[Help/Feature] Battery drains too quickly + suggestion for power switch

[MSmaili]

@carrefinho First of all, thank you so much for the keyboard, it’s fantastic. The build quality is excellent, and overall, it feels top-tier. I really appreciate the work that went into it.

This isn’t my first keyboard, and I’ve tried several others before. I built this one a couple of weeks ago, but I’ve been having issues with the battery life. Even when using it with the USB dongle, the battery only lasts about a week. That surprised me, since my other keyboards with dongles usually last at least a month.

I followed your build guides closely, with the PCB ordered from JLCPCB. I also use this keyboard when I travel. In my configuration, I’ve enabled both soft_off and deep sleep.

Here’s my dongle config:
https://github.com/MSmaili/zmk-config/blob/main/boards/shields/forager_dongle/forager_dongle.conf

And here’s the full keyboard config:
https://github.com/MSmaili/zmk-config/blob/main/config/default.conf

I suspect that the keyboard might not be fully powering down. When I enable soft_off, the keyboard stops responding to key presses until I switch it back on, but even then, why does the battery still drains much faster than expected? To rule out the battery itself, I’ve already tested with different ones, and the result is the same.

Do you have any suggestions for how I can debug this? What should I check or test next?

Again, I really love this keyboard; both the design and the idea of using screws on the PCB are brilliant. If I could suggest a couple of improvements for future revisions, if it is possible:

• Adding a power switch

• Replacing the JST connector with a through-hole JST 2.0 option, since it’s easier to solder and works with most batteries

  • 

Thanks again for the great work on this project, and I’m looking forward to your advice.

[BenRoe]

About the JST, it might be to heigh. There is little space at the bottom.

[MSmaili]

About the JST, it might be to heigh. There is little space at the bottom.

Yeah, good point; the JST might be a bit high. Space is definitely tight at the bottom
That said, I find it a lot easier to solder when the pads are through-hole; maybe that’s just what I’m used to.

Adding a power switch would really help with battery life, I think, or at least it would make it "safer" to carry around, and "safer" to re-solder something if we did something wrong while soldering.

I do not know any other reason why the battery drains quicker than my other keebs (I have another with xiao too), I might have done something wrong while soldering this, but I'm not sure how or what

[peterjc]

I see your switch placement on https://github.com/MSmaili/forager/tree/power-switch/case/case_with_power_switch (looking at the case files), on the side near Qwerty A or semicolon. I could load the PCB, but what part are you using?

And I agree the though hole JST 2.0 would be nice for the battery connection - very easy to buy batteries with that. Do we have 6mm of height clearance though?

[MSmaili]

The power-switch is MSK12C02.

I agree i doubt we have that much space, judging by the battery, the battery fits closely. So no more room for something taller.

PS
The pcb there has through-holes, on my knowledge it is easier to solder

[peterjc]

I have that right-angle through hole JST PH2.0 2-pin power connector for another keyboard, and it is 5mm tall above the board (but there is only 4mm of clearance with the bottom case - and it is only 1mm thick - so impossible!), and the legs stick out too - maybe 0.5mm plus your soldering. So that would need a cutout in the top case which is 2.2mm thick there, so that side is doable at least.

The Forager top case is flush with the PCB, so adding any through hole parts would be a challenge.

The MSK12C02 is surface mounted, so should be fine under the PCB. Have you built a modified Forager with that yet?

[peterjc]

One of the smaller connectors offered with suitable batteries is the JST 1.25mm 2-pin, which might work here with a (MICRO) JST 1.25 2-pin Connector 1.25MM Pitch Horizontal SMD?

I'm trying to find an offical part spec (and KiCad footprint), but that looks to be under 4mm tall from the candidates I found on AliExpress.

Update:. It seems that "JST 1.25mm" is often a third party version of the PicoBlade MX connector. Thus https://github.com/KiCad/kicad-footprints/blob/master/Connector_Molex.pretty/Molex_PicoBlade_53261-0271_1x02-1MP_P1.25mm_Horizontal.kicad_mod from Molex PicoBlade series connector, 53261-0271 http://www.molex.com/pdm_docs/sd/532610271_sd.pdf looks like what I wanted - thank you to Eden on the ZMK Discord for the right name! The offical versions are just 3.4mm high.

[MSmaili]

Sorry for the late reply

The MSK12C02 is surface mounted, so should be fine under the PCB. Have you built a modified Forager with that yet?

Yes i am using the modified forager with the power switch, and it is working fine.

[MSmaili]

I accidentally closed this issue, and I do not have permission to re-open, but the power-switch forager can be found here. I can make a pull request, but I IDK if I should do it because #16 and #17 are newer and better proposals and have a different PCB. (they do not include the power switch though)

[peterjc]

I like the power switch idea from @letmegobacktosleep & the fact you (@MSmaili) have tested this with a 3D case modification. I think that would be a useful community contribution to the Forager design.

Do either of you think it would be easy to solder bridge the switch points (if using the modified PCB without installing the switch)? Or is a proper jumper better (for people happy with the original case)?

I can add the same switch & thru-hole soldering points to my reversible direct wired version of the PCB for issue #16 (see PR #19 which replaced PR #17).

Are you happy for me to cherry-pick your case commit?

[MSmaili]

@peterjc As it belongs to 'jumper', I don’t have an answer since I don’t have experience with PCB design sorry, hope @letmegobacktosleep can help here.

Regarding cherry-picking, please go ahead. I’d love this to be included by default.

By the way, some sellers (like Keycapsss) already sell the Forager with a power switch by default. I think adding a power switch doesn’t reduce the value of the board,it only enhances it.

[peterjc]

The version on the Keycapss https://keycapsss.com/diy-kits/284/forager-wireless-split-keyboard-kit doesn't seem to have a power switch (but perhaps they didn't update their website).

Certainly there are currently multiple AliExpress vendors selling a Forager with a similar switch in about the same place. One has photos showing their PCB is labelled as "rev 2", and is using what looks like the https://github.com/NologoTech/Super-nRF52840 alternative to the Seeed Studio Xiao (pin compatible with extra GPIO pads on the back).

So there is demand for this functionality, and an officical revision would be nice - say https://github.com/letmegobacktosleep/forager/tree/power-switch or something similar.