Basic Electrolysis

[lamare]

A while back when Ravi had mentioned he noticed the glow, I set out to find out what it was and thought it might be cavitational sonoluminescence. I was wrong and found the glow to be a coronal discharge although, I was able to see it without any cathode layer present. I just added some resistance to the cathode which seemed to work as well as the cathode layer.

You may want to take a look here for an explanation of glowing electrolysers:
Borax or Baking Soda Rectifier and the glow.

In the early days of amateur radio, the dc plate voltage power supply for the transmitter, was often made using homemade rectifiers. From what I have read, these rectifiers would usually consist of an aluminum and lead electrode in a jar of Twenty Mule Team Borax solution. Borax is another name for sodium tetraborate. The aluminum becomes the cathode after a forming process of applying some ac current through the rectifier. Often, many jars were used in order to accomodate high voltages. It has been reported from various sources, that these rectifiers would also emit a faint glow when in operation.

While experimenting with these rectifiers, I have found them to work quite well and I have been able to observe the glow. It was also easy to make full wave rectifiers using more than one rectifier in traditional full wave rectifier circuits.

[witsend]

Hi Rose! I'm glad to see you giving a go at electrolysis. Do you have any preconceived concepts of an electrolysis cell? The first thoughts I dealt with before I had ever constructed a cell, I remembered the glass "H" shaped test devices in high school which never impressed me much. What they showed me and taught me was a test and result of electrolysis but with very small and distant electrodes in order to collect the gasses separated. The test is very biased and a poor approach for learning. What they do not allow you to explore, with the apparatus at hand, is the ability to change parameters of the experiment to find anomalies. By simply increasing the surface area of the electrodes and diminishing the space between the plates, we find a very different scenario and our results change dramatically.

HairBear. I'm just catching up here. Missed this completely. NO I never did high school science - and yes THIS IS A GREAT HELP. THANK YOU VERY MUCH. I've been 'caught up' by all kinds of events that have monopolised the attention. But hopefully Monday next week I can get something together.

THANKS again. I'll let you know what, if anything, I managed. I must admit I see so much sense in what you're all saying. I'm just hoping that I can get my old head around actual experimentation. It's the measurements, more than anything, that are worrying me. But if I can persuade a chemist on board - then maybe?

[witsend]

HairBear - Farrah - I'm trying to get my schedule of questions ready for tomorrow to see if I can motivate some interest from the chemistry dept. And there's one outstanding. Can either of you tell me the answer here?

I've been told that the anode is the positive terminal of the battery the cathode the negative. However, under alkaline batteries - in Wiki - it states "In an alkaline battery the anode (negative terminal) ..."

Alkaline battery - Wikipedia, the free encyclopedia

I don't want to go into an anlysis of current flow from which to which because there are so many conflicting ideas on it. Some say electrons flow from the negative to postive and others from the positive to the negative. And frankly I don't think current flow has anything to do with the flow of electrons. But - whatever it is - surely, theoretically, the discharge from a lead acid would represent a recharge to an alkaline battery? Why not simply put the two batteries in parallel to a load with some kind of switching circuitry to enable the lead acid to recharge the alkaline and vice versa?

I'd post that circuit again if I could find it.

Be glad of some advice here.
Kindest regards,
Rosie

FOUND IT. Not the most sophisticated number - but something like this?

[Farrah Day]

Yes, it can be a little confusing. Perhaps this will help.

Anode - Wikipedia, the free encyclopedia

One notorious point of confusion is that conventional current flows from positive to negative, while electron flow is from negative to positive. I think this came about because it was known that current of some sort flowed between points of differing potential, but as the electron was yet to be discovered they guessed which way something was flowing... and guessed wrong! So nowadays conventional current relates to the flow of positive holes, electron current to the flow of electrons.

[witsend]

Yes, it can be a little confusing. Perhaps this will help.

Anode - Wikipedia, the free encyclopedia

One notorious point of confusion is that conventional current flows from positive to negative, while electron flow is from negative to positive. I think this came about because it was known that current of some sort flowed between points of differing potential, but the electron was yet to be discovered they guessed which way something was flowing... and guessed wrong! So nowadays conventional current relates to the flow of positive holes, electron current to the flow of electrons.

Ta muchly Farrah. Still some questions there - but I know you're busy.

[Farrah Day]

Yes, sorry Rosie, my minds to focussed elsewhere to give your diagram any thought at present.

[HairBear]

The positive plate will collect Oxygen, the negative, Hydrogen. Visually, the Hydrogen bubbles are smaller so, with your plates at a good distance apart, you should be able to tell which is which. Does this answer your question?

[witsend]

The positive plate will collect Oxygen, the negative, Hydrogen. Visually, the Hydrogen bubbles are smaller so, with your plates at a good distance apart, you should be able to tell which is which. Does this answer your question?

HairBear - we're not quite on the same page. I'm trying to determine what current would flow between a lead acid and an alkaline battery?

[Farrah Day]

Rosie, to get a very clear picture of what is going on, if I were you I would start treating the batteries as chemical reactors and not simply as +ve and -ve terminals.

What I mean is, if you look and see how the electrochemical charges are working within the batteries, you will have a much better idea of how they will all relate to each other in a cct. You will also get to see why there is the cathode/anode issue.

[witsend]

Farrah - I've done this with lead acid. I get it that there is that required conservation - all good. But what is transferred if an alkaline battery is in series - somehow. But the good news is this. I've put the problem at our local university. Someone's going to try and get the answer. I have NO idea how the alkaline numbers work.

THANKS - thanks anyway. I'll post when I get an explanation. It should be interesting. Theoretically the alkaline discharge would be a recharge to the acid and the acid disharge a recharge to the alkaline. To me that's a marriage made in heaven. LOL

[Farrah Day]

Hi Rosie, my initial impression is that you're not taking battery internal resitance losses into consideration, but I might well be on a completely different page to yourself on this.

Good luck with it anyway.

[witsend]

Hi Rosie, my initial impression is that you're not taking battery internal resitance losses into consideration, but I might well be on a completely different page to yourself on this.

Good luck with it anyway.

LOL - I'm just chasing another flier Farrah. But I think the question's legit. It wasn't immediately tossed - if that's a measure of anything. It's just I'm looking to put it to bed. It's been nagging at me for that long. Can't see where the logic is out. Re battery losses - I'm not sure they're inevitable quite frankly. On our re-charge circuit number it's pretty well maintained. Any losses are circuit ineffficiencies more than anything else. But you're right. It's not going to be easy to find a lead acid rechargeable battery the same size/capacity as an alkaline. And roughly the same mass is required.

Have been following your tests with great interest. Can't wait to hear more.

Kindest, as ever
R

[Farrah Day]

Why do you need an alkaline?

Won't two lead acid batteries work? Or two rechargable alkaline or nicads?

Is there a reason for using two dissimilar batteries?

I do know that some vehicles that use two lead acid batteries in parrallel to boost the starting power can pose problems if both batteries are not in top nick. If one battery is past it's best (for example has a duff cell), the good battery will keep trying to top it up. The poor battery will keep discharging internally and the good battery will keep topping it up and so continue to drain until both batteries are dead.

[witsend]

Why do you need an alkaline?

Won't two lead acid batteries work? Or two rechargable alkaline or nicads?

Is there a reason for using two dissimilar batteries?

I do know that some vehicles that use two lead acid batteries in parrallel to boost the starting power can pose problems if both batteries are not in top nick. If one battery is past it's best (for example has a duff cell), the good battery will keep trying to top it up. The poor battery will keep discharging internally and the good battery will keep topping it up and so continue to drain until both batteries are dead.

Ok. I'm thinking that the current flow from the anode of the lead acid - {positive terminal) - would move to the anode of the alkaline - (negative terminal) as a natural path. But I realise that there are those purists who see current flow from the cathode of the lead acid (negative to the positive). In which case the argument then is that the current flow from the cathode of the lead acid (negative) would go to the cathode of the alkaline (positive). Either way it should recharge. Then reverse this. Another recharge? Either way. I see the one or the other recharging. Is that any clearer?

[HairBear]

How's this Rose? In John Bedini's diagram below, a simple switchless type way of doing it. I can't remember if a motor was needed as a load or not. With plain electrolysis, a pulse is not exactly necessary.