Help, its a minefield!

[Pippy1969]

I am getting a bit confused with all the fill ratios for down sleeping bags.
Is 300g of 850 down better than 500g of 650fill power? The obvious would be more down more warmth, but which scenario is more down?

They can have a similar temp rating but can sometimes vary in cost. I have googled for an answer but that doesn't really clarify

I'm more used to mountain walking and staying in a bunk house at the end of the day so this tarp camping is new to me.

 

[Teepee]

Down is graded by measuring the volume it takes up. A higher grade of down (fill power) will occupy a greater volume.

The units used to grade are cubic inches per ounce (Cu in/oz). 500g of 650 will fill 11'067 cubic inches. 300g of 850 will fill 9'107 cubic inches. On that scale, the 500g of 650 cuin/oz will be warmer.

The higher the fill power of down, the greater the warmth for the weight. It's always best to buy the very best grade of down you can afford, in a sleeping bag that fits well.

 

[Pippy1969]

Down is graded by measuring the volume it takes up. A higher grade of down (fill power) will occupy a greater volume.

The units used to grade are cubic inches per ounce (Cu in/oz). 500g of 650 will fill 11'067 cubic inches. 300g of 850 will fill 9'107 cubic inches. On that scale, the 500g of 650 cuin/oz will be warmer.

The higher the fill power of down, the greater the warmth for the weight. It's always best to buy the very best grade of down you can afford, in a sleeping bag that fits well.

So the 850 fill power will be warmer but they put less of it in a bag making the bag lighter, the lower fill of 650 will need more filling hence making the bag heavier. does that sound right?

 

[cathyjc]

 

[Teepee]

Did you pick the right smilie there Cathy?

You've got it Pippy. The lower the grade of down, the heavier the item for the same warmth. A summer bag with 650 in won't be at as much of a weight penalty as with a winter bag.

 

[murpharoo]

Did you pick the right smilie there Cathy?

@cathyjc has given me the finger in the past also. I'm hoping she means this rather than .
I might be wrong though...

 

[cathyjc]

Whoops - didn't have my glasses on

Sorry

 

[el manana]

ULOG explanation

Which also explains that US and EU fillpower are different - another jumping jack for your field....

 

[el manana]

As a general rule I only go for a bag with 750fp EU / 800 fp US or above.

You can sometimes see the fill power reflected in various manufacturers e.g a Western Mountaineering Ultralite has 450g of high quality down, its a -7C bag. A similar bag by another manufacturer with say 750 fp EU will probably have 500g of down.

There's no exact science, its just very general guidelines for comparing.

 

[Davy]

Whoops - didn't have my glasses on

Sorry

Not my spares but -

View attachment 2860


- Glasses 5 to 10 gms (my scales not accurate enough to be more precise)
- Case 45gms - don't usualy carry the case as glasses spend most of the time on my nose and in a fabric pouch overnight etc.

Best glasses I've ever had and will replace like for like when I need to.
Cost - about the same as a Hillberg - worth every penny IMHO.

Map reading glasses when out - I've just acquired a wee plastic magnifying 'glass'.

PS -the frames are Titanium

 

[Pippy1969]

As a general rule I only go for a bag with 750fp EU / 800 fp US or above.

You can sometimes see the fill power reflected in various manufacturers e.g a Western Mountaineering Ultralite has 450g of high quality down, its a -7C bag. A similar bag by another manufacturer with say 750 fp EU will probably have 500g of down.

There's no exact science, its just very general guidelines for comparing.

Blimey! I will keep looking. I am looking at 850 fill bags so they pack down and are light

 

[Pippy1969]

Thanks all for the input