Author Topic: How to interpret battery charger output  (Read 13612 times)

Offline Lewis Downey

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Re: How to interpret battery charger output
« Reply #40 on: January 25, 2016, 03:15:02 PM »
Quote
:o :o :o :o

Perry,
Half of the time I feel the same way.
Lewis

Offline C. Perry Rapier

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Re: How to interpret battery charger output
« Reply #41 on: January 25, 2016, 03:53:48 PM »
When it comes to this kind of information, I am like the lowly bumble bee. According to 'science' it is physically impossible for the bumble bee to fly. But the bumble bee, he can't read the scientific explanation of why he can't fly, so he just flies anyway.  :-/

Offline Jeff Friend

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Re: How to interpret battery charger output
« Reply #42 on: January 27, 2016, 10:30:15 AM »
Lewis,

Some ammeters can measure only DC.  Others can measure AC and DC.  But we are only considering battery chargers, which are direct current, so we can focus on the DC ammeter, of which there are several types (look on Wikipedia).  They should all indicate the correct current, regardless of what type of load you are measuring.  Remember, measuing current is like measuring the flow of water.  Your water meter measures every gallon, regardless of whether you are watering the lawn, flushing the commode, or filling an ice cube tray.

Perry,

When I saw you in Erie, you were just a regular guy (albeit with a nice No. 4 skillet and lid).  Are you saying that you are now like a bumblebee and capable of flight?  Even though "science" says it is impossible? ;D
Hold still rabbit so I can dunk you in this bucket of lye!

Offline Lewis Downey

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Re: How to interpret battery charger output
« Reply #43 on: January 28, 2016, 02:58:58 AM »
My battery charger is down because the lead that didn't burn up a couple of weeks ago started to smoke. I'll get around to repairing it. Until then I am using a bench power supply that is limited to a maximum output of 10 amps  at 16 volts.

This power supply allows for adjustment of voltage and current. I noticed that when I changed pieces that sometimes the amps change, sometimes the volts changes, and sometimes both change. Just to make sure those changes were correctly observed, I set-up the power supply to provide maximum current (10 amps) for a #6 skillet, then swapped in a couple of other skillets without changing the settings on the power supply.  When I swapped in a larger skillet (10sk) the amperage stayed at the units max. of 10 amps but the voltage required to generate 10 amps dropped. When I swapped in a small skillet (3SK) both voltage and amperage dropped relative to the #6 skillet. When I adjusted the power supply to provide maximum amperage with the small skillet, the voltage increased relative to the #6 skillet.


Power Supply Setting Description
A
power adjusted to provide maximum amperage with #6 skillet
B
power adjusted to provide maximum amperage with #3 skillet


Skillet size Power Supply Setting Voltage Output Current Output Watts DC (volts * amps)
10SK
A
5 Volts DC 10 Amps DC 50 Watts DC
6SK
A
6 Volts DC 10 Amps DC 60 Watts DC
3SK
B
9 Volts DC 10 Amps DC 90 Watts DC
3SK
A
6.5 Volts DC 6.2 Amps DC 40.3 Watts DC


Pics below.

Offline Jeff Friend

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Re: How to interpret battery charger output
« Reply #44 on: January 28, 2016, 09:53:44 AM »
That is some interesting data.  What do you think it means?
Hold still rabbit so I can dunk you in this bucket of lye!

Offline Lewis Downey

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Re: How to interpret battery charger output
« Reply #45 on: January 28, 2016, 10:52:15 AM »
The only thing I can make of it is that as the area of the electrodes increased, the resistance went down. For the same amount of current (DC amps) it took fewer DC volts to make the circuit. Voltage = Current * Resistance if current stayed the same but voltage dropped, resistance had to drop. Maybe there is simply more ion exchange (not sure what to call that) with larger surface areas - leading to less resistance for a given amount of current.

It makes me wonder about volts vs amps in the cleaning process. Is one more important than the other in doing the work to clean cast iron?

If a theoretical power supply would regulate volts and vary amps is that preferable to regulating amps and varying volts... or does it make no difference. A related question, is there an optimal amount of either voltage or current?
« Last Edit: January 28, 2016, 11:13:36 AM by Lewisland »

Offline Lewis Downey

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Re: How to interpret battery charger output
« Reply #46 on: January 28, 2016, 12:47:56 PM »
Jeff,

I make something else of it too. If the theory that resistance is changing based on the area of the electrodes is correct, then it seems likely the battery charger is sending a relatively constant voltage. I think that because if the voltage is the same (or close to the same)  and resistance decreases as pieces get larger (as shown with the measurements from last night) the amperage must go up to satisfy Ohm's law (Voltage = Current * Resistance).


It suggests to me that the amp control on the battery charger actually varies and at least partially regulates voltage -- meaning amps would vary with resistance.  On the face of it, that models the data from my electro. It's a theory.


This broadly describes the test data shown here

Quote
Electrolyte strength: 1.19%
Battery Charger set to 10 amps
DC currentDC current
placement# platesLodge 12SK8" sq skillet
centered4300+ amps38-40 amps
centered260-70 amps35 amps
middle: about 6"122 amps21 amps
max dist.: about 12"118 amps18 amps


After taking those readings I removed half of the electrolyte and replaced it with water, cutting its strength in half.

Electrolyte strength: .6%
Battery Charger set to 10 amps
DC currentDC current
placement# platesLodge 12SK8" sq skillet
centered438 amps24 amps
centered229-30 amps20 amps
middle: about 6"116 amps12 amps
max dist.: about 12"110 amps9 amps




Offline Jeff Friend

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Re: How to interpret battery charger output
« Reply #47 on: January 30, 2016, 04:43:49 PM »
Bingo!

A transformer (like in a battery charger) needs to put out a relatively constant voltage.  The selector switch on the charger changes what windings of the transformer are used, so you actually have three output voltages from a "12 volt" charger. 

Furthermore, since the voltage is constant, varying the size of the pans and the distance from the anode, you are changing the resistance.  The current draw is directly proportional to the resistance since the voltage is constant.  That is Ohm's law.  If it was possible to adjust the output voltage from 0 to 12 volts, you'd have real control of the process.

Since we are trying to move electrons around in the iron molecule (reduce ferric iron to ferrous iron, or add an electron on a Fe+++ to make it Fe++), the supply of electrons is the key.  Flow of current equals flow of electrons. 
Hold still rabbit so I can dunk you in this bucket of lye!

Offline Lewis Downey

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Re: How to interpret battery charger output
« Reply #48 on: January 30, 2016, 07:52:53 PM »
Quote
Bingo!

Woohoo!


Quote
The current draw is directly proportional to the resistance since the voltage is constant.  That is Ohm's law.  If it was possible to adjust the output voltage from 0 to 12 volts, you'd have real control of the process.

Earlier today I was wondering if a voltage regulator on the input side of the battery charger (at the wall plug) would control the output voltage -- effectively giving full control of the process. I might give it a test; there is an almost industrial grade voltage regulator on a shelf in the darkroom. Is there a downside to the battery charger itself if the voltage in is reduced?

« Last Edit: January 30, 2016, 07:59:22 PM by Lewisland »

Offline C. Perry Rapier

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Re: How to interpret battery charger output
« Reply #49 on: January 30, 2016, 11:45:58 PM »
Quote

Perry,

When I saw you in Erie, you were just a regular guy (albeit with a nice No. 4 skillet and lid).  Are you saying that you are now like a bumblebee and capable of flight?  Even though "science" says it is impossible? ;D

Hello Jeff. Yes I remember seeing you there at the convention up in the hospitality room. No I am not going to say I fly, but I'd like to though, not say it, do it. I'd give a hundred and fifty dollars of minimum wage money if my old pal Steve Stephens was here so he could weigh in on this subject here.

This conversation kinda reminds me of this one guy on here, its been a long time ago, but he made an electro in like a big long animal watering plastic tank, said it could clean like twenty or so skillets at a time.  :o :o

Offline James Wilson

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Re: How to interpret battery charger output
« Reply #50 on: January 31, 2016, 01:23:22 AM »
Quote
Bingo!
A transformer (like in a battery charger) needs to put out a relatively constant voltage.  The selector switch on the charger changes what windings of the transformer are used, so you actually have three output voltages from a "12 volt" charger. 
Furthermore, since the voltage is constant, varying the size of the pans and the distance from the anode, you are changing the resistance.  The current draw is directly proportional to the resistance since the voltage is constant.  That is Ohm's law.  If it was possible to adjust the output voltage from 0 to 12 volts, you'd have real control of the process.
Since we are trying to move electrons around in the iron molecule (reduce ferric iron to ferrous iron, or add an electron on a Fe+++ to make it Fe++), the supply of electrons is the key.  Flow of current equals flow of electrons. 

Jeff. Could Lewis introduce a rheostat?

« Last Edit: January 31, 2016, 01:39:40 AM by james »

Offline Jeff Friend

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Re: How to interpret battery charger output
« Reply #51 on: January 31, 2016, 01:03:52 PM »
Yes, I think there is a device that you could put on the 120 volt side of the transformer.  It is called an autotransformer, and it has a knob so you can change the output voltage.  The problem is that they are not cheap.  Here is an example.

http://www.mcmelectronics.com/product/72-110?scode=GS401&utm_medium=cse&utm_source=google&utm_campaign=google&catargetid=530004080000291735&cadevice=c&gclid=CjwKEAiA_ra1BRDV-byb_aDqpQoSJAA-ofB9KMkUiC95VyAZrgY-_pSiFxiBZ6Fam8im-ncQOm_U-xoC-Cfw_wcB

I don't know how your voltage regulator works, so I can't say give it a try. But, yes, if you could put 60 volts AC into your charger, you'd get 6 volts out instead of 12.  The input would need to be AC and probably a clean sine wave, too.  Something else might wreck the transformer.  If you are familiar with variable frequency AC drives, you know what I am getting at.

So, Perry, if I read between the lines correctly I gather that you have fond memories of Steve and have been secretly missing him since he and WAGS parted ways. ;D
Hold still rabbit so I can dunk you in this bucket of lye!

Offline James Wilson

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Re: How to interpret battery charger output
« Reply #52 on: January 31, 2016, 08:43:10 PM »
Quote
Yes, I think there is a device that you could put on the 120 volt side of the transformer.  It is called an autotransformer, and it has a knob so you can change the output voltage.  The problem is that they are not cheap.  Here is an example.
http://www.mcmelectronics.com/product/72-110?scode=GS401&utm_medium=cse&utm_source=google&utm_campaign=google&catargetid=530004080000291735&cadevice=c&gclid=CjwKEAiA_ra1BRDV-byb_aDqpQoSJAA-ofB9KMkUiC95VyAZrgY-_pSiFxiBZ6Fam8im-ncQOm_U-xoC-Cfw_wcB

I don't know how your voltage regulator works, so I can't say give it a try. But, yes, if you could put 60 volts AC into your charger, you'd get 6 volts out instead of 12.  The input would need to be AC and probably a clean sine wave, too.  Something else might wreck the transformer.  If you are familiar with variable frequency AC drives, you know what I am getting at.

Now, that would be a nice bit of kit to have at hand. I was thinking more along the lines of possibly using a stove top rheostat.
My set -up is a transformer with 6 taps, through  some diodes and heatsink on through an old automotive 30-0-30 amp meter to the anode/cathode terminal block. Lately I have introduced rudimentary control of amperage.
On the 240V side of my transformer is my manual adjusted resistor. I have an in-line domestic bayonet fitting and 3 lamps of various wattage to control the final output. Its rough and ready and does the job. Refinements may occur at some point in the future...but I doubt it :)
« Last Edit: January 31, 2016, 08:45:42 PM by james »

Offline Mark Zizzi

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Re: How to interpret battery charger output
« Reply #53 on: January 31, 2016, 09:16:46 PM »
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So, Perry, if I read between the lines correctly I gather that you have fond memories of Steve and have been secretly missing him since he and WAGS parted ways.

 ;D I haven't been around long enough to know the history..but sure wish i had been...must've been pretty good,  ;)
« Last Edit: January 31, 2016, 09:17:34 PM by mark21221 »

Offline C. Perry Rapier

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Re: How to interpret battery charger output
« Reply #54 on: February 01, 2016, 02:15:30 PM »
Quote
Quote
So, Perry, if I read between the lines correctly I gather that you have fond memories of Steve and have been secretly missing him since he and WAGS parted ways.

 ;D I haven't been around long enough to know the history..but sure wish i had been...must've been pretty good,  ;)

Well, if Steve Stephens was here he would have you all wore down to the nub on this subject. And mostly any other topic on the subject of cast iron. Our departed friend Joel Schiff was very windy also. I copied one of his posts one time and counted the words. Now bare in mind this was just one of MANY MANY MANY, did I say MANY, responses? Anyway the response was over fifteen typed pages double spaced with an average of 250 words per page.  :o :o :o ;D ;D



Offline Mark Zizzi

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Re: How to interpret battery charger output
« Reply #55 on: February 01, 2016, 03:42:29 PM »
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Well, if Steve Stephens was here he would have you all wore down to the nub on this subject.

That may be, Perry..but I was referring to the history between you and Steve,  and Jeff's comment on your "fond memories and secretly missing him since he's been gone", lol.

Offline Cheryl Watson

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Re: How to interpret battery charger output
« Reply #56 on: August 07, 2016, 12:05:19 AM »
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Ok..I gotta ask. What is this KISS principle Cheryl...you been makin out with Perry?  ;D :P

KISS Principle:
Keep
It
Simple
Stupid

Just realized I never answered the question posed.
<you may see why!...  ;D>

KISS principle was taught to me by Perry and Family Members that Owned Atlanta Stove Works...... 8-) 8-)
« Last Edit: August 07, 2016, 12:07:53 AM by lillyc »