Matching the Coil to the Batteries resistance

[theremart]

Ok, I have found thru trial and much digging that the small batteries 12V 12 amp hour batteries I have have according to the spec sheet an internal resistance of

.014 ohms = 14 milliohms


My golf cart batteries of my Crown CR-225
Internal Resistance 4.9 mOhm

I did lots of searching but I could not find out what the unit mOhm stands for if it is megaohm or milliohm.

These figures come from when the battery is fully charged and about 80 Deg in temp F.

My question is, how do I make a coil that matches this resistance? Or... is this the target resistance as the battery will be changing from more resistance when it is discharged to less as it is fully charged....?

[theremart]

Found this article on finding the internal resistance.

Hmm maybee I could use the data from my Computer Battery tester to plug into this equation?




Re: internal resistance of battery using voltmeter


Hi Sarah,

That's an excellent question!

Measuring internal resistance is a little more complicated.

In general, the internal resistance of a battery is not a fixed value.
It varies over time as the battery loses energy and also varies depending
on the load, or how much current is drawn from the battery. Engineers
refer to this as a non-linear resistance. You might also find that if
really load down a battery, the internal resistance changes dramatically.

In order to fully characterize the internal resistance, we need to take
measurements over time and for different loads. The result is a set of
graphs, each plotting values of resistance as a function of load current.

This can be an involved process, depending on how much data you want.
We can, however, get an estimate of the internal resistance by taking
only two measurements with a voltmeter. First, we need to measure the
"open circuit" voltage of the battery. This is simply the voltage at
the battery terminals when no current is being drawn. Practically,
it's hard to measure voltage without drawing some current, but most
voltmeters have a high enough input resistance that it can be neglected.

So we first measure the open circuit voltage, Vo. Let's say it's
0.9 volts, as in your case. Now we need to load down the battery and
measure the voltage at the battery terminals again, let's call that
Vl. Let's call the load resistance Rl. Given all those values,
the equation for the internal resistance (Ri) of the battery is:

Equ 1: Ri = Rl * ((Vo/Vl) - 1)

You can derive this equation from the equation for a voltage divider:

Equ 2: Vl = Vo * Rl / (Ri + Rl)

This equation can be derived from application of Ohm law and Kirchoffs law.
You can find that information from any text on electric circuit theory.

Now we need to choose a value of Rl that gives us good numbers.
From inspection of equ 2, we can observe that if Rl equals Ri, the load
voltage will be exactly half of the open circuit voltage. This trick
is commonly used if you have a variable resistor within the range of
internal resistance. This is not always possible, so you might have to
use several fixed resistors of different values.

You will probably find that typical alkaline cells
tend to have relatively low internal resistances when they are new. It's
probably in the range of an ohm or so. You will probably need a resistor
that is not more than 10 times that value to make good measurements. If
you can find a 10 ohm resistor that's OK. Of course, you should start
with higher values to see the effects. Start with 100 Ohms and see what
you get. Then try lower values and run the calculations again. You can
enter your values into a spreadsheet and plot the results.

A word of caution: be careful when using low value resistors with good
batteries, the current draw will be high enough the heat up the resistor
(and the battery!).

I hope that answers your question.
Let me know what you find out!

[Sephiroth]

I'm not sure if we are supposed to match the coils with the internal resistance of the batteries since as you said the internal resistance is variable and the SSG circuits are supposed to lower the internal resistance of the battery over time.

Could you mean matching the impedance of the coil with the batteries?

[theremart]

RE: matching

I'm not sure if we are supposed to match the coils with the internal resistance of the batteries since as you said the internal resistance is variable and the SSG circuits are supposed to lower the internal resistance of the battery over time.

Could you mean matching the impedance of the coil with the batteries?

I did some more re-reading this morning, you are to match the coils to the c20 rate of the batteries. Not matching to the internal resistance of the battery. This makes alot more sense.

But as I think about it, the batteries themselves are a sorta variable resistor which change to lower resistance as they get more charged.

I may try some speaker cable as mentioned below.

-------------------------------------------------------------------
( From Starters Guide-Two.pdf )

http://www.google.com/url?sa=t&sourc...F75khcvrLJRCoA


NOTES ON BATTERIES AND COILS IMPEDANCE MATCHING

Ideally the impedance of each coil should match the C20 rate for the batteries.

As previously indicated, the small 7.0Ah gel cell types have a C20 rate of 0.28A. That is the maximum discharge rate allowed under the C20 rule. The coil specified on Peswiki comes under this value and thus is well suited for new users.

Obviously larger batteries with higher C20 rates will support larger coils or those with heavier gauge wire or more than one coil (for now stick with the one coil). As a quick rule of thumb, Roamer has suggested to buy 100ft of 18AWG twin speaker cable from Radio Shack and make the coil for larger batteries.


Basically, bigger wire coil implies higher RPM and more current. Multiple smaller coils imply higher RPM and less current draw per coil but more overall than just one coil (see notes below).

All this depends on your rotor, the number of magnets, etc… with regards to where the „sweet spot‟ RPM and amperage is going to be for a given coil size or number of coils running at that „sweet spot‟ RPM.

As a further example a coil or coils that draw 1 to 3 amps (as shown on a DMM), will charge a deep cycle golf cart size battery bank. This amperage draw does not even get close to the C20 rating of the battery bank, so that the rest of the charge

[brusers]

Hey theremart,

Just wondering if there was a part one to this pdf?
Or is this the revised version, 2.0?
Some good info on there, I've never seen it before.
Thanks,

Marcel

[theremart]

RE: Part 1..

Hey theremart,

Just wondering if there was a part one to this pdf?
Or is this the revised version, 2.0?
Some good info on there, I've never seen it before.
Thanks,

Marcel

The 2nd PDF originally came from the now dead Bedini group. I have been spending months figuring out all that is in this document. Still have not seen 3 batteries charged from one, but this document has been most helpful to point in the right direction.

Attached is part 1. Not as good as part 2, but some tidbits there.

[Druide]

Thanks theremart for the part 2 link

I've been looking for this kind of information for months !

Thanks again !

Michel

[theremart]

RE: information

Thanks theremart for the part 2 link

I've been looking for this kind of information for months !

Thanks again !

Michel

Me too!

In case you have not seen these links here you go...

--------------------------------------------

Overall best link has TONS of info.
Directory:Bedini SG - PESWiki

Your first SSG

My videos are not as good as others..
YouTube - More on the heart of the SSG the Transistor 9

Much better
YouTube - How to Build a Bedini Motor ... Part 1

Good how to..
Erwin's Work Shop

Another good how to..
YouTube - Bounty Hunter Energy Projects Bedini Circuit Build Step by


Great basics..
AionAlchemy™ - radiant


How to identify the wave on a scope / use a led for pulsing.
YouTube - Inductor In Trigger Circuit




Per the Standard... But you must do it exactly as they put out,

====
Here are some lists that you might consider for continued pursuit of this topic:

* http://tech.groups.yahoo.com/group/Bedini_Monopole3/- beginners, public
* http://tech.groups.yahoo.com/group/Bedini_Monopole2/- intermediate, by invitation, private
* http://tech.groups.yahoo.com/group/Bedini_Monopole/- most advanced, private
* http://tech.groups.yahoo.com/group/Bedini_sg3/- newsletter, info
* http://tech.groups.yahoo.com/group/B...ow_energizer/- advanced, members only

List of Bedini topic groups at YahooGroups:
Yahoo! Groups : Search Results

And some related websites to consider:
- http://energenx.com- - John's company website
- http://r-charge.com- - Rick Friedrich's promotion of John's commercial products

[theremart]

Wow 25 Amps

I just read more on the specs of my golf cart battery.

They recommend 25 amps to charge it. WOW I guess my 2 amps is not gonna touch it to give it the amp hours it needs.
Gonna have to retool to hit this babby.

---------
Recommended Charge Profile
Following discharge, constant current charge the CR-225 battery at 25 amperes until the battery voltage measures 2.42
volts per cell (7.26 volts open circuit voltage).
The constant voltage charge phase begins after the gassing point (2.42 VPC) is achieved. During the constant voltage
phase, the charger voltage limit is regulated to the gassing point of 2.42 volts per cell, while the input current is allowed to
gradually fall off. When the input current drops to the finish rate setting of 7 amperes, the charging phase will change
from constant voltage to a sustained 7 ampere constant current mode. The charging cycle will be terminated 3.5 to 5
hours from the gassing point, with factors such as ambient temperature, battery condition and depth of discharge affecting
the charge completion time.

[Druide]

Me too!

In case you have not seen these links here you go...

--------------------------------------------

Overall best link has TONS of info.
Directory:Bedini SG - PESWiki

Your first SSG

My videos are not as good as others..
YouTube - More on the heart of the SSG the Transistor 9

Much better
YouTube - How to Build a Bedini Motor ... Part 1

Good how to..
Erwin's Work Shop

Another good how to..
YouTube - Bounty Hunter Energy Projects Bedini Circuit Build Step by


Great basics..
AionAlchemy™ - radiant


How to identify the wave on a scope / use a led for pulsing.
YouTube - Inductor In Trigger Circuit




Per the Standard... But you must do it exactly as they put out,

====
Here are some lists that you might consider for continued pursuit of this topic:

* http://tech.groups.yahoo.com/group/Bedini_Monopole3/- beginners, public
* http://tech.groups.yahoo.com/group/Bedini_Monopole2/- intermediate, by invitation, private
* http://tech.groups.yahoo.com/group/Bedini_Monopole/- most advanced, private
* http://tech.groups.yahoo.com/group/Bedini_sg3/- newsletter, info
* http://tech.groups.yahoo.com/group/B...ow_energizer/- advanced, members only

List of Bedini topic groups at YahooGroups:
Yahoo! Groups : Search Results

And some related websites to consider:
- http://energenx.com- - John's company website
- http://r-charge.com- - Rick Friedrich's promotion of John's commercial products

Except the private yahoo groups and the Youtube videos (I can only get a dialup Internet connexion here, at the end of this country road where I live), I have seen these links.

During winter time, I usualy have more spare time and I do some volunteer work at the local community Internet center where they got high speed Internet. Next winter, I intend to take advantage of this work to download some videos so I can watch them at home.

Cheers !

Michel

[Druide]

I just read more on the specs of my golf cart battery.

They recommend 25 amps to charge it. WOW I guess my 2 amps is not gonna touch it to give it the amp hours it needs.
Gonna have to retool to hit this babby.

---------
Recommended Charge Profile
Following discharge, constant current charge the CR-225 battery at 25 amperes until the battery voltage measures 2.42
volts per cell (7.26 volts open circuit voltage).
The constant voltage charge phase begins after the gassing point (2.42 VPC) is achieved. During the constant voltage
phase, the charger voltage limit is regulated to the gassing point of 2.42 volts per cell, while the input current is allowed to
gradually fall off. When the input current drops to the finish rate setting of 7 amperes, the charging phase will change
from constant voltage to a sustained 7 ampere constant current mode. The charging cycle will be terminated 3.5 to 5
hours from the gassing point, with factors such as ambient temperature, battery condition and depth of discharge affecting
the charge completion time.

Hi theremart,

25 amps charging current for a 225 Ah battery is far beyond the C20 - C24 charging/discharging rate recommended by John Bedini and will shorten the battery life. We have to keep in mind that it's not the amps that recharge the batteries, the less current drawn, the higher radiant energy collected.

Michel

[theremart]

RE: amps.

Hi theremart,

25 amps charging current for a 225 Ah battery is far beyond the C20 - C24 charging/discharging rate recommended by John Bedini and will shorten the battery life. We have to keep in mind that it's not the amps that recharge the batteries, the less current drawn, the higher radiant energy collected.

Michel

25 amps is what the manufacture recommends for the battery using conventional charging. No, I do not plan on doing conventional charging with the batteries, but intend on superconditioning the batteries. Yes, I will not use 25 Amps to charge with a Bedini, but I think one must use the right amount of amps. I was thinking around 5-10 amps would be more in the ballpark for charging a bank of 4 golf cart batteries at the same time.

But if I was going by the numbers, 225 the c20 rate would be according to the manufacture specs, 11.25 Amps. The best I have got out of these used batteries is 5 amps for 20 hours.

Thanks for your input.