How bad is wet cell maintenance really?

stereoman405
stereoman405 Solar Expert Posts: 56 ✭✭✭✭
in General Solar Power Topics #1
What's your real world experience? Do you check monthly, weekly, bi-annually? Do you get good life out of then if you do the time?

Still having the AGM vs Wet Cell (high quality like Rolls Surrette) debate in my head and just want to hear what experiences people are having.

Quick question, when you measure the specific gravity and its low all you do is verify water is topped off and equalize when needed right? You don't have to actually stock acid to add back in do you?
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: How bad is wet cell maintenance really?
    stereoman405 wrote: »
    What's your real world experience? Do you check monthly, weekly, bi-annually? Do you get good life out of then if you do the time?

    Still having the AGM vs Wet Cell (high quality like Rolls Surrette) debate in my head and just want to hear what experiences people are having.

    Quick question, when you measure the specific gravity and its low all you do is verify water is topped off and equalize when needed right? You don't have to actually stock acid to add back in do you?

    FLA battery maintenance is not the nightmare some would have you believe. It would be safe to say most solar electric systems use this type of battery without any difficulty. Some people obsess with Specific Gravity and Voltage readings, trying desperately to get accurate numbers down to 0.005. Can't be done: don't bother to try.

    I check my SG monthly, and equalize only if necessary. Got 6 years of service out of Trojan T105's, despite regularly drawing them down to 50% SOC. Replaced with Interstate 'Utility' batteries, one of which suffered a sudden plate failure in the first year. Lesson: buy Trojans, not Interstate. Two of the Trojans are still serviceable, and I keep them for my 'back up' power system which has a small MSW inverter.

    If electrolyte is low, you charge first then add distilled water to bring it to the proper level. The sulphor portion of the sulpheric acid mix does not leave the battery; only the hydrogen and oxygen are gassed off. But the sulphor does end up coating the plates (sulphation) reducing the battery's Amp/hr capacity. No acid stocking is necessary. Good thing too, as it is very nasty stuff.

    Once you get the charge conditions for your specific system 'dialed in' FLA's will last just fine. Because they are cheaper per Amp/hr than AGM's and more forgiving of mis-charging they are recommended for first-time use.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #3
    Re: How bad is wet cell maintenance really?

    In theory, you should never add acid to a cell. The only out-gassing is the water itself.

    If you are getting ready for a full charge/equalize... Check the electrolyte level first. If the plates are covered--don't add any water until the equalization is done. One of the messy mistakes that most of us make at least once is to fill the cell to "water level" -- and then begin a heavy charge/equalize. Between the rising temperatures and bubbles on the plates/electrolyte--it is not unusual for the cell to dump electrolyte around the top of the battery leaving a mess to clean up.

    The one question for me regarding AGM--what is the real world life that people see with them (when properly maintained). For the most part, the warranties (the few I have read up on) for Very Good AGM's is shorter than Very Good Flooded Cell (excluding long term float service for Telecom batteries)...

    Some information in this thread on how to "recondition" AGM batteries. Is very interesting (appears that caytalyst failure (in battery caps) is one of the repairable events for some AGM's. New cat. caps at $24 each or so (at least for the larger cells). Also adding distilled water back into cell (appear to need impedance testing equipment to get correct amount back in).

    You may never need to do this--but was an interesting read/thread.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • blackswan555
    blackswan555 Solar Expert Posts: 246 ✭✭
    #4
    Re: How bad is wet cell maintenance really?

    you could also think of either an auto watering system or hydrocaps,

    http://www.ibiblio.org/pub/academic/environment/alternative-energy/energy-resources/homepower-magazine/archives/11/11pg37.txt

    Tim
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  • Windsun
    Windsun Solar Expert Posts: 1,164 ✭✭
    #5
    Re: How bad is wet cell maintenance really?

    It depends a lot on the location - how hard to get to them, either because they are on a mountain top under 10 feet of snow, or under your porch where you need a tow truck to pull them out :p
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  • peterako
    peterako Solar Expert Posts: 144 ✭✭
    #6
    Re: How bad is wet cell maintenance really?

    After some adjustment time i am now clossing the second year on my battery bank on this moment i check every 3 months and have to fillup around one glass. ( i have 48V 1000AH ).

    After filling up a equalize. Sorry Bill but my understanding is that you must mix the acid/water after filling up. And if there is still air above the battery will not spill. But that counts for the battery that i know in europe maybe there is differend construction in the states.:confused:

    Greetings from Greece8)
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #7
    Re: How bad is wet cell maintenance really?

    Not a big difference in opinion... The big issue is not the fill the cell all the way to the "top" -- leave some room for expansion and the bubbles.

    I agree that leaving the water floating on the top of the electrolyte is not a good thing either.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    #8
    Re: How bad is wet cell maintenance really?

    For my applications, FLA are fine. If one minimizes the number of parallel strings of batteries, like one string, the maintenance is not a big deal. It is often recommended to monitor a single cell of the bank -- the Pilot cell. this is a good indicator of the behavior of all cells. Some mfgs note that the Pilot cell be identified when comissioning the battery bank -- choose the cell with the lowest SG. It is also recommended to change to a different Pilot cell every year or so.

    If my bank seems to be happy, with no signs of distress, will check the pilot cell about once per week or so. Just after a bank is comissioned, it is probably good practice to monitor and record SGs of all cells fairly frequently until you are sure that the bank is being properly charged. After things have settled in, I would take SGs at least once every three months. It might be good to take SGs once per month for the first three months or so on a new bank.

    Flooded cells are forgiving. Nothing needs to be perfect. It is actually a benefit that with flooded cells, one CAN measure the SGs. It is the best method to determine if one is really fully charging the bank.

    And, YES, you need only add pure water -- in my opinion, Steam Distilled Water.

    Good Luck with the selection process. Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #9
    Re: How bad is wet cell maintenance really?

    normally only distilled water should be added as most battery manufacturers do put an excess of acid into the mix in recognition that small amounts of the acid will escape with the boiled out water. (very minute) if one fries their batteries with very high rates of charge it may become necessary in time to add a touch of acid along with the water, but even this is very rare and would be a very small amount of acid. odds are the battery might fail from other factors when fed high charge rates negating the need to add any acid down the road. they are only meant to last so long and to take so much before suffering capacity loss or even death of the battery.
    there are advantages and disadvantages to both types that you need to weigh and i won't get into particulars here on it as the last thread like this i misinterpreted what was being said.
    one last note to mention is that trojan has a new battery configuration coming out in june called t2.
    http://www.trojanbattery.com/Products/t2.aspx
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  • Kamala
    Kamala Solar Expert Posts: 452 ✭✭
    #10
    Re: How bad is wet cell maintenance really?

    I chose to use AGMs in my camper for three main reasons. 1) Outgassing cannot be tolerated, 2) cramped quarters would make maintenance difficult, and 3) vibration while in transit.

    If I were to design a "stationary" system, I would definitely choose FLAs. I am anxious relying on voltage measurements and the battery monitor to determine the "health" of my bank. Regular SG measurements of the cells in a FLA bank might provide early warning of a cell about to fail. In the AGM bank, no such warning is possible.

    K
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  • wtwoods_az
    wtwoods_az Registered Users Posts: 18 ✭
    #11
    Re: How bad is wet cell maintenance really?

    I currently have a 48V bank of Crown 6V 225amp that I bought from NAWS. Can't beat the price and since I am local to PHX, I picked them up; no shipping costs. They are installed outside on the North side of the house and I check SG every month now. During commisioning I checked daily. I adjusted my charger/SC times so that SG and amp in/out seemed stable. Crown recommends a full charge daily and EQ weekly; that's what I follow for a schedule. I've only had to water 3 times in 8 months; very happy with the product so far.
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  • john p
    john p Solar Expert Posts: 814 ✭✭✭
    #12
    Re: How bad is wet cell maintenance really?

    I sometimes think many people worry way too much over batteries and their charging when used for off grid energy. People seem to be obsessed with looking to rectify even the tinniest discrepancy between cells.
    But there are millions of vehicles running around ok with much the same batteries that never get checked one year into the next. And I have as yet to see mass vehicle breakdowns caused by battery failure.
    It would be interesting to know how many of the people that use batteries and give them almost endless loving attention for off grid or backup give the same care and attention to the batteries in their vehicles???????
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  • solarvic
    solarvic Solar Expert Posts: 1,071 ✭✭✭✭
    #13
    Re: How bad is wet cell maintenance really?

    If you have battery failure in a car you only have to buy 1 battery at maybe around $100.00. With a solar system probably at least $1200.00 for 4 l-16 for 24 volt system . Double or quadtruple it for 1 48 volt system. Preety good reason for watching your battery health. S:Dlarvic
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  • john p
    john p Solar Expert Posts: 814 ✭✭✭
    #14
    Re: How bad is wet cell maintenance really?

    solarvic your points are correct. but you missed my point that you just dont see many vehicle breakdowns caused by failed batteries out of millions of vehicles.. And I believe tHey receive almost no attention EVER
    I live a lot of times in Philippines in the provinces where deep cycle or any decent battery is not available,, only"truck" or car batteries and as im not there a lot of the time so they get no attention and the 3 truck batteries (made in Philippines) have been in constant use for nearly 3 yrs now.I have a hydometer but it just took too much time to be checking them, and nobody does in the months im not there
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #15
    Re: How bad is wet cell maintenance really?

    i hate to nit pick, but being from pa and speaking for myself i have seen allot of car breakdowns due to battery failures. they fail in our cold winter weathers left and right often without warning. i have even had one fail due to vibration and from going up and down steep hills with accelerating and braking causing some electrolyte to leak out over time. in general they do tend to go with the onset of our cold wintry seasons as many of the batteries do not function well under duress. water levels and connections, as well as covers and tie-downs, need addressed on car batteries.
    now i do agree that some may be taking this stuff to a level that may border on paranoia.
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  • Ralph Day
    Ralph Day Solar Expert Posts: 1,022 ✭✭✭✭
    #16
    Re: How bad is wet cell maintenance really?

    Remember Neil,

    It's only paranoia if there's nobody out to get you...otherwise it's due diligence ;)

    If my battery conks in the car I call the auto club, if the batteries in the house conk I've got no house club to call....just líl ol me :cry:(hence my persnickity watching of battery SG readings.

    Ralph
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