12.85 dc volts maximum while on battery tender +

Discussion in 'Electrical' started by the real WILDPIG, Sep 25, 2009.

  1. can i get an opinion? after 24 hrs of sitting 80 degree day i read a maximum of 12.80-12.85 dc volts across the battery. i started using the battery tender 2 weeks ago-- harley will fire right up, perfect state of tune. earlier,, without using the batt tender i felt a sluggish starter,, seemingly weak initial starting,, so i hooked up batt tender an the response was a 100% improvement in starter turning motor over an it fires immediatley. bear in mind this is agm harley battery 2 yrs old but compression is 10.5 -1. i'm wondering if 12.80 dcv is a bit on the low side--any comments? was around 12.70 -12.75 several mornings without batt tender + hooked up. also checked charging --perfect 14.75 under running conditons. im opinin here but i really think an odessey battery-- extra heavy load may be in order for this higher compression motor an the oem harley battery just hasnt got the umph needed to get a good strong spin on the engine. anyways mull it over an lemme know what yall think--electrical isnt my best area of hd mechanics..................
  2. TQuentin1

    TQuentin1 Well-Known Member Staff Member Moderator

    That sounds perfect! That is what a fully charged battery is supposed to read. See here:


    With respect to the Odessey, that is my personal choice for power hungry bikes like my UC.

    Last edited: Sep 25, 2009
  3. kemo

    kemo R.I.P

    TQ is correct. 12.7 volts is considered a fully charged battery. Battery Tenders are computer controlled to do a maintainance charge or to charge a dead battery. When doing a maintainance charge it will just do a float charge.
  4. gs34

    gs34 Junior Member

    Sounds like compression release's are needed more than a battery.
    In all reality, any performance enhancements away from stock can have an effect on starting. BUT, most notable of these are raising the compression, timing, and cams.
    ......But then, you knew that.:s
  5. i have seriously considered comp releashs,, i dint mention that i had totaly cleaned brushed all electrical connections so thats not an issue and i have the ev 57 cam--which is fairly hi performance......... couple this with a 13 yr old stock starter-- i have 113,000 on the motor an one can easily build a case for some electrical/ starter upgrades........... most notible how ever was the 100% improvement using every time the battery tender plus every time the bike is sitting at the house.