Minty Boost && FreeRunner

-stacy slm3095om at Millions.Ca
Thu Nov 20 16:50:17 CET 2008

Matthias Apitz wrote:
> Hello,
> A colleague of me was kind enough to build that MintyBoost for me. And
> it is working fine. I'm attaching a screen shoot of it using
> ''; some questions remain:
> - sometimes you can hear in the MintyBoost box (not in the FR) some kind
>   of buzzing, is this normal?

According to the MintyBoost FAQ

{ When I plug in a device, sometimes theres a 'hum', 'hiss', 'squeak',
{ 'whine', etc this normal?
{ 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.

> - sometimes the chip and the electromagnetic coil get very hot,
>   sometimes only warm, anything to worry about?

Again, from the FAQ
{ When I use the kit, the chip/batteries seems warm...Is this OK?

{ 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, or melt or leak fluid....something is wrong! :)

Also, your screenshot indicated you are charging at 1A, the step up 
voltage converter in the MintyBoost is only capable of 600mA, so that 
could explain some of the excess heat and noise.

> - if the FR battery gets charged by the MintyBoost, the MintyBoost at
>   the same time has also to provide the energy for the running FR, correct?

My understanding of the power system on the FR is that some components 
draw their power only from the battery even when an external power 
source is available. But I am sure there are others on the list with a 
more complete understanding of the power system.


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