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Super capacitor polarity

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(@vicmortelmans)
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Joined: 2 years ago
Posts: 4
Topic starter  

Hi,

How should the super capacitor be mounted on the UPS Pico HV4.0 board? The manual only says "mind the sign '-'". But when I look on the board, I don't see a '-' sign clearly attributed to the capacitor headers. There is a '+' sign next to the header that is closest to the edge (see attached picture). Is that the indicator for the capacitor polarity?

Best regards,
Vic


   
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(@piadmin)
Member Admin
Joined: 5 years ago
Posts: 81
 

Hi,

If you see better, then indicate the "-" sign on the PCB. However as we mostly finished the manual and newer firmware, please be patient some hours more for official release of them.

BR Pi Master


   
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 XANi
(@xani)
Active Member
Joined: 2 years ago
Posts: 12
 
Posted by: @vicmortelmans

Hi,

How should the super capacitor be mounted on the UPS Pico HV4.0 board? The manual only says "mind the sign '-'". But when I look on the board, I don't see a '-' sign clearly attributed to the capacitor headers. There is a '+' sign next to the header that is closest to the edge (see attached picture). Is that the indicator for the capacitor polarity?

Best regards,
Vic

@vicmortelmans That's not a capacitor, that's buzzer connection I made the same mistake :). Supercapacitor is 2 pins labeled S CAP close to it.

 

The minus connector is one closer to the rpi pin header, there is minus sign next to it

 


   
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(@piadmin)
Member Admin
Joined: 5 years ago
Posts: 81
 

Hi,

Picture you provided is for BUZZER !!!

See my picture SCAP1.PNG

as also the second one


   
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(@piadmin)
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Joined: 5 years ago
Posts: 81
 

as also this second picture

also please wait a few hours for the new firmware, as it is much , much better

BR Pi Master


   
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(@vicmortelmans)
New Member
Joined: 2 years ago
Posts: 4
Topic starter  

@piadmin 

 

Hi, thanks, I believe I get it, but your second picture is confusing me again, because the capacitor's gray band that indicates the negative polarity is visible and it is turned away from the GPIO header.

Is this just a mistake in the picture?

Best regards,

Vic


   
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(@piadmin)
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Joined: 5 years ago
Posts: 81
 

hi, minus is near the C30 (GPIO26)

BR Pi Master


   
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(@arjenr49)
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Joined: 1 year ago
Posts: 3
 

Hi Ioannis,

I hadn't seen or been able to access this forum and for the installation of the supercap I was misled by the square hole. I took it to be the negative connection of the supercap.

I have operated the UPS - with problems which I have emailed you about earlier - but now that I found this thread and the pictures I measured the voltage left on the supercap while the UPS had been disconnected for at least a day and lately it has been on only short whiles and not very often. The supercap has been charged to its full voltage - with the wrong polarity - as measured by the UPS itself and has given me no cause for concern until now.

Anyway measuring at the capacitor itself - I use extension wires between cap and board - a minute ago I confirmed that the polarity is indeed wrong. It was -0,6 V to start and going up slowly after connecting AC to the Pi/UPS assembly.

Maybe I have been lucky that the SuperCap hasn't exploded .... but now I wonder if I could just reverse the connections to get the polarity right and expect it to still be functional, or should I leave it off?

kind regards,

Arjen, Netherlands


   
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(@arjenr49)
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Joined: 1 year ago
Posts: 3
 

I unsoldered the extension wires from the PCB to the supercap and soldered them back in the right way around.

Based on info from a supercap manufacturer which I found on the internet charging a supercap in reverse doesn't necessarily destroy it, so I tried my luck the right way around.

It gets charged to 2,80 V like before and everything looks normal.

Which leaves me with the restart loop problem ...


   
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(@piadmin)
Member Admin
Joined: 5 years ago
Posts: 81
 
Posted by: @arjenr49

Which leaves me with the restart loop problem ...

Hi,

Please advise model of UPS PIco you have, the Bootloader you have (you can read them via I2C), what Raspberry Pi are you using as also if you have connected any additional hardware to the system. Please also provide info about what powering method are you using (USB, EPR or PPoE). Then I will beable for further support

BR Pi Master


   
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(@arjenr49)
New Member
Joined: 1 year ago
Posts: 3
 

I am the same person who sent you several emails about the restarting with my observations. That was before I found this forum. I will try to put that information in a post here on this forum, under the proper subject, but I cannot do it right now.

However, I don't think I gave the info you requested above, so here it is:

pi@RPI-TST:~ $ sudo i2cget -y 1 0x69 0x35 w
0x4141

No other hardware involved. Just the UPS PIco, battery HAT and SCAP 100 F, and the Pi4 with 2 GB running 64-bit Raspberry OS Bullseye from an SSD. I use the python3 command to run the script.


   
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(@piadmin)
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Joined: 5 years ago
Posts: 81
 
Posted by: @arjenr49

No other hardware involved. Just the UPS PIco, battery HAT and SCAP 100 F, and the Pi4 with 2 GB running 64-bit Raspberry OS Bullseye from an SSD. I use the python3 command to run the script.

OK

Thank you, I will check it here (do similar configuration and come back in 1-2 days. However here I do not seen any of such effect in the last firmware. But let me check again, to be sure. There are many options, so logically we must test everything to be sure.

---

Please also kindly notice that, we imported and staring to sell very soon - a new replacement of the 2550 mAh Battery (LiPO, LF or Li-Ion) - a Super Capacitor of 4000F that is replacing directly battery with unbelievable parameters (>100K cycles, working temperature -30+70, small size, etc). This new Super Capacitor can be plugged directly to the battery socket (like a battery). It can be used instead of "normal battery" and together with the other small Super Capacitor of 100F on all UPS PIco models (former and new). We mostly finalized testing it on various conditions.

---

BR Pi Master


   
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