6v parellel charge, 12v series output?

System
System Posts: 2,511 admin
My wind charger puts out about 7-8 volts max. I want to use the commonly available 12 volt inverter. Is there a way to charge two 6 volt batterys in parallel and draw 12 volt output from them in series? I was thinking this could be done using diodes as to not create a short circuit. Any sugestions?

Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: 6v parellel charge, 12v series output?

    There is no simple voltage doubler circuit for a series parallel for a 6/12 volt battery combination.

    You either are going to need to run a six volt battery with a voltage doubler to run 12 volt loads--or increase the voltage coming out of the wind turbine. Or--charge a pair of six volt parallel batteries when it is windy and then connect them in series for the load.

    I can't think/find any off-the-shelf products that are designed exactly for what you want...

    There are products like this:

    http://www.theledlight.com/misc-controls.html

    out there.

    Or you can look through some various Google Results for 6 vdc voltage doublers.

    Other off-the-wall options... Many (most?) wind turbines use an alternator (like on a car--not like the old brushed DC generators/universal motors like used to be on 40+ year old vehicles).

    If this is an alternator--you have a couple options. One is to access the (typically) three phase output and connect three transformers setup to double or triple the voltage.

    Another option would be to try an AC to DC diode voltage doubler circuit. May or may not be a good fit for your wind turbine electronics (if any).

    One question--are you sure the wind turbine outputs significant current at 7.2-8+ volts? If not (turbine bad, poor design, just too small, not high enough/too much turbulence, not enough wind, etc.)--then it may not really be worth the money/effort.

    To see how much power it pumps out into a 6 volt battery--take a look at one of these DC Watt*Hour / Amp*Hour meters (Watts Up / Doc Watson's looks neat--I have not used the meter or know anything about the vendor).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2
    System2 Posts: 6,290 admin
    Re: 6v parellel charge, 12v series output?

    I thought about about a voltage doubler but the little ones that I could build will not handle the amperage. I'm not sure how many amps it will put out but it does give a nice shock if you touch both wires! It's based on a 130volt 2.5 Hp DC motor. I'm going to get it up on the pole in a couple days, so far I have been turning it by hand and thats probably just not fast enough! I'm just going to hope it puts out over 12v in the wind and that will solve my problem. I guess I'm a little premature on the question but I like to think ahead. Thanks for the info and links!
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: 6v parellel charge, 12v series output?

    If you are getting a "nice shock" then you are generating more than 50V But it might be little current.. You need to get a meter, and set it for amps, and spin the generator somehow. (wrap a rope around the shaft and pull ?) See what sort of amps you get.
    A 2.5HP motor is some serious power at the right RPM
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: 6v parellel charge, 12v series output?

    You might be able to connect it to a variable speed drill and connect it to a load (such as a 12 volt battery) and do a little RPM vs current output graph and see what you get.

    You might not get full power (small drill motor cannot supply enough torque--or a larger drill motor might not supply enough RPM)--but it will give you an idea of what the blades will need to do for good output.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: 6v parellel charge, 12v series output?
    mike90045 wrote: »
    A 2.5HP motor is some serious power at the right RPM


    PS, do NOT apply voltage to the motor - until you have locked it down Solidly! the torque will roll it right off the table/bench and smash it on your toe, putting a big dent into the motor.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • john p
    john p Solar Expert Posts: 814 ✭✭✭
    Re: 6v parellel charge, 12v series output?

    There is no such thing "most DC transformer " i found only produce V/GND output"
    NOT correct the output of a single ended transformer is AC and its not given as V/GND its simply AC output and is Not referenced to ground or anything.. AC has no + and - output wires
    Attached is a split power supply circuit its for 25v ac gives 35v + and- outputs