Specific Gravity Standards
Today I was equalizing my batteries and after measuring the SG and correcting for temperature, all of my cells read 1.244 and all of them were within .005 of each other. These batteries are pretty new and perform to specs. So it occured to me that since these are all healthy, the low SG is probably due to the accuracy of my bulb type hydrometer. So I was wondering if they made a standard test solution with a known SG that I could use to determine a correction factor for my readings. I was thinking the plain H2O had a SG of 1.000 but my hydrometer starts at 1.100 so I need something denser. What hydrometers do you guys use and how do you calibrate them?