Isolated power networks and laser sentry turrets

Ages · Post by **Ages** » Fri Mar 19, 2021 9:02 am

TLDR:

I am using an accumulator as a resistor to restrict energy flow to an isolated grid.
Problem is that the accumulator on the otherwise isolated grid will not maintain a charge.

Hoping someone could help me with:

Identifying if this is a bug or intended feature
Ideas for workarounds (hoping to come up with something both tile-able and simple)

The sentry laser problem:

I am working on a sentry laser wall based on XKnight 's design which disables power to all lasers except for one "sentry" laser which triggers the other lasers to wake up and shoot.

The sentry laser wall works by using three 'separate' power grids:

Main grid (just the power source from base)
Sleeping turret grid (connected to the main grid through a power switch)
Sentry turret grid (single, always powered laser tied to an accumulator which is used to trigger the power switch)

Generally a solar panel (60kW) is used to power the accumulator and a single powered sentry laser draws 24kW.
When this laser fires it draws the full 300kW available output from the accumulator, surpassing the 60kW solar panel.
This reduces the charge in the accumulator and flips the power switch to let power in from the main grid powering the sleeping lasers.
Until nightfall... which is when the lasers all wake up and do nothing but drain power until morning.[/i]

I decided to add a second accumulator overlapping the main and sentry turret grids using the accumulator as a resistor to limit the power flow and removed the solar panel.
In theory this would mean that the main grid can pass 300kW through the overlapping accumulator while the sentry laser could pull the full 300kW from both accumulators for a total of 600kW.
The idea is that the main grid will keep both accumulators charged night and day and the laser would still be able to drop the accumulator enough for the power switch to toggle.
Problem is that the accumulator being used as a resistor between the main grid and the sentry grid does not maintain the charge of the accumulator on the sentry turret grid.
One accumulator overlaps the isolated sentry power grid with the main grid, while the other is connected just to the isolated sentry grid.

Accumulator resister concept I am trying to use: (photo from wiki)

Blueprint of current (broken) design:

Blueprint view:

Out in the wild:

torne · Post by **torne** » Fri Mar 19, 2021 10:35 am

Accumulators don't charge from each other. The accumulator-as-resistor only works to supply actual energy consumers.

Redpossum · Post by **Redpossum** » Sun Mar 21, 2021 11:46 pm

I spent a while looking at this one, and I don't get it.
The wiki page for the Power Switch isn't exactly the most comprehensive https://wiki.factorio.com/Power_switch
But if you have nuclear power, why even bother?

MEOWMI · Post by **MEOWMI** » Mon Mar 22, 2021 1:55 am

I played around with 0 drain laser walls for a bit a while ago, based on viewtopic.php?f=193&t=69537 by Qon, and made a few changes myself, but the gist is, afaik, that the accumulator will drain yes and you need a way to maintain a certain charge level on it. Qon's solution includes a single base-wide circuit to accomplish this. It does so by repeatedly and very precisely turning on the power switch for a few ticks.

I tried making changes to it to make it nicer and cleaner, but I just could not find a better way to accomplish that no matter how I tried, so my own changes were mostly about the layout in general. I think my circuit ended up being programmed exactly the same way.

The situation is just very particular about how you maintain charge on the trigger accumulator, so that you get sufficiently good activation timing. For example, changing the recharge parameters even a little would often lead to incoming attacks doing more damage than seemed warranted - not enough to destroy anything but enough to start outweighing the benefits. As a matter of fact, even the optimal setup fares worse than just keeping your turrets constantly powered (though this only becomes very apparent after testing) but despite that, I still think it's a worthwhile design, especially if your walls are only attacked rarely.

gGeorg · Post by **gGeorg** » Mon Mar 22, 2021 9:57 am

Ages wrote: Fri Mar 19, 2021 9:02 am I am working on a sentry laser wall based on XKnight 's design which disables power to all lasers except for one "sentry" laser which triggers the other lasers to wake up and shoot.

Hello, I am glad someone does proper research to the topic.
Some answears :
battery charge only when there is a surplus of energy in the particular grid.
battery can charge up only from a grid where it belongs, I recommend you use F4 look for "Show power grid number" (or something similar name I dont remeber exactly so it shows you the number of the grid). You will see what is what.
Battery can not charge up from battery leaked energy. -> Battery cant charge up battery
Laser tower can eat battery leaked power.
Also battery belongs to both grids discharge to BOTH grids. It makes some not easily predictable states.

Looking forward to your solution to compare with mine. It took me some months to forge a solution. It will be nice to compare to your result.
Here are targets and measurement:
Laser only wall using separate power grids to detect threats and activate.
Make design tile-able on the wide of roboport.
Measure how many ticks from bug to enter the sentry zone to the activation.
Measure how many ticks to fade out. e.g. after battle to sleep again process.
Make sure it works 24/7. Guarantee safety day&nigh without issues.
UPS friendly
Vanila only

The battery leak trick is a key I think. { Using word rezistor sounds wrong, battery_leak fits. }Nice feature is, the leaking batteries work mainly towards the main grid, so their capacity count into the main grid energy capacity. The perfect ratio of a solar field is broken, so could make a bit discomfort for OCD players, but what you can do.

Looking forward, when you come up with a solution then I come to show mine to compare. Now, I just dont want you spoil with certain way of thinking.

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