A Battery Rejuvenator

[J_J]

ModMech, He said he is going to test out what happens if the diode is shorted, and that means applying 120 AC volts, at .83 amps to a 12v DC battery. I have never done this. Do you have any idea what will happen?

 

[ModMech]

I have never tried it but is is similar to how all the commercial desulfators work.

I suspect nothing of note will happen, I'll explain....

The amount of charge (number of electrons) a battery will accept is dependant on the internal resistance of the battery and the respective cells in it. As the voltage of a cell increases the internal resistance also increases. I liken it to filling an air tank or tire, it's easy to get the first 2/3 of the air in but that last 1/3 takes about 80% of the total energy from flat to full. Applying higher voltages will increase the battery (cell) voltage over disigned but slowly because with each additional 0.10V the internal resistance is also increased making the next 0.10V increase take even longer.

The big thing in his experiment is the critical safety factor is the "current limiting resistor" aka the light bulb. If you take that out of the circuit, I wouldn't even THINK of trying full line voltage! If anything bad happens with the bulb in place, all that is likely to happen is the filliment in the bulb will burn up.

This is why I use telephone cable to monitor battery voltages remotely. The wires are so small, if a short occurs anywhere in the circuit the wire melts opening the circuit w/o damaging the more robust insulation. Not all phone cord is well suited for this however and care must be taken in selection.

 

[slan]

OK battery gods.

I am intrigued by this for sure.

Sometime ago I screwed up and attached a 225 amp hour deep cycle battery to my 1 amp solar panel with the wrong polarity!:laughing:
For a week!

Did I just totally kill it or could I drain all the electrolyte and replace it or is it a 50lb door stop?:ashamed:

Worth asking I guess

 

[J_J]

slan,

It will probably depend on how much lead sulfate is in the battery. How long ago did you do that? You might be able to drain all the acid, and flush out the lead sulfate, and then add new acid, and top off with distilled water, and charge at a low charging rate for a while, Some batteries will recover, and some will not.

 

[ETpilot]

Thanks all for the replys. It has been interesting reading. The problem presented was that the battery will explode if the diode is bad or goes bad during charging.

I am going to test this by charging without the diode and see what happens. Today, I made a battery encasement so that if the battery explodes it will absorb the explosive shock, contain any shrapnel that may want to fly and yet allow sufficient ventilation so that battery gases do not conjest in any area. It is the hydrogen gas that is emitted during charging that is the danger. A quick spark and it could explode.

All of my batteries are good now. I have a friend looking for 2 weak and old batteries that I can use for this test. Just want to see if an explosion is possible.

I have a nice safe spot where I can conduct this test. It may be a short test if the battery does explode. If not, it will be a longer test as I see what the charging does to the battery.

I will post the results.

 

[/pine]

Any ideas how adapt the device for 6 volt batteries?

 

[alltoys]

ETPilot, are the three lights in a parallel or series circuit?

 

[ETpilot]

ETPilot, are the three lights in a parallel or series circuit?

The lights are just in parallel. Just plug them in as you would a lamp.

/pine, not sure about 6 volts. I have not tried it. I will look to see if I can find a 6 volt battery and test it.



I would like everyone to know about this exposion concern. I do not think it is material as no one has experienced it, but I want to test the theory.

I would wait until I test this theory before proceeding. I am set up for the battery test. I am just waiting for a friend to find me some batteries. Once past this test, if it does not explode, I will feel better.

 

[dcyrilc]

ETPilot, are the three lights in a parallel or series circuit?

It's a standard extension cord whip so they would be parallel. I'm sure J_J can tell us the effect one, two, or three bulbs will have on the current to the battery.

 

[J_J]

A 100 w bulb, using 120 v AV, will have a current of .83333 amps, and a resistive load 144 ohms.

Three light bulbs will develop 300 W, and use 2.5 amps.

In this circuit, a half wave rectifier is used to rectify the AS voltage to 60 v DC.

So 60 v divided by 144 ohms, is .41 amps through each leg, three legs will draw 1.23 amps, and three bulbs will develop 221 W, and the bulbs will not be as bright.

I believe this correct. If you find mistakes, please correct. It's been a while since messing with electronics circuits

If you short the diode, then you are putting 120 V AC at 2.5 amps on the battery.