Looks pretty cool. I wish it had a USB, serial port or I2C for status info.
It might be just what I need.
@ skeller - Agreed. Delaying an uncontrolled shutdown is not the same as mitigating the impact of uncontrolled shutdowns.
@ suitable1 - Seems like a pretty small capacity battery for that price. If I’m doing my math correctly (and it’s entirely possible I’m not), that’s just 1500mAh. Loads of external batteries with higher capacity, though admittedly few of them provide 12v. And of course, there’s the switching circuit.
So perhaps the pricing is reasonable given the lack of other suitable solutions. Would still prefer to have a bit more capacity…doesn’t take a ton of juice to run a Pi 2 or a NUC, so it should be possible to back it up for more than 3 hours.
@ devhammer -
Yes, for that price I would like to see some alert mechanism. Although, in the twenty-one years that I’ve lived in this house, there has only been two outages that were over three hours. Most that I’ve noticed have been short enough that the UPS clicks in and then back out again.
@ andre.m - I would agree. For industrial applications I think there could also be temperature range issues, primarily with charging.
Here is a quick overview of the charging temps of various battery chemistry.
Charge - 0°C to 45°C (32°F to 113°F)
Discharge - -20°C to 60°C(-4°F to 140°F)
Li-polymer has the same charging characteristics as Li-Ion according to this document:
Moral of the story, don’t try to charge your Li batteries when below freezing. This eliminates any outdoor applications in the northern half of USA.
I don’t think you can necessarily say don’t charge Li-based batteries unattended, nor really read into what this device is really using. Most Li-battery fires are LiPo’s, and most susceptible are those who are “roughly” handled by remote control toys (planes, helis, quads) where they’re exposed to higher discharge rates and desire to recharge fast, as well as physical damage.
LiFePO4 is a very safe composition for batteries and is becoming widely used in solar offgrid and likely to start moving into other significant use cases too - who knows, they may be using them in this.
Also, 18650 is the ubiquitous cell size these days and are well protected from short/fire