Combining wind and solar generators to one battery storage

Discussion in 'Off Grid Living' started by Yad Tsalach, Feb 20, 2021.

  1. Yad Tsalach

    Yad Tsalach Monkey

    I am trying to merge two systems of wind and solar into one battery storage bank. I am starting with small systems (400w solar and 600w wind) to learn what I'm doing on a small scale in case I screw something up!
    It "seems" obvious to me that since they each have their own charge controller, that I should just be able to run each of the output leads from their respective charge controllers to the same battery bank, which then runs to one inverter, in turn to my electric grid. Will it work, or should I wait till the 4th of July to try it so the neighbors can enjoy my ignorance if it blows up?!
    Secondly, I am curious to know how to set up an overload dump to a secondary battery bank. ANY info to get me started in the right direction will be GREATLY appreciated.
    damoc likes this.
  2. damoc

    damoc Monkey+++

    It should work. I have similar system with 4 turbines and more than 500 watts solar and the only problem I had was when the sun is at its peak it was shutting down the turbines because I did not have heavy enough cable to the battery bank I upgraded the cable and it is no longer a major problem
    BenP likes this.
  3. Merkun

    Merkun furious dreamer

    SB21 likes this.
  4. oil pan 4

    oil pan 4 Monkey+++

    People run multiple charge controllers to one battery bank all the time.
    As long as all all power source run with in their charge controllers voltage range and the charge controllers are the same voltage as the battery bank it will run.
  5. BTPost

    BTPost Stumpy Old Fart,Deadman Walking, Snow Monkey Moderator

    Welcome to the Monkey Tree... At our Alaskan Bush place we have two separate cabins, each with it’s own independent 12Vdc Solar System... Each also has a 50 Amp Linear Regulated AC Power Supply that only runs when our 12Kw Lister Diesel Genset runs... The Solar Charge Controllers are set for 14.3Vdc Bulk, & 13.5 Float... The AC Power Supplies. are set for 14.3Vdc Bulk, and 13.5 Float... During the summers we are usually at full Float by 11Am on each System, and during the winters we run the Genset for a couple of hours each evening to bring the Batteries to full float,.. This system has been in place for a decade and has been fine for us...
    Sobospider and 3M-TA3 like this.
  6. Yad Tsalach

    Yad Tsalach Monkey

    That's the simple answer I was looking for, thanks! I'm going for it!
    thanks for the info!
  7. Yad Tsalach

    Yad Tsalach Monkey

    I'll try that, thanks!

    I love you smart guys! I wish I were a member of your family, but I'm not, so I'll start with one question and go from there. What is "float?"
    Last edited by a moderator: Feb 21, 2021
  8. TnAndy

    TnAndy Senior Member Founding Member

    Float is when they are still charging but only lightly....the bulk charge rate has done the 'bulk' of the work...more like a trickle charge as the battery voltage is close to being fully charged. 12.6-12.7v in the case of 12v systems. Many of the better charge controllers will have a screen telling what mode they are in at any given time.
    DKR and BTPost like this.
  9. Altoidfishfins

    Altoidfishfins Monkey+++ Site Supporter+

    Float charge is the final stage of charge after the other state or states of charge have completed. It is used to maintain the battery at a set voltage with low current - basically just enough to keep it from self-discharging. Batteries usually can be maintained at their float voltage, in BT's case 13.5 volts, (which is probably adjusted for the lower temperatures of up north) almost indefinitely without damage as long as they're watered (where flooded cell type batteries are used).

    Is your charge controller temperature compensated?

    Batteries at higher ambient temperatures will require lower charging voltages to keep from overcharging and when they're at lower ambient temperatures they require higher voltages to keep from undercharging. Temperature compensated charge controllers result in longer battery life.

    Fellow Monkeys - let me know if I just put my foot in my mouth, but I don't think so.
    Last edited: Feb 20, 2021
    BTPost likes this.
  10. Yad Tsalach

    Yad Tsalach Monkey

    This is awesome!!! I love you guys! I've learned more in one day from you guys than I've learned in months of trying read books with words I've never seen before and then try to decipher what they mean! If a battery bank reaches full charge capacity, is it the charge controller that then goes into "float" mode? Then do I have to add another fancy piece of equipment to direct the charge to another backup battery bank?
  11. ghrit

    ghrit Bad company Administrator Founding Member

    The charge controller does the change from bulk to float on it's associated bank of cells. Yes, you'll need something to switch banks when one is floated and you want to charge the other. Of course, if you take one off float and let it sit, the charge will naturally decay and you won't necessarily know it's happening without some kind of monitoring widget. Were it me, I'd use a controller for each bank, if for no other reason than a resident backup "just in case." Two is one, one is none, so 'tis said.

    There IS a gadget that RVers use to charge the service battery in the RV separately from the tow vehicle battery. IIRC it's called a battery isolation switch, but I am completely unfamiliar with them, and no idea if there are any that can handle the type of arrangement needed for off grid living.

    You're close enough. To be remembered is that battery charge/discharge involves current flowing, which by definition puts out some heat due to inherent wire and device resistances. Not good in the summer, but very beneficial when it's cold, keeps the electrolyte happy. Also bear in mind that what you are looking for during charge is the amps. The voltage has to be varied to control the charge (amp) rate. The charge rate will be specified by the battery mfr, the voltage is set by the controller to do what needs done.
    BTPost and Altoidfishfins like this.
  12. Cruisin Sloth

    Cruisin Sloth Special & Slow

    Wind turbines need a braking system so when power is not needed , the turbine will NOT over speed and destruct .
    A KID CC from midnite can trip into a load braking system for small turbines up to 20 amps , Now the kid can do 30 amps solar , but for Wind , (since you can't feather the blades , you use a diversion load , The KID will use a 10 amp portion of its system to slow the blades ).
    Two KIDS and connect them both to cross talk , one solar one wind , wind will tell solar to slow down and let me use the wind more ..
    Make sense ??


    Your correct , and that's WHY we use Temperature compensated charge controllers

    We use the CC internal relays for that as we can set them to the voltage we need to switch on a DTDP relay . The battery isolation systems are just large Diodes , so the voltage drop thru them means the cells are never really charged .. Good enough for car batterys ..
    BTPost and ghrit like this.
  13. TnAndy

    TnAndy Senior Member Founding Member

    Yad....this was what I told you in that PM you sent close attention to the above.
    BTPost likes this.
  14. Cruisin Sloth

    Cruisin Sloth Special & Slow

    We good , I didn't pm him , so all learn from my hunt and peck !
    BTPost and ghrit like this.
  15. Yad Tsalach

    Yad Tsalach Monkey

    You guys are out of my league, but I'm having a blast! I'm like a kid in a candy store with no money! :) But I got to chew on some of this before I can figure out how to ask an intelligent question... ya, tomorrow!
    BTPost and Yard Dart like this.
  16. ghrit

    ghrit Bad company Administrator Founding Member

    Ya gotta start someplace. Pick one of these guys that know stuff and follow their hints and tips. Questions don't need to be intelligent, but the answers have to be.
  17. duane

    duane Monkey+++

    Now those are words to live by. Thank you ghrit!!
  18. DKR

    DKR Raconteur of the first stripe

    You tube has a lot of home energy vids.

    Here's one on how to NOT assemble a system....

    a clean installation using Tesla batteries

    shows a "dump load" for the wind part
    STANGF150 likes this.
  19. Yad Tsalach

    Yad Tsalach Monkey

    OK, you're the one who said questions don't have to be intelligent, so if this is a dumb question, it's your fault! :) Am I correct to say that a volt is a measurement of stored energy and an amp is a measurement of energy being used? So, high volts + low amp draw = long battery life. Low voltage + high amp draw = short battery life. Batteries store volts, tools/appliances/lights draw amps, and watts measure how many electrons were actually used to make that transfer happen irellevant to the time it took to do so??????????? How'd I do? You have permission to laugh at me if I got that wrong! :)
  20. BTPost

    BTPost Stumpy Old Fart,Deadman Walking, Snow Monkey Moderator

    Nope... Volt is a measurement analogous to Pressure in a Fluid System... Amp is a measurement analogous to Flow in a Fluid System.. Power is volts times amps... Storage is Power available times time... which is AmpHours.. No one is laughing, just trying to impart knowledge... If you can find an Old Amature Radio Handbook, it has a great tutorial section on basic Electrical Principals... and yes in battery systems, slow draw amps over time is better than fast draw amps over a short time... Volts is basically irrelevant, except for Higher Voltage is able to supply more power using fewer amps...
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