Originally Posted by Skyliner
Trojan batteries can last about 2900 cycles if discharged only 20% and 500 cycles if taken to 80% discharge.
If accurate, those numbers would argue for fewer batteries and deeper discharge.
Basis: 1 pair of T-105 batteries in series giving 12 volts and 225 AH capacity.
Discharging 20% = 45 AH used. Times 2900 cycles, total "Lifetime" AH delivered is 130,500 AH.
Discharging 80% = 180 AH used. Times 500 cycles, total "Lifetime" AH delivered is 90,000 AH
To get the same 180 AH capacity per charging cycle
that the 80% discharge gives, you would need 4 times as many batteries for the 20% scheme.
If you boondock for 50 days a year and recharge daily, the 80% discharge scheme should give you 10 years of use.