Mini ISRU

[ruiluth]

There doesn't seem to be much information about how well the Convert-O-Tron 125 stacks up against the 250. I'd like to know what others' experience with the two has been before I design and build a whole fleet of ships around one or the other.

Also, the wiki claims:

Quote

Despite its product description, the Convert-O-Tron 125 does not receive any bonus when operated by an engineer.

However the part.cfg claims:

UseSpecialistBonus = true

Pretty sure that means the wiki is wrong, correct? A probe with the mini ISRU will suffer just as much as a probe with the larger one. I'll still have to fly engineers out there.

[Aegolius13]

The scuttlebutt that I've seen is that the small ISRU is much less efficient than the bigger one (even after accounting for mass difference), and is not worth using unless you're constrained by design needs (e.g., need it to fit in a Mk 2 spaceplane).  

Example thread here:

The small drills, however, are supposed to have performance in line with their larger counterparts, so they are more likely to be a useful tool.  In other words, if you need to save a little weight on a mining rig, better to downsize the drills first.

I think the engineer bonus currently applies only to drills, not ISRUs.  But at least with the bigger ISRUs, their processing capacity is so much greater than the drills that even with the engineer bonus, the drills are usually still the bottleneck.  

[Foxster]

I'm not a big user of the ISRU but does it matter if it's slow? Don't you just warp through extraction and processing?

[Reactordrone]

29 minutes ago, Foxster said:

I'm not a big user of the ISRU but does it matter if it's slow? Don't you just warp through extraction and processing?

It does take a long time with the small unit though since you only get a 10% return on the ore input, i.e put in 400kg of ore and get out 40kg of fuel so you need to mine a huge quantity of ore to refuel.

[Foxster]

2 minutes ago, Reactordrone said:

It does take a long time with the small unit though since you only get a 10% return on the ore input, i.e put in 400kg of ore and get out 40kg of fuel so you need to mine a huge quantity of ore to refuel.

Even at max warp? Last time I tried it at a low ore site it still took less than a minute to mine a load of ore and process it. 

[Zamolxes77]

How many junior drills it takes to feed a small ISRU  ? I have like 4, with a 5 star engineer, mining in a 7.9% ore area, getting 0.029 ore/sec/drill. Is that the load % that appears on ISRU control window ? I stopped a drill and load % went down, my guess is yes, so 4 junior drills only load the ISRU 4.7%, damn !

Edited July 31, 2016 by Zamolxes77

[Aegolius13]

Since the small drill requires ten times more ore input than the bigger one, it is basically impossible to bottleneck it with junior drills, regardless of ore concentration or engineer skill.

As far as whether efficiency matters given you can time warp, the general answer is only if you decide to care about time for "story" reasons, or if you use a life support mod or the like.  But if you do your ore harvesting on the surface and your refining in orbit, the small ISRU will be terrible since you'll have to haul up ten times as much ore.

Edited July 31, 2016 by Aegolius13

[bewing]

The other place where time matters is with contracts. They have a time limit to accept them, and another time limit to complete them -- and every second you timewarp is another second off every one of your contracts.

[ruiluth]

9 hours ago, Reactordrone said:

It does take a long time with the small unit though since you only get a 10% return on the ore input, i.e put in 400kg of ore and get out 40kg of fuel so you need to mine a huge quantity of ore to refuel.

This is the information I was looking for, I'll be sure to use the 250 or the one from KPBS. Thanks.

[magnemoe]

I used the small ISRU on my Tylo ssto and on my first Duna base, two issues first its slow secondary it overheat easy. 
Found that it works better if you have it active than while not in focus, 

For uses, only use it where weight or space is critical, or perhaps if you don't need much fuel, if you only need it for an tiny lander on a base you hardly need the large one. 
 

[mk1980]

the small one is ok if time is not a big issue. in many cases of interplanetary trips, you will have to wait months or even years for the transfer window back to kerbin, so the low efficiency doesn't matter much. for a dedicated fuel infrastructure system, i would always use the large one, though.

also worth poining out: the small one is especially bad for asteroid mining. unlike planets, asteroids have a finite amount of ore. wasting 90% of the ore mass is much worse when the ore isn't infinite. you can squeeze out a lot more fuel by using the big ISRU.

you don't need the big drills for asteroids, though. they have very high density, so the small drills work just fine. also, you need a lot less drills overall.

i'd always use the large drill for an exploraton vessel that lands somewhere on other planets. the small drill only works at 2.5% ore concentration or better. it's easily possible to end up in an area with a lower concentration, and then you're screwed. with the large drill, you can at least mine slooooowly in low density areas.

[fourfa]

I'll add that if you play on higher difficulty levels (for instance simply selecting 'Hard' when starting a new game) you will find that most of the surface of every planet has zero ore.  Only a tiny few spots will have over 2.5%, many of those will be in polar regions that may be harder for you to get to, and many will be in very steep canyon areas.  The small drills are a major liability during exploration.  They make more sense once you've done some ground surveys and marked out good LZs.