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From: <bp@www.zefox.net>
Newsgroups: comp.sys.raspberry-pi
Subject: Re: Backup power supply
Date: Thu, 14 Mar 2024 18:11:25 -0000 (UTC)
Organization: A noiseless patient Spider
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Mike Scott <usenet.16@scottsonline.org.uk.invalid> wrote:
> On 14/03/2024 15:51, Joe wrote:
>> I'm using a cheap APC, I believe 650 or 750, with USB monitoring hookup.  Also have my router connected (with VOIP) to keep
>> communication possible for a little while (runtime abt 30 minutes).  Battery replaced once, I believe it was some 7 years old.
> 
> Somehow that makes no sense to me..... current 650 is 227 pounds (maybe plus 
> VAT) on the APC website. 5 times the cost of the Pi. I'm sure it's a 
> very nice UPS, but.... ???
> 

Sense or not, it seems to be a fact of life. The inverter/charger/transfer units
I used have vanished from Amazon, replace by units with four times the power and
double the price. Battery prices seem to have dropped very slightly, but are
still a whisker over $200/kWH.

A 12 volt to 5 volt stepdown converter appears to be less than $10, small 12 volt
batteries range from $20-100 in the few AH range, a 12 volt 5 amp charger ranges
from $11 to $50. The charger would be the iffy part, since a smart charger on a
loaded battery is apt to get confused by what looks like high self-discharge..

Something reliable for less than $100 will take both luck and ingenuity. One
possibility is finding a used UPS unit in e-waste and replacing the battery.

bob prohaska


> 
> 
>> 
>> 
>> On Wed, 13 Mar 2024 13:18:45 -0000 (UTC), usenet@dolik.dev (Andriy D) wrote:
>> 
>>> Hi,
>>>
>>> I'm considering adding some backup power supply for my RPi2 mainly
>>> to avoid filesystem issues which may be caused by a  short power outage.
>>> There are some interesting schematics online as well as some quite
>>> cheap 'manufactured' options. But I'm wondering, maybe someone has
>>> some experience / feedback to share?
>>>
>>> Cheers,
>>>
>>> \aID
>