# Difference between revisions of "1872: Backup Batteries"

 Backup Batteries Title text: If it falls below 20% full, my bag turns red and I start to panic.

## Explanation

A backup battery is a source of energy that may be used to recharge an electronic device. Backup batteries for phones are typically similar in size, shape and energy capacity to a smartphone. Cueball gets stressed when at low battery because a low battery may run out at any moment, interrupting activities being done with the phone.

In an effort to prevent stress, Cueball decides to carry a backup battery. This way he can recharge his phone should its battery run low. Cueball realises that the backup battery is itself prone to depletion, and so carries a second. He then comes to the same realisation for the second backup battery, and indeed every subsequent battery he can carry. This leads to an unending series of backup batteries, hence his speech is cut off, becoming unending as well.

What Cueball never grasps is that his irrational need to hoard a supply of batteries tending to the infinite is the real cause of his stress. In reality, he only needs to consider the maximum amount of time that he spends between recharging his phone, and divide that by the average lifespan of a phone battery, and round up that figure to get the minimum number of batteries required to avoid a power outage (multiplied by 1.5 if the mere state of running low causes stress). If he charges up his phone and backup batteries every night, he would only need 2 to 3 backup batteries, tops.

The title text talks says that Cueball's backpack will turn red if it is below 20% of its energy capacity, which the same thing happens to the battery indicator on an iPhone when at low battery to warn the user. Cueball gets similarly stressed when that happens, perhaps requiring a backup backup-battery backpack.

## Transcript

[Cueball is talking to White Hat. He is wearing a large backpack and holding a phone battery.]
Cueball: I get stressed out when my phone battery is low, so I carry this backup battery.
Cueball: But then I worry about the backup running low, so I carry this second backup.
Cueball: Then I worry—
[Caption below the frame:]
My bag is 90% backup batteries.

# Discussion

This actually sounds like the classic provisioning situation. How many spares do you require, and when do you require additional spares. One of the things that he doesn't mention is whether he carries a USB cord for his phone and USB power supplies for auto and wall outlet use. ( For iPhones, you need one cord for charging the phone and a different cord for charging the power pack.) I have three power packs in my bag normally. When one of the power packs is low on power, I plug it into an electrical outlet while using the phone. I also plug the phone into an electrical outlet when available to prevent the battery from running down. If at home or a hotel room, I can also have one or two power packs charging while I travel with the phone and the third power pack. I also charge the phone overnight. Having multiple power packs doesn't do any good without a means of maintaining them in a charged state. I typically start the day carrying a charged phone and three charged power packs, which is enough to let me use the phone all day. At night, I plug all of the devices into electric power. If I really wanted 24 hour usage or a lot of gaming (games use up the batter faster), I could use six power packs but only carry three with me at a time. The other three would be charging at a base location.

Having too many redundant backup devices can actually reduce the up time of the system. This was seen at the Superbowl in New Orleans. http://www.espn.com/nfl/story/_/id/9082144/relay-device-malfunction-caused-super-bowl-xlvii-power-outage-according-expert It is also very dangerous to assume that your backups are adequate and that you don't have to watch the log files. If somebody had been reading the logs, they would have seen the message that essentially said: "I have reported two power surges and you haven't told me what to do. Although these are not individually dangerous, one more power surge before somebody talks to me and I shut down the entire stadium."

An optimist states that the water glass is half full, while a pessimist states that the water glass is half empty. What an engineer really does is find out where the water faucet is so that he can refill the glass as needed. (The original joke says that the engineer states that the glass is twice as large as needed. This is ridiculous unless he knows how much water is needed and how much is available at the faucet. The size of this glass is irrelevant unless it is too large to be handled easily or too small to transport water at the required rate.)

BradleyRoss (talk) 17:21, 4 August 2017 (UTC)

I'm just wondering at your claim that iPhone users need two cords.... Every iProduct I've seen (and my brother likes to buy them all, or nearly) has only one that ends in a USB plug, which can go into a computer as a data cord, or into a block to be plugged into a wall outlet, or even into a car plug, to charge. Note that I feel it's clear that Randall is talking about additional phone batteries, in order to remove the spent battery and replace it with a battery from the backpack. NiceGuy1 (talk) 06:23, 8 August 2017 (UTC)

Assuming he charges the batteries in series (i.e. the second backup charges the first backup which charges the phone, etc.) I wonder how many batteries he'd be able to go through, before the charging/discharging inefficiency (heat generation etc.) meant none of the original power would get to the phone? Also I can relate to this comic, when traveling I may bring 2-3 batteries, even though in practice I rarely need more than one 😝😂. 18:58, 4 August 2017 (UTC)

EDIT: Replying to below comments, I have a power bank that allows simultaneous discharging and charging. Also I really meant to say it as them being charged/drained in sequence, rather than all simultaneously. PotatoGod (talk)

Maybe the bag turns red when it falls below 20% batteries...Jamgard (talk) 19:20, 4 August 2017 (UTC)

Judging by https://www.amazon.com/What-charge-discharge-Astro-time/forum/FxE1RP8KJUY0ED/TxVACXPN7AJZ1D/1?_encoding=UTF8&asin=B00M3073L4 and a number of similar entries, charging and discharging a metal hydride battery at the same time seems to be highly undesirable. Remember that these batteries have a bad habit of exploding if the charging and discharging rates aren't correct. If there were two batteries in series as you discuss, I believe that my best approach would be to be in another building and have the fire department on speed dial. BradleyRoss (talk) 22:00, 4 August 2017 (UTC)

The phone itself is constructed in way which allow it to run while being charged - likely by operating directly from external power instead of from battery. It would be theoretically possible for the backup batteries to be constructed the same way - although unlikely, as it's not something people would normally do. Also note that those backup batteries might be really just backup batteries (to be switched with device battery), not power banks (capable of charging the device). -- Hkmaly (talk) 03:14, 5 August 2017 (UTC)

I bet Cueball carries recursive battery backpacks as well, as well as recursive battery backpack backpacks, and recursive battery backpack backpack backpacks, and recursive battery backpack backpack backpack backpacks, and recursive battery backpack backpack backpack backpack backpacks, and recursive battery backpack backpack backpack backpack backpack backpacks, and... OriginalName (talk) 18:17, 5 August 2017 (UTC)

What if the backup batteries are actual removable batteries? 141.101.76.226 05:03, 6 August 2017 (UTC)

That's why I've inserted the incomplete tag again!--Dgbrt (talk) 18:00, 6 August 2017 (UTC)
I find there is absolutely no question that Randall does indeed mean a second (and third...) fully charged battery, to remove the spent battery and replace it with a full battery. It's the simplest solution for this issue (nearly tied with a portable charging solution, which is not as easy to come by and would require walking around with the phone plugged to it, but it might be cheaper than a whole second battery, and would avoid the interruption of turning it off for a battery switch). NiceGuy1 (talk) 06:23, 8 August 2017 (UTC)

I think the 20% full doesn't mean the energy capacity of the backpack, but the actual contents of the backpack. If it is less than 20% (charged) backup battery, he panics. Physicalattraction (talk) 11:04, 6 August 2017 (UTC)

That version of the joke with the bag blinking at "20% batteries" is also in another comment. Sure, that could be it, since a percentage of batteries is mentioned in the comic proper. However, it is ambiguous. The bag starts out at 90% batteries. So would the bag start blinking when charged batteries occupy 20% of the initial amount, such as in phones — which is 18% of the space of the bag — or would it start blinking when they occupy 20% of the total space in the bag, which is 22% of the initial amount? Besides, batteries are not removed from the bag when emptied, as they still have to be carried. If the bag is 80% uncharged batteries, I think the bag is still just as "full" of batteries, as worded in the title text. Furthermore, even if you decide that it refers to "charged batteries" (a wording which does not show up in the comic), a battery may be stored while partially charged, which makes it unclear whether it counts as a charged or uncharged battery. If it counts as charged, then it provides less energy than indicated by its count, and if it counts as uncharged, it provides *more* energy than indicated by its count, and may not be picked up by Cueball when he's looking for a charged battery and doesn't known which of his backups he just put back in there without fully using. If it counts as a partial battery, say, 50% of a battery if it's 50% full, then all you're doing is counting the energy capacity of the backpack, which is what is in the article because it makes sense, but with the added ambiguity of whether you have started from the total amount of batteries the backpack is capable of carrying, or simply the amount it started with. Therefore the title text must be referring to energy, which makes the most sense given all of these considerations, and which would most easily allow an actual such bag to be built, if it all the batteries were somehow plugged into some machine inside which would flash red lights when at 20% of the total capacity. Now, while writing this I notice that "energy capacity" is also slightly ambiguous as technically a backpack may have the "capacity" to carry more batteries than are in it, which may be said to be the "energy capacity", however I still believe the term is easily understood by article readers as the energy-carrying capacity of the total of batteries inside the backpack when summed. Lastly, I warn that you do not confuse "capacity" with "capacitance", as that word sprung to mind in this context. 198.41.230.94 14:02, 6 August 2017 (UTC)

TL;DR --Dgbrt (talk) 18:00, 6 August 2017 (UTC)
Also TL;DR, but I got halfway! :) (I can't complain TOO much, I often write a lot. But I try to split into paragraphs to make it more readable, like the first comment above. Except last time someone replied between my paragraphs, LOL!). I feel confident that what the title text means is that if the bag can hold a maximum of 100 batteries, that it turns red when there are 20 charged batteries left. After all, it's not like they're being depleted IN the bag (in theory. In reality batteries lose some charge the longer they're sitting idle), a full battery is taken out and an empty battery is returned. So all the batteries in the bag are either full or empty, none are in between.
As for me, I only charge my battery when it starts to complain (15%, though I try to wait until a little after, but before the bigger complaint at 5%), not every night, and I tend to go 3 or 4 days on a single charge. Though I don't use it for entertainment, I only use it for communication, as a camera, as a flashlight, and looking things up (getting information or finding something to show somebody) NiceGuy1 (talk) 06:23, 8 August 2017 (UTC)
Almost certainly the batteries ARE being depleted in the bag, since in order for the bag to register how many are charged / how much charge they retain, they will have to be connected in some way to the bag, causing them to discharge. Unless the bag is using difference in weight to distinguish between charged and empty batteries, in which case it's going to be extremely liable to false readings. Or if there are separate compartments for full and empty batteries, and it can detect how many are in each, but in that case the warning would be a little redundant, as a simple visual check would suffice.141.101.107.66 11:53, 8 August 2017 (UTC)David
Actually since the idea of a backpack being able to show a charge - and change colours accordingly - is ridiculous and unrealistic, I had understood that the backpack just magically reads the levels without a connection. It just knows. :) I'm just imagining the wiring nightmare of connecting THAT many batteries to ONE spot on the backpack, LOL! 90% full of batteries, the other 10% would be wires! And hey, it happened again, a comment within my comment! Fixed it now. Might have forgotten to indent my second paragraph, might have been my fault. :) NiceGuy1 (talk) 04:09, 15 August 2017 (UTC)

I didn't have any luck finding low-battery-related comics particularly closely related to this one, but I'm still putting mention of 1373 in and removing the incomplete status. OriginalName (talk) 17:03, 25 August 2017 (UTC)