trickles to the base of the post and the battery top, if it 'bubbles' vigorously acid is present.

This is a good way to clean the battery posts and top by the way. If the battery seals are still intact there will not be any 'bubbling' of the baking soda at all. This 'ideal' is actually quite rare as there almost always...

Re: My battery's neg terminal post is disolving!

feeds@yuku.com (kmpres) — Tue, 17 Feb 2009 07:53:42 GMT

I'd agree except that this battery has a built in handle and was never carried by its terminal posts. Carrying batteries that way is the equivalent of lifting a dog by his ears - a horrible thing to do to a battery (and a dog). The only damage the posts have gotten from me is a bit of chewing from the many battery charger clips I've used on them. I use the battery to charge lipo packs for model airplanes - I've never actually used it in a car. You can see the hole in the side...

Re: My battery's neg terminal post is disolving!

feeds@yuku.com (desulfator2) — Thu, 12 Feb 2009 01:54:50 GMT

More than likely the post seals leak because of improper or rough handling and the electrolyte is wicking up the post.

While many auto parts stores sell "Battery Straps" which grip the posts, use them at your own risk. They can cause the post seals to leak.

The best tool made for handling batteries are those that grip the sides of the battery and put no pressure on the posts.

Here is one example which is unlike the ones I use

Re: My battery's neg terminal post is disolving!

feeds@yuku.com (kmpres) — Tue, 10 Feb 2009 07:34:34 GMT

OK, I found the thread that recommended using vaseline or grease to stop the corrosion. Sounds messy but I suppose it's doable. Now can anyone tell me why this is happening? Why doesn't it happen in my car, for example?

Thanks.

My battery's neg terminal post is disolving!

feeds@yuku.com (kmpres) — Mon, 09 Feb 2009 02:38:38 GMT

Hi Guys. Thank you for letting me join this forum.

I have recently build a "Desulfator in an Altoids Tin" using Ron Ingraham's schematic and have written an instructable about it. I'm thankful that my instructable seems to be popular so far.

However, after posting it I noticed a problem that I hope you can help me with.
A peculiar black powder or corrosion has formed around my negative battery post. The post itself has a deep ragged scar in it...