Best way to connect and charge 8 batteries?

BilljustBill
BilljustBill Solar Expert Posts: 219 ✭✭✭
I'll have a 48v system with approx. 1Kw/1.5Kw of solar panels.

What is the best way to wire eight 6v T-105 batteries for a 48v, 1,500 watt Aims PSW inverter and a Tristar 60amp contoller?

Would I use the same wiring pattern when/if I added a second string of T-105's?

What size copper cable between the 6v batteries and 6' away from the controller?

Lastly, would you spend an additional $1,550 to add FOUR Kyocera KD135GX-LPU 135 watt Solar Panels (540 watts) because I have a good solar site or $800 for a smaller 400 watt, 48v wind-gen/tower because I also have a good wind site?

Thanks,
Bill
Bill

Comments

  • RCinFLA
    RCinFLA Solar Expert Posts: 1,484 ✭✭✭✭
    Re: Best way to connect and charge 8 batteries?

    There is only one way to hook up eight 6vdc batteries for 48 vdc and that is in series. When you add a second string take 48v output from diagonal end pos and neg terminals such that the net wire length to inverter will be same on both strings. Another way to describe this is the positive and negative jumpers between strings has the positive jumper on one string's battery positive leg and the negative jumper on other strings negative leg.

    You should use at least #2 cable or larger for 1500 watt / 48 v unit. Welding cable is flexible. Try to get Excelene welding cable as it has good high temp insulation. On the six foot run to inverter, tape the two cables together. This makes some of the magnetic field they create cancel each other out. This reduces line inductance which reduce batttery voltage transients at the inverter when sudden load changes on inverter occurs.

    Remember the AIM's 48v PSW has a fairly high idle current. It requires about 50 watts with no load so you should shut it off when not needing AC power.
  • john p
    john p Solar Expert Posts: 814 ✭✭✭
    Re: Best way to connect and charge 8 batteries?

    On the six foot run to inverter, tape the two cables together. This makes some of the magnetic field they create cancel each other out. This reduces line inductance which reduce batttery voltage transients at the inverter when sudden load changes on inverter occurs.
    It much better to twist the 2 cables together as much as you can, I know it not easy with sizes above#4. but ove a 6ft length you can get a few ttwists.. Its easier if you leave the cables first out in the sun for a few hours.
  • Photowhit
    Photowhit Solar Expert Posts: 6,002 ✭✭✭✭✭
    Re: Best way to connect and charge 8 batteries?
    RCinFLA wrote: »
    You should use at least #2 cable or larger for 1500 watt / 48 v unit.

    ? - 00 to carry a constant 30 Amp load at 48 volts, a 12 foot round trip seams very large to me. Even with 2 gauge wire the loss would be .2%

    Even 8 gauge wire would give you just a .6% loss, One of the reasons to use higher voltages.

    On batteries, be carful about adding new to used batteries, batteries should age together, Perticularly FLA batteries.

    As to a wind turbine, this will have to do with your location and willingness to learn a new system. typically they need a dedicated charge controller, and tend to take more interaction/maintenance that solar. But if your in a good location and have long periods of cloudy winter days when you have wind but no sun... it could be a wise choice.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.