DIY Wireless charger for Droid4

[Adamyno]

Hi!

First, I'm sorry for English, I'm not professional.
A few days ago I made a working wireless charger for Motorola Droid 4.

What are the benefits?

1. People says, the original inductive charging cover is not compatible with most of cases.
   
2. Who live away from USA, can't use a wireless charger, becouse it is only available (officially) in the US. It is very hard to find on eBay or any other site. Almost impossible.
   
3. Very cheap. The original charging cover at US, Verzion is $29.99. (+ shipping, and need a person who ship it to me) It is only a cover, and we still need a charger as well.

So, I found a charging pad with and without receivers. There was a small problem. The receivers are only for Samsung Galaxy S3, S4 and Note. Their connectors aren't compatible with Droid 4, but the charging voltage is OK.

We need to take it to compatible with Droid 4. I looking for a long time, which one can I choose. Fortunately I made the right decision.
I bought that: Qi Inductive Wireless Charging Upgrade Kit for Samsung Galaxy S3

Link here

That is only for $30.10 with EU plug. The package include charging pad, usb cable, 1500mAh charger and S3 compatible receiver, and worldwide free shipping.

The size of receiver unit is compatible with free space of phone. We need some cutting but it isn't horrible.

1. First, I recommend you try, how fits the module in your phone.
   
2. Then mark with a felt.
   
3. The electrical connector pins are big, (and incompatible) we need to remove it carefully. I used a rework station with hot air (360°C) but you can use a medium sized soldering iron. I think, about 50-60W of power is enough. It took for about 30 secs per pin.
   
4. It is important, you need to place the receiver in such a manner, if you remove the back cover, the S3 and some other text need to be visible! Otherwise it will not work!
   
5. You see backside of the phone, and the camera is on top. Removed cover. In the right side, you can see four copper pins. The top row is irrelevant. We need tha bottom row. In the bottom row, on the left tere is the +5 V pin. On the right, there is a Ground pin.
   
6. We need to make contact between +5V pin of the phone and the +5V charging pin of the receiver unit.
   
7. Place the receiver unit to the phone, and see what size of copper wire you need. The lower pin of receiver unit is the +5V. We need to connect it.
   
8. I used a wire,1 mm in diameter. It is lacquered, I cycled down it from an electrical part (coil).
   
9. I think, that half millimeter in diameter is enough, but a found that, and it is recommended due to the relative high current (about 1A).
10. When you use thinner wire, you can easier take the cover to the phone.
    
11. So you need to solder wire to receiver's +5V pin. Please use the minimum quantity of soldering wire, becouse if you make a big knot there, you will have not enough place to take cover back.
    
12. When it is done, you can see how can you bend (or cut) the wire for best connectivity with phone's 5V pin.
    
13. Now you need to solder a wire to ground, like the previovus one, but not sure, that the two wore have enough space, and we can make easily short corcuit.
    
14. For this reason, we will use the iron cover of the SD card slot. This is a very good ground point.
    
15. So, one cable will go down, other is go up. They can fit and the soldering is more easy.
    
16. PLEASE BE CAREFUL! I recommend, before you make any electrical or hot operating you need to put an aluminium foil or an iron plate to top of the battery. I think to taking out battery and then in, is not easily possible, becouse after soldering there are the receiver. The battery can damage and explosive! The plastic parts of pohone can tolerate the heat for sort time! If you can not solder succesfuly, you need to wait while the parts cooling down! I recommend, use flux and/or high quality of soldering tin. Take out the SD Card! Please don't make short circuit!
    
17. It is not too difficult, but you need to be careful and attentive.
    
18. When the soldering done, you can try the charger.
    
19. Before you can take cover to phone, you need to cut the lower center of receiver. (you can see on the cover, exactly where. There are a claw and on the phone there ara a hole) Important! We need all of holes on phone, so the wires must not hang in to holes.
    
20. I cut the piece of receiver unit from lower left side, at the speaker.
    
21. Thats all. We are done. I think it longer to read than make :cyclops:

I made some pictures, I will mark these and upload in short time.

I'm going to measure the charging time with:

• 1,5A USB charger (direct cable)
  
• 1,5A USB charger with wireless charging pad
  
• 1,5A USB charger with wireless charging pad (phone in a 1 mm thickness of Trident case)
  
• 0,5A standard laptop USB (direct cable)
  
• 0,5A standard laptop USB with wireless charging pad
  
• 0,5A standard laptop USB with wireless charging pad (phone in a 1 mm thickness of Trident case)

I use that from 3 days ago. It works correctly. By the factory, the charging current is 1000mA with the 1,5A charger. About 66% of efficiency.
The USB charger's stand by consumption is 0,4W.
When the charging pad is connected and it is in stand by mode, the consumption is 0,98W

I'm going to bring images, and refresh the post, but here (Hungary, GMT +1) the time is am 2:31.

Good luck guys!

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

Uploaded images,
here are the original, better quality images. (11.5MB zip)

 

[WickedWayz]

That great way to charge the phone. i know that my usb plugin is getting a little wore out.......glad to know that there another way to charge up the phone in case of emergency. Congrats.

 

[mifritscher]

Hi,

thanks, it works for me
My IQ receiver was a bit higher, or the battery, so I had troubles to fit it in. My solution was to cut every superfluous piece and pull the uper layer of slide away. Additionally, I put it a bit nearer to the camera, The last thing was to horizontally cut the gold contacts and solder the wire directly on them.

During charging, the usb charger+pad+droid 4 use 7W, without the droid 4 the pad+charger draw 0,4W, both measured at the primary side ot the charger.

Best regards,
mifritscher

 

[LuH]

Thanks for the info, looks promising I love your using Micro SD casing as GND

BTW the pad + receiver can be found at eBay for as low as US $12 Gonna try out for myself soon.

Did you get to measure the charge times?

 

[Adamyno]

Thanks for the info, looks promising I love your using Micro SD casing as GND

BTW the pad + receiver can be found at eBay for as low as US $12 Gonna try out for myself soon.

Did you get to measure the charge times?

Charging times are about equivalent

 

[zuloo.de]

Different approach, same result

Hi, thanx 4 the great idea.

I took a different approach to install the charging pad. I felt not comfortable to solder directly to the phone, so I used copper-tape, capton-tape and some short wires I took from old headphones to mod the pad directly into the back cover of my phone. it got a little bit bumpier (half a mm), but it charges perfectly.

I applied some solder to the ends which connect to the pins, so the copper wont oxidize and the connection has more pressure.







The pictures in better quality:
View attachment goodquality.zip

 

[StevePritchard]

Hi, thanx 4 the great idea.

I took a different approach to install the charging pad. I felt not comfortable to solder directly to the phone, so I used copper-tape, capton-tape and some short wires I took from old headphones to mod the pad directly into the back cover of my phone. it got a little bit bumpier (half a mm), but it charges perfectly.

I applied some solder to the ends which connect to the pins, so the copper wont oxidize and the connection has more pressure.

View attachment 2842634

View attachment 2842635

View attachment 2842636

The pictures in better quality:
View attachment 2842637

That's a nice solution, and pretty much how the "real thing" was probably set up. I noticed that the back has an internal indentation where the pins are to accommodate the connector, and I had experimented with how I might fit a charging pad in there (actually, it was the connectors that I saw as the biggest challenge), but didn't manage to get anything that I thought was robust enough (I was using cut down parts of a SIM card for the pins to make contact with - you look to have done a better job with the copper tape.

I'm really surprised that we can't buy a new back with all of this gubbins already installed - perhaps you should manufacture a few?

 

[mirddes]

mugen 3800mAh inductive charging cover required!!!

i'm tempted to try this myself. the droid4 keeps getting better.

i just experimented with cardboard, seems to have plenty of room between the cover and the battery. i definitely need inductive charging.

 

[Flash-A-Holic]

Update 2016

@zuloo.de
Hi! I copied your method for wireless charging but I was too lazy for soldering. That is why I used only copper tape. I ordered under 5$ charging pad and receiver for Galaxy S3 (cheap from China) and it is working good. My receiver says that it can output only 0.8A so I guess it is little bit slow. Can you tell your feelings about the heat? I think that my Droid 4 is pretty hot but I never used wireless charging on other phones so I don't know if it is normal. But thanks anyway posting your method :good:

Here is pictures. I tried to take picture about the bump. It is not bad but you can feel it.