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Bernd
Fireman

USA
2603 Posts

Posted - 07/10/2018 :  2:29:44 PM  Show Profile  Visit Bernd's Homepage  Reply with Quote
I'm going to experiment with wireless charging of battery operated HO scale locomotives.

I received my order for wireless charging boards from the Robot Store today. My hope is to see what can be done in this area of using battery power to run engines.

I'll post more in the next post in the next day or so. Hopefully DanT can coach me along in this project.

Bernd

A PESSIMIST sees a dark tunnel
An OPTIMIST sees light at the end of the tunnel
A REALIST sees a freight train
The LOCOMOTIVE ENGINEER sees three idiots standing on the tracks

Bernd
Fireman

USA
2603 Posts

Posted - 07/10/2018 :  7:34:30 PM  Show Profile  Visit Bernd's Homepage  Reply with Quote
In a previous forum I used to visit a discussion about wireless charging mention a vendor selling wireless charging boards. The vendor is the Robot Shop located in Swanton, Vermont. They have several other stores around the world for our over seas model friends.

I ordered a 12V 600mA Wireless Charging Module ( https://www.robotshop.com/en/12v-600ma-wireless-charging-module.html )



The transmitter is to the left and the receiver on the right. I'll need to dig through my power supplies and see if I have a 12 volt supply. Failing that I could always used a computer power supply since perhaps they'll have a ripple free DC current.

The one spec that needs to be considered is the distance from transmitting coil to receiving coil. The specs are Transmit-receive distance: 1-20mm or .039 to .787 inches. It looks like it would work for mounting the receiving coil under the fuel tank of a diesel.

I'll report back when I get it set up to see how this charger works.

Bernd

A PESSIMIST sees a dark tunnel
An OPTIMIST sees light at the end of the tunnel
A REALIST sees a freight train
The LOCOMOTIVE ENGINEER sees three idiots standing on the tracks
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DanT
New Hire

37 Posts

Posted - 07/12/2018 :  01:26:44 AM  Show Profile  Reply with Quote
Hi Bernd,

You're at a higher wattage level than I am. You might recall a few years ago I posted how I estimated power consumption for my Broadway Limited Hudson steam engine. At 10.5V, with drivers slipping on the rails, current consumption was about 150mA. So power consumption was about 1.5W (10.5V x .15A). It worked out that a 3W wireless charging arrangement would let me recharge batteries over a period of several hours, which was what The Wireless Power Consortium was initially experimenting with. Test kits were available from various manufacturers that followed the Qi Standard and were powered via USB connectivity. 5W devices became available shortly thereafter and they are higher now.

For my purposes, i.e., HO Scale, where I'm using 3.7V x 2000mAh up to 3400mAh batteries, a 3W system is adequate to demonstrate feasibility. In other words, proof of concept is my goal and not performance, not at this time anyway. I would caution you to remember we are dealing with electro-magnetic fields and therefore shielding may be an issue that needs to be addressed, another reason for me to stay at lower power levels. After testing various arrangements for over a year, a 13mm round or 13mm x 24mm rectangular coil between the rails is where I'm headed. This is much smaller than the coils shown in your photo, but obviously, and likely, suitable for larger scales.

But all that is just the tip of the iceberg. I've spent a lot of time studying not only coil geometry, but wire diameter, wire material, insulation material, number of turns, single layer or double layer, sources of supply, heat issues, shielding issues, distance issues, Qi Standard or not, transmitter and receiver operation and protocols, just to name a few.

I'll be assembling a test track for demonstration purposes and for taking a lot of data. Good luck with your experimentation, and be careful.

Dan


Edited by - DanT on 07/12/2018 01:27:21 AM
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Bernd
Fireman

USA
2603 Posts

Posted - 07/12/2018 :  3:49:07 PM  Show Profile  Visit Bernd's Homepage  Reply with Quote
The kit I ordered from the Robot Shop has no specs on wattage. Dave (d10ng)mentioned the Robot Shop on Freerails in his post on Wireless Charging and posted a link to the kit. This is all new to me. My main purpose is to set up a fixture for testing so I can understand how it all works. I do recall your post on the Hudson engine.

I did a bit of research and came across the Wireless Power Consortium and learned about the standards. What Qi is. Also learned an interesting fact about wireless and Litz wire. I've heard of skin effect and high frequencies before.

I'm using Tenergey 1.2 2/3A Ni-Mh size batteries for my first experiment. Using 10 for 12 volts. So I need a 12 volt charging system, at least for now. I'm wondering if 6 volt motors would work for this application. I do have three steamers that use 6 volt motors. They were an easy motor swap. The 12 volt motor in the steamers are the same size Pololu uses in one of their reduction drives with 6 volt motors.

I'm not looking for performance I just want to prove battery power is a viable option. I understand that I'm dealing with electro-magnetic fields similar to AM radio and understand the higher the power and frequency the more interference with home appliances. I took a mail order radio course to satisfy my curiosity of how radio works.

I see in your post in Wireless Charging your coils are much smaller. Where these purchased or home made? You mention using a 13mm X 24mm rectangular coil for a transmitter. I've seen transmitters using three coils so you don't have to be accurate with the placement of the receiver. Have you given any thought to that? Would it be feasible to make one's own Tx and Rx circuit boards and how hard would it be to design your own?

Bernd


A PESSIMIST sees a dark tunnel
An OPTIMIST sees light at the end of the tunnel
A REALIST sees a freight train
The LOCOMOTIVE ENGINEER sees three idiots standing on the tracks
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Bernd
Fireman

USA
2603 Posts

Posted - 07/12/2018 :  4:35:06 PM  Show Profile  Visit Bernd's Homepage  Reply with Quote
I did a search on building your own wireless charger. Discovered there is more to it than I thought. Didn't realize the Tx and Rx communicate with each other. I now see why there is so much circuitry on the board. Still question on making your own coils, if it's feasible or not.

Interesting link to the DYI design question I have: https://electronics.stackexchange.com/questions/290808/how-to-build-a-self-made-qi-compatible-wireless-charger

Another interesting find. https://www.adafruit.com/product/1407

This is called an inductive charging set. Same thing I got from the Robot Shop only it has a different voltage, 5 volts versus the 12 volt I have. Total confusion now. Time to see if I can let the magic smoke out of the chips.

Bernd

A PESSIMIST sees a dark tunnel
An OPTIMIST sees light at the end of the tunnel
A REALIST sees a freight train
The LOCOMOTIVE ENGINEER sees three idiots standing on the tracks

Edited by - Bernd on 07/12/2018 4:50:12 PM
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DanT
New Hire

37 Posts

Posted - 07/12/2018 :  11:53:26 PM  Show Profile  Reply with Quote
You are beginning to appreciate the complexity of this subject. I also use the 3W system since many boards have mini USB connectors allowing me to power the Tx board with USB outfitted "pocket juice" batteries or my PC if I'm near one. I can also use a standard cell phone wall charger. The coils in the photo are mainly from eBay. A prototyping kit was given to me by a company in exchange for sharing test results. I do have fine stranded and insulated bead stringing wire from a craft store and some coated transformer wire from Radio Shack to experiment with. But I think there are enough coil manufacturers out there now, so will probably not make my own coils.

I thought about the multiple coil approach but my test setup works on the basis of LED's on both the Tx and Rx lighting up together when EMF coupling is achieved with a pair of coils. Re making your own wireless charging boards, way too complex for me. The R&D has already been done by thousands of engineers over many years.

BTW, don't use steel track (Bachmann E-Z Track) to experiment with.

Dan

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tloc
Fireman

USA
2089 Posts

Posted - 07/13/2018 :  07:32:55 AM  Show Profile  Reply with Quote
Dan, Bernd

I will follow this but I think this is way over my head. I kept the batteries for Dead Rail in a dummy in the consist and would love to not have to unhook everything. I was using 11.1v 800ma LiPo’s.

The pricing seems very reasonable so when you guys figure it out I will jump in. Be assured though, I am here following and wishing you both great success.

TomO
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Bernd
Fireman

USA
2603 Posts

Posted - 07/13/2018 :  11:07:14 AM  Show Profile  Visit Bernd's Homepage  Reply with Quote
quote:
Originally posted by tloc

Dan, Bernd

I will follow this but I think this is way over my head. I kept the batteries for Dead Rail in a dummy in the consist and would love to not have to unhook everything. I was using 11.1v 800ma LiPo’s.

The pricing seems very reasonable so when you guys figure it out I will jump in. Be assured though, I am here following and wishing you both great success.

TomO



TomO,

Glad you're following along. Thanks for posting.

Dan is way ahead of me on the knowledge of BPRC and wireless charging. He's been doing it for several years now. I'm some what familiar with electronics as at one time I designed my own PCB's. I've always been fascinated with electronics, but at the pace that electronics advances I've been left in the dust so to speak.

I'm trying to prove a concept for the DYIer. I want to show what one could do if interested in a DYI project and isn't afraid of letting the magic smoke out. Dan is approaching it in a more of a commercial adventure from what I've seen.

I'll be using Ni-Mh batteries to start. Still working on the F7 A-B-A consist. At present I'm redoing the eddy current transmission. Once that's done it'll be on toward installing a Deltang receiver and doing some test running. That's the plan anyway.

Bernd

A PESSIMIST sees a dark tunnel
An OPTIMIST sees light at the end of the tunnel
A REALIST sees a freight train
The LOCOMOTIVE ENGINEER sees three idiots standing on the tracks
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Bernd
Fireman

USA
2603 Posts

Posted - 07/13/2018 :  11:22:35 AM  Show Profile  Visit Bernd's Homepage  Reply with Quote
Dan,

I've noticed through my internet searching that the wireless charging concept is geared more toward cell phone charging. Very little is written about just the circuits themselves or prove of concept of wireless charging or even for other use. Doesn't seem to be many experimenters out there writing about using this concept in other applications, like model railroading or use in other hobbies.

Also, correct me if I'm wrong, it looks like there are two different ways of wireless power transfer. The Qi for commercial use of charging batteries were the Tx and Rx communicate with each other and the plain simple inductive transfer of power, which seems to be the case with the system I purchased.

Complex subject? Yes. I also realize that making your own boards is way to complex. Although I'd like to experiment making my own coils. I'm assuming they will need to be tuned to the electronics to function properly, like tuning an antennae to a CB radio.

Bernd

A PESSIMIST sees a dark tunnel
An OPTIMIST sees light at the end of the tunnel
A REALIST sees a freight train
The LOCOMOTIVE ENGINEER sees three idiots standing on the tracks
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quartergauger48
Fireman

USA
5602 Posts

Posted - 07/13/2018 :  2:45:24 PM  Show Profile  Reply with Quote
Hey Bernd, maybe you are the gut that will invent and develop this new system for the model railroader'... interesting, keep going[:-alien]



Ted
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Bernd
Fireman

USA
2603 Posts

Posted - 07/13/2018 :  4:17:56 PM  Show Profile  Visit Bernd's Homepage  Reply with Quote
quote:
Originally posted by quartergauger48

Hey Bernd, maybe you are the gut that will invent and develop this new system for the model railroader'... interesting, keep going[:-alien]



Hi Ted,

No it won't be me. DanT has done lots more work than me. He's been at this for a approximately 6 years as far as I know from his posts in another forum. Thanks for the encouraging words.

Bernd

A PESSIMIST sees a dark tunnel
An OPTIMIST sees light at the end of the tunnel
A REALIST sees a freight train
The LOCOMOTIVE ENGINEER sees three idiots standing on the tracks
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Bernd
Fireman

USA
2603 Posts

Posted - 07/13/2018 :  4:23:39 PM  Show Profile  Visit Bernd's Homepage  Reply with Quote
Just finished up soldering on some longer wires to the wireless charging boards. Hooked up one end to a computer power supply on the 12 volt circuit. Hooked a volt meter up to receiver and turned the power on. Surprisingly the magic smoke stayed in the chips. Transfer of electricity was surprising. At about .250" distance I was getting a little above 10 volts. Now to build a jig to better position the transmitter coil and receiver coil for better control of the distance between the two coils.

More later.

Bernd

A PESSIMIST sees a dark tunnel
An OPTIMIST sees light at the end of the tunnel
A REALIST sees a freight train
The LOCOMOTIVE ENGINEER sees three idiots standing on the tracks
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DanT
New Hire

37 Posts

Posted - 07/13/2018 :  6:32:15 PM  Show Profile  Reply with Quote
Hi Bernd,

Don't get sidetracked by the cell phone craze. The same principles apply to any device that would benefit from wireless charging. You can join WPC to get all their trade secrets. Last time I checked it was $1,000 to join. I'm looking forward to something like a winter coat that's heated by batteries and recharged when you put it back on a hanger. We already have flashlights and shavers.

I think one ultimate goal of WPC is the ability to charge electric cars. You say you can already drive your Tesla Model 3 up to a Tesla charging station and plug in your car like you now fill up your car with gasoline? True, but let's say you're getting off the Thruway in Rochester, NY in January to get a bite to eat at one of the restaurant stops. By the way, it's sleeting and bitter cold, and like 5 degrees above zero. Now do you really want to plug in your car? Wouldn't it be better to simply park your EV over a designated spot on the pavement and charge your batteries via magnetic induction? Given this scenario, one can see that induction charging lends itself very well to garden railroads since everything can be waterproofed. That's the way I see the future. Sorry for getting a little off topic here.

Regarding Qi, engineers have figured a way for the Tx to acknowledge an appropriate Rx before charging begins and to stop supplying power when batteries are fully charged. The Qi system can even detect unwanted debris at the coils and stop or delay the charging process. I think we'll need this sophistication, even for model trains. And I'm sure you're right about coils wanting to be matched to Tx/Rx boards even though current flowing through any coil will have an effect on any other coil adjacent to it. It's a matter of optimization.

Dan
________________________________________________

"Understanding the problem is half the solution"

Edited by - DanT on 07/13/2018 6:36:53 PM
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Bernd
Fireman

USA
2603 Posts

Posted - 07/14/2018 :  07:50:27 AM  Show Profile  Visit Bernd's Homepage  Reply with Quote
Dan,

Cell phones seem to be the thing that pops up when doing a search on wireless charging. Perhaps because everybody has one. I understand the principles are the same, sending out a magnetic wave and then capturing it and use the power for some purpose. I do like the coat idea. I'd go along with a pair of gloves too.

A little off topic doesn't hurt once in a while. As long as it doesn't go completely off the tracks. (pun intended) I wonder if electric vehicles will ever catch on. You never know somebody may find an alternative method of propelling yourself from one place to another. Star Trek Transporter anybody? Ok, back on topic.

So Qi (pronounced "chee") is a bit more of a sophisticated system than just plain magnetic induction? I think if wireless charging can be made to work in our model engines, battery power may be more excepted than it is now. One of the biggest complaints I keep reading about on the subject in various forums is having to plug in a battery charger. Kind of equates to your analysis of fueling the car in a New York winter.

Here's a site I occasionally visit do to there interesting modeling subjects, the Central London Area Group. They have put up a page on battery power and wireless charging. Interesting thing is that board shown in the picture looks similar to the wireless boards I have. About halfway down, with the post starting with "Bachmann Class 24", they show a wireless charging circuit. The board looks similar to what I have. The coil is much smaller and has many more turns on it. Makes me wonder if the poster wound his own. Speaking of induction coils. Would you know off hand if both transmitter coil and receiver coil need to be the same size? It seems to me if you have more windings and perhaps a larger diameter transmitter coil you would be able to put out more power, thus being able to use a smaller receiving coil in the engine.

http://www.clag.org.uk/battery-radio.html



A PESSIMIST sees a dark tunnel
An OPTIMIST sees light at the end of the tunnel
A REALIST sees a freight train
The LOCOMOTIVE ENGINEER sees three idiots standing on the tracks

Edited by - Bernd on 07/14/2018 07:56:14 AM
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Frank Palmer
Fireman

USA
4713 Posts

Posted - 07/14/2018 :  08:49:56 AM  Show Profile  Visit Frank Palmer's Homepage  Reply with Quote
Bernd and Dan, this is going to be fantastic.
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Norton
Engine Wiper

USA
175 Posts

Posted - 07/14/2018 :  11:52:54 AM  Show Profile  Reply with Quote
Bernd,

As part of your experimentation process I might suggest trying different ratios on the Xmit and Rcv coils to see what results you get from the test. If memory serve me correctly, the turns ratio should produce either a higher or lower voltage based on which way the ratio goes. That's the basis for how a transformer works. It either is a step-up or a step-down transformer based on the turns ratio between the coils. That may assume the same size for the coils but I have never experimented with this so I could be wrong. This test would require you to make your own coils but I get the impression you would be doing that anyway.

The V & T lives in my garage. Soon...

Norton
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