What is the "normal" rate at witch a 12 volt battery dies? I thought I had a battery that was going away just a bit to fast and perhaps it was. But maybe it was only a one cell death. It would drop from over 12.9 to about 11.8 in about 14 days, but stay there for a long time. What giveve?????
Death, one volt at a time!Or from the workbench to the grave
- Thread starter gtsun
- Start date
- Status
- Joined
- Dec 10, 2008
- Messages
- 7,253
Re: Death, one volt at a time!Or from the workbench to the g
If your talking about a conventional battery with some use on it that doesn't sound too unusual. The surface charge will be 1/2 to 1 volt and will go away pretty fast. A hygrometer would tell you if one cell is loosing it's charge before the rest.
Newer conventional batteries with lead calcium plates and a bit of sulfate buildup will self discharge pretty fast. Most will go from full charge to flat in 90 days or so depending on the sulfate buildup and the temperature.
A good AGM will hold a charge for 6 months to a year but you will still loose the surface charge quickly. Jim
If your talking about a conventional battery with some use on it that doesn't sound too unusual. The surface charge will be 1/2 to 1 volt and will go away pretty fast. A hygrometer would tell you if one cell is loosing it's charge before the rest.
Newer conventional batteries with lead calcium plates and a bit of sulfate buildup will self discharge pretty fast. Most will go from full charge to flat in 90 days or so depending on the sulfate buildup and the temperature.
A good AGM will hold a charge for 6 months to a year but you will still loose the surface charge quickly. Jim
- Joined
- Oct 19, 2005
- Messages
- 18,978
Re: Death, one volt at a time!Or from the workbench to the g
Mechanics use a battery hydrometer to test cells and state of each cell's charge. If this volt drop was not noticed before then likely sign its over the hill on life span but still serviceable especially if kept topped off. Often can wake them back up with the EDTA solutions you add to cells to clear the crust off. Eventually enough oxides drop to bottom to short em out, Sometimes can dump it out filter acid and put back and go some more in a pinch. Once Cdo running should not need a battery if idle kept up but electric ignitions may catch you out on low charging battery dragging alternator down with it. 4 yrs is pretty decent some get more.
Mechanics use a battery hydrometer to test cells and state of each cell's charge. If this volt drop was not noticed before then likely sign its over the hill on life span but still serviceable especially if kept topped off. Often can wake them back up with the EDTA solutions you add to cells to clear the crust off. Eventually enough oxides drop to bottom to short em out, Sometimes can dump it out filter acid and put back and go some more in a pinch. Once Cdo running should not need a battery if idle kept up but electric ignitions may catch you out on low charging battery dragging alternator down with it. 4 yrs is pretty decent some get more.
- Joined
- Nov 11, 2008
- Messages
- 834
Re: Death, one volt at a time!Or from the workbench to the g
Perfectly right there Jim, but shouldn't the battery voltage start at closer to 13.8 for fully charged? Down at 12V sounds like it's got a dud cell. After the surface charge dissipates a healthy battery should be still well above 12V.comnoz said:
- Joined
- Dec 10, 2008
- Messages
- 7,253
Re: Death, one volt at a time!Or from the workbench to the g
Yes, full charge would be 13.8 but most Commandos with the stock charging system seldom ever reach full charge. If it goes to 12 volts quickly after a full charge then it could have a shorted cell. Jim
davamb said:
Yes, full charge would be 13.8 but most Commandos with the stock charging system seldom ever reach full charge. If it goes to 12 volts quickly after a full charge then it could have a shorted cell. Jim
- Joined
- Oct 19, 2005
- Messages
- 18,978
Re: Death, one volt at a time!Or from the workbench to the g
My chip controlled charger builds in low small batteries to 13.8 initially then backs off to 13.6, then floats at 13.2. If the battery case can take it and you don't boil off too much water you can equalize, blast scale off by over charging into 15-16 v's for a while.
My chip controlled charger builds in low small batteries to 13.8 initially then backs off to 13.6, then floats at 13.2. If the battery case can take it and you don't boil off too much water you can equalize, blast scale off by over charging into 15-16 v's for a while.
Re: Death, one volt at a time!Or from the workbench to the g
I have one of those cell test things if you want to check your battery, possibly before riding over to Scottie's for Bike Nite. I also have a complete spare GB500 battery you can have as I switched it out to one of the AGM jobs.
Any British bike folks in Orange County CA who want to get together can drop in at Scottie's Thursday nights and join us. It is an informal friendly crowd with all sorts of bikes, mostly old ones. We need to get our British bikes out and show the flag so the younger folks don't get the idea there were no motorcycles made before the 750 Hondas. The chow is first rate if you like BBQ.
http://scottiessmokehouse.com/
Vintage Paul
I have one of those cell test things if you want to check your battery, possibly before riding over to Scottie's for Bike Nite. I also have a complete spare GB500 battery you can have as I switched it out to one of the AGM jobs.
Any British bike folks in Orange County CA who want to get together can drop in at Scottie's Thursday nights and join us. It is an informal friendly crowd with all sorts of bikes, mostly old ones. We need to get our British bikes out and show the flag so the younger folks don't get the idea there were no motorcycles made before the 750 Hondas. The chow is first rate if you like BBQ.
http://scottiessmokehouse.com/
Vintage Paul
- Status
