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Wireless Charging
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 Posted: Sun Oct 21st, 2018 08:27 pm
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Bob D
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Nice "Inline" drive system you got there Dan!!! I've heard of a "Straight Eight" but never a "Straight One".

It's been so long since I had a HO engine apart, I might have to crack open one of my old Athearn GPs and take a look!



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 Posted: Mon Oct 22nd, 2018 01:24 am
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dan3192
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@ Bob

Thanks, I trust you noticed that's a Hobbytown drive.

BTW, I looked back at Posts 10, 11 and 12 and I should have mentioned what you need for charging more than 1 battery. If you include a step-up voltage regulator between the receiver coil and battery management board, you should be all set.

But I'm hung up on that Battery Management Board, so please don't try this right away. I have 2S and 3S BMB's I'm not 100% on how to wire up. I got them on eBay from China. It shows the connections around the board, but I need more info. The power coming to the board for charging the batteries and the power from the board via the batteries use the same 2 connecting points, one positive and one negative.

This makes me wonder if I can operate my engine while I'm charging, or do I need a switch to select one or the other. I've noticed I can use my cell phone while it was charging, also my shaver when it was low and needed charging. If anyone knows the answer, please post!

Another unknown is if I need the exact voltage for charging, or can it be higher. One Li-ion or Lipo needs 4.2V, two of them need 8.4V, three need 12.6V, etc. As an example, if I have two batteries in series, the question is can I use a 9V voltage regulator or do I need to get an adjustable voltage regulator and set it to exactly 8.4V?  Could use some expert opinion here too.

And on that DPDT switch I mentioned earlier, I think one can get away with using a SPDT switch. Actually, I have some SPST center off switches that should work just fine.

So, comments please!...so we can get this project "back on track"

Dan         

Last edited on Mon Oct 22nd, 2018 01:31 am by dan3192

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 Posted: Thu Nov 22nd, 2018 05:43 pm
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dan3192
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I've done a little homework on my own questions, so will finish up on the wiring and check it out.

For the 1S arrangement, the receiver coil will be connected to the battery pcb via the run/off-charge switch. The pcb should receive around 5V which should be OK from what I've read. For the 2S setup, a VR will be used to boost the voltage to 9V, which also appears to be OK.

The engine is half wired and a little tricky to do since I'm modifying existing wiring instead of starting from scratch.


Dan     

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 Posted: Thu Nov 22nd, 2018 07:02 pm
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dan3192
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If you haven't been following what's new in batteries, here's one I hope to try soon. It's Samsung's INR21700-48G Li-ion battery intended, I believe, for the vaping crowd. Maybe also to compete with the Tesla batteries produced at their factory in Nevada.

It has an incredible 4,800mAh capacity compared to the 18650's I'm using now with a 3,400mAh capacity, which at the time I also thought was incredible. The battery is rated at 9.6A max. continuous, 4.8A max. for optimum cycle life.

If these more powerful types become more common, it suggests higher wattage charging systems will be more desirable to more closely match the higher C ratings of these batteries. Time will tell.    

Dan



Last edited on Thu Nov 22nd, 2018 10:26 pm by dan3192

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 Posted: Sun Dec 23rd, 2018 03:50 am
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dan3192
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A little more rework on the GP35 road switcher. The old 5V voltage regulator was removed and replaced with a Pololu 2116 9V regulator just to the left of the switch. Pretty small device. The wire over it is the negative for the system. The assembly will go back on top of the battery.

Below that is a 1S battery management board and a receiver coil with its electronics for charging the Li-ion battery, which will go under the fuel tank. This is a rewire of the original arrangement to confirm the feasibility of on-board induction charging.

Doing this so I don't have to remove the battery for charging. 

Dan


Last edited on Sun Dec 23rd, 2018 03:51 am by dan3192

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 Posted: Sun Dec 23rd, 2018 07:40 am
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davecttr
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Dan, I am confused, that receiver coil is huge, will it fit in that chassis?

What charging rate are you expecting from the system?



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 Posted: Sun Dec 23rd, 2018 06:05 pm
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dan3192
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Dave, the coil is 29mm wide and goes under the fuel tank, which is 35mm wide. The coil matches up nicely with the transmitter coil which is that 3W, 29mm diameter coil shown earlier.

Charging rate will depend on how close I'm able to bring the coils together. I'd be happy, for now, to charge at a rate of 400-600mA. The whole idea is to prove to myself that on-board induction charging is practical and doesn't need track, wiring or hand removal of the shell to charge batteries...they could stay untouched forever in the engine.

Dan       

  

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 Posted: Sun Dec 30th, 2018 10:12 pm
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dan3192
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This is the coil I'll be using, given all the variables I had to consider. At least the price is right.    

https://www.ebay.com/itm/Wireless-charger-receiver-module-PCBA-board-coil-Universal-qi-Andrews-diy-/173021522528?hash=item2848e2ea60

Dan

Last edited on Sun Dec 30th, 2018 10:12 pm by dan3192

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 Posted: Sun Dec 30th, 2018 10:51 pm
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dan3192
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This is the battery I use for narrow bodied HO engines, and the one for this test with my GP35. About US$6.00 on eBay.

Two are used in my BLI 4-6-4 with a 12V voltage regulator to satisfy the sound decoder. 

I'll be using two 18500 types which I found fit nicely in an Athearn AMD-103 diesel with Hobbytown chassis . They are rated at 2000mAh.

If you follow the 0.200A curve, which I think is typical, you can see the long run times possible with these batteries. I run lower mA on the passenger diesel, thanks to the Escap coreless motor.    


Dan

Last edited on Mon Dec 31st, 2018 05:10 pm by dan3192

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 Posted: Sun Dec 30th, 2018 11:51 pm
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Tony Walsham
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Hi Dan.
For those of us who are red/green/brown colour blind, would you kindly find another way of indicating which of the curves is green please



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