Battery Bank/Charger Question

Discussion in 'The Projects Forum' started by snerious, Apr 14, 2015.

  1. snerious

    Thread Starter New Member

    Apr 14, 2015
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    I bought two 6v Golf Cart Batteries from Costo and connected them in series to bring the voltage up to 12v. I've been searching all over the internet and it's so confusing to find a straight answer. I have a 12v 10/2/50 amp charger from Harbor Freright. Is this a bad charger to use? Should I hook the charger up to one battery or to the positive of the first battery in the series and the negative of the 2nd in the series?
    I plan on adding 2 batteries at a time to increase my capacity and this summer I want to add some solar panels. Right now I am powering the charger with a 1600w Yamaha genterator from Harbow Frieght. Please let me know if I am doing anything wrong as you can tell and if you have any tips for a more successful longer lasting system.

    Right now I am using it to run my internet modem/phone/router and lights when the generator isn't on. Works pretty good lasts 24 hours. I want to add the mini-fridge and flat screen when I get more batteries. Any tips?

    Thanks,
    Matt
     
  2. wayneh

    Expert

    Sep 9, 2010
    12,145
    3,055
    Don't charge a single 6V battery by connecting it to a 12V charger. You must have two in series. A single battery will be rapidly, perhaps explosively, damaged.

    I would avoid using the powerful charger if/when the batteries are discharged. The current might be excessive. You could place an auto headlight in series with the 2 batteries, to limit the current to ~5A. When the light goes dim, you could remove it from the circuit.
     
  3. #12

    Expert

    Nov 30, 2010
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    6,818
    You can connect the (2) 6 volt batteries in series and use a 12 volt charger if both batteries are the same. You have a 10 amp setting and a 2 amp setting. The 50 amp feature is not for maintaining batteries.

    As an old person, I hate to think of the complications you are making for yourself. Every time you add another battery, it's a different age than the first two. Batteries lose some of their capacity over time and you will constantly be working to charge each one correctly without over-charging or under-charging the one next to it. That said, I hope this is fun and educational, because it surely won't be convenient.
     
    Johann likes this.
  4. snerious

    Thread Starter New Member

    Apr 14, 2015
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    Well then maybe I should just put the two batteries on a small inverter to run the critical stuff and buy 6 batteries together later for the main system. Charge them seperately?
     
  5. wayneh

    Expert

    Sep 9, 2010
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    Why not get a much larger, 12V battery to begin with?
     
  6. snerious

    Thread Starter New Member

    Apr 14, 2015
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    0
    I just found this deal on Golfcart batteries at costco and found a lot of people using them. $85 each puts me in business for $170 and a $50 charger makes it $230. Using a friends old inverter for free so the system was under $250. All i need immediately is to have my internet and phone stay on and maybe use a few lights at night. I plan on building a better system for the whole house after I've learned a bit. Perhaps 12v batteries would be better. I did read a few things that said that 6v was good for this type of use.
     
  7. #12

    Expert

    Nov 30, 2010
    16,318
    6,818
    A matched pair of 6 volt batteries (3 cells each) is every bit as good as one box with 6 cells in it, but the more diversity you include, the more details you have to care for. Plan accordingly.

    Let's run some numbers. Maybe, 12 volts and 200 amp hours worth of deep cycle batteries. That's 2400 watt hours. At 120 VAC and 90% efficiency in the inverter, that can give you maybe 18 amp hours. If you use LED lights, you might keep the load down below 3 amps. Your batteries will last 6 hours at the most.

    Almost all of those numbers were educated guesses. The intent was to show you the math. Try inserting the right numbers and you will get the right answers.
     
    Last edited: Apr 14, 2015
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