Author Topic: How to interpret battery charger output (Read 13610 times)

Lewis Downey · « **Reply #20 on:** January 04, 2016, 08:59:31 PM »

Jeff,

Thanks! The DC Current readings came from the meter on the battery charger.

For the next round, I can check the current with our multi-meter. It is a BK Precision Test Bench Model 388a. The model was discontinued long ago but this one is still working just fine. It has a mechanism for reading amps. Do you think it would be an improvement over the battery charger's built-in meter? At this time it is the best option available to me.

Cheryl Watson · « **Reply #21 on:** January 04, 2016, 11:03:08 PM »

Well, the bottom line is ...
you are using sodium hydroxide as the electrolyte... which requires different handling...

Most of us use sodium carbonate which is more predictable...

I got me one of those fancy bench testers 4 years ago... and even my electrician's eyes crossed on helping me use it... so..

I adopted the KISS principle which Perry helped me learn...

;D ;D ;D

Lewis Downey · « **Reply #22 on:** January 04, 2016, 11:34:22 PM »

Cheryl,

Yes, the meter has features I have never used and do not necessarily expect to use in the future. I believe I can set it up to measure amps and touch the leads to the clamps of the battery charger if the result will be more accurate than the charger's built-in meter.

A friend recommended that specific meter about 20 years ago when I was building interconnect cables for a stereo system. That is the reason I have a soldering iron too. The meter has a continuity tester which made it possible to confirm that current flowed from one end of the interconnect to the other. Helpful I guess :-)

I have been happy using sodium hydroxide as the electrolyte. I am sure both work fine. When I switched form an low-powered DC power supply to the battery charger, I failed to figure out that the electrolyte was too concentrated for the extra power. It's pretty likely that I would have made the same mistake with any other electrolyte.

Jeff Friend · « **Reply #23 on:** January 05, 2016, 10:18:05 AM »

Lewis,

When you use the meter to measure current, the leads are in series with the anode and cathode, so the full flow of current goes through the meter. Your meter is rated for 20 A max. You won't be able to measure anything higher than that without blowing the fuse (your meter says "fused" across the jacks for the 20 A reading). It should work just fine to determine if the meter on the charger is in the ballpark.

Jeff

Mark Zizzi · « **Reply #24 on:** January 05, 2016, 11:39:23 AM »

Ok..I gotta ask. What is this KISS principle Cheryl...you been makin out with Perry? ;D :P

Jeff Friend · « **Reply #25 on:** January 05, 2016, 09:32:45 PM »

There is a lot of information in this thread, so let me summarize. Lewis suspected that too much current was flowing in his electro system. A wooden support block was charred and one of the clamp connections overheated, both of which suggest too much current.

1. Theory - The current flow depends on two primary factors: voltage and resistance. Ohm's Law says current equals voltage divided by resistance (i = V/R).

2. Experiment - The output voltage of a battery charger was checked. We found that the output current setting of a battery charger does nothing more than change the output voltage. Another test showed that charger output voltage affects the current that is flowing through a electrolytic cleaning system, but does not control it.

3. Theory - Resistance is dependent on the conductivity of the electrolyte solution, the distance between the anode and cathode, and the size of the anode and cathode. Electrolyte solution conductivity is determined by several things, including solution strength, the specific ions that are in solution, and solution temperature.

4. Experiment - Lewis ran a few trials and found that he could change the current flow by changing the geometry of his electro unit and by adjusting the concentration of NaOH in the electrolyte solution.

The bottom line is that at least 6 factors affect current flow. An understanding how these factors affect current will help you to make adjustments to get the current flow you want.

Oh, Mark, by the way . . . keep it simple, stupid.

Mark Zizzi · « **Reply #26 on:** January 06, 2016, 07:22:45 AM »

Thanks Jeff..I should've guessed that. Good rule to live by! ;)

Here's another question. What would be the best way to check the accuracy of the chargers built in meter if you take the electro tank out of the equation. Hook it to a battery and test? I suspect mine might be off ever since I had an accidental contact with the annode and cathode in my tank, but I'm not sure, given so many factors involved.

Jeff Friend · « **Reply #27 on:** January 06, 2016, 09:29:24 AM »

Mark,

I don't know what your anode/cathode configuration looks like, so it may not be possible to do this. I have one plate for the anode, and if your system is similar, give this a try. If the pan is drawing 10 amps when it is 6 inches from the anode, and you move it so it is 3 inches away, the ammeter should show roughly twice the current flow. If you have a charger with the 2A/40A switch, we found that changing the position from the lower to higher setting increases the voltage. So if you change the setting of this switch, the ammeter should indicate an increase in the current flow.

So, there you have two simple tests you can perform to see if the ammeter responds like you would expect it to. If it does not, there may be a problem.

Jeff

Mark Zizzi · « **Reply #28 on:** January 07, 2016, 09:28:23 PM »

Hi Jeff, Well my setup is a 28 gal tote lined with a square ring of SS that I made to fit around the inside. A couple of the bigger skillets I've had in there barely cleared by an inch or two.. maybe 3/4" for a long griddle I had in there once. My charger has 2 settings..12v 15A or 12v 60A. I always have run it at the 15A position and it used to read around 10 amps when I was cleaning a piece. But the last couple times it read around 5A and the bubbles seemed not quite as vigorous too. It did clean the piece, but took longer than it used to. The change seemed to coincide with the time I had the contact in the soup, but with so many variables it's hard to say if it's the ammeter or some other factor. Next time I use it, I'll try moving the piece farther away while I watch the meter. But I was really wondering how someone who doesn't even clean cast iron could test the accuracy of their chargers ammeter. That way you could rule that out and focus more on the electrolyte, distance, size of piece, etc.

Jeff Friend · « **Reply #29 on:** January 08, 2016, 10:32:52 AM »

If you really want to check the cheap-o ammeter that the chargers have, you need to use something reasonably accurate to test it with. Here is one you can get on eBay.

http://www.ebay.com/itm/New-100V-100A-DC-Digital-Voltmeter-Ammeter-LED-Amp-Volt-Meter-Current-Shunt-/291079963241?hash=item43c5b7c269:g:F9IAAOSwVFlT7b11

If anyone is interested, I will get one and try it out. The results will be published in the newsletter.

Lewis Downey · « **Reply #30 on:** January 08, 2016, 06:46:05 PM »

Jeff, Cool. I just ordered one. Thanks!

Meanwhile the next amperage test has expanded in scope. It will take a few more days to put together and compile. As long as the electro is being re-configured for amperage testing, the data might as well include more configurations and more skillets sizes. No promises but I think I can have all of the data in hand next week.

Lewis Downey · « **Reply #31 on:** January 08, 2016, 11:20:54 PM »

Quote

There is a lot of information in this thread, so let me summarize....

1. Theory - The current flow depends on two primary factors: voltage and resistance. Ohm's Law says current equals voltage divided by resistance (i = V/R).

2. Experiment - The output voltage of a battery charger was checked. We found that the output current setting of a battery charger does nothing more than change the output voltage. Another test showed that charger output voltage affects the current that is flowing through a electrolytic cleaning system, but does not control it.
...

The easily demonstrated fact that the current (amp) setting on the battery charger does not, in an absolute sense, control the amount of current that flows has been the most eye opening result for me.

I am also surprised that it is easy to tune the amount of current that flows by changing the area of the electrodes (especially the anode), the distance between the electrodes, and the concentration of the electrolyte.

For effective cleaning is there an optimal amount or range of current? Sez me, there can be too much, but if you haven't gone that far, does it matter?

Mark Zizzi · « **Reply #32 on:** January 10, 2016, 05:38:39 PM »

Quote

If you really want to check the cheap-o ammeter that the chargers have, you need to use something reasonably accurate to test it with. Here is one you can get on eBay.

http://www.ebay.com/itm/New-100V-100A-DC-Digital-Voltmeter-Ammeter-LED-Amp-Volt-Meter-Current-Shunt-/291079963241?hash=item43c5b7c269:g:F9IAAOSwVFlT7b11

If anyone is interested, I will get one and try it out. The results will be published in the newsletter.

I'm interested, Jeff, and I'm sure others are too. Looking forward to reading that. Can you tell me the procedure you will use to test the chargers ammeter? I might have a good test meter already, I just need to know the best way to test the on-board meter with no electrolysis tank involved. I inherited a bunch of tools from my late father-in-law who was an electrician, and can do a few things like testing voltage, but that's about it.

Lewis Downey · « **Reply #33 on:** January 19, 2016, 11:52:12 PM »

Mark,

After some research and an exchange with the good people at BK Precision (the makers of my 20 yr-old multi-meter) the drawing below represents my plan of attack. I sent a follow-up question with this same drawing to Elnar from BK Precision. If he indicates that I have misunderstood something, I'll let you know. (Or perhaps someone else will jump in if the drawing represents something dangerous or ineffective.)

Meanwhile here is the response from BK Precision. The second attachment is a picture of the page in the manual for my multimeter. It is the pic that Elnar refers to.

Lewis, I am attaching a picture regarding how to do current measurements taken from the manual for the 388A. You have to identify what is the positive and negative cables going to the tank. This is because you have to break that circuit and place the meter in between the power source for your tank and the tank itself. The positive cable from the power source will be connected to the positive side of the meter and the negative side of the meter to the tank. Coming out of the tank (the negative cable) will kept as it was before. The meter has to be place in series with the tank to do the measurements. (search: Series Circuit, also there are many videos online on “how to measure current”). Do not hesitate to contact me if you have more questions.

Mark Zizzi · « **Reply #34 on:** January 20, 2016, 09:44:36 AM »

Makes sense to me Lewis..and he said that was taken from the manual so it should be correct. But I was wondering how to check the accuracy of the chargers built in ammeter without the use of an electro tank. Your average homeowner doesn't have one, so I'm assuming there must be a way to do it. Could be just to substitute a car battery for the electro tank in the diagram, but I'm not sure. :-/

Jeff Friend · « **Reply #35 on:** January 21, 2016, 09:12:19 AM »

Mark,

Current is the flow of charge per unit time, which is analogous to the flow of water through a pipe (volume per unit time). The circuit must be complete so the charge will flow. Once the meter on the charger is reading X amps, you need another meter that you know is correct and then compare the two readings. A meter like Lewis has must be in the circuit with all of the current flowing through it. The meter is in "series" with the charger and the load (electro unit). The meter could be in the wire between the pan and charger, too, because the flow of current is the same through the entire circuit.

Jeff

C. Perry Rapier · « **Reply #36 on:** January 23, 2016, 01:58:47 AM »

:o :o :o :o

Mark Zizzi · « **Reply #37 on:** January 25, 2016, 09:25:48 AM »

Hi Jeff, So if I'm reading that correct, you could do the same test if the charger was hooked to a car battery?

Jeff Friend · « **Reply #38 on:** January 25, 2016, 10:08:44 AM »

Mark,

That is correct. Current is the amount of charge that is flowing through a circuit. It doesn't matter to the meter what the load is - battery, light bulb, motor, electro. As long as you have a power supply in a complete circuit, you will have current. The current that is flowing will depend on the circuit, so you might get different readings depending on whether you have a battery or your electro rig attached to your charger.

Jeff

Lewis Downey · « **Reply #39 on:** January 25, 2016, 02:44:18 PM »

Jeff,

Is it plausible that the Mark's meter (or anyone's) would be more accurate for one load, say a battery, than another - like an electro. Is it likely to be more accurate under a specific load.

Unrelated: the black lead on my battery charger started to smoke. I need to solder it to the other side of the clamp like the red lead. Meanwhile I have switched back to the 10amp bench power supply. The bench power supply has nice lab quality meters on it (needles in this case, it is an old power supply). It has two meters, one for DC amps and one for DC volts. It shows somewhat different output information than the meter on the battery charger. Smaller pieces of CI use more voltage, although amps also vary.

I might run the next round of tests with this power supply instead of the battery charger - it yields more data. On the other hand its circuits are presumably doing different things than the battery charger.

News:

Author Topic: How to interpret battery charger output (Read 13610 times)