This is a common problem with iPods/iPhone/iTouch. These devices have very large batteries and they have an annoying bug that if they -think- they're being charged they'll stay on and not 'go to sleep' conserving power. That means that if the AA batteries die before the device is done charging, the device will stay on at full power because it thinks it is plugged into the wall. This can cause it to drain the battery. The best suggestion is to use fresh/charged batteries and don't leave it plugged in overnight.
This is especially true of iPhones, as they suck out all the battery power in a little less than an hour in order to 'quick charge'. This reduces the capacity of the batteries, but means that your phone will be up and running faster
Once you see the charging icon change from a plug, the mintyboost is 'dead' and you must unplug it.
iPhone/iTouch's have batteries that are so large there is no way to fully charge them on 2 AA's. You can only charge 1/2 of a battery because the AA's will die before finishing.You should use the Mintyboost to 'boost' it, but not as a way to fill the whole battery to full.
Very likely! A list of devices is on the front page and is updated all the time. If you find a new device that it does/doesn't work with, please post on the forum (thanks!)
Nearly all USB-charging devices and any device that charges with 5V power (up to 250mA+ 400mA+ with v2.0 of the kit) can be used.
If you are having problems with your device, see the other FAQ's below
Don't panic! Post to the forum (don't send email) about your problem.
A high resolution photo of the top and bottom of your kit will be extremely helpful in debugging your problem
We don't sell assembled MintyBoosts, only kits. However, if you post on the forum, people sometimes offer to sell manufactured kits at low cost.
The kit comes with a PCB and all components necessary to build the kit. It does not come with an altoids tin or tools or batteries. The tin isnt necessary but MintyBoost is designed to be placed in one for protection and aesthetics.
This question is hard to judge because every device has different power usage. However, a simple way to calculate approximate run-time is: take the size of the internal Lithium-Ion battery (for example, many iPods have 750mAh batteries) and divide 1000 by that number. So for a 750mA battery, 1000/750 = 1.3. The MintyBoost will fully charge the device about 1.3 times, as a best case. Remember, this is only an approximation and has a lot to do with the quality of the batteries you use (expensive alkalines v. cheap rechargables) and the internal circuitry of the device for recharging the battery.
If you are using rechargeable batteries (NiMH or NiCad) then 3 batteries is better than 2. However, if you are using Alkalines, you won't get significantly more run time this way. In fact, with 4 batteries, the output voltage is 6V which is too high and could theoretically damage your device! The charger is optimized for about 3V input. For longer run time, use 2 C or D size batteries.
Under no circumstances should you use a 9V battery. You could damage the kit and your device, the voltage is much too high!
In general, its never suggested to put batteries in parallel, only in series. The reason is that if they're unevenly charged (not 'matched') they'll drain into each other and can overheat and get damaged. If you're experienced in electronics and battery management, and confident you can keep the batteries matched well, it is possible to have batteries in series.
However, we strongly discourage this, its risky and can end in melted batteries. Instead, use 3 AA's or 2-3 C or D cells!
Its normal for the chip and batteries to be warm or a little hot, especially when charging a device that is nearly drained. The chip should not get hot or very warm when nothing is plugged in.
However, if the batteries/chip are so hot that its painful to touch, start to smoke, burn or melt or leak fluid....something is wrong! Unplug it immediately and remove the batteries if it is safe to do so.
Yes, sometimes the inductor resonates with the boost converter and that resonance leaks into the audible range. While it's not good for it to always vibrate, it does happen occasionally and is not harmful to the charging device. you can try moving the inductor a little with your finger but the noise is electrical in nature so its hard to stop completely.
Another thing is that it depends on how much power the device is drawing and what kind of batteries are inside.
If this is a charger, why are the data (D+ and D-) lines used?
Why doesn't the 3Gs work with the Mintyboost, but the older iPhone does?
What are the pullup/down resistors used for, and which should I use?
Even though no data is transmitted using the data lines, many devices seem to use the data lines as a way of determining whether it is plugged into a computer or a charger. It is also used by some companies (such as Apple) to make sure people use only 'authorized' chargers with their devices.
The 'official' resistor string used in Apple-made chargers is as follows, we put in 5% resistor values and then in ()'s the precise measured values
D+ (pin 3) should be at ~2.06V and D- (pin 2) should be at ~2.76v
In general, 100K resistors tied as pullups to the 3V battery voltage seems to do a pretty good job of being detected by pretty much all iPod devices. With the 3Gs, the detection circuit was upgraded, now its pickier and it -really- wants to see that precise divider. It's possible theres some other resistor value that will work fine with the 3Gs (we'll try to experiment soon although if you know of one offhand we'd appreciate the hint) Since the Mintyboost v2 is a few years older than the 3Gs, the PCB would need to be redesigned to allow 4 resistors instead of the 2 currently used.
Also, this may change in the future and there is no known way to figure out what any particular device use - (Normally you'd license this info from the company for $$$). There is a lot of discussion on the forums about this but since there is no 'official' way to know and most companies will not tell what method they use, expermintation may be necessary.
Version 2.0 pretty much works with iPhones/iTouch devices but the v1.0 cannot because it is not powerful enough. To get it working you will need the LT1302-5 which can provide 500mA (compared to 200mA from the MAX756)
No, they are completely different designs requiring new PCBs are components, they are not drop-in replaceable at all.
These parts are optional: they are for the low battery indicator. there wasnt enough space to add them to the PCB using through hole parts so they are surfacemount and on the bottom. They're an 'extra' capability which you may add if you feel experienced with SMT soldering.
It is pretty much impossible to get good ouput from the kit if it is breadboarded. A custom PCB or proper perf-board is essential. Most components cannot be swapped, and must be used as indicated, even if they're difficult to find in your area. All documentation is on the site.
I can't provide any support or help to 'DIYer's because of the time and difficulty in debugging these projects. Please endeavor to work out your project on your own.