Solar panels and batteries: number nerdiness

Started by Slev, November 20, 2013, 04:05:19 PM

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Slev

In the Let's Play videos I've seen, people always seem to build huge battery chambers. That got me to wondering how much storage is actually needed.

I put together some sums based on building descriptions. I haven't managed to test these in-game yet, so I'd be interested to hear if anyone else has.
(For those of you who are as much of a dork as I am:
https://docs.google.com/spreadsheet/ccc?key=0At-nwHqB-9gNdG4zVUJMNldHc3ZOWFdSRldiVTdGYWc&usp=sharing)

Based on hitting pause halfway through each hour, it looks like solar panels produce 1700 Watts between about 07:00 and 16:00, nothing between 20:00 and 03:00, and change in a roughly linear way in the morning and evening. (Perhaps someone with a knack for code, or inside knowledge, can tell us if the transition is actually quadratic or sinusoidal or something).

That gives solar panels an average output of 1000 W over the 24 hour cycle.

Batteries have a 50% efficiency; in 24 hours, one panel will charge up a battery by 467.6 Watt-days (OK, I tested some things in-game). That fits with a roughly 1000W average power.

If some of that power is being used directly, rather than inefficiently stored, I reckon a single solar panel can support something like 750 Watts of demand. At some point I'd like to try hooking up a panel-battery-sunlamp (800 Watts) and seeing if it slowly charges or suffers blackouts in the wee hours.

And if you're thinking it, because I did, no; You can't light up a solar panel with a sunlamp and build an over-unity loop. Solar panels don't seem to register artificial light at all (granted, there is no reason for them to do so in-game, other than exploits).

The point of all this is that, by my calculations, the rule of thumb should be that for every four solar panels you only need one battery to give a continuous supply.

The reason to have a whole hallway full of batteries is for the eclipse (or unforseen accidents taking out the panels, I suppose). Does anyone know how long the eclipse lasts? Is it always the same?

By my numbers, a base that is just getting by on X solar panels will go through X fully-charged batteries a day (or one battery every five days, if they go dark on everything except the paste dispenser).

So, what's your preferred approach? The more the merrier? Are occasional blackouts and micro-managing your standing lamps worth it to avoid the Short Circuit event?

deadbeat88

I tend to have atleast 50 disconnected full batteries and 4-8 connected ones.
disconnected ones are divided into 5 groups placed further apart from other groups.

-I realised that having this minimises the chance of short-circuit.
-putting batteries 1 space away from the wall further reduces the risk
-having more connectors does too.

reserved power are used during fog and eclipse(usually 2days long)
Whatever you do, don't do it!

laser50

It's weird, because throughout my time of playing, it didn't really seem to matter howmany batteries I had hooked up, it'd drain just the same.. You would expect it to go slower as you have more batteries, thus less need for power, but it doesn't seem that way..

Slev

Do the disconnected cells of 5 ever have short-circuits, or does that only happen if there's a change in charge?

In reality I think disconnected batteries would discharge over time, but I guess that doesn't happen here.

Galileus

Quote from: laser50 on November 20, 2013, 05:29:38 PM
It's weird, because throughout my time of playing, it didn't really seem to matter howmany batteries I had hooked up, it'd drain just the same.. You would expect it to go slower as you have more batteries, thus less need for power, but it doesn't seem that way..

The drain is the same - say -5W per second or whatever. The more batteries you have the more storage you have - so it's 1k with few and 50k with a lot. Obviously, if you drain -5W per second from 1k storage you're empty after 200s, if you have 50k - it's suddenly almost 3h you can drain them. Drain stays the same - the time you can drain them for changes.

enystrom8734

#5
Quote from: Slev on November 20, 2013, 05:53:23 PM
Do the disconnected cells of 5 ever have short-circuits, or does that only happen if there's a change in charge?

In reality I think disconnected batteries would discharge over time, but I guess that doesn't happen here.

Short circuit events only occur if connected to a conduit or wall. They are the vessel of which the explosion occurs.

Also a sun lamp connected to a battery and solar panel is consistently on. However as of right now they draw 600w and Im not sure they are supposed to...
E Nystrom - @enystrom8734

Wopian

I have enough batteries to supply my base with no power input for 2 months (never know when those buggy solar storms will last forever)


Bobstudios | James Harris Creative Design

Nasikabatrachus

I prefer to build multiple chambers of batteries, divided into groups of five batteries each, which I charge and then disconnect for long term storage, leaving five batteries permanently connected to the grid to even out any variations in power input. So far this strategy hasn't given me any significant benefits, since it turns out that raiders almost always ignore external, undefended geothermal generators, and those are practically batteries anyway. It does appeal to my hoarding instincts, but those five permanently connected batteries can handle almost all of the problems I've encountered.

Anyway, I'm glad someone sat down and did the math, because I would almost certainly never do it myself. !!SCIENCE!!

W1Z25

i honestly have never disconnected batteries.. i will have to start doing that.. i generally just have 30 batteries all hooked up

laser50

Quote from: Galileus on November 20, 2013, 06:07:10 PM
Quote from: laser50 on November 20, 2013, 05:29:38 PM
It's weird, because throughout my time of playing, it didn't really seem to matter howmany batteries I had hooked up, it'd drain just the same.. You would expect it to go slower as you have more batteries, thus less need for power, but it doesn't seem that way..

The drain is the same - say -5W per second or whatever. The more batteries you have the more storage you have - so it's 1k with few and 50k with a lot. Obviously, if you drain -5W per second from 1k storage you're empty after 200s, if you have 50k - it's suddenly almost 3h you can drain them. Drain stays the same - the time you can drain them for changes.

But if the drain is the same, then there is no change in time, because if they're all equally draining, you will lose as much on 10, as you would on 1 battery, no?

MrRobSteel

That's not how it works. It's drain on the whole powernet that doesn't change. Drain per battery is powernet drain divided by the number of batteries you have. So if you drain 50w and you have 50 batteries is 1w per battery.

deadbeat88

Quote from: MrRobSteel on November 21, 2013, 09:52:04 AM
That's not how it works. It's drain on the whole powernet that doesn't change. Drain per battery is powernet drain divided by the number of batteries you have. So if you drain 50w and you have 50 batteries is 1w per battery.

that is correct.

also note that batteries have 50% efficiency so if you fill up around empty 10 batteries at once, it will take a very long time to reach their full level.

always fill up around 2-3 empty batteries at once(at most) so that it'll be faster.
Whatever you do, don't do it!

enystrom8734

Quote from: deadbeat88 on November 21, 2013, 11:37:08 AM
Quote from: MrRobSteel on November 21, 2013, 09:52:04 AM
That's not how it works. It's drain on the whole powernet that doesn't change. Drain per battery is powernet drain divided by the number of batteries you have. So if you drain 50w and you have 50 batteries is 1w per battery.

that is correct.

also note that batteries have 50% efficiency so if you fill up around empty 10 batteries at once, it will take a very long time to reach their full level.

always fill up around 2-3 empty batteries at once(at most) so that it'll be faster.

The difference between filling 1 battery up with a solar panel and 10 up with a solar panel in one day is about 60Wd. 2-3 is roughly only a differnce of 5-10Wd
E Nystrom - @enystrom8734

jjgoldman

This whole topic stinks of un-fun micromanagement.  I prefer these tactics not be effective in the final version.

Galileus

You mean, you prefer if people who spend a lot of time thinking stuff over don't get better result than ones who half-ass it through? o_O