But if you just connect them then steam/nuclear power is used to charge the accumulators. Which makes them basically pointless. You might as well just power the base all night with steam/nuclear for the same fuel consumption.
There are some simple circuits that detect when the accumulators are low and when the sun is rising. But I can't remember any that detect when solar panels produce just enough to power the whole base and don't charge accumulators from steam/nuclear. So I made one:
- power-overview.png (4.61 MiB) Viewed 4940 times
Note that the power controller sits between the boilers and the steam engines. The controller needs to measure steam being used accurately. That only works if 1 unit of steam is used over 9 ticks, which comes to about 225kW. That is 225kW over what solar panels provide. You don't have to route all your steam through the power controller but the more the better it works.
- power-control.png (2.49 MiB) Viewed 4940 times
Each tank then has 2 combinators attached, one turns the steam signal into water to create a 1 tick delay, the other subtracts steam from water to signal the change in steam level in the tank. For each that is then filtered for steam > 0 to only report used steam and not the refill.
Then at the bottom are a bunch of combinators each + 0 = each that simply delay the signals and all flow into a final decider combinator on the right that outputs 1 steam if steam > 0, i.e. if any steam was used in the last 9 ticks. All this so far is just to measure if steam is being used or not.
Now comes the power control: Again a fish loop is used, this time to eliminate fluttering of the power switches. The fish is removed from the chest when the accumulators are below 2. This turns on the steam engines. I assume that 1% charge is enough to run the base for 1 tick. You can increase the trigger if not, but really what is the point of the accumulators if they don't hold at least 100 ticks worth of power. This will also disconnects the accumulators so they don't recharge from the steam engines.
Then when the sun rises the solar panels will slowly take over power production and less and less steam is used. When steam usage drops below 1 steam per 9 ticks for a while (you can see the inserter stutter a bit if you watch closely, it needs quite a few ticks without steam signals to pick up the fish) the fish is put back into the chest. This will turn of the steam engines. The accumulators on the other hand already connect when the inserter holds the fish. This means that for ~0.1s the accumulators charge from the solar panels and steam engines. This gives them a little boost to give them a charge of >= 2. Without the boost the fish would get removed and make another loop (or two or three).
Here is how it looks in the power graph:
- power-graph.png (108.24 KiB) Viewed 4940 times
Note: Since solar and accumulators provide most of the power for the base the actual steam used on average is low. You can run a small number of boilers 24/7 and store the steam and then power a large number of steam engines or turbines for the short times they are needed. With just solar panels one boiler can power 6 steam engines. With more solar panels and accumulators this goes towards infinity (if you have enough the steam never runs). On the other hand if you power demands rise the ratio can go the other way. But then the accumulators will be pointless and remain uncharged and unused. Start with a 1:6 ratio and then add more steam engines in parallel with accumulators. A 1:20 or 1:30 ratio is totally reasonable.
Caveats:
1) If you don't have enough solar panels then steam will run all the time and the accumulators will never be used. But that is a stable setup and won't cause brownouts (provided you produce enough steam). So start by building solar panels until steam turns off during the day and then some. No point adding any accumulators before that point.
2) At dusk the accumulators have to supplement the solar panels to power the base. At night they have to provide all the power. But accumulators have a limited throughput. They might not be able to provide enough power for the base even if they have a charge left. I think they would drain during dusk while you still have a mix of solar and accumulator power but that is untested. So you might get brownouts if you have enough accumulators to outlast the solar panels but not enough to power the whole base (throughput wise). At the moment I assume that can't happen but let me know if it does. The fix is to place more accumulators.
3) If you have a backout at night the controller will remain stuck in whatever state it is. Which would make it impossible to switch steam tanks or turn the steam engines on. You probably want some solar cells near the controller and make damn sure biters don't damage the controller.
4) Since steam is controlled by the pumps no steam flows without power. A brownout means the pumps may slow down and then the steam engines may not get enough steam and you have a death spiral. This should recover on it's own at sunrise. Still something to watch out for. The controller could be detached from the normal power and run on it's own set of solar panels and accumulators. At 75kW 2 solar panels and one accumulator should do.
What do you think? Is there a simpler way?
I'm fine with the first fish loop that alternates between 2 tanks, one filling, one draining.
