How to make a solar iPod/iPhone charger -aka MightyMintyBoost

Step 2 Build the Minty Boost kit

First build the MIntyBoost kit according to its instructions. It's really easy to assemble- even a complete novice can do it.

Instead of connecting the battery holder in the kit, we're going to solder a JST connector to the MintyBoost PCB. This tiny connector will then allow the MintyBoost circuit to connect to the Lithium Polymer battery charger circuit. Make sure you get the polarity correct!

Test the MintyBoost by connecting the battery pack (make sure the battery pack has a charge) and charger circuit. The MintyBoost connects to the connector marked SYS on the charger board and the lithium polymer battery connects to the connector marked GND.

Now cut a notch in the Altoids tin for the USB port and use some double sided adhesive to mount the PCB to the Altoids tin.

Comments

[pfricks]

Keep in mind that the iphone & battery was not made for extreme heat

[Honus]

Sorry but I don't understand your comment. Could you please elaborate?

[waterlubber]

He meant "Keep in mind that the iPhone and the iPhone's battery was not made for use in extreme heat"

[arvindhimalayan]

wher is a circuit diagram?

[Honus]

Have a look at the FAQ section- at the bottom of the page there is a link to the LiPo charger and MIntyBoost web pages that have all the data sheets and circuit diagrams.

[solarpowerplusaltoids]

this is also basically the same jst cable just a different color http://www.sparkfun.com/commerce/product_info.php?products_id=8670

[Aeniph]

I like this post. For two reasons, one, I did the same thing a couple months ago except I got the 6000 mAh battery from Sparkfun, the one with three cells, and I integrated the whole thing into a backpack, and two, it's really really quite well done. Good job :)

[arjunface]

The 2-pin JST jumper cable is out of stock on SparkFun's website. Can I just by a cheap rechargeable battery and just use the wire?

[Honus]

Use this cable- just cut off the end you don't need:
http://www.sparkfun.com/commerce/product_info.php?products_id=8599

[carottopsrgreen3]

Do you know where i can get a MintyBoost kit? or the Lithium battery charger/ battery itself? Other than the Internet i mean. Radio Shack doesnt seem to have even heard of these before. thanks!

[Rtc443]

To my knowledge the only place to get the mintyboost kit is at http://adafruit.com/

Mintyboost is kind of a diy thing, radio shack will defiantly not carry it.

As for the battery Radioshack i think only sells replacement batteries for cameras, phone etc.

[IDSKoT]

Looking at this schematic for the charger, it doesn't say the wattage of any of the resistors or the volts of the capacitors, and I have no clue what SJ1 is supposed to be. Any help?

[Honus]

The nice folks at Sparkfun confirmed my guess- it is indeed a jumper so you can boost the USB connection to the 280mA max current by tying it to the 5v in line.

[IDSKoT]

I don't understand the point of it... if it's a jumper, why put it in the schematic? Is it because they had to summarize everything on the board regardless of what it is?

[bpappin]

It's standard to label the jumpers as well. For instance, how would you provide instructions for using it? It's easier to say "SJ1" than to say "connect the thingies 3mm from the top of the XYZ chip and 5mm to the right of the 10uF cap"

[Honus]

It's just two little tabs for a solder bridge so you can increase the USB charge current if you want. They probably made it optional because it's not technically within USB specification.

[IDSKoT]

OH! I SEE! Wow. Sorry. I was completely confusing that. I thought it was necessary. I'm sorry.

[Honus]

No sweat! Since the current charger board is slightly different from the earlier version I have it's good for me to find out these things.

[Honus]

For resistor watt values figure that a max input of 7v and max current of 280mA equals 1.96 watts so I'd imagine using 2 watt resistors or higher would be fine. Since the max voltage is 7v, I would think a capacitor rated at 10v would be fine. As for the mysterious SJ1, if you look at the photos of the charger PCB, that looks to be a trace gap jumper- you flow solder across the two pads to join the PCB traces (for what reason I don't know). It looks like it would tie the USB in to the 5v in so that maybe you would use that if you had a USB connection that you wanted to exceed 100mA input current. I'd ask the Sparkfun guys- their tech email is: [e-mail] The charger board I have is the previous version and it doesn't have that on the PCB.

[samkim]

Hi Friends, I am new to this forum, well I am trying to make a Li-Ion charger using Max 1555, has any one tried out doing this, if so please do tell me, I have been unsuccessful many a times doing this experiment. I am enclosing the circuit used for this experiment.I have done all the circuit connections as shown in the diagram but still when the battery has been charged after being discharged till 3.55V, while charging the LED will be in ON state, when it reaches the maximum(4.15V), the LED has to turn off, but in my case it remain to be ON. Could any one know the exact reason behind this.I am using DC input instead of USB for charging.Is it okay with it.Thank You.

[bpappin]

Battery charges can be hard, even if you have the circuit diagram. The circuit is very important and directly related to the type of battery.

[Honus]

Do you have a circuit diagram?

[momsgonnafindme]

i love the idea but i was hoping i could pull off something simaler without having to buy that minty boost thing any ideas?

[Honus]

I thought you wanted something smaller- oops! Yes it is possible to build it from scratch- both the circuit schematics for the MIntyBoost and the Sparkfun charger are posted online and all the parts are readily available.

[momsgonnafindme]

hey, its no problem. thanks for commenting and being willing to help.. i think i just may attempt my handy work at this

[Honus]

Now I'm already thinking about making a micro version.... LOL.

There's a schematic for the charging circuit here: http://www.sparkfun.com/commerce/product_info.php?products_id=726

Here's the manufacturer's page on the MAX1555 IC used in the charging circuit:
http://www.maxim-ic.com/quick_view2.cfm/qv_pk/4002/t/al

[hitch]

yep. You can build the kit from scratch, choosing to leave out any of the unnecessary parts.

http://ladyada.net/make/mintyboost/make.html

[momsgonnafindme]

thank you for posting a link _{its always nice to have someone point you in the right direction}

[hurricanepkt]

the minty boost project is based primarily on the LT1302 sample 5V output circuit (with 2 additional pull up resistors for iphone rondoness) schematics for both are available...also some people like to use a female cable adapter instead of just the socket (gives a cleaner cut for the tin)

[momsgonnafindme]

im not sure id even use a tin, the size really doesnt matter that much to me. i build things just to be able to say that i CAN do it from scratch. you know? it gives me a sort of saticfaction. i think i have to work on my schematic reading skills though... any tips?

[Honus]

The last electronics class I took was over 20yrs ago so I just started reading electronics basics books. Have a look here: http://www.forrestmims.com/

One of the best books I bought last year was Physical Computing by Tom Igoe. For anyone wanting to use microcontrollers to actuate motors and servos and learn basics about transistors and things like that it's awesome.

[Honus]

Just looking at the space needed for the electronics you could fit it into a case that internally measures 2 3/8" x 2 3/16" x 3/4"- pretty small. Using a smaller 1100mAh battery you could get it into a case as small as 2 3/8" x 1 1/2" x 3/4" (internal measurement.) That battery would probably be enough to charge any iPod. The solar cell wouldn't fit on top of either smaller case but if you wanted to plug in a remote mounted solar cell (like on a backpack) it would be pretty cool.

All this is assuming you still are using the MIntyBost PCB. Just looking at it I think it would be hard to make a PCB boost circuit smaller than that. Maybe using surface mount components you could do it but it would be a fair bit of work. You would save more room by altering the charging circuit as it has a much larger footprint- if you combined the boost circuit and charging circuit on one PCB with a minimum of connectors that would really shrink it down.