Keeping batteries in camper over winter?
There's a lot of advice out there that says the best way to maintain deep cycle batteries over the winter is to remove them from the camper and put them in warm storage. However, I'd like to use the ...
Forum Discussion
Storage, aka non-use battery conditions are important to attain maximum battery cycles/life, especially the farther you deviate on either side of ~25C (77F). Self discharge increases with higher temperature and age. Combine that with any parasitic draws if you don't disconnect the battery, and your battery capacity won't last long due to sulfation, if you don't follow the white paper from:
Trojan PDF - Deep Cycle Battery Storage
In the cold, you get the benefit of a 2x slower chemical reaction for every 10 degree C decrease (Arrhenius equation). Sulfation slows down, but nothing is free. The capacity of the battery (a chemical reaction) also decreases, it also takes more voltage to recharge the battery, if you don't have temperature compensated charging. So only a partially charged battery.
So if you aren't monitoring or keeping your battery charged in the winter, in addition to sulfation, the electrolyte freezing point also gets higher, the more discharged the battery. Resulting in a frozen/destroyed battery, if it isn't an AGM.
40% discharged; Freezing point -30F
50% discharged; Freezing point -14F
60% discharged; Freezing point -3F
70% discharged; Freezing point 9F
80% discharged; Freezing point 16F
90% discharged; Freezing point 23F
You can read more about all of the above in:
Trojan - User's Guide PDF
Or if you like even more info:
Sandia National Laboratories - PDF
Temperature effects on sealed lead acid batteries and charging techniques to prolong cycle life
Trojan PDF - Deep Cycle Battery Storage
In the cold, you get the benefit of a 2x slower chemical reaction for every 10 degree C decrease (Arrhenius equation). Sulfation slows down, but nothing is free. The capacity of the battery (a chemical reaction) also decreases, it also takes more voltage to recharge the battery, if you don't have temperature compensated charging. So only a partially charged battery.
So if you aren't monitoring or keeping your battery charged in the winter, in addition to sulfation, the electrolyte freezing point also gets higher, the more discharged the battery. Resulting in a frozen/destroyed battery, if it isn't an AGM.
40% discharged; Freezing point -30F
50% discharged; Freezing point -14F
60% discharged; Freezing point -3F
70% discharged; Freezing point 9F
80% discharged; Freezing point 16F
90% discharged; Freezing point 23F
You can read more about all of the above in:
Trojan - User's Guide PDF
Or if you like even more info:
Sandia National Laboratories - PDF
Temperature effects on sealed lead acid batteries and charging techniques to prolong cycle life
