Seminole Wind
Well-known member
if you are in an area of lots of golf courses with clients shingling their roof with black amex cards you should have no trouble finding used golfcart batteries just a couple years old for cheap.
check out the interstate batteries storefronts. ask about their econo power golf cart batteries. also check other "mom n pop" family (not chain) battery only stores, if you have golf courses around you will have these store. i spend a lot of time in a city metro area of way less than 100,000 people and we have 3 of those stores and the next city down the highway has several more. they all have the used/reconditioned golfcart batteries. especially in the spring as the weather start getting nice
as for RV batteries, if you dont have a decent charging system in place then ya, go for them cause you will kill the golfcarts just as quick if you dont get the fully charged regularly. so if you are just going to sacrifice batteries buy the cheapest
once you get a decent charging system put together that can fully recharge your batteries the golf carts will far out last the RV batteries. especially if you look at life time amphours . for example of what i mean in life time amp hours consider a battery that you use 100 amp hours per cycle and you cycle this each day and lets say it lasts a year. that would be 36500 amp hour lifetime. now if you had a battery that you use 200 amp hours per cycle and you cycle that each day you would hit the same 36500 amp hour lifetime in only 6 months. so ya, the battery lasted half the time but provided the same lifetime amp hour capacity.
now if we look at the trojan charts for lifetime cycles vs depth of discharge which can be found here under "cycle life chart" https://www.trojanbattery.com/products/deep-cycle-flooded/signature-line-flooded-2/
if we look at the "50% discharge" it shows 1200 cycles. then when we look at the "80% discharge" it shows 750 cycles. so if we do the math on a 200 amp hour battery 50% discharge would be 100 amp hours times 1200 cycles for 120,000 amp hours life time capacity. and at 80% discharge from the 200 amp hour battery we have 160 amp hours per cycle times 750 cycles for 120,000 amp hours life time capacity. this chart if from trojan and covers all their big deep cycle batteries 6 volt golf carts and some of their big 12volt deep cycles.
as you see the life time amp hour capacity is the same. the old "50%" rule of thumb (that's all it was) comes from the days of homestead type systems where weight/space had no bearing (i was there) and systems were designed around the 50% rule of thumb to allow a system that has aged and lost capacity to still perform satisfactory and for a system to handle the occasional extended/unexpected storm
as mobile users where weight is important why would i carry around extra batteries just so they last a couple extra years. dont fret over the mythical 50% depth of discharge rules. use a lighter smaller and cheaper battery bank and in the end you will pay the same per amp hour lifetime.
you also get the added benefit of more efficient charging all the way from 80%dod (depth of discharge) to 20%dod where the power in, is damn near equal to the power stored. where as once you get past approx 20%dod the efficientcy of charging drops of considerably
it is FAR MORE IMPORTANT to get your batteries fully charged as often as possible than it is to worry about the mythical 50% dod
partial state of charge (POSC) cycling kills lead acid batteries due to sulfation regardless of their quality cost or composition... and that results in fewer life time amphours and just costs you money
check out the interstate batteries storefronts. ask about their econo power golf cart batteries. also check other "mom n pop" family (not chain) battery only stores, if you have golf courses around you will have these store. i spend a lot of time in a city metro area of way less than 100,000 people and we have 3 of those stores and the next city down the highway has several more. they all have the used/reconditioned golfcart batteries. especially in the spring as the weather start getting nice
as for RV batteries, if you dont have a decent charging system in place then ya, go for them cause you will kill the golfcarts just as quick if you dont get the fully charged regularly. so if you are just going to sacrifice batteries buy the cheapest
once you get a decent charging system put together that can fully recharge your batteries the golf carts will far out last the RV batteries. especially if you look at life time amphours . for example of what i mean in life time amp hours consider a battery that you use 100 amp hours per cycle and you cycle this each day and lets say it lasts a year. that would be 36500 amp hour lifetime. now if you had a battery that you use 200 amp hours per cycle and you cycle that each day you would hit the same 36500 amp hour lifetime in only 6 months. so ya, the battery lasted half the time but provided the same lifetime amp hour capacity.
now if we look at the trojan charts for lifetime cycles vs depth of discharge which can be found here under "cycle life chart" https://www.trojanbattery.com/products/deep-cycle-flooded/signature-line-flooded-2/
if we look at the "50% discharge" it shows 1200 cycles. then when we look at the "80% discharge" it shows 750 cycles. so if we do the math on a 200 amp hour battery 50% discharge would be 100 amp hours times 1200 cycles for 120,000 amp hours life time capacity. and at 80% discharge from the 200 amp hour battery we have 160 amp hours per cycle times 750 cycles for 120,000 amp hours life time capacity. this chart if from trojan and covers all their big deep cycle batteries 6 volt golf carts and some of their big 12volt deep cycles.
as you see the life time amp hour capacity is the same. the old "50%" rule of thumb (that's all it was) comes from the days of homestead type systems where weight/space had no bearing (i was there) and systems were designed around the 50% rule of thumb to allow a system that has aged and lost capacity to still perform satisfactory and for a system to handle the occasional extended/unexpected storm
as mobile users where weight is important why would i carry around extra batteries just so they last a couple extra years. dont fret over the mythical 50% depth of discharge rules. use a lighter smaller and cheaper battery bank and in the end you will pay the same per amp hour lifetime.
you also get the added benefit of more efficient charging all the way from 80%dod (depth of discharge) to 20%dod where the power in, is damn near equal to the power stored. where as once you get past approx 20%dod the efficientcy of charging drops of considerably
it is FAR MORE IMPORTANT to get your batteries fully charged as often as possible than it is to worry about the mythical 50% dod
partial state of charge (POSC) cycling kills lead acid batteries due to sulfation regardless of their quality cost or composition... and that results in fewer life time amphours and just costs you money
