I got a little under three years of life on my first Braille battery, it was a 15lb model. The folks at Braille say their batteries are not fond of cold weather and it would last longer if on a maintainer over the winter. The 15 lb unit worked fine, but when I replaced it I went with their 21 lb battery because I have a couple of good sized, outboard amps in my audio system. Below is the info from their website on the unit I am using,
Ed
Braille SKU #B3121Model
Name:21 lb Extreme Use Battery
Length:6.6"Width:5.2"Height:6.8"Minimum Weight:21 lbs
12 VoltsFull Charge Voltage:13.8 Volts
Short Circuit Current (Max Cranking Amps):3000
Pulse Cranking Amps (PCA) 5 sec @ 80F: [?]1380Pulse
Cranking Amps (PCA) 10 sec @ 80F:1207
Pulse Cranking Amps 20 sec @ 80F:1066
Cranking Amps 30 sec @ 80F:892
Cranking Amps 30 sec @ 32F:742
Cold Cranking Amps 30 sec @ 0F: [?]
550Reserve Capacity: [?]1hr 15mins
Capacity (C/20 rate): [?]31 amp hr
Internal Resistance:4.0 milliohms (.004 ohms)
Life Cycle @ 10% DOD: [?]3100 cycles est.B3121 - Gallery