I woke up this morning to a text from my ISP, “There is an outage in your area, we are working to resolve the issue”
I laugh, this is what I live for! Almost all of my services are self hosted, I’m barely going to notice the difference!
Wrong.
When the internet went out, the power also went out for a few seconds. Four small computers host all of my services. Of those, one shutdown, and three rebooted. Of the three that ugly rebooted some services came back online, some didn’t.
30 minutes later, ISP sends out the text that service is back online.
2 hours later I’m still finding down services on my network.
Moral of the story: A UPS has moved to the top of the shopping list! Any suggestions??
Laptops
My favorite part about using an old laptop as a 24/7/365 plugged-in server is the anticipation of when the lithium battery will explode from overcharging.
“overcharging” doesn’t exist. There are two circuits preventing the battery from being charged beyond 100%: the usual battery controller, and normally another protection circuit in the battery cell. Sitting at 100% and being warm all the time is enough for a significant hit on the cell’s longetivity though. An easy measure that is possible on many laptops (like thinkpads) is to set a threshold where to stop charging at. Ideal for longetivity is around 60%. Also ensure good cooling.
Sorry for being pedantic, but as an electricial engineer it annoys me that there’s more wrong information about li-po/-ion batteries, chargers and even usb wall warts and usb power delivery than there’s correct information.
Isn’t dendrite formation and the shorts they can cause a much bigger concern when dealing with old batteries that are being charged 24/7? Asking a genuine question here, so please don’t shoot me if I’m wrong. 🙂 I’d love to hear more about the most common failure modes and causes for li-po/ion batteries.
Those are symptoms of sitting at that operation point permanently, and they are a of course a concern. What I’m after is that people think that energy gets put in to the battery, i.e. it gets charged, as long as a “charger” is connected to the device (hence terms like “overcharged”). But that is not true, because what is commonly referred to as “charger” is no charger. It is just a power supply and has literally zero say in if, how and when the battery gets charged. It only gets charged if the charge controller in the device decides to do that now, and if the protection circuit allows it. And that is designed to only happen if the battery is not full. When it is full, nothing more happens, no currents flow in+out of the battery anymore. There’s no damage due to being charged all the time, because no device keeps on pumping energy into the cell if it is full.
There is however damage from sitting (!) at 100% charge with medium to high heat. That happens indipendently from a power supply being connected to the device or not. You can just as well damage your cells by charging them to 100% and storing them in a warm place while topping them of once in a while. This is why you want to have them at lower room temperature and at ~60%, no matter if a device/“charger” is connected or not.
(Of course keeping a battery at 60% all the time defeats the purpose of the battery. So just try to keep it cool, charged to >20% and <80% most of the time, and you’re fine)
For many li-ion laptop batteries, the manufacturer’s configuration of a 100 % charge is pretty much equivalent to overcharging. I’ve seen many laptops over the years with swollen batteries, almost all of them had been plugged in all the time, with the battery kept at 100 % charge.
As an electrical engineer you should know that technically there is no 100 % charge for batteries. A battery can more or less safely be charged up to to a certain voltage. The 100 % charge point is something the manufacturer can choose (of course within limits depending on cell chemistry). A manufacturer can choose a higher cell voltage than another to gain a little more capacity, at the cost of longterm reliability. There are manufacturers that choose a cell voltage of 4250 mV and while that’s possible and works okay if charged only occasionally, if plugged in all the time, this pretty much ensures killing the batteries rather quickly. I would certainly call that overcharging.
Since you already mentioned charging thresholds, I just want to say, anyone considering using a laptop as a server should absolutely make use of this feature and limit the maximum charge.
If you say it quickly enough it may sound plausible to some but this is not how battery technology works, as explained by @[email protected]
Amen. I appreciate my UPS for sure!