its not only the level of discharge, its the discharge rate
I thing we would have to use them (amps draw) at the 100 Hr rate
its very hard to get the battery life that some mfg claim
although batteries like "Rolls" and some others do seem to achieve this a according to customer ratings
for most users including my self, we can expect only a few yrs of use
boondockdad wrote: MrWiz,
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)
-Joe
Options, always have options, and the journey goes much smoother ....
Connected thru Verizon with HotSopt WiFi using a Samsung Galaxy Nexus
Member of the Verizon Wireless Customer Council
I BOUGHTthis phone
By the time even half the amount of cycles claimed expire, the battery capacity would be down to near useless amounts.
Sure it would still be able to cycle, at 5% of it's former capacity.
In July 07, I bought 3 date matched dc 27 Everstarts.
One lasted 13 months of 5 to 20 percent nightly discharges till a cell shorted.
The Second one lasted 23 months till a cell developed super high resistance under sightly more aggressive nightly discharging.
The third was then moved to my engine compartment and was the solo starting battery, isolated each night around sundown, and then paralleled to the house batteries the next day, which then had 130 watts of solar feeding them.
Nearly 5 years later, It Still cranks over my engine on a cool morning, but slowly. The thing never needs water either. It has been years Since I added water. It's been spending an hour a day at 15 volts, and probably 3 hours over 14 on it's way to 15.
I got those 27DCs at Walmart because the U-2200 6s I wanted at the time were more expensive. 27DCs were $90 (now $110) and the 6s were $150 (now $180) I got 5 years out of the first set of 6s so that was $300/5 = $60 per year. The pair of 27s lasted three years, so that's $180/3 = $60 per year. Same.
But the 27s were a PITA to keep "recovering" to 100%, so I wanted 6s instead. Much easier to keep them going so this time I paid the extra, and expect the 6s to last longer to break even on cost.
Of course, no access to those Sams/costco $90 U-2200s here but if you are in the States, it is a no-brainer.
2003 Chev 2500HD Gas, 2003 Komfort 26FS 5er
See Profile for Equipment List
re: "Not true. Deep cycle batteries do exist, are made with heavier plates, and are designed to withstand repeated long discharges."
bull.
I really don't know of any more polite way to respond to this myth.
The curve for cycle life vs depth of discharge as linked up thread is typical for all batteries. It just shifts slightly depending upon chemistry, type, and whatnot.
Modern battery design and manufacturing is mature and highly optimized. Batteries commonly available at retail for RV and automotive use are more alike than different. Differences are in the same range as variability in available energy capacity due to age, temperature, cycle to cycle variations, and use profile. Look at the specifications and warranties and costs!
See http://www.mpoweruk.com/reliability.htm and other pages on that website for some good information about batteries.
For RV use, you generally need sufficient battery for two or three days off grid and then a reserve to handle cool nights or other contingencies. All of these factors mean that RV cycle depth is usually at 25% DoD or less. That leads to the conclusion that cycle life is not an issue for RV use.
What is an issue is use and maintenance. Anyone talking about their RV battery life is telling you about how well they take care of their batteries and not about the battery itself.
For best battery service satisfaction, you need a converter that does multiple stage charging and has a storage mode that will maintain a full charge and apply a sulfation inhibiting technique. You should avoid extremely large currents, deep discharges, and heat, You should recharge promptly with appropriate vigor and allow for a full and complete battery charge at least once a week (this sort of charge can take 8-12 hours).
BTW, re myths: the link above has a page that notes that capacity is a matter of electrolyte and current capability a matter of plate surface area. Think about those ideas and the implications of the 'deep cycle thick plates' rationalizations. -- I do know that this 'deep cycle' thing is all over the place but popularity does not make it correct or applicable to this context. Use critical thinking based on empirical measures and you'll get a much more useful outcome, I think.
My word of advice is ,before buying any battery ,find out where its made.
buying anything made in China is like playing russian roulete!
crappy build from my experience..!!
and as Ive noticed lots of stuff in WM is china made..
mind you that doesnt mean US made batteries are best,since my new Lifeline AGM lasted exactly 7 months with normal use,no deep discharges,before unable to hold charge..
now Im using Fullriver AGM 110 amphr making dam sure not to discharge it more then 20% anytime..thats about 12.2 V ..
so far it works great and recharges to 100% in an hour with 3 stage charger,,,,
using 80 W solar panel takes about 5 to 6 hrs ...wish I made adjustable panel as to raise it more steeply towards the sun,,something for everyone to consider when building your solar!!
thist batt is not cheap at 450$ but since I dont pay rent and can deduct it as biz expense,anyway,,is well worth it...
MrWizard wrote: 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
Perhaps I'm missing something here. DC loads and generator and controller, are all connected parallel to the battery. When you use 35 AH a day and receive same 35 AH from controller or generator, your consumed 35 AH don't all come from the battery because when the battery is full or almost full, you are running your loads from generator or controller, with a fraction of that power diverted to battery charging. It's when you are consuming and NOT getting any power from controller or generator at the same time - usually during the night - then your DOD is going down, reaching 10% DOD or whatever it will reach by the moment the sun goes up or generator turns on.
WOW! They must have *really* improved batteries since I designed cyclable car jar .105" 5% batteries. We used to average ELEVEN 100% DOD cycles* before the 20 amp hour rate slumped 50%.
Optimum 20% DOD cycles yielded 500+ cycles, while 50% DOD yielded an average of 200 to 240 cycles before 50% A/H was broached.
Must be dilithium crystals added to the paste. Maybe they now green raw batteries in 200% humidity.
It is PURE B.S. to discharge a cyclable battery at a rate greater than 10% of total A/H in order to establish cycle life. Now this is *my* turf and I fought the BCI for years about this. Batteries should be discharged to 0.00 volts @ 10% A/H rating upon which time they should be recharged to nominal OEM specific gravity at a rate of 10% of A/H rating. All test material should be NIST certified traceable.
IN ADDITION! Batteries should be weighed via a digital strain gauge (digital) method to determine loss of weight before and after each cycle. Resolution should be .05 oz.
* This post was
edited 04/07/12 07:00pm by an administrator/moderator *
yes maybe you get some of "your" 35 AmpHrs from a genetator
I easily use 120 AmpHrs on just the inverter, powering the fridge, TV, PC, and 120v lighting
this measured guaranteed use and has nothing to do withthe MW and coffee maker running from the generator
I easily use 60 AmpHrs per night just for the fridge, and most of my PC TV and lighting use is night time, and in cold weather we run an electric heated mattress pad
so tell me how I'm getting that power from generator or solar at night
I can easily use 100 AmpHrs during night time quiet hrs
the statement I had replied too was about using 10% of battery and recharging
I'm just as sure that most of your 35 AmpHrs?? is mainly at night
that means yours is not coming from generator or solar controller either
and must be returned during the day some how, but the majority of it was subtracted/removed from the battery not supplied during the day from the solar or generator, because it was used at night
not mention bad weather, cloudy days rain, or days that we are simply gone and cannot be there to run the generator so every amp used has to come from the batteries or solar
and if the solar is only doing 5 amps and the fridge is using 10, well the batteries are operating at a deficet in the charge system
so again I say if some one wants to maintain 10% dod on a Measily 35 AmpHrs per day he needs a 350 AmpHrs system
remember I did not specify the 10% use figure
I have almost 1000amphrs actually 956 AmpHrs total if all batteries were new (they are not)
I know I use more than 10%
that's why I run a generator every day and why I'm building out / expanding my solar panel system
yes when the generator is running some of the power from the 100amp wfco 68100 does go to 12v use while the remainder goes into charging the batteries
the point is the bulk of most campers/Rv'ers use is during the dark hrs when there is NO auxiliary power
so whether is lights, TV, stereo, heater fan or PC
the majority of the power consumed is consumed at night directly from the batteries, and there fore the bank must be sized accordingly, IF you are on shore power the whole battery DOD level is mute
chose the level of discharge you are willing to accept/tolerate/work with and size according, 10% means a bigger bank, even for power misers that use very little
Almot wrote:
MrWizard wrote: 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
Perhaps I'm missing something here. DC loads and generator and controller, are all connected parallel to the battery. When you use 35 AH a day and receive same 35 AH from controller or generator, your consumed 35 AH don't all come from the battery because when the battery is full or almost full, you are running your loads from generator or controller, with a fraction of that power diverted to battery charging. It's when you are consuming and NOT getting any power from controller or generator at the same time - usually during the night - then your DOD is going down, reaching 10% DOD or whatever it will reach by the moment the sun goes up or generator turns on.
* This post was
last
edited 04/07/12 11:14pm by MrWizard *
View edit history
Offline
but if you are in the States, it is a no-brainer.
Online
