FlightSketch mini battery issue

[MProcket]

I’m having an issue with the FlightSketch mini. When the battery is placed in the white holder, I’m unable to get it to turn on. It only turns on if there is applied pressure on the top and bottom of the board. However, when I just put the battery in the slot without the white plastic holder, the altimeter functions normally without any pressure. Moving the white battery holder to another altimeter replicates the problem. I don’t see anything obviously wrong with it.

Has someone else had this problem before or could help? Thanks!

 

[mh9162013]

When you compare the white battery holder that works (which I presume you have) with the one that seems to be faulty, what differences do you see?

 

[MProcket]

None that I could see. The one on the left is good.

 

[mh9162013]

None that I could see. The one on the left is good.

That is odd. My guess is that there's some small change in the shape of the faulty battery holder that can't be easily seen with the naked eye, but it's there.

There might be some FS Mini experts (like @BEC) who have dealt with similar issues.

The good news is that it's probably not the altimeter itself that's the problem, so there's that.

 

[BEC]

Two things:

First of all, your two batteries in the pictures are not the same. Not all of those tiny coin cells are exactly the same size, and I remember when the MicroPeak was new that they recommended specific brands of cells.

Second, I have had this issue occasionally as all of my Minis have had quite a bit of use. The combination of a fresh cell (I usually but not always use the same brand as Russ does — Renata — that I get from Amazon) and bending down the two little tabs that are in the back of the holder toward the board (with the tray/cell removed, of course) takes care of it.

Since you must have two Minis to have two trays, what happens when you swap them? Does the problem follow the cell with the Chinese writing on it?

 

[MProcket]

Two things:

First of all, your two batteries in the pictures are not the same. Not all of those tiny coin cells are exactly the same size, and I remember when the MicroPeak was new that they recommended specific brands of cells.

Second, I have had this issue occasionally as all of my Minis have had quite a bit of use. The combination of a fresh cell (I usually but not always use the same brand as Russ does — Renata — that I get from Amazon) and bending down the two little tabs that are in the back of the holder toward the board (with the tray/cell removed, of course) takes care of it.

Since you must have two Minis to have two trays, what happens when you swap them? Does the problem follow the cell with the Chinese writing on it?

Ahh, I think you figured it out. So it seems to be the battery problem rather than the battery holder itself. The Japanese writing one is 0.07 mm thinner than the Renata one. Bending the two tabs of the holder doesn't solve the issue, which makes me think that the difference in thickness occurs on the underside and the battery is unable to be depressed below the level of the plastic holder to contact the pad underneath.

 

[rocketace]

I have also experienced this... Bending tabs helped but putting a very thin wire helped more. Just make sure not to short it. I am thinking of hot gluing a small lipo on the back.

 

[BEC]

Ahh, I think you figured it out. So it seems to be the battery problem rather than the battery holder itself. The Japanese writing one is 0.07 mm thinner than the Renata one. Bending the two tabs of the holder doesn't solve the issue, which makes me think that the difference in thickness occurs on the underside and the battery is unable to be depressed below the level of the plastic holder to contact the pad underneath.

As I say, Altus Metrum cautioned about particular brands of cells for the MicroPeak, which uses a smaller version of the same type of cell holder. As I recall they favored Panasonic or Eunicell. But yeah, if the issue is with the negative terminal bending the tabs down won't help. I suppose you could shave the plastic tray a little on the negative side, but then it would not be as tight, leading to power glitches at ejection and such. Probably better to just get some more cells of a different brand. I've used Eunicell as well as Rentatas with FS Minis.

There is a drop of solder on the board under the cell holder (after the first production run) intended to address this by building it up a bit, but in your case it seems as if it's not enough (or yours is one of the earlier ones that doesn't have this).

 

[MProcket]

As I say, Altus Metrum cautioned about particular brands of cells for the MicroPeak, which uses a smaller version of the same type of cell holder. As I recall they favored Panasonic or Eunicell. But yeah, if the issue is with the negative terminal bending the tabs down won't help. I suppose you could shave the plastic tray a little on the negative side, but then it would not be as tight, leading to power glitches at ejection and such. Probably better to just get some more cells of a different brand. I've used Eunicell as well as Rentatas with FS Minis.

There is a drop of solder on the board under the cell holder (after the first production run) intended to address this by building it up a bit, but in your case it seems as if it's not enough (or yours is one of the earlier ones that doesn't have this).

I'll get some of the Renata batteries. I did not see any solder on the pad on the board, so this must be an early one. I was debating if I could put some solder there myself but not sure of how steady my hands would be to not cause a bridge with something else. But thanks for the help with this!

 

[gtg738w]

The official answer as @BEC noted is to look for cells that match the 1225 spec the trays are designed for. I think you described it above, the issue is the "button" part of the cell is thinner than the lip on the tray so it doesn't make contact. That's why bending the tabs doesn't really help. The unofficial answer is you can thin out the tray slightly and it should work. Tape a pice of 220 or 400 grit paper to the table and just gently rub the tray over it until you take off that 0.07mm.