USB charger built in for nicostick

[stevo_tdo]

This is a continuation of a post of mine on the thread discussing the nicostick. I wanted to make a seperate thread to keep the other one uncluttered.

Yeah, I need to get a magnifying glass to read the info off the main chip. No time cutoff that I know of. I'm including some pics for reference.

Here's the nicostick with the cover off. That batt is just a spacer till i get the 3.7v's in

Here's just sitting the board in there. The white fluff is just a spacer to show it will have to be epoxied at angle slightly away from the battery to allow removal of the batt.

Here's just the board

Yeah, any info that would be helpful to change the mah output for quicker charge would be helpful. That is as soon as I post the info from the board. If i put this charger in one of these it will be one from scratch so I can reroute the wire as needed and get a mini usb in the casing and extend the led light from the charger to be visible outside the box. What would be best, a switch to turn on when charging to keep the power from flowing back through the board when not charging or a one way diode or whatever.

 

[kinabaloo]

Yes, as I thought (in previous thread): take a charger board out of its box and insert into NicoBox. Great idea!

Th board should cut-off when the battery is charged rather than by time.

Might be possible to grease the two lower corners of the board and while two hot-glue blobs are still warm in the case, push in to create holding, without being permanently fixed. If no chips are covered in glue (either way), this will be fine so long also as the board can't move about.

 

[kinabaloo]

"Yeah, any info that would be helpful to change the mah output for quicker charge would be helpful. That is as soon as I post the info from the board. If i put this charger in one of these it will be one from scratch so I can reroute the wire as needed and get a mini usb in the casing and extend the led light from the charger to be visible outside the box. What would be best, a switch to turn on when charging to keep the power from flowing back through the board when not charging or a one way diode or whatever."

A quicker charge would probably require a whole different board (circuit).

USB socket (care re polarity) and extend out charge LED to case - good.

A low drop power diode would be best i think - it's simplest though the battery would get 4.0v rather than the ideal 4.2v. And once the flat battery has been on charge for say 1/2 hour one can vape and charge simultaneously (i think no problem there). Otherwise a 2-way switch, yes.

The chip itself might be one of these: VA7205 LT1510 LTC1731 MAX8814ETA
Most likely the VA7205. Once we know, can check re max charge current changeable.
Might be a resistor value. Might be a setting, such as: "The charge current can be set to either 100mA or 500mA using logic control, allowing it to meet the USB current standards." (http://www.maxim-ic.com/view_press_release.cfm/release_id/323)

A good read on charging circuits connected to USB: http://www.edn.com/article/CA6531593.html

 

[caesar]

Yeah, any info that would be helpful to change the mah output for quicker charge would be helpful. That is as soon as I post the info from the board. If i put this charger in one of these it will be one from scratch so I can reroute the wire as needed and get a mini usb in the casing and extend the led light from the charger to be visible outside the box. What would be best, a switch to turn on when charging to keep the power from flowing back through the board when not charging or a one way diode or whatever.

You must read the markings on the chip to be able to find it's datasheet.
It's a possibility that the charger will draw no more than a few microamps from the battery so you can leave it permanently connected to the batt.
Again we need the datasheet

 

[stevo_tdo]

Let me go find my magnifying glass and get to it. I see no problem hooking everything together the way it is. Just want to wait until all the info is on the board to see if the mah is fixed for charging.

 

[kinabaloo]

Let me go find my magnifying glass and get to it. I see no problem hooking everything together the way it is. Just want to wait until all the info is on the board to see if the mah is fixed for charging.

I can make out what looks like 05 but i cant really see it

 

[stevo_tdo]

Here's the back of the board. Still trying to magnify the front.

Well, here's what the front says

 

[kinabaloo]

I can't find any info on the chip

 

[stevo_tdo]

Me neither

made by Shenzhen Smolder Technology Co., Ltd

 

[kinabaloo]

Where it says 'R5' on the board is next to pin5 of the chip. Does that pin (pin 5) connect to the transistor (the three-pin black thing)? Ground (-) to pin 3 and +IN to pin 8; right?

If so, looks to me like this chip is a VA7205.

ps: A really small neat unit

 

[kinabaloo]

I am fairly sure that the charge current is set by the resistor marked 1R0; presumably 1 ohm; you can check with a multimeter. A 0.3 ohm resistor there would give a higher charge current. The resistor market R6.

The datasheet (pdf) is available from here: http://www.datasheet4u.com/html/V/A/7/VA7205-1_Vimicro.pdf.html The pdf is linked from a box on the right. The current setting is discussed on p7.

 

[stevo_tdo]

"Where it says 'R5' on the board is next to pin5 of the chip. Does that pin (pin 5) connect to the transistor (the three-pin black thing)?"

Yes as far as i can tell

Ground (-) to pin 3 and +IN to pin 8; right?

Believe so, whats the easiest way to check

If so, looks to me like this chip is a VA7205.

ps: A really small neat unit [/quote]

 

[kinabaloo]

"Where it says 'R5' on the board is next to pin5 of the chip. Does that pin (pin 5) connect to the transistor (the three-pin black thing)?"

Yes as far as i can tell

Ground (-) to pin 3 and +IN to pin 8; right?

Believe so, whats the easiest way to check

If so, looks to me like this chip is a VA7205.

ps: A really small neat unit

[/quote]

Chips have a small round indent on the top next to pin 1, then the numbering goes anti-clockwise around the chip.

Follow the paths of the board.

Ground (-) to pin 3 and +IN to pin 8; right?

 

[stevo_tdo]

Worthless post used to be right here

 

[kinabaloo]

Yes. Voltage across IN- and pin 3 is 4.26 the same as the output to charge the batt.
In+ to pin 8 is 5.26. That sounds right, right. With no batt in the charger with it on it would return the 4.26 though the IN- to complete the circuit right.

I meant that pin3 is directly connected to IN- and pin 8 is connected to IN+. Don't worry about voltages, just see if the board connects these as I said.

Or, if measure voltages, all relative to IN-, pin3 should be 0v and pin 8 would be the same as IN+.

 

[stevo_tdo]

"Or, if measure voltages, all relative to IN-, pin3 should be 0v and pin 8 would be the same as IN+. "

IN- to pin3 0v, IN- to pin8 4.26 v, In- to In+ 5.42v

I know it's frustrating working with me

 

[kinabaloo]

But looks like pin 4 is connected directly to OUT+, which is not right in tems of the VA7205.

The chip is probably something else.

The 1R0 resistor might still be the one to change but it's too uncertain to recommend. Just have to make do with 100mA.

My 901 charger is also 100mA, although it is a mains charger rather than usb. So perhaps these cheaper (and smaller) type chargers can only really handle the 100mA. Otherwise they would be set up for 500mA already.

 

[stevo_tdo]

True True. Thats my thought on the low mA through these chargers. Might try to get a closeup pic for you to inspect. Otherwise i'd need to build a board around the VA7205 or settle for a trickle charge.

 

[kinabaloo]

True True. Thats my thought on the low mA through these chargers. Might try to get a closeup pic for you to inspect. Otherwise i'd need to build a board around the VA7205 or settle for a trickle charge.

As only 40% of the charge is used up before recharging, a 1000mAh battery could be charged in 4 hours with 100mA.

I have had a thought on this issue and will create a new thread about it shortly.

 

[stevo_tdo]

Sounds good to me. I think I'll just go ahead and incorporate it into my next nicostick and time how long till the green light says it's charged from dead. And of course wait for your thread. Thanks for all the help.