Alkaline Batteries and Vacuum Chamber - Page 1
Forum section: electronics / general

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: December 27, 2014, 03:28:03 pm
content: Does anyone know if there would be any negative effects on Alkaline batteries in a vacuum chamber? I need to run a small logging device inside the chamber which is pulled down to -29. For the most part, the device is small, LCD display, SMD, no electrolytic's and is powered from 2 AAA. The batteries should be relatively safe inside considering they have very little gas inside to expand. I don't have a spare unit I could sacrifice for this experiment so I am trying to get as much info on the topic as possible. The duration of exposure that the logging device will be at -29 is upwards of 45 - 60 minutes per session.If I have to, I could drill a hole and mount a sealed pass-through connector and wire the device that way but would rather not if possible.Thanks

author: Lightages
author_rank: Unknown
timestamp: December 27, 2014, 03:32:54 pm
content: I would not do it without testing multiple times in a sacrificial vacuum system. If the battery vents or boils it could cause quite a bit of contamination in the system. I think I would want to take small samples during the testing with an RGA too.

author: SeanB
author_rank: Super Contributor
timestamp: December 27, 2014, 03:47:57 pm
content: I would suggest instead a small lithium battery, as these are both better sealed and have less liquid inside them that can boil off. The LCD display is also not likely to survive, as it will boil off any gas in the liquid and crack the glass. VFD or LED displays will survive though, though any wet electrolyte capacitors ( aside from soldered wet slug tantalum) probably will vent quite a lot of vapour.

author: amyk
author_rank: Super Contributor
timestamp: December 27, 2014, 03:50:07 pm
content: Bad idea... alkalines are prone to leaking as it is, the seal is not very strong and exposing them to vacuum will make things even worse. They do contain moisture inside which will easily boil off. Also, they produce hydrogen gas internally when discharging.

author: Stonent
author_rank: Super Contributor
timestamp: December 27, 2014, 05:31:53 pm
content: I would think pairing up zinc carbon batteries would be safer.

author: Artlav
author_rank: Frequent Contributor
timestamp: December 27, 2014, 05:40:10 pm
content: How hard would it be to seal the batteries in a pressurised box, with wires coming out?

author: Lightages
author_rank: Unknown
timestamp: December 27, 2014, 06:05:46 pm
content: If the batteries aren't part of the environmental test, it would be easier to feed power in with a power feedthrough.

author: Zero999
author_rank: Super Contributor
timestamp: December 27, 2014, 06:12:18 pm
content: Quote from: Terabyte2007 on December 27, 2014, 03:28:03 pmYou can make a very cheap vacuum chamber with an old fridge motor, test it, then if it goes wrong, you've not lost much.

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: December 27, 2014, 06:16:14 pm
content: Quote from: Artlav on December 27, 2014, 05:40:10 pmI thought about using a passthrough connector for the batteries to be located outside the chamber. Another problem according to SeanB, I may have issues with the small LCD display that's on the logger instrument. I just did not want to add anymore holes that could be a leak potential down the line.

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: December 27, 2014, 06:17:32 pm
content: Quote from: Hero999 on December 27, 2014, 06:12:18 pmActually, I had that thought. I was going to see about building a cheap sacrificial chamber and do a few tests just with the batteries.

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: December 27, 2014, 06:19:10 pm
content: Quote from: Lightages on December 27, 2014, 06:05:46 pmYes, I agree. Just trying to cut down on the holes I add to the chamber. I already have some dedicated to a heating plate with temp control.

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: December 27, 2014, 06:22:09 pm
content: Quote from: Artlav on December 27, 2014, 05:40:10 pmIt would have to maintain a relative pressure to atmosphere and be air tight without exploding out. Hmmm, possible.

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: December 27, 2014, 06:26:17 pm
content: Quote from: SeanB on December 27, 2014, 03:47:57 pmLithium might be an idea, even a small one to power for that 60 minutes. I don't think there are any electrolytic's, a few small SMD ceramics and SMD IC's. The LCD could be an issue, Thanks...

author: electr_peter
author_rank: Unknown
timestamp: December 27, 2014, 06:39:41 pm
content: Quote from: SeanB on December 27, 2014, 03:47:57 pmI had experience were 16x2 type LCD failed after travelling with air parcel post. Screen did not show any signs of life, there was some discoloration pattern (center color was a bit different then the sides).

author: sunnyhighway
author_rank: Frequent Contributor
timestamp: December 27, 2014, 08:02:54 pm
content: I would put everything outside the harsh environment (i.e. vacuum chamber), except for the stuff that absolutely needs to be inside that chamber (sensors and only the necessary pre-amps). I see no point in making a datalogger vacuum proof if a simple air-tight connector would do the trick.And what is the point of having an LCD-displayinsidethe vacuum-chamber anyway?

author: Stonent
author_rank: Super Contributor
timestamp: December 27, 2014, 08:13:47 pm
content: Another thought. Pot the batteries in epoxy with the wires coming out.

author: SeanB
author_rank: Super Contributor
timestamp: December 27, 2014, 08:17:09 pm
content: Might work, depending on how pure the vacuum is required to be, as the epoxy will outgas for a long time. If the battery swells it might still burst the epoxy.

author: mzzj
author_rank: Super Contributor
timestamp: December 27, 2014, 08:49:57 pm
content: Go for Tadiran lithium batteries.

author: ozwolf
author_rank: Regular Contributor
timestamp: December 27, 2014, 09:05:10 pm
content: What is the vacuum chamber made of? Glass, plastic? If so, how about inductively coupling? Power supply on the outside, then inductively couple through the chamber wall. I've done a chamber using a stainless steel cooking pot with glass lid. Seems feasible to me to epoxy a coil on outside of glass lid, with secondary inside lid. Simple circuit to rectify and supply DC inside the chamber with no batteries.It sounds like you are doing data collection, so implies a micro-controller inside. If so, then get a little Bluetooth board and wirelessly transmit the information collected to an external (to the vacuum chamber) display. Only have solid state electronics inside the vacuum chamber.Ozwolf

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: December 27, 2014, 09:11:34 pm
content: Quote from: sunnyhighway on December 27, 2014, 08:02:54 pmI did not plan on placing a LCD inside, the data logging module has a small LCD screen on it, that's all. I kind of figured I would have to modify the data logger and place only the sensors inside. I was just trying to get an idea if it would be at all possible.

author: calexanian
author_rank: Super Contributor
timestamp: December 28, 2014, 12:17:34 am
content: Feed through is the only safe way to go. On the inside of your chamber you can either wire wrap, silver solder, or spot weld your connections to whatever sensor you have. What level of vacuum are you using? 29 inches of vacuum is a little to vague. If this is just rough vacuum then you can make a feedthrough with a sheet of metal with holes drilled in it and really good quality epoxy. Torr seal, or epoxy patch brands work well. if you are using a bell jar you can feed copper ribbon conductors under the lip, surrounded by dux seal and dux seal the remainder of the bell jar to the gasket. This will all work down to about 50 micron. Below that you gotta go the full clean vacuum route. KF or CF flanges, welded connections and such.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 28, 2014, 12:48:32 am
content: Quote from: ozwolf on December 27, 2014, 09:05:10 pmYou can get receiver modules for inductive phone charging on ebay, and the chargers are also very cheap - these give 5V oute.g.http://www.ebay.com/itm/Qi-Wireless-Power-Charger-Charging-Pad-Receiver-Lot-For-Samsung-Galaxy-S5-/371207652445?pt=US_Cell_Phone_PDA_Chargers&var=&hash=item566db3445d