Freerails Home 
Home Search search Menu menu Not logged in - Login | Register

Freerails IS ACCEPTING new Members ... To join Freerails ... See how to Register as a Member in the 'Joining Freerails' Forum

Wireless Charging
 Moderated by: W C Greene Page:    1  2  3  4  5  Next Page Last Page  
New Topic Reply Printer Friendly
 Rate Topic 
AuthorPost
 Posted: Sat May 5th, 2018 10:52 am
  PMQuoteReply
1st Post
d10ng
Registered
 

Joined: Thu Jul 19th, 2012
Location: Lichfield, United Kingdom
Posts: 55
Status: 
Offline
Has anyone done any serious work on wireless charging on board yet? I've found a few set of tx and Rx chips and coils that would be suitable and will charge upto 600mah. However most of the coils diameters are to wide to fit between the wheels (HO and UK proto scale 4mm). 

Modules https://www.robotshop.com/uk/12v-600ma-wireless-charging-module.html

But TDK sell wireless charging coils designed for wearable devices. These coils are either round or oblong and will fit between the wheels. 

Seperate coils https://product.tdk.com/info/en/products/wireless-charge/wireless-charge/rx-coil-module/catalog.html

However I'm not great with electronic theory and unsure whether it would be possible to swap the coils over and whether it would even work. I use mainly 1s lipo cells and I have a few small locos with low mah/size cells,  for which wireless charging would be a huge time saver. 
Most of the TDK coils state output at between 1&3W but can't find much info on the coils in the tx/Rx module sets. 
Any one have experience or the knowledge to put me straight? 
Thanks
Dave

Last edited on Sat May 5th, 2018 10:54 am by d10ng



____________________
Thanks for your time
Dave

Visit my Modelling Blog http://dlmr.wordpress.com/
Back To Top

 Posted: Sat May 5th, 2018 12:34 pm
  PMQuoteReply
2nd Post
Helmut
Registered


Joined: Sun Feb 17th, 2013
Location: Friedberg, Germany
Posts: 1072
Status: 
Offline
When using 1S LiPos, this one is better suited.
No need for external coils etc, all is ready to use, provided you have the space for the receiver (41x31mm²). The 5mm distance between TX and Rx may also become an issue.
However oblong or round the coils are, the distance must not be greater than 2...5mm at most.



____________________
Regards, H.
Back To Top

 Posted: Sat May 5th, 2018 01:18 pm
  PMQuoteReply
3rd Post
d10ng
Registered
 

Joined: Thu Jul 19th, 2012
Location: Lichfield, United Kingdom
Posts: 55
Status: 
Offline
Thanks, That does look useful if not a little big, but as you say the 5mm distance isn't great.
The exterior coiled module suggests in can do upto 20mm but at 2mm thick it may perform better than the thinner smaller coils I was looking at.



____________________
Thanks for your time
Dave

Visit my Modelling Blog http://dlmr.wordpress.com/
Back To Top

 Posted: Mon May 7th, 2018 03:34 am
  PMQuoteReply
4th Post
dan3192
Registered
 

Joined: Thu Oct 14th, 2010
Location: Connecticut USA
Posts: 212
Status: 
Offline
Dave, your post regarding on board wireless charging caught my attention. I've been working on this project for over 2 yrs. I'm at the point of adding the required parts to a 1S Li-ion powered GP35 road switcher. The system appears to work very nicely.

Magnetic induction charging applied to HO models is complex. I've had to consider power levels (3W,5W), coil sizes and types, Tx/Rx board sizing, coil spacing and efficiencies, EMF shielding, parts interoperability, integrating charging and BPRC circuitry and fitting OBWC components into an already crowded environment. Testing and evaluating the data to determine an approach has taken considerable time. Outsourcing of parts to accomplish this was also time consuming. Companies such as Texas Instruments, IDT, Wurth Electronics, Digi-Key and the Wireless Power Consortium have been a great source of needed information, one loaning me test equipment for evaluation. Below is a photo of some of the components that will be used for a charging track and the fuel tank mounted electronics.

Many thanks for starting a dialogue on this important topic. The only "fly in the ointment" for me is major surgery scheduled for later this month, so model trains will shortly be on the back burner, hopefully temporarily.

Dan 
        

Back To Top

 Posted: Mon May 7th, 2018 11:46 pm
  PMQuoteReply
5th Post
d10ng
Registered
 

Joined: Thu Jul 19th, 2012
Location: Lichfield, United Kingdom
Posts: 55
Status: 
Offline
Dan, That's great work , glad your efforts are starting to pay off. How are you integrating the wireless rx board into the bprc circuit? Are you having to manually switch to the charger as you would with a hardwired charging port?
I'm hoping that I can use the rx/tx board and use a oblong coil which will fit between the wheels, providing a close enough proximity to charge well.
All the best for the operation. 
Dave



____________________
Thanks for your time
Dave

Visit my Modelling Blog http://dlmr.wordpress.com/
Back To Top

 Posted: Tue May 8th, 2018 06:08 am
  PMQuoteReply
6th Post
dan3192
Registered
 

Joined: Thu Oct 14th, 2010
Location: Connecticut USA
Posts: 212
Status: 
Offline
Dave, thanks, and yes, that's my plan. My Tx board will power a round 15mm Tx coil attached to the underside of a piece of grooved plastic to simulate a wooden track crossing. The top surface will be positioned at the same height of the track. I'd like it higher, but I use Kadee couplers which have uncoupling pins that come down to about 1/16 inch above the rails. The plastic piece, with coil underneath, will be attached to the Bachmann E-Z Track you see in the photo. The coil wires will connect to the Tx board hidden under the ties. The light from the board will be seen at ballast level via fiber optic tubing from the Tx LED. The Rx coil may be larger and will be mounted under the engine fuel tank and connected to the Rx board either under the frame or above the Li-ion cell inside the engine shell. Likewise, fiber optic tubing brought to the outside will tell me charge coupling is established when Tx and Rx board lights are on together.


Now to your question. Initially, I'll connect the Rx coil and board wiring, via a double throw switch, to a 1S battery management board, with the battery also connected to the board. When the switch is thrown the opposite way, power will flow from the battery and board to a step-up voltage regulator and then to a Del Tang Rx61x Rx/ESC. I say initially because I've been thinking of a way to completely turn off my engine using a toggle or PB and an on board servo, in which case the wiring would be a little different. This would eliminate quiescent battery drain since it is hard wired to the battery management board. 


Re oblong coils, I found some copper beading wire at a local crafts store that might be perfect for forming my own Tx and Rx coils. Thin transformer wire may also work well. This is a tricky subject all by itself, i.e., what gauge wire, how many turns, single layer or double layer, insulating material, bonding material, solid or stranded wire, etc, etc. Suggest you visit the Digi-Key website (digikey.com) to see if their coils are of interest to you. You should be able to get most of them in the U.K. I don't know if the Tx/Rx imprinted coils referred to earlier can reach stated capacity without almost touching. I think it's a neat idea though. The best I think I'll be able to do is in the area of a 4 or 5mm gap.  I'm trying to stay with the Qi Standard for wireless charging so future parts are compatible. Visit the Wireless Power Consortium website for background information. You will also find useful videos on YouTube. Hope this helps.

Dan                        

Last edited on Tue Jul 31st, 2018 03:50 am by dan3192

Back To Top

 Posted: Sat Jul 14th, 2018 03:20 am
  PMQuoteReply
7th Post
dan3192
Registered
 

Joined: Thu Oct 14th, 2010
Location: Connecticut USA
Posts: 212
Status: 
Offline
Finally spending more time putting together a test track for on board charging. The transmitter (Tx) boards are hard to come by, so have decided to use them off the track assembly and connect the output leads to individual coils mounted in the track bed as needed.

A 15mm round coil is too big; will try a 12mm x 22mm coil instead. Also, the charger receiver (Rx) board gets pretty close to the drive shaft between the trucks, so will need to consider mounting it inside the shell. Photos soon.  

Dan

Last edited on Sat Jul 14th, 2018 07:01 am by dan3192

Back To Top

 Posted: Sun Jul 15th, 2018 12:40 pm
  PMQuoteReply
8th Post
Bob D
Registered
 

Joined: Wed Apr 1st, 2015
Location: Portsmouth, USA
Posts: 607
Status: 
Offline
Great stuff Dan!!!

I want to do it with my O-scale engines, but I'm using 9.6, 11.1, and 12.0 batteries, I don't think there's anything out yet that can provide what I need to charge them.



____________________
BobD
O-SCALE BPRC
Back To Top

 Posted: Sun Jul 15th, 2018 12:41 pm
  PMQuoteReply
9th Post
Bob D
Registered
 

Joined: Wed Apr 1st, 2015
Location: Portsmouth, USA
Posts: 607
Status: 
Offline
Great stuff Dan!!!

I want to do it with my O-scale engines, but I'm using 9.6, 11.1, and 12.0 batteries, I don't think there's anything out yet that can provide what I need to charge them.



____________________
BobD
O-SCALE BPRC
Back To Top

 Posted: Sun Jul 15th, 2018 04:30 pm
  PMQuoteReply
10th Post
dan3192
Registered
 

Joined: Thu Oct 14th, 2010
Location: Connecticut USA
Posts: 212
Status: 
Offline
Bob,

You'll be pleased to know the basic electronics and related are already out there for what you want to do. The challenge is putting all the pieces together.

Sounds like you need some 18650 or 26650 batteries, a 3S battery management board with balance, a DPDTCO switch and a 12V, or higher, power source along with a Qi Standard wireless charging arrangement.

Would also recommend a voltage regulator to maintain consistent voltage and performance as batteries deplete and their voltage drops off. You may lose 10% or so in efficiency, but my experience is, given the powerful batteries we have today, it is well worth it and I would not assemble any future engines without a step-up or step-down voltage regulator.

Another nice thing about induction charging is that you can weatherproof the system for outdoor use.

Keep the faith...

Dan

Last edited on Sun Jul 15th, 2018 04:36 pm by dan3192

Back To Top


 Current time is 05:26 am
Page:    1  2  3  4  5  Next Page Last Page  

Top



UltraBB 1.172 Copyright © 2007-2016 Data 1 Systems