Looking at the US Battery curve, and assuming the same curve shape for these batteries, the 50% rate is about 2.2 times the 100% rate so that would make these batteries (at 50% Discharge) about 140 for the Everstart and 180 for the Maxx....
if you full time with only 2 batteries that would be easy to do
we started with 4 house batteries and now have 8 house batteriesand two starting batteries
boondockdad wrote: I may be misinterpreting this, too...
but, to put this US Battery chart another way:
if I run my battery down to 50% DOD every night, then charge it back to 100% SOC every day, I'll get 1150 of these cycles out of it.
That's over 3 years of, what I consider, extreme heavy duty.
No way.
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If the word "Start" appears in the name of the battery it is NOT a deep cycle. They are the so called 50/50's that are very popular with the boating crowd. For RV's since you have nothing to start you have no need for a starting battery of any kind. Buy a quality deep cycle and never discharge it below 50%. Unless you are trying to shorten the life of the battery there is no reason to do so as most DC motors either stop working efficiently or stop all together when the voltage falls below 12 volts and even lights dim noticeably as voltage falls.
MrWizard wrote: if you full time with only 2 batteries that would be easy to do
we started with 4 house batteries and now have 8 house batteriesand two starting batteries
boondockdad wrote: I may be misinterpreting this, too...
but, to put this US Battery chart another way:
if I run my battery down to 50% DOD every night, then charge it back to 100% SOC every day, I'll get 1150 of these cycles out of it.
That's over 3 years of, what I consider, extreme heavy duty.
cruz-in wrote: Looking at the US Battery curve, and assuming the same curve shape for these batteries, the 50% rate is about 2.2 times the 100% rate so that would make these batteries (at 50% Discharge) about 140 for the Everstart and 180 for the Maxx....
My bank of three WalMart 27DCs had two from May of 2008 that I tossed last Fall after three and a half years of hard use doing 50-90% and recharging them at 30% rates usually. I was surprised to go back and find that came to only about 130 or so of those hard working cycles.
I spent a lot of time at home after 50-90s doing reconditioning to 100% before the next set of 50-90s as part of the price of using these instead of 6s which don't take so much "recovery" effort as they gas more than the 27s do.
Unless you are a full timer it is hard to get many cycles done per year. Six months of long weekends is 78 days and if you recharge every second day that is say 40 cycles per year and so only 120 in three years as an idea of that.
By the time I tossed those two they were at maybe 95AH (rated 120AH) from some tests I tried to measure them with, and they were still working ok for camping. I wanted 6s instead, so I figured I had my money's worth from those two 27s. I still have the newer third 27 and it is in decent shape.
They are JC made, Walmart 27DC "deepcycle/starting" marine with 675 CCA, 850 MCA, 180 RC, and 120AH on their labels - Model 27DC-850N
I certainly can't complain about those "not really deep cycle" batteries.
Good that they define end of life as 50%. That would be no good for many RVers who barely have enough battery capacity when new. Each RVer has to decide when he no longer has enough capacity to get by, and that will even vary between winter and summer by quite a lot.
So now you want a curve that shows after you decide how much margin you have in capacity, how many cycles that is.
10% i would need at 1200 amphrs of capacity (maybe more) to use only 10%
how many ampHrs per day do you use 25 AH, 35AH, 50AH
lets assume your conservative and only use 35AH per day
you would need at least 350 Amp Hrs of capacity
that means (3) big 12v grp 27 or 29 batteries or (4) 6v GC batteries to use only 10% and get that phenomenal battery life
NOT to mention the aging of the chemical compositions are used during the discharge/recharge process
boondockdad wrote:
MrWizard wrote: if you full time with only 2 batteries that would be easy to do
we started with 4 house batteries and now have 8 house batteries and two starting batteries
boondockdad wrote: I may be misinterpreting this, too...
but, to put this US Battery chart another way:
if I run my battery down to 50% DOD every night, then charge it back to 100% SOC every day, I'll get 1150 of these cycles out of it.
That's over 3 years of, what I consider, extreme heavy duty.
I'm pretty simply when it comes to electricity and batteries, so help me out here... but I think we're saying the same thing: claiming 1150 'cycles' to 50% is bunk, right?
My (2)27's lasted two years with light use... if I had to guess, I'd say maybe 100 cycles, and never below 60% (Trimetric reading)
garym114 wrote: 'Deep Cycle' is a marketing term just like 'New' and 'Improved'.
WalMart does not sell any true deep cycle batteries.
Not true. Deep cycle batteries do exist, are made with heavier plates, and are designed to withstand repeated long discharges.
The statement about Walmart, hoever is right on. That's what I found when I was looking for a trolling motor battery. Same with AutoZone. Dual Purpose is not the same as deep cycle. I had to go with a Delco Voyager. Sears also has a DieHard Deep cycle battery. I don't know about Sams or CostCo because I don't shop there.
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