[DIY] Altoids USB Charger

[aeroencychris]

Unfortunately no those are for 18650 cells which are lithium ion cells not the NiMH one you have, the main issue is that a single 18650 are 3.7V which that charge controller will use and go up at approx 4.0V when fully charged when the ones you have are 1.2V each.

Okay, so I guess I'm back to this. How would it fit into this schematic? @thekeemo

[thekeemo]

Okay, so I guess I'm back to this. How would it fit into this schematic? @thekeemo

No idea.

[W-L]

Okay, so I guess I'm back to this. How would it fit into this schematic? @thekeemo

 

For that it would be fairly simple, you would need to take the ends of the charging leads and connect them to the batteries as they did on the unit either in parallel or series. for the power side you can have it directly going into the USB by solder on power wires to let you connect the solar panel and a small micro USB instead of the current USB that's in place.

[aeroencychris]

For that it would be fairly simple, you would need to take the ends of the charging leads and connect them to the batteries as they did on the unit either in parallel or series. for the power side you can have it directly going into the USB by solder on power wires to let you connect the solar panel and a small micro USB instead of the current USB that's in place.

I'm confused, could you make a diagram if you have time? (can be ms paint sloppy, just need a visual)

Edit: Thanks so much to all of you again, this is super helpful!

[W-L]

I'm confused, could you make a diagram if you have time? (can be ms paint sloppy, just need a visual)

Edit: Thanks so much to all of you again, this is super helpful!

 

Sure give me a bit.

[W-L]

I'm confused, could you make a diagram if you have time? (can be ms paint sloppy, just need a visual)

Edit: Thanks so much to all of you again, this is super helpful!

 

This is what I was saying using the previous diagram since the power going into the charge controller(red) is all 5V it can just work via the positive and negative points on the USB input and the usb charging ciruit taps off the batteries themselves.

[aeroencychris]

This is what I was saying using the previous diagram since the power going into the charge controller(red) is all 5V it can just work via the positive and negative points on the USB input and the usb charging ciruit taps off the batteries themselves.

mdvSVq0.png

Okay, so the controller will have two positive and two negative places for me to solder to?

[W-L]

Which are which? And I'm assuming I want the + and -?

 

Yes what thekeemo said.

[aeroencychris]

Yes what thekeemo said.

And just to clarify I should use diodes on both positive wires coming from the female microUSB and solar panel?

[W-L]

And just to clarify I should use diodes on both positive wires coming from the female microUSB and solar panel?

 

I don't believe you need one on the micro USB but it wouldn't hurt the solar panel for sure since you wouldn't want current to flow from the micro USB through the panel when you plug it in to charge.

[aeroencychris]

I don't believe you need one on the micro USB but it wouldn't hurt the solar panel for sure since you wouldn't want current to flow from the micro USB through the panel when you plug it in to charge.

Okay, cool. I'm ordering the charge controller and female microUSBs now.

[aeroencychris]

Update: The charging board just came in. Here's what it looks like: http://imgur.com/a/8SoYz

Not sure how it'll fit into the schematic, though. The USB port is soldered onto the board so I'd probably unsolder that and wire up the microUSB + solar panel. Not sure how output to my battery holder will work though. I could probably unsolder the two short wires, but what do I do about the third long wire? It looks like it's soldered to the USB port, not sure why. Thoughts?

[W-L]

Update: The charging board just came in. Here's what it looks like: http://imgur.com/a/8SoYz

Not sure how it'll fit into the schematic, though. The USB port is soldered onto the board so I'd probably unsolder that and wire up the microUSB + solar panel. Not sure how output to my battery holder will work though. I could probably unsolder the two short wires, but what do I do about the third long wire? It looks like it's soldered to the USB port, not sure why. Thoughts?

 

That's a bit more basic than I was hoping basically a voltage dropper from 5V down to the voltage for the Nimh batteries but I guess that's what you get for that price. Basically for your batteries you would need to wire them in parallel like they do with the original holder. The long wire is solder to ground or the metal housing of the USB, ideally it should be on the ground pin.

[aeroencychris]

That's a bit more basic than I was hoping basically a voltage dropper from 5V down to the voltage for the Nimh batteries but I guess that's what you get for that price. Basically for your batteries you would need to wire them in parallel like they do with the original holder. The long wire is solder to ground or the metal housing of the USB, ideally it should be on the ground pin.

So how would this fit in the schematic we have? Also will it still work as a charge controller or is it just a voltage dropper?

[W-L]

So how would this fit in the schematic we have? Also will it still work as a charge controller or is it just a voltage dropper?

 

It will work more as a voltage dropper to give the proper voltage to the batteries when connected via USB or the mini solar panel so you would need to keep an eye on it when charging. To install it basically what was in the diagram previosuly with the two short wire to the positive lead of the batteries and one longer lead to both ends of the negative. For the USB side you just need to solder on the micro USB accordingly to + and - on the PCB, also you can desolder the plug end if it gets in the way since your replacing it.

[aeroencychris]

It will work more as a voltage dropper to give the proper voltage to the batteries when connected via USB or the mini solar panel so you would need to keep an eye on it when charging. To install it basically what was in the diagram previosuly with the two short wire to the positive lead of the batteries and one longer lead to both ends of the negative. For the USB side you just need to solder on the micro USB accordingly to + and - on the PCB, also you can desolder the plug end if it gets in the way since your replacing it.

Ehh, not to happy about the lack of a charge controller. Is there a better place to buy one? Also, how can you tell it doesn't have one?

[W-L]

Ehh, not to happy about the lack of a charge controller. Is there a better place to buy one? Also, how can you tell it doesn't have one?

 

Usually for good ones there is a small surface mount IC or circuit that controls it and shuts it off after a certain voltage, that one is fairly basic and just a voltage dropper with the two large resistors.

[aeroencychris]

Usually for good ones there is a small surface mount IC or circuit that controls it and shuts it off after a certain voltage, that one is fairly basic and just a voltage dropper with the two large resistors.

I see. My question remains: good place to buy them?

[W-L]

I see. My question remains: good place to buy them?

 

Unfortunately I wouldn't really know where to get a premade one other than guessing and taking apart units, there are chips and circuits you can build to make one however.

https://www.maximintegrated.com/en/products/power/battery-management/DS2715.html

[aeroencychris]

Unfortunately I wouldn't really know where to get a premade one other than guessing and taking apart units, there are chips and circuits you can build to make one however.

https://www.maximintegrated.com/en/products/power/battery-management/DS2715.html

You don't see any on even eBay? If you were in my position trying to build a simple project like this, what would you do?

[W-L]

You don't see any on even eBay? If you were in my position trying to build a simple project like this, what would you do?

 

Well there are two options mainly when charging keep an eye on the batteries to not overcharge them by timing it or build a small charge controller. I would probably try to get the parts for a charge controller, the thing is you can't really tell what they have inside like the previous one which will work but is only a basic voltage dropper.

[aeroencychris]

Well there are two options mainly when charging keep an eye on the batteries to not overcharge them by timing it or build a small charge controller. I would probably try to get the parts for a charge controller, the thing is you can't really tell what they have inside like the previous one which will work but is only a basic voltage dropper.

As long as it's not too expensive I'd consider buying another one again. Do you see any you'd consider gambling on? Building seems pretty hard and expensive.

[W-L]

As long as it's not too expensive I'd consider buying another one again. Do you see any you'd consider gambling on? Building seems pretty hard and expensive.

 

For some cheapy one I would say it's ok but I think most of those are going to be resistors to drop the voltage, the ones with controllers are going to be more expensive usually like this sanyo eneloop one but I wouldn't want to take it to bits:

http://www.cpfreviews.com/Batteries-Sanyo-Eneloop-USB-Charger.php

 

There are schematics and parts lists out there to make ones yourself also:

http://www.stefanv.com/electronics/usb_charger.html

[aeroencychris]

For some cheapy one I would say it's ok but I think most of those are going to be resistors to drop the voltage, the ones with controllers are going to be more expensive usually like this sanyo eneloop one but I wouldn't want to take it to bits:

http://www.cpfreviews.com/Batteries-Sanyo-Eneloop-USB-Charger.php

 

There are schematics and parts lists out there to make ones yourself also:

http://www.stefanv.com/electronics/usb_charger.html

Do you think it's bad for the batteries to keep it plugged in so long?

[W-L]

Do you think it's bad for the batteries to keep it plugged in so long?

 

Well it just deteriorates them overtime if you keep overcharging it at a USB charging rate of 1Amp. It will basically make the batteries heat up and dissipate all that extra energy so it's not exactly the best thing for them, with a charge controller it would either lower the charge rate or stop once it reaches the proper voltages.