Companion forum thread to:

Stoves, Tents and Carbon Monoxide - Deadly or not?
Supplement 6: Primus Eta PackLite System

I've been curious about this stove for awhile! Thanks. Can you expand on its ability to run the canister inverted? My primary use is in cold conditions where that's kind of important.

Due to Roger telegraphing this report in advance I was encouraged to buy one of these stoves and have made the amendments he mentions. All of them work. The loss of the strainer lid to a piece of standard foil was not much loss and I think the foil windscreen is better protection than the raised original. I also cut off the feet the windscreen stood on and cut away bits of the base that seemed uneeded, cut most of the rim off the pot leaving only 2 pour spouts and drilled some lightening holes in the locking plate of the handle. An absorbent cloth protects the non stick coating. I find the pivots of the legs a little loose so sometimes a leg rotates when I do not want it to. All in all it is fast and melts snow fast and economically. A 1200 pot is small for 2 but as we were using a jetboil cut down to 800ml it is comparative luxury.
I think I got the package of burner, windscreen, lid piezo, pot down to 400 grams. In comparison our reduced Jetboil is 300 grams.
As far as inverted use We start the stove low put on the pot then invert the canister. It then roars away quite happily. It could go faster but that is fast enough. You can reduce it a bit but to simmer I find it best to go back to gas feed. It then simmers pretty well. The trick to save gas is to uninvert the stove at the right moment to use up all the liquid gas in the flexible tube so that your water boils and you can switch off quickly. If you switch off inverted you have a long time lag before the gas goes out that can fill your cold tent with steam. You can imagine I have been there.

Edited by Derekoak on 03/10/2010 10:02:18 MST.

> its ability to run the canister inverted?
I would not bother using this stove with an upright canister. If conditions are warm enough I would use a Snow Peak GST-100 on the upright canister. This (Packlite) is a stove for use in winter with an inverted canister.

Cheers
PS: another review, of the Primus Express Spider, is coming. Same burner, same performance, even lighter weight. But no Heat Exchanger pot.

But the pot is available as a separate unit.

The packlite can be used with any reasonable light pot. I only carry the heat exchanger pot if the trip is going to use enough gas to make the saving worthwhile. The spider would need a heat exchanger pot too to be as versatile

"PS: another review, of the Primus Express Spider, is coming. Same burner, same performance, even lighter weight. But no Heat Exchanger pot."


Roger, I'm very excited about this stove and I've been waiting for your review of it.

@ Derek: In Roger's "Heat exchanger Shootout" article he states that the Heat exchanger pot will only save a minuscule amount of fuel. So little that carrying the extra weight would not equal out unless you hiked an infinitesimal hike between resupply stops.

My syntax is crap.

Try this: No human can go far enough between resupply points to make the extra weight overcome the savings in fuel.

Search "heat exchanger shootout" and read it- very informative.

He probably made it all up though. You know Roger- always making generalizations and never really getting to the nitty gritty of whats really going on;)

Hi Jeff

> unless you hiked an infinitesimal hike between resupply stops.
Perhaps you mean an infinite hike? Infinitesimal means very very tiny.

Cheers

...and he never knows the definitions to any words.

I've used this stove on five outings so far this winter and have been pleased. In a howling wind I've found the overweight windscreen to actually be a convenience; it's not fiddly and doesn't get blown over. When it was frozen in ice the rivet broke, but I replaced it with a bombproof machine screen and wingnut.

nm

Edited by jbrinkmanboi on 03/14/2010 22:57:49 MDT.

Hi Jeff,
I read and contributed to the "heat exchanger shootout". Roger's remarks have to be taken in the context he was talking about at the time. Take Roger's results and change the context and interesting things happen. Dont read and shut your mind. To save you looking I have copied the last post in the heat exchanger shoot out discussion. This is Me quoting myself, but shoot me down if you wish.

"I can see I might be jumping the gun before part 4 of this interesting series but I want to reanalyze Rogers results for the windpro, the best non heat exchanger and the packlite, the best heat exchanger stove, for use in winter and melting snow.

Roger has the bottom line that you need 34 litres of water boiled before the packlite starts to beat the windpro. People will look at this and even for 2 people they will say that is 10 days or so, the contest is over, use the windpro.

As Roger tested them the weight difference is 132 grams but the packlite has a 90 gram windshield but could have been tested with the 71 gram windshield the windpro was tested with, that is 19 gram difference. The packlite has an igniter, to be fair head to head this should be removed I guess 15 grams. The windpro was tested with a 1.5 litre pot that comes with a pot lifter weight 29 grams, but it was not included. The packlite has an integral handle. Head to head the handle should be removed or the pot lifter included. 29 grams difference. make these amendments and the weight difference is down to 69 grams.

I use similar amounts of water to Roger. In winter we use 3 litres per camp maybe more but he has tested with an 80 degree C rise. In winter 100 degree would be closer. so I will multiply the fuel cost per litre by 25% to allow for the colder water. The sum is therefore how many litres does it take to use up the 69 grams of packlite extra weight. Each litre of water takes 3.85 (Roger's figure) x 1.25= 4.81 grams of extra fuel with the windpro so 69 /4.81 = 14 litres. By this time the windpro will have used more than one canister, 220 grams of gas. For us I see the break point as 4+ days. that is still a long time.
I do not own a packlite but it looks as if the base plate could be lightened. Also if you decided not to carry the packlite windshield and use a lighter one you could cut the windshield supports off the packlite feet. The only way to find those savings would be to do it.


If you must melt snow and boil, at camp only, you must almost double the gas used. If you must melt snow for the next day too you could triple the gas usage. In this final scenario anything more than one camp and the packlite would be lighter.

Most of the difference in weight is now the weight of the heat exchanger pot. The lightest winter stove is probably a primus eta packlite with an ordinary pot for short trips that dont melt snow, and take the heat exchanger pot for snow melting and longer trips"

I have now made these weight savings. I have also been on several trips extreme enough to see the savings. Camping high on long frozen ridge walks, melting snow for tomorrow,as well as camp and 2 people to a stove, a few extra hot drinks for comfort, a hot water bottle. You can get to the break point in one night if you want, how far from "infinitesimal" is that!

edit to add the weight difference between my heat exchanger pot and my Ti 1.2 litre alternative is about one empty 100gram canister so as soon as you need to carry more than one canister of any size it might be worth using a heat exchanger pot ( given my context)

Edited by Derekoak on 03/15/2010 05:46:28 MDT.

Man, to be honest- I can't handle all of those numbers and variables. My brain starts hurting.

I look over the 'how and why' parts of these articles, but I really can only make sense of the conclusion. (usually its pretty lay- friendly) The bar graphs are cool too, but some of those line graphs... eww! My technical prowess is infinitesimal (Yessss!)(that was for you, Roger:)

I guess I just showed my hand (my DUMB hand- HAHA)

I read the article to get info on the Packlite- cause I drool over it at work for my winter stove choice.

So... what you (both of you) are saying, if I may, is that essentially, if I take the Packlite and do a few weight saving mods, and use a Ti pot unless I'm melting snow (where I'll use the exchanger pot) I'll have a pretty bada$$ winter stove and carry the most efficient combination of weight in both cases?

Or is it more like:
3 season/ short winter trips= packlite w/ Ti pot
and
Long winter trips= Packlite w/ exchanger pot

I'm trying, man... I'm trying:)

Hi Jeff,
I would not dare speak for Roger of course but yes that is what I was saying. Heating water for one, double all the times. We have done some weight saving mods and if it is cold I take the packlite and invert the canister, if it is more than 3-4 camps I take the heat exchanger pot otherwise my alternative. If I expect to melt snow, I count that camp as 2 times and if I expect to melt snow for the next day too I count that camp as 3 times.
The packlite is so fast that I would cook for 3 on it. Then it would really be light.

Edited by Derekoak on 03/15/2010 10:55:28 MDT.

Altho' I haven't read the article, I would suggest that a heat exchanger pot is only worthwhile if you are melting lots of snow eg for drinking liquids as well as cooking.

Note that melting a given quantity of snow takes the same amount of energy (fuel) as heating the melted snow by 80C

In other words, twice as much energy (fuel) is required to make boiling water when starting with snow, compared with starting with water @ 10C

Hi all

General agreement with all the figures being thrown around.

Mind you, if you WANT to use a heat exchanger pot, the weight penalty is not high compared to half a water bottle full of water. One can agonise over 25 grams ... but does it matter too much? One can turn the stove up full bore and waste that much fuel (heat lost up the sides of the pot) in a couple of days too. The heat exchanger pots seem better at collecting all the available energy at high power compared to plain pots, btw.

Enjoy!

Cheers

Somehow this article and comments seem to be aimed solidly at stove system weight and performance, rather than the titled carbon monoxide emphasis. Guess that's because it performs well from a CO perspective (i.e. nothing to talk about)? Anyway, that's great by me because that's my interest, and since the discussion has already gone there, I figure my questions won't be considered a highjack...

So what I am wondering, is whether someone can draw some head-to-head performance/weight conclusions between the Eta PackLite and the Express Spider? They both seem to use the same valve, hose, preheat, and burner. And if I am reading right, the heat exchanger pot only makes up for its weight penalty if you are heating like a few gazillion ounces? Looks like the Spider has other weight benefits too. So wouldn't the Spider be the clear choice for anyone who isn't solely in love with heat exchanger fins and the plastic parts needed to protect them?

If it's not too late, maybe Roger can add a auxilary discussion to the Spider installment to cover this very thing. Or perhaps it's bigger than that - a new article series perhaps?

Am I missing something? Will it all become obvious when Part 7 lands?

Hi Jason

> I figure my questions won't be considered a highjack...
Ve are Vatching You!

> head-to-head performance/weight conclusions between the Eta PackLite and the Express Spider?
Spider is the same stove minus all the extras.

> wouldn't the Spider be the clear choice for anyone who isn't solely in love
> with heat exchanger fins and the plastic parts needed to protect them?
Yep. For winter use.

Review in the pipeline. But basically, it seems that Primus has slowly and painfully managed to reduce their pack weight ... :-)

Cheers

I'm really eager to see the Spider review. I like the packlite for its winter ability but the pot is too small to make it a viable addition to my stove fleet (currently have a reactor and an eta-express which both have smallish pots and looking for something appropriate for 3-party groups in snow).

However, I DO have a 2.1L etapower pot already and just really need a winter stove to use it on.