Battery Tender

Discussion in 'Sportster Models' started by CoreyV, Oct 1, 2011.

  1. CoreyV

    CoreyV Member

    Just purchased a battrey tender and wired in the quick plug directly to the battery. In prior years I've always took the battery off and brought it in for the winter....but when it got warm enough for a day to ride I didn't because the battery was in the basement. So this year I'm going to try leaving it on the bike and plugged into the tender. The battery on my 2010 is much more difficult to get out than my previous 1995. My question is...Do I need to leave it plugged in even during the riding season or just when it's put up for the winter months?
  2. SimsHD

    SimsHD Member

    My part-time job now is working for a company called Battery Specialists. I have worked there for 14 years now. I can confidently say that I know you made a good decision by buying the battery tender. I will explain how and why it works. I will start by agreeing with CoreyV by saying that if you are riding daily in the season, it is not necessary at all to hook it up. If it sits for a week or longer, I always hook mine up. The way the Tender works is that it has a maximum amperage output (The Deltran Tender Plus is 1.25A). The Tender will charge at 1.25 amps until the battery voltage nears 13.2 volts. The Tender will then switch to "float" mode in which it only puts out enough amperage to maintain the 13.2 volts. Deltran has picked 13.2 volts because 12.6 is static battery voltage (full charged without any load or discharge). Also, 14.6 volts is the point at which a battery will begin to boil water. By maintaining 13.2 volts in the battery, the specific gravity of the electrolyte is maintained without sacrificing the loss of the water element to boiling.

    When a battery discharges, the acid separates from the water and enters the plates. This is when sulfation of the plates begins. When the battery is charged, the acid is expelled from the plates and remixes with the water. You must remember that a battery will drain itself at a rate of 8 to 10% per month, depending on humidity. The drain occurs as a dead short bleed between the posts through the available moisture in the air. So in fact, a battery will actually drain itself faster if kept in a heated environment than if left in a cooler one. However, if you plan to leave a battery in the cold, you must make sure it is charged-up. The acid acts as an antifreeze and prevents a full charged battery from freezing. If the battery is discharged, the acid is in the plates and all that is left free is the water, which will freeze and bust the battery case, or least begin to warp the plates in the battery.

    This is true for flooded cell (wet cell or conventional) as well as for the absorbed glass mat "AGM" maintenance free batteries that most of us use now.

    Long explanation, but once you know how it works, things make a lot more sense. Also, I am glad to be able to offer advice/information back to the other users. Some of you are helping me now with the problems I'm having with mine.

    Hope you enjoy the Tender and the extended life you can expect now out of your battery.:s
  3. steve saunders

    steve saunders Member

    Wow thanks simsHD that was very interesting information! I allways use a tender in the winter
  4. fin_676

    fin_676 Experienced Member Staff Member Moderator Contributor

    I have 3 bikes and 2 chargers
    during the riding season i tend not to hook up to my charger during winter i will always have 2 bikes hooked up and rotate on a weekly basis
    the chargers i use are optimate 3 which are a popular choice in Europe

  5. deucedog

    deucedog Active Member

    My bike is on the battery tender whenever I'm not riding, winter included.
    I like to keep the bike ready for those occasional winter days where it's cold but the roads are clear and dry.
    (the bike is in an insulated, but unheated, standalone garage)
    The battery is going into it's 7th winter and still working just fine.