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? Ed On 7/28/2014 10:56 AM, Brooke Clarke wrote: > Hi: > > 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: > http://prc68.com/I/office_equip.html > > Have Fun, > > Brooke Clarke

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... 73 Alex 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? > > Ed > > On 7/28/2014 10:56 AM, Brooke Clarke wrote: >> Hi: >> >> 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: >> http://prc68.com/I/office_equip.html >> >> Have Fun, >> >> Brooke Clarke > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there.

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 will vent. 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. Regards Paul. WB8TSL On Mon, Jul 28, 2014 at 1:44 PM, Alexander Pummer <alexpcs@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... > 73 > Alex > > > 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? >> >> Ed >> >> On 7/28/2014 10:56 AM, Brooke Clarke wrote: >> >>> Hi: >>> >>> 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: >>> http://prc68.com/I/office_equip.html >>> >>> Have Fun, >>> >>> Brooke Clarke >>> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/ >> mailman/listinfo/time-nuts >> and follow the instructions there. >> > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. >

That said, I have never seen a gel cell, or a glass mat lead acid battery leak acid, or emit fumes. I'm not saying it can't happen, just that in all of my battery work, I haven't seen it... [unlike with nicads, where I think something is wrong when I don't see leakage.] The seal is something they take very seriously, and is typically some form of elasomeric plastic/rubber. Even the seal between the plastic case and the faston tabs is flexible. If the battery has a cell that is seriously overcharging, due to a short in another cell, it will out gas hydrogen and oxygen due to the electrolytic breakdown of the water in the electrolyte. Probably better that it do that than to blow up. -Chuck Harris Alexander Pummer 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... > 73 > Alex > > 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? >> >> Ed

Hi Ed: I don't know. When I got the unit the batteries had been removed. The power supply consists of two 723 based voltage regulator curcuits the first to drop the line voltage to about 20 V (float charging 3 each 6 V Gell Cells) and the second 723 circuit to take in battery voltage and supply a lower voltage to run the unit. The key problem was the short distance between the batteries and the hot oven. Maybe the oven was also heating the batteries. Something to keep in mind today. Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html http://www.prc68.com/I/DietNutrition.html 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? > > Ed > > On 7/28/2014 10:56 AM, Brooke Clarke wrote: >> Hi: >> >> 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: >> http://prc68.com/I/office_equip.html >> >> Have Fun, >> >> Brooke Clarke > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. >

Clearly under an abused situation I have seen cracked/fractured gel cells as an example. Due to I speculate pretty much the poorest of charge design. This includes powdery stuff, corrosion and metal that has been etched from what at sometime was a liquid. Almost the first thing I check is the batteries on test gear I manage to pickup. Regards Paul WB8TSL On Mon, Jul 28, 2014 at 3:18 PM, Chuck Harris <cfharris@erols.com> wrote: > That said, I have never seen a gel cell, or a glass mat lead acid battery > leak acid, or emit fumes. I'm not saying it can't happen, just that in > all of my battery work, I haven't seen it... [unlike with nicads, where I > think something is wrong when I don't see leakage.] > > The seal is something they take very seriously, and is typically some > form of elasomeric plastic/rubber. Even the seal between the plastic > case and the faston tabs is flexible. > > If the battery has a cell that is seriously overcharging, due to a short > in another cell, it will out gas hydrogen and oxygen due to the > electrolytic > breakdown of the water in the electrolyte. Probably better that it do that > than to blow up. > > -Chuck Harris > > Alexander Pummer 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... >> 73 >> Alex >> >> 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? >>> >>> Ed >>> >> _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. >