I have a question about generator run time to charge a battery bank

henry1
henry1 Solar Expert Posts: 51 ✭✭✭✭
I was given a brand new never been used Honda EU3000 gas powered generator as a gift for helping out a friend after her husband passed away .

Here is the set up i'm working on right now a set of Eight 140.AMP hour's battery to make up 12.volt power

The basic question is how many hour's does the generator have to run to charge the eight battie in the bank

Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: I have a question about generator run time to charge a battery bank

    Generally, the Honda eu3000 family has an 12 amp unregulated 12 volt output used to recharge small batteries/emergency car battery recharging, etc.

    For many reasons, it is not really useful for recharging a large battery bank.

    Regarding your battery bank:
    set of Eight 140.AMP hour's battery to make up 12.volt power

    Are those 6 volt or 12 volt batteries?

    If 6 volt, that would be 4x140AH=560AH 12 volt battery bank.

    If 12 volt, that would be 8x140AH=1,120AH at 12 volt battery bank.

    In general, we recommend 5-13% for solar charging and you can go as high as 25% of battery bank capacity with an AC charger...

    If you are using standard battery charger... They tend to be 80% efficient and may have power factor of ~0.6... For a 2,800 watt rated genset charge a 12 volt battery bank, the maximum charger rating would be around:
    • 2,800 watts * 0.80 eff * 0.6 PF * 1/14.5 volts charging = 93 amps maximum
    The minimum rate would be 5% of rated capacity:
    • 1,120 AH * 5% = 56 Amps minimum recommended charging (if 8x12 volt batteries)
    Normally, we would recommend that people cycle a battery bank to 75% to 50% of state of charge...

    So depending on how large a battery bank, how deep the discharge, and size of battery charger, would affect how fast you could recharge. Also, there is 2-4 hours or so of taper charge (last 80-90% to 100% of charging cycle).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: I have a question about generator run time to charge a battery bank

    Welcome to the forum.

    As Bill suggests using the DC side of the EU is not a very good idea.

    I suggest that you read the following links:

    http://www.windsun.com/Batteries/Battery_FAQ.htm#Lifespan%20of%20Batteries

    http://www.batteryfaq.org/

    Tony
  • TheBackRoads
    TheBackRoads Solar Expert Posts: 274 ✭✭
    Re: I have a question about generator run time to charge a battery bank

    What are your loads/ what are you running? Seems like a lot of batteries for a 12V system... why not go to 24 or 48v bank (as it sounds like you haven’t purchased the batteries)?