I'm curious if anyone else is using the Pi-UpTime UPS 2.0 board and if they have any data on the efficiency of the 3.7 to 5v boost converter on it?
I'm researching the best battery option for a long-term project and am doing a bunch of power tests. I have a USB-C multimeter that helps me to log some data while using wall power, but I don't have a good way to get much data while using a battery with a PH 2.0 connector into the UPS board, so I just have to run Pi on batteries until they die and do some math.
Even doing that, one variable that is unknown is the efficiency of the UPS board's boots converter. USB power banks seem to have between 80-85% efficiency so a 10,000mAh USB power bank usually ends up around 5,920 actually after the 5v conversion (if it's even up to the stated rating, which many are not even close).
Based on a few tests I've done on some known battery packs though, the UPS board seems to be REALLY efficient at better than 95% and/or my battery packs are doing 120% of rated capacity and/or my Pi is pulling way less than my cheap multimeter is reading.
Some real numbers: Pi measures 100-140mA for an average of 130mAh for my workload. I'm in the middle of a test with a 6,600mAh rated battery pack from Adafruit that has been running for over 19 hours and appears to be on the way to a 45-hour runtime. The only way I get to 45 hours is with 100% efficiency and 105mA load or 90% efficiency with 96mA load (or similar math in between there).
The cheap amazon USB multimeter is easy to blame, but it's been pretty plausible with its numbers so far. If the load reading of 130mA is correct, and the UPS board is 90% efficient, that makes this Adafruit battery pack 139% of rated capacity after sitting in a box for 2 years. Adafruit stuff has been good for me, but not THAT good, so I'm either missing something, or this battery pack is about to plummet. The voltage graph of the battery looks like the opposite though.
In the first 5 hours, the battery dropped from 3.96v to 3.78 (-0.18v). In the second 5 hours it went from 3.78 to 3.62 (-0.16v). In the third 5 hours it went from 3.62 to 3.53 (-0.09v). In the last 4 hours it went from 3.53 to 3.47 (-0.06v), with one more hour to go of course. The voltage drop has been trending down from .04v per hour at the start to .01 or .02v per hour now. The UPS board cuts off power at 2.8v to protect the battery so at present I have 0.67v left to go and at .02 per hour that would be 33.5 hours left. I have seen most batteries fall off a cliff with their voltage much faster at the end, but usually just the last hour or two.
I'm researching the best battery option for a long-term project and am doing a bunch of power tests. I have a USB-C multimeter that helps me to log some data while using wall power, but I don't have a good way to get much data while using a battery with a PH 2.0 connector into the UPS board, so I just have to run Pi on batteries until they die and do some math.
Even doing that, one variable that is unknown is the efficiency of the UPS board's boots converter. USB power banks seem to have between 80-85% efficiency so a 10,000mAh USB power bank usually ends up around 5,920 actually after the 5v conversion (if it's even up to the stated rating, which many are not even close).
Based on a few tests I've done on some known battery packs though, the UPS board seems to be REALLY efficient at better than 95% and/or my battery packs are doing 120% of rated capacity and/or my Pi is pulling way less than my cheap multimeter is reading.
Some real numbers: Pi measures 100-140mA for an average of 130mAh for my workload. I'm in the middle of a test with a 6,600mAh rated battery pack from Adafruit that has been running for over 19 hours and appears to be on the way to a 45-hour runtime. The only way I get to 45 hours is with 100% efficiency and 105mA load or 90% efficiency with 96mA load (or similar math in between there).
The cheap amazon USB multimeter is easy to blame, but it's been pretty plausible with its numbers so far. If the load reading of 130mA is correct, and the UPS board is 90% efficient, that makes this Adafruit battery pack 139% of rated capacity after sitting in a box for 2 years. Adafruit stuff has been good for me, but not THAT good, so I'm either missing something, or this battery pack is about to plummet. The voltage graph of the battery looks like the opposite though.
In the first 5 hours, the battery dropped from 3.96v to 3.78 (-0.18v). In the second 5 hours it went from 3.78 to 3.62 (-0.16v). In the third 5 hours it went from 3.62 to 3.53 (-0.09v). In the last 4 hours it went from 3.53 to 3.47 (-0.06v), with one more hour to go of course. The voltage drop has been trending down from .04v per hour at the start to .01 or .02v per hour now. The UPS board cuts off power at 2.8v to protect the battery so at present I have 0.67v left to go and at .02 per hour that would be 33.5 hours left. I have seen most batteries fall off a cliff with their voltage much faster at the end, but usually just the last hour or two.
Statistics: Posted by archaic0 — Thu Aug 21, 2025 12:26 am