Reworking the Battery Shield

Troubleshooting
1

Battery Shield Modifications

There are two know issues with the current version of the Battery Shield (ver 1.0).

  1. It fails to power the Core if the attached battery is even slightly discharged.
  2. The shield will pull in more than 500mA current when charging a depleted battery (which is above the USB port limits).

Solution to 1: Desolder C2 capacitor.
Solution to 2: Power the battery shield with an external USB charger when charging a completely depleted battery.

NOTE: If you have received a battery shield with the capacitor, we will be sending out a replacement soon. This document shows you how to modify the battery shield to an ideal working state in the meantime.

Solution1:

If you are have experience working with SMT components, this should be a straight forward rework job.

Things you’ll need:
1. Soldering iron with a needle tip
2. Pair of fine tweezers
3. Pair of steady hands

Alternate between heating the two pads of the capacitor and gently pull the capacitor with a pair of tweezers once it starts to free-float. This may take a while, patience is the key. Be careful not to desolder the adjacent resistors accidentally!

Ideally, you may also use a hot air gun with a narrow nozzle to do the rework.

Proposed future revisions:

  1. Remove C2 completely
  2. Provided a jumper to select maximum charge current. Default to be 500mA or less.
  3. Make the shield more compact. Retaining the mustache shape is still open to debate.
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3

My vote is more compact, NO mustache. It seems that a stack-on shield made the Spark stand too high. Nonetheless, the width of the shield should be smaller. I can’t image putting that thing in a case with the Spark. It would be nice to have a battery/shield combo (stacked?) that can be connected via a short cable with the micro-usb so it can be placed freely. I would also be nice to add another JST connector for a solar panel like the seedstudio lipo rider pro. That would be the ultimate battery shield!

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This is my first SMT rework attempt. I think I’ve created a solder bridge across the bottom three pads and the top left pads. I’m guessing some of that will be problematic, so do you have any advice on how to remove those solder bridges?

I have desoldering braid, but not a pump, and the braid is a bit unwieldly in such a tight space.

5

The braid is probably your best bet; if you use some flux, it should work just fine. If you’ve got a hot air rework station that’s your best bet, but without that I think you’re on the right track.