[time-nuts] OT Gel Cell question
paulswedb at gmail.com
Mon Jul 28 14:20:39 EDT 2014
I think we crossed some wires here. Pun intended.
Brook said the fumes ate away the traces and he is right. On a flooded cell
batteries such as he describes the fumes are nasty. Its quite normal on a
flooded cell to purposely drive them into overcharge. This is known as
equalizing. I have to do that on my 2000 Lbs battery from time to time.
On Gel Cells that is a very bad process and you don't do it because they
My only wisdom is this. Stay away from hamfest/flea market batteries. They
are almost always bad and nothing really revives them. Pay the money and
make sure you get a recent build date.
On Mon, Jul 28, 2014 at 1:44 PM, Alexander Pummer <alexpcs at ieee.org> wrote:
> as long as it is not a gals/ceramic seal, there is no way to stop sulfuric
> acid to get out from the cell, just imagine the dilatation diffrence
> between plastic and metal...
> On 7/28/2014 10:12 AM, Ed Palmer wrote:
>> As I understand it, the only time that any sealed lead acid battery will
>> vent is in the case of gross overcharging. The battery is designed so that
>> normal charge rates and correct float voltage will result in recombination
>> of any hydrogen and oxygen produced. Was there a fault in the charging
>> circuit or perhaps, the charging circuit didn't have proper temperature
>> compensation of the charge voltage?
>> On 7/28/2014 10:56 AM, Brooke Clarke wrote:
>>> Using lead acid batteries and a precision frequency standard is not a
>>> good thing if they are too close together.
>>> A number of decades ago (before the Time Nuts or the internet) I was
>>> able to purchase a rack mount Gibbs 5 MHz double oven frequency standard
>>> that used a very nice Bliley glass tube crystal because it was not as
>>> precise as is was supposed to be. It used GelCell backup batteries that
>>> were physically in the same rack chassis as the oven. The fumes from the
>>> batteries when charging etched some traces off the PCB inside the oven
>>> defeating the temperature control but leaving the oscillator. It took a
>>> long time to reverse engineer and repair it. I've added a photo of the
>>> cord wood construction of the cylindrical oscillator. The core of the
>>> cylinder holds the glass bottle crystal and the glass piston coarse tuning
>>> capacitor, surrounded by the first heater, circuitry for the oscillator and
>>> dual temperature control circuits on ring shaped boards. These fit inside
>>> a cylindrical cavity which is the outer oven. I've added a photo of the
>>> inner assembly at:
>>> Have Fun,
>>> Brooke Clarke
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