Heated vests - Do they actually work ?

[RVBldr]

Just a point of caution: do use diving specific heat. Had a buddy that used converted motorcycle vest and the fuse sparked under water. Unfortunately, he plumbed his suit off of a BO bottle with 50% and ended up with a suit fire, burned through suit, and some 3rd degree burns on upper back.

 

[MidOH]

That's awesome. With enough oxygen, even velcro turns into fuel. Nasa screwed that one up.

Make my own:

https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://m.youtube.com/watch%3Fv%3DMrnCDKB1hE0&ved=2ahUKEwinrK3n8OSDAxU4jIkEHVf3BOoQwqsBegQIDxAF&usg=AOvVaw2Z_LoT8zgExTITs-H1VAhE

 

[Roy_W]

Some interesting comments,

@Imla

I have never thought about the idea of Merino or woolen underwear ( that's not such a bad idea).
For the 1st actual layer we usually use the same first layer as we do for skiing, Odlo Thermal Underwear which are synthetic wicking garments... Odlo also make Merino versions of the same.. obviously this is the least expensive step, not a large budget..

For the 2nd layer I use the SFTech garments, both the Sweater and the Trousers which are top quality garments ( Equivalnt to Thinsulate 400 - it's easy to get very sweaty when kitting up).
My wife uses is the same except that she has a Kwark romper suit..

We have Rolock dry suit gloves and we both use woolen gloves, my wife has Merino gloves.

I usually wear 2 pairs of skiing socks. I don't normally have any problem with my feet getting too cold.

I have never even thought about a neck liner...( sounds also like a good idea).

We usually dive in the morning, around 09:30 and always have a good breakfast usually about 1h30 before the dive - I often also eat a banana just before the dive on the drive over to the site.

It looks like I could get a Trojan vest + valve + 15.6 AH Accu for around the 1000 Euros mark so I will give them a little study..

@Cio + @flymolo
I have no idea how you guys are doing 60+ dives in 7°, as I mentioned almost all the divers are out of the water around the 35 min mark.. And these are local divers who are used to the conditions. There are a couple of divers, the exceptions, using SF Tech heating and battery systems but we are talking 2500 Euros worth of heating equipment, that's big budget heating...

@RVBldr
Agreed I wouldn't use motorbike stuff. I only use dedicated diving gear..

In regards to those of you who do use vests :

1 : Do you have internal or external batteries.
2 : At which point in the dive do you turn on the heat ? ( Before , during, at the end) ( DiveLikeAMuppet's comment sparked my interest about putting the heating on only for deco)
3 : A vest must add bulk and positive buoyancy, therefore I presume that his means having to add some extra weight.. How much extra are you guys taking. ( I imagine the accu is negatively buoyant so that must offset a little)

Batteries :
What can cause those battery to explode or fail. As I mentioned I find this very surprising, especially in the diving words when things usually get very heavily tested ?

 

[Kendall Raine]

+2 for Venture Heat. Designed to work wet or dry-many people use under a wetsuit. Important when (not if) your drysuit floods. Also, when diving dry always assume you will be diving wet and wear appropriate undergarments in case the vest STB and the suit floods.

Rule of thumb is stay cool during on gassing phase and warm during off gassing phase. Hence, I keep the vest off/on low during the working phase and crank it up on deco.

As for batteries blowing up/catching fire, this can happen. However, that is far more likely to happen during charging phase or after deep discharge or after the batteries get old or mistreated (e.g. crushed). Out board batteries are one way to deal with this, but battery/vest care is the first line of defense. Also, burns happen not just from batteries but, more likely, from shorting wires in the heating element of the vest. As such, take care when packing and transporting the vest. Don't fold it or put heavy gear on it during transport. Clean it regularly. Store it properly. Test it before each dive. Common sense stuff.

 

[Cio]

Some interesting comments,

@Imla


@Cio + @flymolo
I have no idea how you guys are doing 60+ dives in 7°, as I mentioned almost all the divers are out of the water around the 35 min mark.. And these are local divers who are used to the conditions. There are a couple of divers, the exceptions, using SF Tech heating and battery systems but we are talking 2500 Euros worth of heating equipment, that's big budget heating...

@RVBldr
Agreed I wouldn't use motorbike stuff. I only use dedicated diving gear..

60 would be the short side here 90-120 is pretty usual. Admittedly, I am pretty cold tolerant and headed up the line @ 60-75 min., since I am using the heater on deco if I'm chilly, its really 60-75 min in the cold. I wear a one-piece undergarment medium weight (same one I use for skiing), weezel extreme, thickest socks I have ever seen, neoprene drysuit booties and sneakers, no dry gloves, 3mm neoprene. (the 3mm in 7C water does not do the best job and stiff fingers are normal, this is something I need to change but I really like the functionality of them (until my fingers freeze)

Rebreather also helps.

Obviously no motorbike stuff but the diving stuff isn't 100% reliable either, a few years ago someone with a name brand suit got zapped repeatedly on their dive. everyone laughed it off since nothing serious resulted but everyone heard her screaming underwater while it was happening, obviously she lost heat. If you're not doing any deco, I guess it's less consequence but I'd try and get it figured out without heat first and then add heat. It's not low quality, its just a flexible heater, comfortable enough to wear is going to be a delicate item, limited trust would be my recommendation.

1. I have batteries on the vest (internal) which is nice in some regards but I am pretty sketched out that they will burn up with me in there which would be a disaster. I will go external on the next one.
2. End of dice, ascent and deco only.
3. the net effect, battery and vest is negative buoyancy. (not much)

 

[davehicks]

Venture and Themolution vests are very popular and work great. They do NOT replace or let you use a lighter undergarment. They just add comfort and take the edge of the cold in a big way. I've been using a Thermolution heated vest for a long time now, and over the last 3 years or so it seems like everyone I know who dives in the Pacific Northwest (48f / 10c) is using a heated vest now.

 

[flymolo]

I have no idea how you guys are doing 60+ dives in 7°, as I mentioned almost all the divers are out of the water around the 35 min mark.. And these are local divers who are used to the conditions. There are a couple of divers, the exceptions, using SF Tech heating and battery systems but we are talking 2500 Euros worth of heating equipment, that's big budget heating...

i think proper layering helps. merino wool wicks sweat and condensation better than any synthetics and that seems to make a large difference. when i use heat i don't always switch it on right away but i will once i start to feel the cold. have the light monkey heated undergarment and an external light monkey battery. i'm pretty sure the light monkey undergarment is just a repurposed heated motorcycle shirt.

 

[VikingDives]

This is an exclusive quality of wool. Synthetics will not keep you warm if wet.

I'm with you on everything except this. Wool is still the best, but polyester fabrics also keep you warm when wet.

 

[grf88]

I use merino wool base layer under Fourth Element Arctic and when it gets really cold like low 30's I add this vest:

X-Core

fourthelement.com

I also wear Alpaca socks and Ragg wool glove liners.

 

[Roy_W]

After reading the replies and also some other threads I am surprised that no-one appears to state that a heated vest is a "must have".

Reading between the lines I would now almost suggest that it appears to be a nice to have but not a vital.. Alternatively, I am starting to take far more interest in the layers/undergarments. I will definitely begin by sourcing some good quality merino layers + heavier socks//gloves before I make any rash decisions about vests/batteries..

Thanks to all, it has given me food for thought.