Hacking 333Mhz kills battery, polyfuse?

[romanaOne]

I mostly use gpsp on my PSP and have never had a problem with the (modded 2000 mah attached to board pulled from el cheapo) battery before. I was trying out the RACE! Neo Geo Pocket Color emulator and suddenly my PSP shut down and would not turn back on.

I took out my multimeter and saw that the big battery was still almost full with 4.1V across B+ and B-. But the PSP still wouldn't turn on except when plugged in. I set it aside for a few days after not finding any info about the problem. Figured it was something with the battery board.

Then I found this guide below and tried removing all power from the mysterious battery circuit board for a few minutes. (I cut the wire to B+ and soldered it back on.) The PSP works again! Battery percent looks right and it charges when plugged in.

I played a little more with the RACE! emulator and in about 10 minutes the PSP shut down and would not start. I disconnected the battery board again and it was fixed.

I examined the settings in RACE and noticed that the clock speed was 333MHz. I can't find any cpu speed setting gpsp, so I guess it is running at the default(?) of 222MHz? Could it be that there is an el cheapo polyfuse on the el cheapo battery board that can't handle the current at 333MHz? What's this about EPROM in the guide below? What does this board do, besides make it a pain to replace PSP batteries?

https://gbatemp.net/threads/guide-psp-battery-recovery-eeprom-crash.3481

 

[FAST6191]

For most around here the EEPROM was what triggered the recovery mode. See pandora battery.
"make it a pain to replace PSP batteries" is pretty much the official use in most batteries with such things -- technically they can count charge cycles, note any radical defects and thus determine the best discharge levels and charge parameters but practically they mainly just provide something to cause the "wallet too fat" error in everything I have ever seen attempt it. Some might also try to tell you they will make sure it is a nice official battery and third parties can be dangerous.

As for guessing what goes. At this point any battery still standing is probably pretty old. I would not be surprised if the increased clock knocked the current draw up enough that it caused fun here.

 

[romanaOne]

For most around here the EEPROM was what triggered the recovery mode. See pandora battery.
"make it a pain to replace PSP batteries" is pretty much the official use in most batteries with such things -- technically they can count charge cycles, note any radical defects and thus determine the best discharge levels and charge parameters but practically they mainly just provide something to cause the "wallet too fat" error in everything I have ever seen attempt it. Some might also try to tell you they will make sure it is a nice official battery and third parties can be dangerous.

As for guessing what goes. At this point any battery still standing is probably pretty old. I would not be surprised if the increased clock knocked the current draw up enough that it caused fun here.

Further experimentation in RACE! suggests even mild overclocking to 333MHz was the cause. I set the speed to 222MHz and played over an hour in the same game without any shutdowns or funny battery numbers.

I also noticed the battery temperature displayed in the gpsp menu is a crazy 4000C. Maybe it's reading 40C and just missing a decimal point. It doesn't matter, as the board is nowhere near the battery which lives in the UMD drive bay. I'm gonna try to get hold of a dead real Sony battery and use its board in future big battery mods.

 

[Ryccardo]

The regulator in 3rd party PSP batteries (at least the kind widely used nowadays) is indeed very poor, having to short pins to reset it is far from uncommon (just loot at PSP's reddit), the thermometer is probably a fixed resistor or none at all given your report, and neither they did really try with the EEPROM (which the PSP doesn't really care for, unlike let's say most laptops)