theoretical question

[urge38]

Hi Guys,

If one was to build a sealed unit metal detector control box, that included to circuit board, its own power supply (ie battery) and the charging circuit necessary to charge the battery, would there be issues with expanding gasses (or the air trapped inside) when charging

[waltr]

What type of Battery?

Should be no gasses given off (vented from battery) for NiCd, NiMHd or Li.
However, Lead Acid batteries can vent and this will be corrosive.

[urge38]

maybe I did not explain myself to well.

i am concerned about the charging heat, and its effect on the air inside,

we all know about thermal expansion right.

look at the whites beachunter TDI, sealed (not premiant mind) control box, battery outside this control box in its own sealed unit. BUT when charging, you have to remove the battery,

I am seeing that the heat generated from charging can cause problems, there is a lot of heat in a charging circuit and battery,

I am wondering how this would affect a control box that houses everything in one compartment

[waltr]

Guessing the box is for under water detecting. True?
Then box should be pretty strong since it must withstand water pressure and also temperature changes.

But then again, you should need to open it so it does dry out the moisture from condensation.
Would be be difficult to open while charging?
Maybe just a small closable vent.

[Tinkerer]

Guessing the box is for under water detecting. True?
Then box should be pretty strong since it must withstand water pressure and also temperature changes.

But then again, you should need to open it so it does dry out the moisture from condensation.
Would be be difficult to open while charging?
Maybe just a small closable vent.

I have seen underwater metal detectors exploding when charging. This happened with Nicad batteries getting old and high ambient temperature.
On my underwater detector design, built in 1986, I added a venting screw with an O ring seal that I loosened for opening and closing the detector.

[urge38]

Does make you think how the likes of XP deal with a permanently sealed control box and sealed battery in their coils Or Nokta with the Legend or Minelab with their Equinox etc

[waltr]

Does make you think how the likes of XP deal with a permanently sealed control box and sealed battery in their coils Or Nokta with the Legend or Minelab with their Equinox etc

LiIon or LiPo

and efficient charge circuit

[Skippy]

You could equip the box with an 'expansion bellow'. I had in mind the sort of part that is used in barometers, or the thermostatic actuator used in refrigerators to control the compressor on/off switch.
Google image search only seems to produce pics of enormous high-pressure pipeline fittings, not helpful.

[moodz]

https://ocean-innovations.net/OceanI...ifications.pdf

or you could just use a relief valve ��