Svbony Dew Heater - Anyone Tried?

[Ian McCallum]

Has anyone ever tried one of these dew heaters? 🤔

https://www.ebay.co.uk/itm/285052210212?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=MsnxS3WGSCy&sssrc=2349624&ssuid=FlQ80JPwRca&var=&widget_ver=artemis&media=COPY

[bosun21]

I had originally bought one of these for my 102 refractor and was happy with it but I unfortunately left it behind during a visit to a dark site. I ended up buying a load of dew bands for my three scopes. All 12v now from Dew Control as the sizes I needed were out of stock at FLO.

[wookie1965]

Yes I have two I use them with my power bank saves snagging cables.

[Barry Fitz-Gerald]

I have two as well that I use with 80mm binoculars and they appear to be very good value for the price. Of course having a USB connector you cannot plug in to conventional Dew Controller like a Hitech Astro one, but I am sure if you searched you could find an adapter to allow you to do so.  The USB connector is of course fine for use with a Power Bank, and the controller lets you increase the heating as required. What I particularly like is the way the cable attaches to the band - which means that you do not have to snaggle the elastic fastener around the cable or have a 90 degree bend in it when the dew band is in place. Cannot work out why all dew bands do not have this cable configuration.

[Ian McCallum]

I looked at the 12V dew heaters from FLO, but see that many of the UK made controllers are now unavailable.  I was thinking that it maybe possible to build a controller from scratch, using a suitably rated potentiometer...🤔

[westmarch]

17 minutes ago, Ian McCallum said:

I looked at the 12V dew heaters from FLO, but see that many of the UK made controllers are now unavailable.  I was thinking that it maybe possible to build a controller from scratch, using a suitably rated potentiometer...🤔

You may find these links helpful.

https://www.blackwaterskies.co.uk/2013/05/a-cheap-multi-channel-dew-heater-controller/

https://www.blackwaterskies.co.uk/2013/05/making-your-own-nichrome-dew-heater-bands/

John

Edited December 19, 2022 by westmarch
additional link

[Elp]

I bought these recently as I was fed up powering two separate bands, these you can power with one 5v usb connection, they warm up very quickly and hot too. Best bit they dont draw as much power as my individual ones, lasted during a 6 hour shoot and only drained my 12v power bank by half, the individual ones I've got would have drained the whole power bank per band:

https://www.amazon.co.uk/Fast-warm-Spliceable-Astronomical-Telescopes-Celestron/dp/B09D7FSHBH/ref=mp_s_a_1_13?crid=XUYTJTTXBRLD&keywords=dew+heater&qid=1671448595&sprefix=dew+heater%2Caps%2C159&sr=8-13

 

Edited December 19, 2022 by Elp

[rnobleeddy]

I use these too. They work well and seem like good value.

[JeffC]

Does anyone find the included 3-setting temperature controller seems to cut out after a couple of hours?  Can the heater be run continuously without the controller, directly to a 5V USB source?

[Elp]

44 minutes ago, JeffC said:

Does anyone find the included 3-setting temperature controller seems to cut out after a couple of hours?  Can the heater be run continuously without the controller, directly to a 5V USB source?

It will run continuously but I guess it depends how hot they get in the first place. I dabbled in getting some 5v fan controllers (basically a simple circuit connected in line via usb with a control knob so you can regulate the resistance, thus power to the band), didn't really need it in the end. Pair it with a decent dew shield as they usually work well, they'll take longer to un-dew if the optics are already cold by being left outdoors.

[jjohnson3803]

I bought one made for camera lenses that's very similar.   Works fine on my refractors and the USB connector allows me to use whatever power brick is charged and ready.  My dew band has three heat settings, so no controller necessary in my experience.

I've only used it continuously for maybe 2 hours at most though, so I don't know if it shuts down after a long session.  I'd guess the battery would die first.

 

Edited December 20, 2022 by jjohnson3803

[bosun21]

On 19/12/2022 at 11:25, Elp said:

Best bit they dont draw as much power as my individual ones,

They draw virtually the same power as the 12v dew bands.

[LDW1]

On 18/12/2022 at 15:23, Ian McCallum said:

Has anyone ever tried one of these dew heaters? 🤔

https://www.ebay.co.uk/itm/285052210212?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=MsnxS3WGSCy&sssrc=2349624&ssuid=FlQ80JPwRca&var=&widget_ver=artemis&media=COPY

I have one but have yet to use it under actual conditions but the price was sure right.

[Ian McCallum]

I've ordered a couple of 12V versions from Auntie @FLO.

[Elp]

13 hours ago, bosun21 said:

They draw virtually the same power as the 12v dew bands.

My individual usb ones (non branded) I plug into a Celestron Lithium LT power bank, one power bank per band. Around the 4 hour point the power banks are dead (very cold condition). The following night, similar temperature cold night, I used the twin usb one I've mentioned above, one power bank per two bands. The power bank had only drained by half after the same time. So they're not all built the same.

[Ian McCallum]

13 hours ago, bosun21 said:

They draw virtually the same power as the 12v dew bands.

I'll be using mine at home, with a 13.8V DC mains power supply. It's capable of providing upto 30A at a push, so power shouldn't be an issue. 

[ScouseSpaceCadet]

I have a very, very similar version from Amazon. I run it off a Talentcell power bank.

https://www.amazon.co.uk/TalentCell-Rechargeable-6000mAh-12000mAh-Lithium/dp/B0713T4XT9/ref=mp_s_a_1_3?keywords=TalentCell&qid=1671655388&sr=8-3

I've not noticed the dew band cutting out, but did find the heat controller to be a waste of time if the band is strapped around my 4" refractor. I found only the highest setting is really effective and must be switched on before dew settles on the objective.

 

 

[bosun21]

5 hours ago, Elp said:

My individual usb ones (non branded) I plug into a Celestron Lithium LT power bank, one power bank per band. Around the 4 hour point the power banks are dead (very cold condition). The following night, similar temperature cold night, I used the twin usb one I've mentioned above, one power bank per two bands. The power bank had only drained by half after the same time. So they're not all built the same.

They are wired in parallel and therefore divide the current causing them to be running at half of their designed heat output. False economy unless you can get by at this reduced output. If it gets really cold then turning up the controller will still equate to half power.

[Elp]

The ones I've recommended run hot, even when they share their usb input via one connection hence the recommendation. I was using them with two samyang 135mm lenses which are a lot of glass elements in -4 Deg C temps and they didn't dew over once during a 4 hour session.

 

[bosun21]

My bad! It’s the total resistance that will half if two identical resistors are wired in parallel. They will indeed be operating at their normal rating. Sorry 😞