A Battery Rejuvenator

[Egon]

Experiment is fine but on a battery I'm gona use I'll pass.

It would be my luck to have this rejuvenated battery fail at some remote spot and getting everything back to normal would cost much more than the savings achieved by the extended battery life!:thumbsup:

 

[Matt_Jr]

Thanks a lot Egon. That's what's gonna happen to me now.

 

[dcyrilc]

Thanks a lot Egon. That's what's gonna happen to me now.

When it does, just remind yourself that it would have broke down last time you were in a remote location and it saved you the agrivation and expense until now.

 

[patrick_g]

I was a Navy aviation electronics technician for about 12 years, and I did many experiments.

What model of Wright Flyer did the Navy have when you were in?

I was USAF and I think I remember Wilbur and Orville coming to our base to try to sell us airplanes.[/QUOTE

The internal resistance of a battery is quite low (otherwise it would have a difficult time sourcing 100-200 amps or more.)

When a battery is charging the current flow into the battery is reduced by the battery voltage, i.e. if you apply 20 volts through a 10 ohm resister, don't expect anywhere near 2 amps because the battery will subtract its voltage (10-13 or thereabouts depending on state of charge) Say the battery was down to 10 volts, then in the example above you'd be giving it about 1 amp. Don't call the electricity police as Ohm's law is not being violated. You have to use a little 'rithmetic (Algebra?) to account for the "backwards" voltage of the battery which subtracts from the "frontwards" voltage of your charger machine thingy.

Need proof? Put three flashlight batts in series but with one of them backwards to the other two. (They are about 1.5 volts each. Measure the voltage across the combination and you'll see it is equal to about one batt, i.e. 2-1=1 and there is no Magic Conveyor Belt involved.

Pat

 

[Redbug]

I have had this page bookmarked, but have never tried it. Then I ran across this thread.
Lead_Acid_Car_Battery_Repair

The magnesium sulfate helps dissolve the sulfation. Think it works?
What say you?

 

[J_J]

I was a Navy aviation electronics technician for about 12 years, and I did many experiments.

What model of Wright Flyer did the Navy have when you were in?

I was USAF and I think I remember Wilbur and Orville coming to our base to try to sell us airplanes.[/QUOTE

The internal resistance of a battery is quite low (otherwise it would have a difficult time sourcing 100-200 amps or more.)

When a battery is charging the current flow into the battery is reduced by the battery voltage, i.e. if you apply 20 volts through a 10 ohm resister, don't expect anywhere near 2 amps because the battery will subtract its voltage (10-13 or thereabouts depending on state of charge) Say the battery was down to 10 volts, then in the example above you'd be giving it about 1 amp. Don't call the electricity police as Ohm's law is not being violated. You have to use a little 'rithmetic (Algebra?) to account for the "backwards" voltage of the battery which subtracts from the "frontwards" voltage of your charger machine thingy.

Need proof? Put three flashlight batts in series but with one of them backwards to the other two. (They are about 1.5 volts each. Measure the voltage across the combination and you'll see it is equal to about one batt, i.e. 2-1=1 and there is no Magic Conveyor Belt involved.

Pat

No, I am not that old, but I did stay at the Holiday INN, and I did fly in P2V, and P3C aircraft for about 22 years.

Now tell me Patrick, have you ever charged a 12 volt battery with 120 v AC? This all started with a circuit to rejuvenate a 12 V lead cell batteries. Now someone said it would be dangerous if the diode shorted, so he was going to test out what would happen. So, if you know for sure what will happen, . by all means go ahead and post your theory. I think you jumped in here not fully informed. I don't discredit what you know, so just tell the true facts as you know them.

 

[Egon]

Golly, I was in an Argus!

 

[WVBill]

...and there is no Magic Conveyor Belt involved.

Pat

Pat - are you trying to revive the "will it take off" thread. :laughing:

 

[patrick_g]

Sorry, JJ, I'm not intending to rile you. Stuff doesn't always come across like we wish it did. I don't claim to be a battery expert but I have some experience and knowledge with them although most of my electronic engineering experience was with much lighter duty circuits than batteries. I did get involved with the design/modifications of a battery operated arc welder and managed to blow the caps off a 12V batt. They went 20 ft in the air and hit the overhead pretty hard. I was lucky not to take any lead shrapnel and get a sulphuric acid shower.

The rejuvenate thingy has some merit but since the circuit is not transformer isolated if anyone (child, pet, user...) touches parts of it or anything connected to it (like if the batt is in the car, plane, whatever) they could be touching 120VAC with no protection except a 15-20 amp breaker. Not a good idea. In fact, it would be Consumer Reports rated lethal, first time every time!

Decades ago when 6 transistor Japanese radios were popular and used up 9 volt "transistor" batteries too quick for my limited funds, I built a battery eliminator. I used the X sub C of a capacitor to make a series voltage drop and a full wave bridge of diodes to rectify the AC to DC and a capacitor to filter the DC. IT worked fine BUT... if any of the metal trim on the radio was connected to the ground of the radio ckt board you could touch it and get a nasty shock. In theory and practice it worked fine but it was not safe. UL would have had a heart attack.

If anyone persists with experimenting with the rejuvenate thingy to be safe they need to get a 1 to 1 transformer capable of handling an amp or two to isolate the line voltage from the test circuit. If you have difficulty finding a 1 to 1 then use two identical transformers and connect their secondaries together. The first will transform the 120 volts to xx volts and the second will transform the xx volts back up to 120. The 120 volt windings need to be able to handle the amp or two you are messing with and the secondaries must be able to handle the same power as the primaries. For instance:

IF the transformer takes 120 down to 12 then the current in the 12 volt winding is 10 times as much as in the 120 volt windings. Suitable transformers are cheap on the surplus market and not that bad new.

There, I did a good deed for the day. I offered a way to experiment without electrocuting yourself (so easily.)

With a fuse or breaker of any reasonable size there will never be 120 volts across the battery. The internal resistance of the battery is very low and will act almost like a short (with a 10-15 volt reverse voltage coming out of it.) Any reasonable size fuse will blow out first.

Dumping the electrolyte, filtering it and returning it to the battery after flushing the battery is a good thing to do if you want to go to the trouble. If I were going to "rejuvenate" my battery I would definitely want to flush it afterward since rejuvenation removes some "gunk" from the plates which in turn falls to the bottom of the battery (if you are lucky it doesn't bridge across the neg to pos of a cell and short it out--- another good reason to flush it.)

Again, I'm sorry if I inadvertently hit a nerve with anyone. This is NOT the proper forum to try to teach a class on battery maintenance. Discussing a rejuvenate thingy is a fine topic here I think. If we have any ex diesel boat submariners on board with battery experience,. they can tell you what is what. I have a friend who rebuilt batteries onboard ship when he was in the Nav but he isn''t interested in getting into the fray. He has some exploding battery stories that are truly amazing.

Pat

 

[Coyote machine]

ETpilot,
To answer a question you posed early on in the discussion of your gizmo- the date of Sept '03 is the put into service date of the battery and NOT the manufacturer's date of manufacture. The date of manufacturer is 'coded' and usually embossed on the edge of the battery case. It is decoded by the manufacturer like a vin on a car.