evolvingpowercat
Well-known member
I saw the recent post on frozen battery electrolyte and thought I would post this for information:
Battery voltage of 12 volt battery that has been off charge for at least 4-6 hours:
Six volt battery, divide by 2.
If you have a battery cut off switch and make sure there is zero drain on your batteries during storage and make sure your batteries are charged when you put your TT into storage, loss of charge on stored batteries is very little, I still had over 50% charge on my stored batteries after 3 months storage last winter.
Based on this I may do one battery voltage check to makes sure batteries are open and maintaining voltage, and boost charge once this winter in particular if temperatures are forecast to go below -10 F in February where I have my RV stored late this winter.
Its amazing how the freezing temperature of the electrolyte changes over 100 degrees F between full charge and zero charge. Of course letting a lead-acid battery go to 0 % has already severely damaged it and it will never hold a full charge again SO NEVER LET THIS HAPPEN EVEN WHEN ITS NOT COLD ! NEVER LET A LEAD ACID BATTERY DROP BELOW 20% CHARGED AND TO MAXIMIZE ITS LIFE TRY TO KEEP ABOVE 50% CHARGE.
Dead dead dead = freeze at + 27 F
A more precise means to measure electrolyte freezing temperature is to use a specific gravity tester and measure the electrolyte directly:
Battery voltage of 12 volt battery that has been off charge for at least 4-6 hours:
Six volt battery, divide by 2.
If you have a battery cut off switch and make sure there is zero drain on your batteries during storage and make sure your batteries are charged when you put your TT into storage, loss of charge on stored batteries is very little, I still had over 50% charge on my stored batteries after 3 months storage last winter.
Based on this I may do one battery voltage check to makes sure batteries are open and maintaining voltage, and boost charge once this winter in particular if temperatures are forecast to go below -10 F in February where I have my RV stored late this winter.
Its amazing how the freezing temperature of the electrolyte changes over 100 degrees F between full charge and zero charge. Of course letting a lead-acid battery go to 0 % has already severely damaged it and it will never hold a full charge again SO NEVER LET THIS HAPPEN EVEN WHEN ITS NOT COLD ! NEVER LET A LEAD ACID BATTERY DROP BELOW 20% CHARGED AND TO MAXIMIZE ITS LIFE TRY TO KEEP ABOVE 50% CHARGE.
| charge? | voltage? | electrolyte freeze point? |
| 100 % | 12.60 no load > 12.1 under load | -75 F |
| 75 % | 12.06 under load | -35 F |
| 50 % | 11.58 under load | -17 F |
| 25 % | 11.04 under load | +5 F |
| 5 % | 10.5 under load | + 18 F |
Dead dead dead = freeze at + 27 F
A more precise means to measure electrolyte freezing temperature is to use a specific gravity tester and measure the electrolyte directly:
| Specific Gravity of Electrolyte | Freezing Point (degrees F) |
| 1.265 | -75 F |
| 1.225 | -35 F |
| 1.200 | -17 F |
| 1.150 | +5 F |
| 1.100 | +18 F |
| 1.050 | +27 F |
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