Worklog The Wii SPii

StonedEdge

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Unfortunately I might be out of the contest. My batteries just won’t charge, no matter what I have tried it seems futile. I know I said it was complete, but I don’t want to submit a half assed non-complete project. I have tried replacing the BQ several times, I even replaced the BQ25895 with the M variant but it made no difference. No idea what it is, but because I can’t take time off work this week I think I will most likely be out!

Good luck to all other contestants this week, I hope you all are able to submit your projects!
 
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StonedEdge

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And I’m finished! Here’s a quick little shitty video showing that it works. I will record my contest video this weekend! As you can see it’s pretty chonkalicious, but this helps with it feelin’ extra bootilicous.

I recorded this at 3am with my toaster so you’ll have to forgive me for the abhorrent quality. I promise the contest video will be much better than this!

Enjoy!

 

GingerOfOz

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StonedEdge

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Okay, so I have disappointing news again. After playing it for an hour or so, the same issue arose and I had to pull it out of the case and basically restart the entire build, so I am now “officially” not participating any longer :'(

I don’t know what the issue is at this point, but the PCB really isn’t following good design principles because of the limited size of the board. Everything really needs a third revision. For what it’s worth, here is my issue. It seems like BATFET is getting disconnected from VSYS after plugging in the charger. I removed all USB-C circuitry and simply tried to charge it from a 12V 1A DC power brick, but the same issue is happening which rules out the USB-C being the problem. See below my issues:

Basically what happens is this. As soon as I connect a charger source, sometimes it will charge the cells. Other times it will not charge. It seems to be very random. If it turns out cells don’t charge, then when I disconnect the charger, the batteries get disconnected, and VSYS becomes low until I reconnect the batteries. Basically, the portable can be played with charger connected, but the batteries won’t work at all. The chip does get extremely hot when charging immediately, leading me to believe that it is poor layout. Here are my guesses:

- Charging VBUS cap is not close enough to the IC, with the trace going under a single small via and returning to a small via rather than using big polygons like I should have

- The VSYS output caps for the BQ are not grounded to the IC itself and instead are grounded to the GND plane.

- One small via connecting the GND pins of the BQ to the GND plane. I have thermal vias underneath the GND pad, but I guess this still might not be enough.

Perhaps someone else (Gman/Aurelio) who are more familiar with the BQ25895 can let me know if they do know why BATFET would shut off in this scenario. For now, I am going to read the datasheet back to front and head back to EAGLE to try a third revision.
 

MRKane

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NO! I'm not letting you give up over something like this! If you can still play it without charging the batteries then it's still "portable" it just needs a battery charger. Not unlike the GameBoy, GameBoy Advance, GameGear, or Lynx! You're not allowed to drop out over something as small as that!
 

Dmcke5

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NO! I'm not letting you give up over something like this! If you can still play it without charging the batteries then it's still "portable" it just needs a battery charger. Not unlike the GameBoy, GameBoy Advance, GameGear, or Lynx! You're not allowed to drop out over something as small as that!
I'll second that vote. Just make the case a little bigger and jam a TP4056 in the bottom and call it done! You can always revise your board after the competition is done!
 

StonedEdge

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I'll second that vote. Just make the case a little bigger and jam a TP4056 in the bottom and call it done! You can always revise your board after the competition is done!
I might throw a PMS in there for now just to make it work, although it isn’t an ideal solution really but let’s see, maybe it’s best to have a working solution than nothing at all just so I can enter.
 
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Hi,
despite the fact I'm relatively new to the scene, I might have an idea: the BQ25895 gets pretty hot in a short amount of time when its Charging and delivering power through the BATFET. On a perfect PCB layout thats not an issue, but when there is not enough copper to quickly dissipate the heat, it sometimes happens that the Overtemperature Protection kicks in before the Thermal Regulation can reduce the charging Current. For me this resulted in a disconnected BATFET and a relatively low Charge Current. My solution was to reduce the the Charge Current (in REG04) and the Input voltage (With 12V it got extremely hot, 9V is just fine). The, by far biggest improvement was setting the Thermal Regulation to 80°C instead of the default 120°C (REG08)

Sorry for my rusty Englisch, I did not write something for a pretty long time.

Good luck!
 

xsping

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I hope i can help you,stoneedge. because i met the same charging problem before, it is beacuse the r15 resisitor 10k was not soldered by me as below picture. this resistor playing role in PMS charging function and ignored by me due to being nearing the thermal resisitor
 

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StonedEdge

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I hope i can help you,stoneedge. because i met the same charging problem before, it is beacuse the r15 resisitor 10k was not soldered by me as below picture. this resistor playing role in PMS charging function and ignored by me due to being nearing the thermal resisitor
Thanks for your help! Unfortunately I don’t think that this is the problem I’m facing. Rather, I think the BQ25895 ICs thermal pad does not have a good ground connection for heat and thermal conductivity to the GND plane. Upon further inspection of the PCB layers in a gerber viewer, you can see the problem I’d discovered... for some reason the package I had used had prevented the ground plane from covering the IC, despite putting thermal vias everywhere.

823C0EBE-D77C-4B24-B297-B06081A642FA.png


As you can see below, I already had put the 10K ohm pulldown resistor for the thermistor attached to to the PIC (R27), so I don’t think that really was the problem in the end. Open to other ideas, though!

5EC6EFF9-348E-432A-A533-261CDC16B9BF.png
 

xsping

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Thanks for your help! Unfortunately I don’t think that this is the problem I’m facing. Rather, I think the BQ25895 ICs thermal pad does not have a good ground connection for heat and thermal conductivity to the GND plane. Upon further inspection of the PCB layers in a gerber viewer, you can see the problem I’d discovered... for some reason the package I had used had prevented the ground plane from covering the IC, despite putting thermal vias everywhere.

View attachment 13732

As you can see below, I already had put the 10K ohm pulldown resistor for the thermistor attached to to the PIC (R27), so I don’t think that really was the problem in the end. Open to other ideas, though!

View attachment 13733
most of situation i met with charging problem occured when bad soldering,reflow or change BQ will solve problem ,pay attention to R16 on standard PMS,somestime i misuse 10k on r16, it also makes issues
 

xsping

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Thanks for your help! Unfortunately I don’t think that this is the problem I’m facing. Rather, I think the BQ25895 ICs thermal pad does not have a good ground connection for heat and thermal conductivity to the GND plane. Upon further inspection of the PCB layers in a gerber viewer, you can see the problem I’d discovered... for some reason the package I had used had prevented the ground plane from covering the IC, despite putting thermal vias everywhere.

View attachment 13732

As you can see below, I already had put the 10K ohm pulldown resistor for the thermistor attached to to the PIC (R27), so I don’t think that really was the problem in the end. Open to other ideas, though!

View attachment 13733
Have you tried original gman's pic16 programming codes v2, because you change some codes in the programming, it looks like BQ goes to shipping mode when changer plugs in and you also can try 5v charger without type c instead of 12v
 
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