Forum Discussion

HiTech's avatar
HiTech
Explorer
May 23, 2013

Checking hydrometer accuracy with charged battery voltage

Is it true that: Specific Gravity = Cell Open Circuit Voltage - 0.845? Could one average the specific gravity readings across cells in a battery, and use this formula to check the accuracy of th...
mena661's avatar
mena661
Explorer
May 24, 2013
HiTech wrote:
12.78v predicted. Pretty close given likely error in hydrometer and volt meter. Even more so if it had settled slightly at 24 hours.
I know you didn't ask but I use a Victron battery monitor for voltage (does other stuff), it uses a shunt (like the Trimetric), and a Freas hydrometer which I understand to be pretty accurate.

About Technical Issues

Having RV issues? Connect with others who have been in your shoes.24,344 PostsLatest Activity: Dec 31, 2025