http://www.webbikeworld.com/r3/heated-vest/battery-heated-vest/ http://www.jett.us.com/ anyone own one of these? Looks very interesting indeed.
I have owned one for a couple of days now... If your question is 'how effective is it' I have to admit I haven't had a chance to use it on a ride in the cold weather and it will have to wait a bit since it is summer here in Oz. But I believe combined with a riding jacket it should be very effective indeed... what else would you like to know? I'm happy to answer any specific questions.
I'm wondering how well it works, how well the batteries hold up, how well made is it, do I really want to sink that kind of money into something I've just read about, etc etc. The usual neurotic questions
Well, the jacket appears well made. It is soft and comfy, not bulky by any means but it feels pleasantly substantial. It was a cooler day yesterday so I wore the vest around the house for a couple of hours, using the low setting. It was a very, very pleasant sensation, for some reason it just feels very nice and comforting! The heat comes on almost the moment you turn it on (well, maybe 10 seconds later, then it might take another 20 seconds or so to reach its operating level) and the heat is distributed quite evenly. Well, I thought it is actually most concentrated around the kidney areas, but it is even in the sense I can't feel where the heating elements are located the way I can in my old electric blanket. They warn not to leave it on for more than one hour at a time, so I had it on for about 50 minutes, off for 10 and on again, for about 4 hours in total. Batteries are still fine. According to webBikeWorld, they should be now at around half of their capacity. At this point I am satisfied with my purchase and I think this vest is quite a good value, especially with the additional battery pack thrown in. What makes it doubly useful is the fact that it can be used off the bike as well; I suspect when the winter comes I will be wearing it at least as much around the house as on a bike.
My Gerbings heated jacket draws about 50 watts, which in some climates is only adequate. The Jett vest specs don't include wattage, but I can't imagine being able to draw anywhere near 50 watts from a light-weight battery pack for any reasonable length of time. Regardless of technology, heating a human comes down to watts, BTUs, calories, or other units...there's no magic bullet to improve efficiency and defeat the laws of physics... In the cold, on a motorcycle, I can't imagine that this thing could supply enough heat for enough time.
True, and yet startling improvements are sometimes possible. New energy-efficient 20W light bulbs give as much light as the conventional 100W - how is that possible? It is possible because the conventional design is actually incredibly inefficient, converting only around 5% energy into visible light and wasting the rest as heat. I freely admit I have no idea how the Jett vest works, but it is possibly more efficient than your old Gerbing. For your conditions, you might well be right - quite possibly if the temperatures drop well below freezing point, this thing will not be adequate. But these are extreme conditions and I think not that many people will ride in the depths of NY winter. I believe combined with a jacket, this vest should do the job in the conditions down to and around freezing point and that will be enough for many users, including myself.
not watts. Calories is likely the closest unit. And yes, there are lots of magic bullets to improve efficiency. The question is, not how much power does the unit draw, but how much heat does it deliver? The manufacturer says 140 F. That's pretty damn hot, if you've tried 140 F water lately. Anyway, the WBW reviewer seemed happy about the heat output.
I've been out of school for a while, but isn't electric-resistance heating virtually 100% efficient, in terms of converting electrical energy to heat? If so, how could that be improved upon?
<BR>Yea I had some initial questions too. Making resistive heat is very efficient, but getting the heat into the object varies widely. Sort of like the amount of energy used to cook a potato in an electric range/oven, is different that the amount of energy needed to cook it in a microwave. So maybe the vest does not use resistance heating. Maybe the vest uses RF heating like non-invasive interstitial heating of an internal tissue growth. But generates the heat in the IR band. Or, maybe the vest uses inductive heating. Or maybe the claims are just marketing. And the only thing happening is the resistance wire is making heat in the IR band. Maybe all resistance wire makes heat in the infrared band. The product IS very interesting. And so is the absent information in the website advertising. I mean, it could be that the valid claims about medical uses of infrared heat are just that, valid. But the relationship to their heated vest is only inference. If Jett sends me one I'll give it an honest evaluation. And I'll send it back on my nickel. - Jim<BR><BR>
I'm betting marketing hype, mixed with junk science. But, I'd like to be shown wrong. My Gerbing's 50-watt heated liner is proving to be a real challange to my bike's alternator output. If I forget to turn off the heat several minutes before shutting off the bike, there's not enough battery reserve to crank the starter. Something producing that amount of heat but using half the electricity would be welcomed.
well, I'm trying to talk the frau into buying one, so we'll see. I'll get a full review up when that happens. Again, the WBW reviewer was very happy with the thing, so it must put out some heat.
The battery label shows 14.8V, 3300 mAh. If my math is correct, 3300mAh @ 14.8 vdc will provide 48 watts for one hour, or 24 watts for two hours, or 12 watts for four hours... Can someone smart check this?
<BR> The math is right. But in practice the numbers on the battery aren't as direct as that. For instance, the controller for the vest may be a 'boost' type. It might raise the output voltage to the vest, and a higher voltage might be more efficient at the heating element. The two numbers 3300mAh (3.3Ah) and 14.8V are not directly related to the total battery capacity. It is really more of a load rating. It isn't exactly that either, but it is more representative of a load rating. It's a load rating in the same way that the Cranking Amp (CA) rating of a car battery is a load rating. It says more about rate, and not as much about volume or capacity. For example, start with a fully charged battery, and place one of two loads on it until fully drained. One load draws a constant current and the other load draws a constant voltage. If the 'constant current' load is placed on the battery, as the battery drains the voltage output drops. And if the 'constant voltage' load is placed on the battery, the amperage output drops as the battery is drained. You can see that a graph showing battery drain will always be a curve. And that the 'total capacity' of the battery say, is the total area under that curve. As batteries become used more and more as a primary power source, a new 'capacity' rating may be developed. For those times when you're not playing 'dominate your environment', and care less about horsepower and more about how far can you get on that tank. The 'primary power source' configuration was commonly known as a 'total loss' system. If batteries are to succeed as the primary power source in the funhouse ride, that term and many other concepts yet have to die. - Jim<BR><BR>
I believe someone on their website made a mistake because the label on my battery states 14.8V 3300mAh
Reply from Jett: ============================ "Thanks for the thread. Tried to reply to the site but unable to at present. I noticed that someone had said that you can only wear the vests for an hour at a time - this is incorrect as this warning was printed on the vests by our manufacturers by mistake. We make sweat vests with very high temperatures for jockeys and the warning related to these. We have included a letter with each heat vest to disregard the warning as they can be worn safely all day. The vests have 3 heat settings low is 45, medium 55 and high 65 degrees C, . Body temperature is 37C so you can see they are very efficient at keeping you warm. It is a safe far infrared heat which is absorbed by your spine. The battery lasts up to 4 hours on high, up to 6 hours on medium and up tp 8 hours on low. The battery is the latest lithium polymer technology. The vests are great for motorbike riders as they do not have to be plugged into the bike. They can also be worn anywhere, when you want to stay warm. For the best results wear a thin thermal top underneath and whatever you like overtop. Jacket, etc. The batteries take 3 hours to charge and can be recharged up to 800 times. We have sold the vests to many motorbike riders in Australia as well as overseas and never had one sent back, everyone has been very happy with them. If you have any more questions, please feel free to contact me. Regards Rob Vassallo rob@jett.us.com www.jett.us.com"
Hi, i've been reading the concerns about the Jett Heated Vest & I would like to answer any questions as I am the inventor of the product....rob vassallo from Australia the vest works really well, i wanted to build a product that really kept you warm & which gave you instant heat... hated waiting to get warm with other type of vests... the batteries range in voltage for our different type of products, such as our Sweat Vest, which we need to only heat person for a few hours at high temps.to lose weight . for motorcyclists we give them a 14.8 volt battery which can range from 2.8 - 3.3 amps, made up of 4 lithium polymer batteries 3.7 volts joined in series to make 1 battery pack... the vest has 3 heat settings & you should get 4 hours on high- 6 hours on medium & up to 8 hours on low heat... the high setting is very hot, mainly used for quick heat boosting & then turn down to medium.... the temps are controlled in our switch & the the thermostat in the element cuts out when peaks - then switches back on when temp falls to programmed setting... this is why the batteries can last so long.... the best thing is that the element is made from carbon fibre & it is safe as it has no Electro-Magnetic field which is related to cancer? most other vests have a wire element which emits an electro magnetic field just like your mobile phone- this cannnot be doing your health any favours... also our element emits no current -only heat, so there is no voltage within the carbon wire system. the heat emitted is "FAR" infra red heat which is therapeutic, so not only will the vest keep you toasty but also will heal any back aches & muscle stiffness, which i'm sure riders get from sitting on bike for long periods- this technology was invented by NASA in the 80's for astronauts during long space travel.. we have used this same technology and perfected into a wire which can be worn portably in clothing.. that's the other feature also is that you don't only have to wear it on your bike... you can go anywhere in the vest, sporting events, work place, fishing, hunting,etc.... which gives you value for money as it has many multiple uses... i could go on all day... but more than happy to answer any questions that you or others have...regards rob vassallo
<TABLE class=tborder cellSpacing=0 cellPadding=4 width="100%" align=center border=0><TBODY><TR vAlign=top><TD class=alt1>Hi, i've been reading the concerns about the Jett Heated Vest & I would like to answer any questions as I am the inventor of the product....rob vassallo from Australia the vest works really well, i wanted to build a product that really kept you warm & which gave you instant heat... hated waiting to get warm with other type of vests... the batteries range in voltage for our different type of products, such as our Sweat Vest, which we need to only heat person for a few hours at high temps.to lose weight . for motorcyclists we give them a 14.8 volt battery which can range from 2.8 - 3.3 amps, made up of 4 lithium polymer batteries 3.7 volts joined in series to make 1 battery pack...(30 watts) the vest has 3 heat settings & you should get 4 hours on high- 6 hours on medium & up to 8 hours on low heat... the high setting is very hot, mainly used for quick heat boosting & then turn down to medium.... the temps are controlled in our switch & the the thermostat in the element cuts out when peaks - then switches back on when temp falls to programmed setting... this is why the batteries can last so long.... the best thing is that the element is made from carbon fibre & it is safe as it has no Electro-Magnetic field which is related to cancer? most other vests have a wire element which emits an electro magnetic field just like your mobile phone- this cannnot be doing your health any favours... also our element emits no current -only heat, so there is no voltage within the carbon wire system. the heat emitted is "FAR" infra red heat which is therapeutic, so not only will the vest keep you toasty but also will heal any back aches & muscle stiffness, which i'm sure riders get from sitting on bike for long periods- this technology was invented by NASA in the 80's for astronauts during long space travel.. we have used this same technology and perfected into a wire which can be worn portably in clothing.. that's the other feature also is that you don't only have to wear it on your bike... you can go anywhere in the vest, sporting events, work place, fishing, hunting,etc.... which gives you value for money as it has many multiple uses... i could go on all day... but more than happy to answer any questions that you or others have...regards rob vassallo <!-- / message --></TD></TR><TR><TD class=alt2> </TD><TD class=alt1 align=right><!-- controls --></TD></TR></TBODY></TABLE>
