Watering batteries

Greetings:

During the first year of my batteries, it was almost unnecessary to water them, except, maybe, once every month or every 2 months.

Now, 2.5 years later, I need to add water almost every 2 weeks, and even every week.

Is this normal?

What dries cells faster, under-voltage or over-voltage?

P.S.: Batteries are PowerFast from Exide, golf cart type, 6 volts; 4 of them in series.

Comments

  • soloronesolorone Solar Expert Posts: 254 ✭✭✭
    Re: Watering batteries
    JESSICA wrote: »
    Greetings:

    During the first year of my batteries, it was almost unnecessary to water them, except, maybe, once every month or every 2 months.

    Now, 2.5 years later, I need to add water almost every 2 weeks, and even every week.

    Is this normal?

    What dries cells faster, under-voltage or over-voltage?

    P.S.: Batteries are PowerFast from Exide, golf cart type, 6 volts; 4 of them in series.

    Over charging consumes water.

    I have no faith in golf cart batteries, seems everyone must ruin one set of them before moving on to real deep cycle units, which cost more.

    Had you bought a better battery at that time, you "might" have missed part of the price increase, gosh they are $$ now.

    Some one will correct me if I'm wrong, but my reading on battery technology leads me to point out this. Golf cart batteries are designed to give off a steady known load, I do not think they will function well under the demands of an Inverter, where loads can hit 250 to 500 amps.

    The same goes for the telephone batteries we lusted for 30 years ago, while massive in their design, they were not built to give up huge amounts of amperage to the modern inverters.

    These are old axioms. You get what you pay for. Buy the best you can afford and you will not usually be disappointed.
  • rplarryrplarry Solar Expert Posts: 203 ✭✭✭✭✭
    Re: Watering batteries

    Jessica
    Charge current and voltage will cause batteries to bubble and consequently lose hydrogen and oxygen (water)and there can be several reasons why your amount of loss changes over time. If the plates in your batteries ever got dried out, then that part of the plate will not work anymore and the rest of the plates have to make up the difference, making more bubbles on that part of the plate. Or maybe there might be some sulfation on the lower part of the plates causing the same thing, the upper part of the plates are now doing most of the work. It is pretty much just the nature of FLA batteries. Are you having to clean corrosion more often than normal? If so then maybe you are over charging them or over filling them. The electrolyte just needs to cover the plates, it does not need to be filled all the way to the top. Exide has an excellent website and maintenence section on how to care for their batteries: http://www.trojanbattery.com/Tech-Support/BatteryMaintenance.aspx but you have probaly already seen that site.
    Also this time of year, since the warmer weather causes batteries to use more water (batteries do not need as high a charge voltage when they are warm) so be sure to use a remote battery temp senso with your charge controller.
    Good luck with yours,
    Larry
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Watering batteries

    how deeply do you cycle your batteries? if you often go deep it can affect the cycle life of the batteries. batteries like that are usually in the 3-5 year range and you can correct me on it for your specific batteries. you might just be seeing the normal onset of premature old age.
  • PhotowhitPhotowhit Solar Expert Posts: 5,082 ✭✭✭✭
    Re: Watering batteries
    solorone wrote: »
    Over charging consumes water.

    I have no faith in golf cart batteries, seems everyone must ruin one set of them before moving on to real deep cycle units, which cost more.

    Had you bought a better battery at that time, you "might" have missed part of the price increase, gosh they are $$ now.

    Some one will correct me if I'm wrong, but my reading on battery technology leads me to point out this. Golf cart batteries are designed to give off a steady known load, I do not think they will function well under the demands of an Inverter, where loads can hit 250 to 500 amps...

    ...These are old axioms. You get what you pay for. Buy the best you can afford and you will not usually be disappointed.

    WOW!!!

    "Over charging consumes water." I agree...

    ...no faith in golf cart batteries...
    ...moving on to real deep cycle...

    Golf cart batteries are 'real' deep cycle batteries, it's the first and last battery many people use with solar. I was in a battery shop and met a fellow from central Missouri who was replacing his 9 year old T105's, 16 of them ( 48V)! he ran a household on a double string 'Golf Cart' batteries, including a central A/C and Shop! He lost faith in them due to age! They tested good and were working when he pulled them.

    "...price increase, gosh they are $$ now..."

    Not sure why, golfcart batteries have returned to pre '08 prices when lead went through the roof. Perhaps it's because they are made in small quantities...

    As to loads Golf Carts stop, start go up and down hills, the load varies.

    "...demands of an Inverter, where loads can hit 250 to 500 amps..."

    This looks like a poor understanding of battery banks and loads. Even with a 12 volt system a 250 amp load would be a 3000 watt load and you'd want an inverter with a yet higher capacity to run this. With knowledge of battery banks you would have a larger battery bank, 24 or 48 volt, reducing your amperage to a more reasonable level, 125 amp for a 24 volt system and 73 for a 48 volt system.

    I have a 24 volt system and reached a new peak of 40amps Friday running an AC, a foreman grill and a fridge at the same time. What is my battery bank? 4 golf cart batteries, from my old system, I'd like to replace them with a larger capacity battery bank, but they are still healthy and showing good capacity, they'll turn 5 years old in Oct.

    Batteries use more water as they age, are you filling correctly? most it's an 1/8 of and inch below the plastic, have you done regular equalizing?

    If they are often deeply cycled this could use more water. Hopefully someone will post links to the Battery FAQ,

    Battery mizer caps might reduce the need for watering, available here;

    http://store.solar-electric.com/batwatmiscap.html

    Lets see... Old Axioms, a penny saved is a penny earned, look before you leap...

    Golf Cart batteries are often the most cost effective storage, study your over all needs and evaluate your willingness to invest a little time to maintain them.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, 660 ah 24v ForkLift battery. Off grid for @16 of last 17 years. Assorted other systems, and to many panels in the closet to not do more...lol
  • JESSICAJESSICA Solar Expert Posts: 289 ✭✭
    Re: Watering batteries

    Solorone:

    "I have no faith in golf cart batteries..."

    Me neither... now!

    Niel:

    "how deeply do you cycle your batteries?" Never below 24.4/24.5 volts (To be honest, I don't know how deep a discharge that number represents.)

    Solorone:

    "Exide has an excellent website and maintenence section on how to care for their batteries: http://www.trojanbattery.com/Tech-Su...intenance.aspx but you have probaly already seen that site..."

    Are Exide batteries manufactured by Trojan?

    Photowhit:

    "have you done regular equalizing?" Yes. every month, 29.4 volts.

    Thanks to all.
  • soloronesolorone Solar Expert Posts: 254 ✭✭✭
    Re: Watering batteries
    Photowhit wrote: »
    WOW!!!



    Golf cart batteries are 'real' deep cycle batteries, it's the first and last battery many people use with solar. I was in a battery shop and met a fellow from central Missouri who was replacing his 9 year old T105's, 16 of them ( 48V)! he ran a household on a double string 'Golf Cart' batteries, including a central A/C and Shop! He lost faith in them due to age! They tested good and were working when he pulled them.

    The T 105s are a tad different from my early experience. My personal experience was they were not up to the job, that was 1983. Also most every book I have read, has suggested the same.

    "...price increase, gosh they are $$ now..."

    Not sure why, golfcart batteries have returned to pre '08 prices when lead went through the roof. Perhaps it's because they are made in small quantities...

    Sorry if I am off here, but I assumed by the current L16 and rolls prices, we were way past the $45 price I paid. LOL


    As to loads Golf Carts stop, start go up and down hills, the load varies.

    They may very, but I feel that they fall with in a design set, so plate construction would follow that need.

    "...demands of an Inverter, where loads can hit 250 to 500 amps..."

    This looks like a poor understanding of battery banks and loads. Even with a 12 volt system a 250 amp load would be a 3000 watt load and you'd want an inverter with a yet higher capacity to run this. With knowledge of battery banks you would have a larger battery bank, 24 or 48 volt, reducing your amperage to a more reasonable level, 125 amp for a 24 volt system and 73 for a 48 volt system.

    "This looks like a poor understanding of battery banks and loads" Oh no. The OPs profile is empty, I have no idea of the needs.

    Before affordable 24 V. inverters were a reality, I could spike my 600 amp fluke meter starting a water pump. Currently I commonly see 150 A loads at 24 V, and last week, saw 256 A load at 24 V for 40 Amps AC. So your statement can not be a blanket that covers all. It just depends on what one is doing with all this gear.


    I have a 24 volt system and reached a new peak of 40amps Friday running an AC, a foreman grill and a fridge at the same time. What is my battery bank? 4 golf cart batteries, from my old system, I'd like to replace them with a larger capacity battery bank, but they are still healthy and showing good capacity, they'll turn 5 years old in Oct.

    Happy for you, 5 years is a long time for many batteries, you must take very good care of them, but can't imagine you did that for very long on a 4 "cell" battery. Maybe design has changed. Rather than have solid plates, if I am remembering what I read right, newer batteries are designed to give up these huge amounts of amperage, with improved circulation such as holes in the plates, to improve convective flow of fresh acid to the plate surface. This is what I meant by serious/real deep cycle batteries.

    Please except my comments with good intentions, and colored by 27 years of off the grid life, where batteries live a serious real world hard life.

    I am currently on 10 YO Rolls, and they are showing some serious age issues.


    Seems I have to add some text in order to post this, since my comments are within the quotes.
  • PhotowhitPhotowhit Solar Expert Posts: 5,082 ✭✭✭✭
    Re: Watering batteries

    Sorry Jessica, I was too upset about what solorone had said to give some more information, I find I add water more often in the summertime, I believe it's do to the ambient temperature being higher and the batteries reach a temperature high enough to out gas easier.

    Still I only check the batteries every 3-4 weeks. As noted I cycle them very heavy over the summer, often taking them down close to 50% DOD (depth of Discharge)

    Do you find liquid on top of your batteries?

    Are your batteries stored in a temperature controlled enviroment? Do you have a temperature probe for your charge controller or is the charge controller in the same enviroment as the batteries?

    I have my bulk set at 28.6 I think the equalizing is set for 30.4 (off the top of my head) So I might think your set a bit low, but it sounds like you've read the info at their website.

    Do you find one cell requiring more water than others? This might indicate a problem cell. Might be worth checking the Specific Gravity(SG) of each cell before and after an equalizing cycle, They might be considerable differences before equalizing, but after they should be very close.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, 660 ah 24v ForkLift battery. Off grid for @16 of last 17 years. Assorted other systems, and to many panels in the closet to not do more...lol
  • PhotowhitPhotowhit Solar Expert Posts: 5,082 ✭✭✭✭
    Re: Watering batteries

    Solorone,

    As for me I've been off grid for 9 years, not including a year spent cycling. And maintained a solar for my boat for years before this.

    If you purchased L16's for $40 each you are old indeed, I shopped around and paid @$200 each in the early 90's (I think this includes a core charge) for my sailboat. FWIW I can buy them for just a tad more than that today.

    My "Golf Cart" batteries have been regluarly drawn down close to 50% DOD for the last 4 summers running an AC, they "live a serious real world hard life." indeed!

    ?We were talking about Golf Cart batteries? Perhaps I know something about them...
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, 660 ah 24v ForkLift battery. Off grid for @16 of last 17 years. Assorted other systems, and to many panels in the closet to not do more...lol
  • JESSICAJESSICA Solar Expert Posts: 289 ✭✭
    Re: Watering batteries
    Photowhit wrote: »
    Do you find liquid on top of your batteries? [Answer: No; never.]

    Are your batteries stored in a temperature controlled enviroment? Do you have a temperature probe for your charge controller or is the charge controller in the same enviroment as the batteries? [Yes; Batt and CC (mx60) are just 3 feet apart; average temp in the room is 86f]

    I have my bulk set at 28.6 I think the equalizing is set for 30.4 (off the top of my head) So I might think your set a bit low, but it sounds like you've read the info at their website. [No; What I have indeed read is all posts in this forum!]

    Do you find one cell requiring more water than others? [No, It is something like a cycle: Every week is a different cell; nevertheless, two specific cells, where cables from CC and to Inverter are connected are seldon dry!]This might indicate a problem cell. Might be worth checking the Specific Gravity(SG) of each cell before and after an equalizing cycle, They might be considerable differences before equalizing, but after they should be very close.[Can you recommend a DIGITAL hydrometer, please.]


    Thanks for all the advise.
  • soloronesolorone Solar Expert Posts: 254 ✭✭✭
    Re: Watering batteries
    Photowhit wrote: »
    Solorone,

    As for me I've been off grid for 9 years, not including a year spent cycling. And maintained a solar for my boat for years before this.

    If you purchased L16's for $40 each you are old indeed, I shopped around and paid @$200 each in the early 90's (I think this includes a core charge) for my sailboat. FWIW I can buy them for just a tad more than that today.

    My "Golf Cart" batteries have been regluarly drawn down close to 50% DOD for the last 4 summers running an AC, they "live a serious real world hard life." indeed!

    ?We were talking about Golf Cart batteries? Perhaps I know something about them...

    Sorry if I am off here, but I assumed by the current L16 and rolls prices, we "meaning golf cart" were way past the $45 price I paid. LOL

    Sorry, I had an incomplete sentence. I did use a set of L16s, think I got about 5 years out of those. 200$ is a good price, I have not looked hard but have not seen then much under $300, but then I have not talked to my local source either.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Watering batteries

    "Niel:

    "how deeply do you cycle your batteries?" Never below 24.4/24.5 volts (To be honest, I don't know how deep a discharge that number represents.)"

    first of all i don't have a 24v battery bank, but in any case for the cycle life you will need to get the figures from the manufacturer for the average dod you normally achieve. on the subject of the at rest voltage as a reference to dod take 100% - the soc % to get the dod % and the at rest voltage reference is in the faq under soc.
    http://www.windsun.com/Batteries/Battery_FAQ.htmof note, some prefer to get the soc and dod % from specific gravity readings.
  • JESSICAJESSICA Solar Expert Posts: 289 ✭✭
    Re: Watering batteries
    niel wrote: »
    "Niel:

    "how deeply do you cycle your batteries?" Never below 24.4/24.5 volts (To be honest, I don't know how deep a discharge that number represents.)"

    first of all i don't have a 24v battery bank, but in any case for the cycle life you will need to get the figures from the manufacturer for the average dod you normally achieve. on the subject of the at rest voltage as a reference to dod take 100% - the soc % to get the dod % and the at rest voltage reference is in the faq under soc.
    http://www.windsun.com/Batteries/Battery_FAQ.htmof note, some prefer to get the soc and dod % from specific gravity readings.

    Niel:

    It seems my poor English got in the way, and I did not make myself clear.

    What I tried to do was to quote your question and answer it, not to ask you a new question. So here I go again: I never let my bank go below 24.4/ 24.5 volts, but I do not know the formula to determine if that voltage (24.5) equals 80% or 70%, etc., DOD.

    My point is that I do take care of my batteries (I think I do!), and I want to understand why they require so much watering now.

    Thanks again.
  • BB.BB. Super Moderators, Administrators Posts: 29,994 admin
    Re: Watering batteries

    It sounds like there may be an issue with your charge controller...
    • What is the output voltage of the charge controller/battery bank when fully charged under good sunlight?
    • What is the battery bank temperature?
    • Does your charge controller have a remote battery temperature sensor?

    If the bank is much above 28.8 volts and/or the batteries are very hot (with high voltage)--then you will use a lot of water. You need to measure this voltage at the battery bank with a known-good volt meter (we have run across people with bad DVM/DMM (digital volt meter/digital multi-meters) and/or near dead DVM batteries).

    It sounds like your batteries are over 30 volts (equalizing) to be using so much water?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • JESSICAJESSICA Solar Expert Posts: 289 ✭✭
    Re: Watering batteries
    BB. wrote: »
    • What is the output voltage of the charge controller/battery bank when fully charged under good sunlight?[ At "float": 27.4 volts (Absorbing settings are 28.4)]
    • What is the battery bank temperature? [Don't know]
    • Does your charge controller have a remote battery temperature sensor?
      [No]Guess I have to buy one

    If the bank is much above 28.8 volts and/or the batteries are very hot (with high voltage)--then you will use a lot of water. You need to measure this voltage at the battery bank with a known-good volt meter (we have run across people with bad DVM/DMM (digital volt meter/digital multi-meters) and/or near dead DVM batteries).

    It sounds like your batteries are over 30 volts (equalizing) to be using so much water?

    -Bill

    My settings for equallizing are 29.4, 1 hour, once a month. I don't think there is anything wrong with my mx60.
  • BB.BB. Super Moderators, Administrators Posts: 29,994 admin
    Re: Watering batteries

    What is the Bulk/Absorb/Float settings and how is the absorb charge (to float) transition programmed (by current, by time, etc.)?

    What is the battery voltage as measured by a DVM while charging vs the Outback meter reading?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • KamalaKamala Solar Expert Posts: 452 ✭✭
    Re: Watering batteries

    As has been said many times, judging the SoC of a battery (bank) by voltage is dubious at best. To do so by this method the battery (bank) must have been at rest for a few hours. And not under load.

    Would that I could measure the SoC of my bank with a hydrometer. But I use VRLA AGMs and that is not possible.

    As has been suggested in previous posts, there may be several reasons that your batteries lose water. Overcharge, too frequent equalizations (my best guess), higher temperatures, etc.

    My main point here is that it is very difficult (and unreliable) to measure state of charge by voltage. At best, you can come close to an estimate if no loads are connected and the battery has been at rest for two to three (ideally more) hours.

    K
  • PhotowhitPhotowhit Solar Expert Posts: 5,082 ✭✭✭✭
    Re: Watering batteries
    JESSICA wrote: »
    My settings for equallizing are 29.4, 1 hour, once a month. I don't think there is anything wrong with my mx60.


    Sorry I've been in and out today, I'll check out your link to the battery website, a 1 hour at 29.4V doesn't sound like much of an equalizing charge at all.

    There aren't cheap digital hydrometers, a quality glass one with a thermometer can be had at NAWS for under $30.

    Curious as to how much water your having to add? More than a turkey baster to each cell? They do start reducing after you fill them. Perhaps we're just on different planes as to how much, my 5 year old batteries require as much as 2 of the turkey baster battery fillers, I think they are 2 or 3 onces, likely this is as much as half the distance from the plates to the correct fill height.

    Of course your using distilled water.

    While not as accurate, I feel it's good to get an Idea of the battery health by looking at the voltage, just be aware there are 3 different basic scales as to the voltage, a battery charging, a battery at rest (no use in 2-3 hours) and a battery under load w/o charging. these of course vary from depending on the loads. Lots of conflicting things here, but soon you'll be able to not panic in the morning when your voltage reads less than 24 volts, but you see someone's running the microwave.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, 660 ah 24v ForkLift battery. Off grid for @16 of last 17 years. Assorted other systems, and to many panels in the closet to not do more...lol
  • JESSICAJESSICA Solar Expert Posts: 289 ✭✭
    Re: Watering batteries
    BB. wrote: »
    What is the Bulk/Absorb/Float settings and how is the absorb charge (to float) transition programmed (by current, by time, etc.)?

    What is the battery voltage as measured by a DVM while charging vs the Outback meter reading?

    -Bill

    I have only changed 2 settings in my mx60: Battery Voltage (Obviously!) and Equalization (As I said, I equalize at 29.4, 1 hour every month.) All other settings are the default settings of the mx60. Thus, Absorb is set to 28.4, and Float is set to 27.4. Readings with my Craftman Voltimeter are identical to those the controller shows.

    Given what Photowhit has said, I now intend to equalize every 2 months.
    Temps. in PR have been really high these past 2 months: above 92 is the average.
  • JESSICAJESSICA Solar Expert Posts: 289 ✭✭
    Re: Watering batteries
    Photowhit wrote: »
    Curious as to how much water your having to add? More than a turkey baster to each cell? They do start reducing after you fill them. Perhaps we're just on different planes as to how much, my 5 year old batteries require as much as 2 of the turkey baster battery fillers, I think they are 2 or 3 onces, likely this is as much as half the distance from the plates to the correct fill height.

    Of course your using distilled water.

    I use a dropper that I bought at the drugstore. I have to add about 40ml to each cell, though as I have said, not all cells require the same ammount of water nor they dry at the same pace.
  • MangasMangas Solar Expert Posts: 547 ✭✭✭✭
    Re: Watering batteries

    I use a plastic automotive type battery filler which has a sliding tip controlling how much water enters the battery to help prevent overfilling. Puts the water where it belongs.

    Flooded cell water consumption varies with the age and use of the batteries. I water mine about every three months depending on how hard they're being used. In my case, winter seems to use more water than summer. A combination of less charging and the air handlers working harder may be the reason. As batteries age, they will use slightly more water.

    But, if you find a flooded cell alternative battery(ies) in the string using water say every two weeks while the others don't the offending battery(ies) may be shot.

    On my 64 batteries, each 1 1/2 hour fill session takes about 8 quarts or so of distilled water. I remove all the water miser caps rinsing them in a bucket of distilled water.

    I noticed that my specific gravity levels vary with how hard the batteries are being used. During periods where not much is being demanded of them, specific gravity levels are much higher than when they're being asked to produce a lot of power day in and day out. I don't know if this fluctuation is normal but thats the way my banks perform with no seeming ill effects.

    As a side note, I recently sprayed battery terminal protectant on the terminal posts which has stopped corrosion and problems associated with it.

    Hopes this helps.
    Ranch Off Grid System & Custom Home: 2 x pair stacked Schneider XW 5548+ Plus inverters (4), 2 x Schneider MPPT 80-600 Charge Controllers, 2 Xanbus AGS Generator Start and Air Extraction System Controllers, 64 Trojan L16 REB 6v 375 AH Flooded Cel Batteries w/Water Miser Caps, 44 x 185 Sharp Solar Panels, Cummins Onan RS20 KW Propane Water Cooled Genset, ICF House Construction, all appliances, Central A/C, 2 x High Efficiency Variable Speed three ton Central A/C 220v compressors, 2 x Propane furnaces, 2 x Variable Speed Air Handlers, 2 x HD WiFi HVAC Zoned System Controllers
  • BB.BB. Super Moderators, Administrators Posts: 29,994 admin
    Re: Watering batteries

    Hmmm... If the cells are not using water at the same rate (some cells use a lot, some cells use hardly any)--I wonder if you have either
    • a failing shorted cell would drop the voltage of one string--and the rest of the cells in the string would use lots of water
    • a failing open/high resistance cell--not much current flow in one string, other parallel string(s) carrying load/charge currents
    • or possibly dirty/loose connections/corroded cable somewhere (parallels strings, one string not getting much load/charge current and other(s) carrying much more of the load)
    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • JESSICAJESSICA Solar Expert Posts: 289 ✭✭
    Re: Watering batteries
    BB. wrote: »
    • a failing shorted cell would drop the voltage of one string--and the rest of the cells in the string would use lots of water
    • a failing open/high resistance cell--not much current flow in one string, other parallel string(s) carrying load/charge currents
    • or possibly dirty/loose connections/corroded cable somewhere (parallels strings, one string not getting much load/charge current and other(s) carrying much more of the load)
    -Bill

    Bill:

    No dirty/loose connections or corroded cables. In fact, in 2.5 years there has never been even any built-up in the terminals. I check nuts and bolts regularly.

    Now, regarding alternatives 1 and 2: How do I know if there is a shorted cell or a high resistance cell?

    P.S.: I finally bought a digital camera. I have included some pics. Hope they are viewable.
  • BB.BB. Super Moderators, Administrators Posts: 29,994 admin
    Re: Watering batteries

    Check the voltage across each 6 volt battery with your meter (looking for miss-matches--either too high or too low with heavy charging or loading current).

    Also, if you measure the specific gravity of the electrolyte and see a difference between cells when discharged and charged (again, looking for differences--one or more cells reading high or low, or not "moving" from charge to discharge to charged, etc.).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Watering batteries

    jessica,
    what i'm about to side mention here pretty much has no bearing on your dilemma, but i thought i should mention it anyway concerning what you said,
    "I have only changed 2 settings in my mx60: Battery Voltage (Obviously!) and Equalization (As I said, I equalize at 29.4, 1 hour every month.) All other settings are the default settings of the mx60. Thus, Absorb is set to 28.4, and Float is set to 27.4. Readings with my Craftman Voltimeter are identical to those the controller shows."

    i believe 28.4v for absorb is too low and the default would've been 28.8v. even agms take up to 28.8v (edited due to my putting 28.4v instead of 28.8v) and fla types often like it even higher. the float seems a bit high as it should be 27.2v and these statements are based on what the default settings should be for the mx and my general understanding of fla batteries. some fla batteries are speced even higher and it's not unheard of to see batteries speced at 29.0 for absorb and your current float setting at 27.4v or even higher. of course the default eq is at 30v which is going to use even more water if you go to it.

    i might suggest to see what specific gravity readings could be obtained if you didn't already mention that you had done so. this tells a story that the voltage can't always come through with. going higher on the voltage as the default settings would suggest would consume more water. i should mention my old fla batteries did consume lots more water at the end of their life-cycle.
  • JESSICAJESSICA Solar Expert Posts: 289 ✭✭
    Re: Watering batteries
    niel wrote: »
    jessica,

    i believe 28.4v for absorb is too low and the default would've been 28.8v. even agms take up to 28.4v and fla types often like it even higher. the float seems a bit high as it should be 27.2v and these statements are based on what the default settings should be for the mx and my general understanding of fla batteries. some fla batteries are speced even higher and it's not unheard of to see batteries speced at 29.0 for absorb and your current float setting at 27.4v or even higher. of course the default eq is at 30v which is going to use even more water if you go to it.
    .

    Niel:

    My mistake.
    Absorb is indeed set to 28.8; and, if no one else disagrees, I will lower float settings to 27.2.
    Nevertheless, I keep the 29.4 volts for Eq., since I am convinced too high a voltage can eventually harm the batteries.
    In addittion, I will order a hydrometer to check specific gravity, but that will take one or two weeks. Meanwhile, I will go on watering my thirsty batt.

    Thanks to all.
  • PhotowhitPhotowhit Solar Expert Posts: 5,082 ✭✭✭✭
    Re: Watering batteries
    JESSICA wrote: »
    Niel:

    My mistake.
    Absorb is indeed set to 28.8; and, if no one else disagrees, I will lower float settings to 27.2.
    Nevertheless, I keep the 29.4 volts for Eq., since I am convinced too high a voltage can eventually harm the batteries.
    In addittion, I will order a hydrometer to check specific gravity, but that will take one or two weeks. Meanwhile, I will go on watering my thirsty batt.

    Thanks to all.

    As your battery ages it's not uncommon to increase the float voltage a bit, but I think your fine either way.

    As to the Equalizing, I recomend doing it every month, your link did not work, but even the trojan site recomends a 31 volt current for equalizing( http://www.trojanbattery.com/BatteryMaintenance/Charging.aspx ) and most all suggest 2 hours as a starting point. If you do buy and use a hydrometer I would follow their instructions for the T105 batteries the first time as they will have you check the SG and continue until they are close or no change for couple hours.

    Thanks for the post, I was sure I needed to fill the water to within 1/8th of an inch from the bottom of the fill tube, in looking at the sites I see 1/4 inch is the general recomendation. I'll check to see if mine say anything on them.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, 660 ah 24v ForkLift battery. Off grid for @16 of last 17 years. Assorted other systems, and to many panels in the closet to not do more...lol
  • JESSICAJESSICA Solar Expert Posts: 289 ✭✭
    Re: Watering batteries
    Photowhit wrote: »
    ...Thanks for the post, I was sure I needed to fill the water to within 1/8th of an inch from the bottom of the fill tube, in looking at the sites I see 1/4 inch is the general recomendation. I'll check to see if mine say anything on them.

    Are there any harmful side effects if too much water is added? Like 1/4-1/2 inch?
    Wouldn't is be wise to "overfill" each cell just a little bit, to prevent rapid evaporation?

    Thanks.
  • BB.BB. Super Moderators, Administrators Posts: 29,994 admin
    Re: Watering batteries

    The water level "rises" from both bubbles in the water/on the plates during charging (particualarly as battery approaches 100% state of charge) and as battery temperature increases.

    The recommendation is to check electrolyte levels before charging and see that the plates are covered. At the end of charging, then check for final fill levels.

    The recommendation to keep the water level down a bit is to prevent the increased water level from exceeding the vent slots (usually cut in the sides of the fill tubes) from being "topped' by expanding electrolyte and then have electrolyte "pushed" out of the cells and on top of your battery. That is both messy and you loose sulfuric acid. Now you are left either filling the cell with distilled water (which dilutes the electrolyte) or with dilute sulfuric acid (and how much is unknown).

    Hence the recommendation to keep electrolyte levels more towards the "middle" of the cell to prevent pumping electrolyte out of the cell in the first place.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • PhotowhitPhotowhit Solar Expert Posts: 5,082 ✭✭✭✭
    Re: Watering batteries

    Thanks Bill,

    Thats likely where I got the 1/8th inch as I never seem to find the time in the morning and check and fill in the late afternoon.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, 660 ah 24v ForkLift battery. Off grid for @16 of last 17 years. Assorted other systems, and to many panels in the closet to not do more...lol
  • bryanlbryanl Solar Expert Posts: 175 ✭✭✭✭✭
    Re: Watering batteries

    Loss of electrolyte indicates that the float voltage is set too high. It is very difficult to maintain a proper float voltage as it changes due to temperature, age, and probably other factors. That means it is almost always too low or too high.

    The problem with solar system batteries in residential settings is usually float. That is also rather hard on most lead acid batteries.

    Many solar systems are really rather too gentle on charge currents as well and that can be a problem, too, I think.

    A proper equalization charge may compensate for a low float voltage but it has its own risks and costs. One technique that has come up is to use a low float with a periodic short charge bump to maintain batteries and that seems to work fairly well for battery maintenance.

    re: "Golf cart batteries are 'real' deep cycle batteries"" -- boy have I been run through the mill for challenging the idea that there are 'deep cycle' lead acid batteries that are significantly different from other types. The fact is that deep cycling any lead acid battery is a sure path to a shorter life on an exponential basis. It isn't a trivial topic, though, and that may cloud things.

    Battery satisfaction really boils down to use and maintenance with the proper equipment first. Those are what needs most attention for tuning to get best battery life with minimal fuss.
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