3 Battery Generating System

[Majestic81]

Geoffrey,
Looks very interesting and should be more interested in this it would seem.

Just drinking some hot coffee while reading your website. Many thoughts and questions indeed. Thanks for posting here.

I want to get restarted here but stopped to evaluate which way to proceed. I stopped building this pass summer on the upright generator. Want to learn more about battery switching technology and the benefits.

Anyhow time to refresh the coffee and get breakfast on the stove,
wantomake

I've received the switching board and have a design for setting up the relay's in the 3 bgs configuration.

The unboxing
https://www.youtube.com/watch?v=8oyQt3uMv9k

[wantomake]

Looks interesting

I've received the switching board and have a design for setting up the relay's in the 3 bgs configuration.

The unboxing
https://www.youtube.com/watch?v=8oyQt3uMv9k

Congratulations,
It's a good thing to get new tech in the mail. Can't wait to see your build and the switching by the relay board.

So you will be using the 3BGS configuration? Hope all testing goes well, keep us informed if possible.

wantomake
Coffee needs nuked.

[Turion]

Single battery circuit

Has ANYONE built the single battery circuit we posted and compared run times to just running the motor straight off the battery?

[voltan]

Hi Dave. I’d be keen to have a go at that. It’s multiple battery banks that make Tesla switch/3bgs systems impractical for electric cars, bikes, planes etc.
Can you post the page number or date or if it was fairly recent I’m happy to look for it. I was thinking about using caps with a brushless ac motor like in the pic recently. Switches 1 and 2 close, the motor coil is energised for one stroke, then 1and 2 open. 3 and 4 close, energising the motor coil for one stroke with the current reversed. 3 stays closed, 4 opens and 1 closes with a brief overlap to recharge the source battery. 3 opens, 1 stays closed, 2 closes and repeat. The diodes are the built in to most semiconductors ones or maybe add speedy diodes like fr302’s across the switches. They direct the switch off spikes to one cap at at a time provided the right switch opens first. maybe a booster could play a part as well. I haven’t checked it all over yet For flaws or conflicts. It’s a concept in its infancy. Okay, for a start it looks like the diodes on 1 and 3 would have to be blocked with additional diodes or some other way. And without a booster this still needs 24v to drive a12v motor, so no bulk weight saving over a 2bgs. For a mobile application a booster or 2 would be the big weight saver.
Cheers.

[bistander]

Single battery system

If you have the stuff, give this a shot. It's as CHEAP as you will get.

Post #3883, 7/13/2018

[bistander]

Single battery system

Has ANYONE built the single battery circuit we posted and compared run times to just running the motor straight off the battery?

I did. Posted data.

bi

[Turion]

Data

So bi,
What is your honest evaluation of the potential of that circuit from the data you collected and do you see a way to move forward to get more out of it or scale it up?

What we see on the bench, good or bad, should influence the direction we take, so I am curious what direction you would go with this, based on what YOU have seen, not what I have seen.

What, if anything was positive about it and what was negative?

[voltan]

Cheers Dave. Page 130.

[bistander]

Test results

So bi,
What is your honest evaluation of the potential of that circuit from the data you collected and do you see a way to move forward to get more out of it or scale it up?

What we see on the bench, good or bad, should influence the direction we take, so I am curious what direction you would go with this, based on what YOU have seen, not what I have seen.

What, if anything was positive about it and what was negative?

Turion,

I was attempting to be objective and completely unbiased so I just presented the data. With that it is easy for anyone to calculate system efficiency and draw their own conclusions, or suggest further investigation, which I would have, could still do, although the set-up has been torn down. At the time I did inquire of you what your results were, what the objective of the system was and what to do further. But you know how that discussion went.

I still feel it is in the best interest if I keep my opinions to myself and let the data stand. What do you think of my results (system efficiency)?

bi

[Turion]

Thoughts

Your data

Boost module 1
Input 12.11V, 5.27A, 63.8W
Output 27.67V, 1.99A, 55.06W, 86.3% efficient.

Boost Module 2
Input 12.4V, 1.28A, 15.7W
Output 14.13V, 1.01A, 14.27W, 90.9% efficient.

bi

Just looking at the data that you collected doesn't tell you anything about what is possible, or even exactly what is GOING ON with this system. That's why I asked for your opinion. All you really did was measure what is coming out of the two boost modules. As to the data, I think it's probably pretty close to what I would expect. I am usually getting close to 93% with my boost modules. I have some expensive ones that push that number up several % points, but that isn't important. With the little ones I put a couple in parallel so I get a LITTLE bit better efficiency, but like I said, that's not critical.

The only way to tell if you really HAVE something with this system is to run your modified motor connected to a load directly off the battery until it is run down, and then charge the battery back up and run it on this system. See which one lasts longer.

When I run this setup, I have a second motor shaft connected to the first, rectify the output of the second motor (as a generator) and measure watts out to a load. That's how I calculate which system gives me MORE output from the run time of a single battery.

All this simple circuit was designed to do was prove, with A SINGLE BATTERY that the energy does not HAVE to be consumed by the load. It CAN be reused. Now this little system is just proof of concept.

You will notice that boost module 1 is running in a conventional manner, which WASTES energy, but it is necessary for the purposes of this demonstration. Normally, I would NEVER run anything this way as it is so wasteful. I will also say that if you do not use the modified motor, the setup will NOT work, because the modified motor pulses the battery like a battery charger does. There is a pulsed input going into the second boost module, so there is a pulsed output coming out of it, even though the boost module itself pulses, it is at the wrong frequency, so the correct motor is necessary.

That's all this system was designed to do, give you a longer run time. Other systems are designed to do much more than that, but ya gotta start somewhere.

[bistander]

Your data


Just looking at the data that you collected doesn't tell you anything about what is possible, or even exactly what is GOING ON with this system. That's why I asked for your opinion. All you really did was measure what is coming out of the two boost modules. ...

You just looked at the converter efficiency test I did to show Matt. Go a bit further and see two system tests. Both using battery power as input and load resistor power as output.

Here are data from most recent test.

Wattmeter on battery:
12.05V, 3.4A, 40.97W, 9.09Ah, 111.21Wh

Wattmeter on 50Ω load resistor:
18.31V, 0.33A, 6.1W, 0.885Ah, 15.3Wh



Regards,

bi

I ran that system for 3 hours. That took 333 watt hours from the battery. If I would have run a 6.1 watt load directly from the battery, it would have run for 54.6 hours.

And with a converter between the battery and motor, those pulses are blocked.

What's your opinion of the real data?

bi

[bistander]

Single battery circuit results

Has ANYONE built the single battery circuit we posted and compared run times to just running the motor straight off the battery?

With system = 3 hours.

Straight from battery = 54.6 hours.

Just one test on one system. Not to be considered conclusive. Disappointed not to see anybody else running this test.

bi

[hherby]

I ran that system for 3 hours. That took 333 watt hours from the battery. If I would have run a 6.1 watt load directly from the battery, it would have run for 54.6 hours.

And with a converter between the battery and motor, those pulses are blocked.

What's your opinion of the real data?

bi

Hi Bi,
Just wondering if you remember the pre-test resting voltage of the battery and the resting voltage of the battery after the test?

Matt mentioned in a post somewhere that the pulses from the motor are being captured by the output capacitors of the boost converter thereby decreasing the load on the battery a certain amount.

My thoughts on your data.
First, thanks for sharing.
There will be a certain amount of overhead to run the motor-generator.
The 50 ohm load was not letting enough current through to help overcome the overhead. The system was not in balance. Example, a load with a resistance of 3.72 ohm would allow 4.88 amps to flow to the battery which would balance with the output to boost 1 (assuming the motor-generator does not draw more current under an increased load). At that point the voltage on the battery will remain constant as the system would be in balance. For a little more clarity, lets move the connection of the second boost converter negative from the battery negative pole to the negative input to boost converter 1. Now place an amp meter between the battery negative and boost converter 1 (and now 2) negative. When the system is in balance, you will be running the load for free (in conventional terms) and the reading on that amp meter between the battery negative and the boost converter negative should read zero.

From my tests that Dave mentioned in post #4265, the meters are not showing the whole picture. There is less load on the battery than what appears to be drawn by the boost converter when running the load between two positive potentials. When I ran my tests the battery resting voltage returned to the pre-test voltage level or higher.

In this one battery circuit, the output of the boost converter goes to the positive of the motor and the negative of the motor goes back to the battery positive. The motor is running between two positive potentials. It is not going back to the battery negative so it will not be contributing to destroying the dipole of the battery. So what is happening with the power that was run through the motor and back to the battery positive? Since it is not connected to ground, it is a separate dc loop is it not?

How do we measure exactly what is going into/coming out of the battery when we are running between positive potentials? I'm not sure which is why I am asking. I suspect when running the load between two positive potentials in this setup, the energy used by the boost converter is to simply create a higher potential than the battery.
Thoughts anyone?


Cheers,
Alex

[bistander]

Analysis

Hi hherby,

Thanks for chiming in. No, I don't have those battery resting (no-load or open circuit, I assume you mean) voltage readings.

Member dragon had a good take on it here:

To me it looks like the battery is supplying 12.2 volts at 4.47 amps to the boost, 54.53 watts. The motor sees 20.6 volts at 2.18 amps or 44.9 watts. Around 83% efficiency. The 6.78 amp reading is deceptive because that is the combined current in that loop ( 4.47 + 2.18 = 6.65 amps ).

The output of the generator is 11.7 watts and the output of the 2nd boost is 10.57 watts, there we see around 90% efficiency. The battery is clamping the voltage at 12.2 with a .36 amp return or around 4.4 watts going back to the battery and 6.58 watts being dissipated by the load or 10.98 watts total.

He was using test 3 data, IIRC.

If you compare tests 3 and 4, you see input power of 54 and 41 watts for essentially the same output power to load resistor. Obviously everything was warmer when I took data readings in test 4 after running for three hours.

I recall attempting larger load (more output power) but input power increased substantially and some of the components were overloading or becoming unstable.

Regards,

bi

[bistander]

Battery measurements

...
How do we measure exactly what is going into/coming out of the battery when we are running between positive potentials?
...

Cheers,
Alex

Simple. Put the wattmeter directly on the battery terminals and all other connections on the other side of the wattmeter. You can verify that with a scope also probed on battery terminals.