Our off-grid system & life - Page 3
Register

Welcome to the Prepper Forum / Survivalist Forum.

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed.

Our off-grid system & life

This is a discussion on Our off-grid system & life within the Alternative Energy (Wind, Solar, Hydro etc) forums, part of the Off-Grid Lifestyle category; John. Please explain; what do you mean by a C/10 rate?...

Page 3 of 15 FirstFirst 1 2 3 4 5 13 ... LastLast
Results 21 to 30 of 147
Like Tree251Likes

Thread: Our off-grid system & life

  1. #21
    Senior Member


    Join Date
    Feb 2016
    Location
    Central PA
    Posts
    1,687
    John. Please explain; what do you mean by a C/10 rate?

  2. #22
    Banned


    Join Date
    Nov 2014
    Location
    None
    Posts
    4,010
    FLA (flooded lead acid) batteries, especially tall ones like yours, need to charge hard enough to stir the electrolyte occasionally. If not it stratifies making accurate SG readings impossible and reducing battery capacity. This means you need to have enough charging current to bubble the electrolyte well occasionally. With your limited number of panels charging your large battery bank you probably aren't capable of really bubbling those cells well. The 7000 watt generator can do it but from your posts I suspect you guys have only used the generator once or twice in the last year.

    Simplifying this but.... as I said earlier throughout the day panels rarely put out full rated power. In addition the charge controller loses about 2% of the energy so when designing a system solar professionals assume that panels/controller will put out about 77% of the panels rated power into the batteries.
    Your system 2115 watts in panels X 77% = about 1628 watts (68 amps at 24v) going into the batteries.

    At 24v your battery bank capacity is 1712 amp/hrs.
    1712 / 68 = 25.3 so your solar charging at a C/25 rate

    If you had double the panels (136 amps at about 24v) it would look like this
    1712 / 136 = 12.6 so you'd be charging at about a C/12 rate.
    you can get the same effect by reducing the battery bank size.

    Most if not all reputable battery manufacturers have a minimum charge rate to maintain the warranty, usually at least C/20 (Iron Edison minimum charge rate is C/10). This is because it you don't charge the batteries hard enough you can't properly stir the electrolyte (bubble the batteries) resulting in uneven battery charging and stratified electrolyte inside each cell.

    A C/13 charging rate is generally the accepted rate for a full time system. Most FLA (flooded lead acid) batteries do not do well if charged at faster than a C/8 rate because it makes them heat up too much. Heat is a battery's enemy. Solar panels put out more power when it's colder outside. @Chiefster23 @MountainGirl
    Last edited by 8301; 11-01-2017 at 06:53 AM.

  3. #23
    Senior Member


    Join Date
    Oct 2016
    Location
    North Mississippi
    Posts
    1,972
    John, you do a great job of making a complex process understandable. Thanks for taking the time to explain so well.
    A Watchman and 8301 like this.

  4. Remove Advertisements
    PrepperForums.net
    Advertisements
     

  5. #24
    Senior Member


    Join Date
    Sep 2015
    Location
    Northeast Texas
    Posts
    11,426
    Quote Originally Posted by Slippy View Post
    @MountainGirl

    Great job! Y'all got it going on up in the mountains!

    Most certainly, SLIPPY APPROVED!

    Yea, she may just turn out to be the real deal ...... might have to let her into our good ole' boy club here, huh? (she could bring the bourbon)
    Redneck likes this.
    I will choose to enjoy the journey that God has prepared for me. Hidden Content

  6. #25
    Senior Member


    Join Date
    Oct 2016
    Location
    North Mississippi
    Posts
    1,972
    Quote Originally Posted by A Watchman View Post
    Yea, she may just turn out to be the real deal ...... might have to let her into our good ole' boy club here, huh? (she could bring the bourbon)
    Wonder if she realizes ole @Slippy doesn't approve of much. To get his seal of approval is something to be proud of.

    Hey @MountainGirl , you drink bourbon?
    A Watchman and Slippy like this.

  7. #26
    Senior Member


    Join Date
    Feb 2016
    Location
    Central PA
    Posts
    1,687
    Thank you John. I use crown golf cart batteries. Just visited their site and yes, according to their guidelines I am not charging the batteries hard enough. They say 10 to 20% of total AH (20 hr rate). I have six 205 a-hr, six volt batteries connected in series/parallel to produce 615 amp-hr of 12 volt power. So I guess I should be charging at 60 amps or greater. My 600 watts of panels probably never do better than 40to 45 amps. Adding panels is not an option at this time. How about charging with a 55amp charger once a month? Still not ideal but maybe better than nothing?

  8. #27
    Senior Member


    Join Date
    Oct 2017
    Location
    Selkirk Mountains
    Posts
    1,805
    Quote Originally Posted by John Galt View Post
    Lot to cover so I'm just going to hit the high points. ....
    John Galt, first, thank you for taking the time to go into such detail. I wish my husband and I had your aptitude for this, we do not. What I can do, however, is print out your posts and run this by Randy (my solar pro) - for his input and suggestions. There were concerns, when choosing options for the system, that this type of monitoring and maintenance of lead acid batteries was above our skill-set; we did consider silicon-salt, but the cost was prohibitive. If, as things stand, we'll lose them way too soon, perhaps that would have been the better choice - but, that's water under the bridge. So... maybe what we'll do is have Randy come up to handle this aspect. We should have some nice venison steaks for trade.

    Thanks again for all your help!
    ~~~~~~~~~~~
    Not even that.

  9. #28
    Senior Member


    Join Date
    Feb 2016
    Location
    Central PA
    Posts
    1,687
    Mountaingirl. John hasn’t weighed in yet but might I make the following suggestion. It should be relatively easy to divide your battery bank into two separate banks with a few switches. Simply alternate, running one bank on even days and the other on odd days. This would double your charging rate while you would still have the same total battery capacity ( just half held in the reserve bank). I may have to do something like that with my bank because more panels are not an option right now.
    MountainGirl likes this.

  10. #29
    Senior Member


    Join Date
    Oct 2017
    Location
    Selkirk Mountains
    Posts
    1,805
    Quote Originally Posted by Chipper View Post
    I do like the setup but only 8 acres, seriously?? Must have a lot of neighbors/friends close by. Are they on the same page or a liability?? Envy not hardly, you'll burn up those few pine trees the first hard winter. Hows the garden going??
    Hi Chipper, 8 acres out here are probably a lot different than 8 acres where you are. Nearest neighbor is half-mile away (as the hawk flies) and the handful of folks around here (5-mi radius) sing in the same choir, if ya know what I mean. Luckily, there's more wood within reach than we could burn in a few lifetimes...some pine, but mostly fir. Thanks for your reply!
    Slippy likes this.
    ~~~~~~~~~~~
    Not even that.

  11. #30
    Banned


    Join Date
    Nov 2014
    Location
    None
    Posts
    4,010
    Quote Originally Posted by Chiefster23 View Post
    Thank you John. I use crown golf cart batteries. Just visited their site and yes, according to their guidelines I am not charging the batteries hard enough. They say 10 to 20% of total AH (20 hr rate). I have six 205 a-hr, six volt batteries connected in series/parallel to produce 615 amp-hr of 12 volt power. So I guess I should be charging at 60 amps or greater. My 600 watts of panels probably never do better than 40to 45 amps. Adding panels is not an option at this time. How about charging with a 55amp charger once a month? Still not ideal but maybe better than nothing?
    615 amp/hr batteries charging at 40 amps = C/15 rate or at about the 7% rate.

    Golf cart batteries have some (can't remember the name but it starts with an A) mixed into the lead plates to make them harder and more resistant to being bumped around. But this additional element makes them less wiling to accept a charge. Because of that they require a stronger charging current.

 

 
Page 3 of 15 FirstFirst 1 2 3 4 5 13 ... LastLast

Sponsored Links

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Similar Threads

  1. Off grid water system.
    By budgetprepp-n in forum General Talk
    Replies: 20
    Last Post: 07-15-2014, 12:10 AM
  2. Small Off and On Grid ICE system
    By john10001 in forum Alternative Energy (Wind, Solar, Hydro etc)
    Replies: 7
    Last Post: 05-11-2014, 10:39 AM
  3. Rehearsal for an attack on the grid system?
    By Notsoyoung in forum News & Links
    Replies: 16
    Last Post: 12-29-2013, 06:27 PM
  4. Started on My Off Grid Solar System Today
    By Montana Rancher in forum Alternative Energy (Wind, Solar, Hydro etc)
    Replies: 81
    Last Post: 12-19-2013, 07:54 PM
  5. Installing your first off grid solar system 101
    By budgetprepp-n in forum Alternative Energy (Wind, Solar, Hydro etc)
    Replies: 76
    Last Post: 06-15-2013, 10:44 PM
Back to Top