NOTE: this is not OT to those of you with a battery in your T.
Back when the hygrometer was the standard measuring device for lead-acid battery charge, precise voltmeters weren't widely available outside the lab. Now we have low priced 1% accuracy digital voltmeters measuring in tenths of volts.
Curiously, I haven't found a chart plotting battery voltage vs. per cent of charge. The maker of the sealed lead-acid batteries we use in my younger son's business hasn't replied to my queries, so I turn here for the expertise on all things technical.
TIA, thanks in advance.
Ralph - Please don't take this as criticism,....I know it was just a "typo". This is just so's not to cause any confusion,...harold
HyGrometer - measures humidity
HyDrometer - measures specific gravity
Would this help even though it is 12 volt?
1.265 SG is a fully charged battery. It makes no difference if it's 6v or 12v.
Here's a quickie pic.
Keep in mind, that while knowing volts and percent is all very well,
it does not tell you the main info needed to judge a batteries ability to do the job.
The following photos are of testing a battery that was charged two weeks ago.
First the percent and voltage (in test mode) from my computerized charger/tester . . .
Now the important info from a computerized tester . . .
Charts can be useful but very misleading. With lead acid battery you must not have charged the battery within the last 24 hours to even use the chart but then it really isn't very accurate at that charge time. Added to that is that many people confuse digital meter accuracy with digital meter resolution. Most digital meters can easily resolve to 3 digits but while a meter might read 6.01 volts it does not mean the meter is accurate to within .01 volts. Most of the el cheapo meters are very accurate for what they cost but most are not 1% accurate everywhere on the range they are set to. The Gates chart I am posting is in fact for AGM type batteries but the terminal voltage really won't be too far away from a standard lead acid battery given that these sort of charts are at best about 5% accurate anyway. Lead acid batteries are in fact rather crude devices. Hope this helps.
Forgot to mention this is for one cell so for a 6V battery multiply by 3 and for 12V multiply by 6.
I sure hope no one was close when that battery blew up.
The others already have provided your answer.