Tag: battery testing

APC Back-UPS capacity upgrade (#P11F1)

Was that foreseeable? Not sure, but the design called for it…

Now that my modified APC UPS is running smoothly again (#P11), I still had two pairs of these nice XT60 connectors laying around. And as old, to-be-recycled lead acid batteries from UPSes pile up at work, I took one or two of them with me for testing at my electronic load. Like previous batteries, quite a lot of them are really toast, but some of them are in decent condition. Not as in “like new, ready for another year of service in a commercial fire alarm system”, but still holding a significant fraction of their original capacity and delivering a suitable amount of current. […]


APC Back-UPS external battery mod (#P11)

Good thing I’m a doofus. While tidying up cables after some keystone module action, I also moved the bulky power supply of my monitor. And then I noticed that the only thing that absolutely has to be on the battery backup outlets of my UPS unit was in fact…assigned to the surge-protected ones that fail when mains power is gone. D’oh. After some cable identification in that tight space, I moved the UPS around a bit and I discovered a drop of liquid. A very dubious drop at a place where liquid would have to seep through 4 centimeters of a wooden table, or somehow permeate 1.5mm of solid steel against gravity’s pull. […]


26650 LiFePO4 8S battery pack with BMS (WHL #27)

This weeks article is another by-product of the ADC testing (WHL #26) from last week. Could’ve packed in there, but I wanted to share some remarks on Chinese battery technology…

So first of all, this isn’t a piece of kit that I bought myself. After testing two 12V/2.2Ah lead batteries from work that were sitting unused on a shelf for five years, I needed another victim. Those quality Panasonic cells were flat as Kansas – the LC-R122R2PG datasheets recommends 8.6V cutoff voltage at 3C = 6.6A or 9.7V at 1C. Fully charged, they delivered 1C at 7V or 1.5C at 2.5V at full charge – slow 10.5V discharging to 0.1C cutoff and recharging didn’t help much. […]


16 Bit I2C ADS1115 Module ADC 4 channel with Pro Gain Amplifier RPi (WHL #26)

Meep. We finally have a new product review, after all that editorial, recap and electronic load rubbish ;)

Today’s item in the mail is an I²C ADC on a small PCB, running four channels (or two differential ones) with 16 bit precision. Sounds nice? Well, if it holds the claimed specs, it IS a nice product! I bought it in mid-June on AliExpress for 2.06 USD. Adafruit, by the way, charges 15 bucks for the exact same thing. Do I smell profit margin?

Here’s how it looks straight out of the ESD bag:

Backside is a tad boring (keep the VDD in mind):

(there’s a floating island on the GND plane, boo!)

So, what does the friendly Asian seller claim? […]