Newb help/ideas

Ideas and questions about MintyBoost kits

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Freedy500
 
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Newb help/ideas

Post by Freedy500 »

Hi I read over your article and tutorial for the minty boost kit and I just bought two. Now what I'm hoping to do is either 1, fit both kits (running off of AAs) into the one large altoids can and make a duel USB charger with switches, so I can charge two devices at once if I want, and if not i can flip a switch to deactivate one side. Or 2 make 4 3000mah NIMH or NI-CAD 1.2 volt AAs for into one large can, and still use it as a USB charger but I would be using it to charge an ipad which is why I need all that extra juice. A few questions I need answered are, 1) will the minty boost kit(s) be enough to charge my IPAD 3 (lightning connector one) and if so will I need to change the voltage for it (input/output?) as I am not sure if they all take the same voltage and such. I know the ipad sucks 2.1 amps instead. And 2) will this be possible/achievable? And 3) just as a little bonus to make it look a bit cooler, I was wondering If I can add a tiny LED to the board or something that lights up when I turn it on.

Thanks for any and All help.

That summarizes it and I mainly want to do both 2 and 3 but would like to know if i can also do number 1. And to clarify, I will be using 4 AAs that contain 3000mah each at 1.2 volts.

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adafruit_support_bill
 
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Re: Newb help/ideas

Post by adafruit_support_bill »

Building a dual charger is possible. Although it will be a lot of stress on the batteries if you plan to run them from the same pack. You might consider going to a LiPo pack if you are going to do that. http://www.adafruit.com/products/353

You will not be able to charge an iPad. A single Minty can source about 500mA and combining regulators in parallel is generally not a good idea.

Adding a 'power-on' led is certainly possible.

Freedy500
 
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Joined: Wed Sep 11, 2013 1:45 pm

Re: Newb help/ideas

Post by Freedy500 »

What could I do to make it charge an ipad? What would I be able to do to modify the output and all to have the ability to charge an ipad 3. That's what I really need it for and is what I would mainly be using it for. I like your product and all, I just need to modify it to fit my uses a bit more.

As for the duel batteries, I would essentially just put 2 minty boosts in one container, they would be separate circuits (2 AAs per USB port) so it would not strain the batteries as much as it would be/should be.

And as for the LED,would it really take a noticeable/major amount of juice away? I would assume not but just want to make sure. And what would I do to add that and where would I buy a cheep (sorry for the spam word) set of these. I would assume they would be relatively affordable and power efficient.

Also, I thought since I would total up to around 12000mah capacity with 4 batteries that I would be able to conveniently charge my ipad on the go (while in class or on an airplane/trip) when it's being used for a prolonged period of time. Plus I would probably use it to charge my or a friends cell phone or electronics from time to time. This would also (12000mah pack) be a single USB port with a whole lotta power, and then I will make another but with 2 USB ports.

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adafruit_support_bill
 
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Re: Newb help/ideas

Post by adafruit_support_bill »

There isn't really much you can do to increase the output of the Minty by that amount. We are running at close to theoretical max for the chip as it is. You would really need to do a complete redesign of the boost converter.

If charging an iPad is the goal, why not go with a higher voltage battery pack (6x NiMH cells is 7.2v) and use a buck converter like this one: http://www.adafruit.com/products/1385 That will handle up to 3A and do it more efficiently than a boost converter.

You can wire up an led to have minimal current drain if you size the current limiting resistor right. Most are rated for up to 20mA, but will produce visible light with only 1 or 2mA. http://learn.adafruit.com/all-about-leds

Freedy500
 
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Joined: Wed Sep 11, 2013 1:45 pm

Re: Newb help/ideas

Post by Freedy500 »

So to clarify, If I find a practical way to add that buck converter then I will be able to use 6x AA 3000mah NIMH NI-CAD batteries to charge an ipad (requires 2 volts or so) it should work? I am a newb but i have a buddy who is an EE and could get his help. Would this be with or without the minty kit? As in would I still be using most, if not all parts or will I be able to keep the kits I just had shipped intact and have to order this instead?

Freedy500
 
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Joined: Wed Sep 11, 2013 1:45 pm

Re: Newb help/ideas

Post by Freedy500 »

To summarize that, all I have to do is add that buck converter? Yes or no? I would feel 3000x 4 AA NIMH-NICAD batteries would be sufficient enough to get that wattage needed. I will really just fit as many AAs as I can into a Altoids container with room left for the circuitry and (if possible) a 5mm led. Thanks again.

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adafruit_support_bill
 
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Re: Newb help/ideas

Post by adafruit_support_bill »

You do not need the Minty Boost. You need is a battery pack between 6 and 23 volts and the UBEC. You can use the design notes from the Minty Boost project to figure out the resistor network for the data lines on the USB connector. http://learn.adafruit.com/minty-boost/icharging

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