Step 9: Extending the Switch

As I built the case, the switch that changes the battery pack from charging mode to discharging mode did not extend past the aluminum casing, and therefore could not be switched.  To fix this, and make the switch look nicer, I made an extension for the switch out of a thin rod of stainless steel I had lying around.  I drilled a small hole in the plastic sliding bit of the DPDT switch, and inserted a short length of the stainless steel rod into it.  The bit of stainless steel extends past the aluminum housing, and lets the user actuate the switch.
<p>hi there how many volts it da battery packs </p>
Would this work with a lightning cable as well
Not a useful comment, just a thank you! <br> <br>Don't know if there are any other rechargeable USB battery packs on here, but yours was the first I found and it is excellent. <br> <br>Kudos to you.
Hard drives are insulated against magnetic damage for the most part...you can get some mighty strong neo magnets out of a nice old hard drive<br>
what a nice pipebomb.<br><br>http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries
There is no danger of overcharging the batteries (assuming that overcharging would cause the batteries to explode, as you say), as the charger I am using was designed for charging Li-Ion batteries. Once the batteries reach the correct voltage, the charger shuts off.
despite you didn't mention about the li-ion charger in the instr, i was quite sure you used one of those to charge those batteries.<br>the point of what i didn't say (at least what link say), handling batteries is not rocket science and also over-discharge is something to take in consideration.<br><br>nuff said.<br>
I actually did mention it - Step 4 is entirely devoted to the charger. Over-discharging should not be an issue, because once the battery cells drop below about 6.5-6V, (3-3.25 volts per cell) the output voltage will be below 5V, and the charger will not charge any devices. 3 volts is above the typical bottom threshold of about 2.7 volts, so the cells should not be damaged.
i missed step 4, my bad.<br>from what i can remember about the 7805 datasheet, as you mention, you're working below the ideal input voltage to work in the linear regulation range and despite what many people think the 78XX family is not predictable in that range, so whatever is the differential voltage the regulator may feed current to the load (or maybe not), so be careful, that's it.
Hi there,<br><br>great work and nicely documented!<br>I particularly like how you dealt with the charging and discharging problem :)<br><br>But I have two minor concerns:<br><br>First, how hot does the heatsink get in operation? Maybe there are better options than hotglue to hold it in place?<br>The other is, minature, but strong neodymium magnets close to a magnetic harddrive like in an Ipod, &quot;possibly&quot; could cause problems (?!).<br><br>And now an additional idea, what are the measurements of the components? Maybe one could fit all of it into a external harddisk case instead of custom-building one.<br><br>Regards,<br><br>Confu<br><br>
The heatsink gets very warm, but not nearly hot enough to melt the glue. I was a bit worried about how hot it would get as well, but it has been fine so far.<br><br>As far as the magnets, I would personally not use a hard drive based iPod with the charger, because as you say, it may very well cause problems. However, I do not own a hard drive based iPod, and the trend is moving away from magnetic storage. <br><br>As I built it, the components are 6.5cm by 11.5cm by 2cm (at the very thickest point, which could be reduced), so all the parts could easily fit inside a 2.5&quot; portable hard drive enclosure.

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