1. Attachments are working again! Check out this thread for more details and to report any other bugs.

12v battery maintainer/desulfator

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by ozarkretiree, Sep 12, 2014.

  1. ozarkretiree

    ozarkretiree Member

    Joined:
    Oct 10, 2008
    72
    26
    0
    Location:
    Missouri
    Vehicle:
    2007 Prius
    Model:
    Four Touring
    Is it okay to use the jump start terminal and ground for topping off the 12 volt? This seems too simple to me and it is probably necessary to go to the battery terminals.
     
  2. ozarkretiree

    ozarkretiree Member

    Joined:
    Oct 10, 2008
    72
    26
    0
    Location:
    Missouri
    Vehicle:
    2007 Prius
    Model:
    Four Touring
    BTW, this is the original battery and the car has 173,000 miles so I know I am waaaay pushing it.
     
  3. edthefox5

    edthefox5 Senior Member

    Joined:
    Jul 25, 2007
    10,096
    4,795
    0
    Location:
    Clearwater, Florida
    Vehicle:
    2007 Prius
    Model:
    Two
    Yes you can use the front terminals for just about anything you want. The whole car load is on that line so it can support any charger.
     
  4. ozarkretiree

    ozarkretiree Member

    Joined:
    Oct 10, 2008
    72
    26
    0
    Location:
    Missouri
    Vehicle:
    2007 Prius
    Model:
    Four Touring
    Thanks for the reply. Now I won't have to worry about a convenience pigtail from the battery.
     
  5. edthefox5

    edthefox5 Senior Member

    Joined:
    Jul 25, 2007
    10,096
    4,795
    0
    Location:
    Clearwater, Florida
    Vehicle:
    2007 Prius
    Model:
    Two
    No...do anything you need on that jump point. Its a big old wire the whole fuse box hangs off of it.
    I routinely charge my car since new off it. Its a hassle to get into the trunk.

    Just use the strut nut right above the terminal box on the strut tower as your ground. And be aware under the red plastic terminal they have bolted a vertical plate so attach the charger clamp on that metal tab that sticks up not the bolt holding it down. Lots of folks have asked about that bolt and they can't get the clamp on it.
     
  6. nh7o

    nh7o Off grid since 1980

    Joined:
    Dec 10, 2011
    1,686
    338
    0
    Location:
    Hawaii
    Vehicle:
    2009 Prius
    Model:
    II
    For a conventional charger, yes, use the front terminals. However, a battery desulfator uses short, fast rise time pulses to clear the sulfation. I have designed, built, and used these myself, and they work. The problem is that the long run of cable to the rear of the car will rather reduce the effect of these pulses.

    A real desulfator worthy of the name needs to connected as close to the battery as possible. Other electronics, with their internal electrolytic capacitors on the 12V buss, will also damp out the desulfating pulses, so the optimum situation is to have the battery disconnected. Unfortunately the only way to know if any other situation is acceptable is to use an oscilloscope. It is possible to isolate the pulsing to a connected battery by using high permeability clamp on ferrites on the leads, which raises the impedance of the cables at the high frequencies which make up the pulses.

    Desulfating an old battery is a slow process, and is best used on a new battery to keep the plates clean. Sorry if this is too technical, but I been dere, dun dat.
     
  7. Easy Rider 2

    Easy Rider 2 Senior Member

    Joined:
    Aug 5, 2014
    1,584
    257
    0
    Location:
    Ocala, FL
    Vehicle:
    2013 Prius c
    Model:
    Three
    True but it does NOT support providing a "jump" to a non-hybrid car........even directly from your battery. It just doesn't have enough capacity.
     
  8. Easy Rider 2

    Easy Rider 2 Senior Member

    Joined:
    Aug 5, 2014
    1,584
    257
    0
    Location:
    Ocala, FL
    Vehicle:
    2013 Prius c
    Model:
    Three
    Three things about that:
    A new battery has no sulfation to clean off.
    AGM type batteries do not sulfate nearly as much as conventional wet cells.
    Sulfation is not really a big problem unless and until the scales flake off the plates and accumulate in the bottom and short out the cell.
    THAT will never happen in an AGM battery.
    Worrying about sulfation is pretty much a thing of the past.......unless you use the cheapest batteries you can find.