battery discharge

[gutzi]

At the risk of sounding really stupid, here goes.  I have been away from riding for a long time.  Just got a new to me cali ss.  The battery seems to discharge rather quickly.  I recently put a new battery in, started just fine.  That was about 2 weeks ago.  Started it today and it cranked, but rather slowly, but it started.  Now I dont ride it very frequently, but if my memory serves from many years ago, i dont recall batteries discharging that frequently.  Didnt ride it today, but when I went out this evening, the battery was low and would not crank at all.  So, should this be on a tender all the time, or am i looking at something draining the battery, or both?  Please be kind in your responses, an old newbi:laugh:

[Howard R]

This is definitely not normal, it could be one of two things: 

1) there is some parasitic drain on the battery (even with the switch off) that shouldn't be there.

B) charging system is not working properly.  Get the bike started and measure voltage at the battery ~3k rpm, if not >13.5 V you have found a problem.

Actually thought of another thing while I was typing, just because the battery is new doesn't necessarily mean it's good.  Infant mortality is not entirely unheard of in the battery world so it's worth charging and doing a load test.  The battery should still be under warranty, no?  Also, a new battery needs to be charged correctly before it is placed into service.  Ask the (battery) dealer if it was properly charged before it came into your hands.  If you bought a new AGM battery online, it should have arrived ready to install with no further charging needed on your part.

Howard

[pehayes]

Charging circuit is suspect.  Start.  Fast idle.  What is the voltage measured at the battery terminals?  This series of bikes had a rash of voltage regulator failures.  Both of my EV's  failed the VR within months of each other.

Please specify what battery you bought.  What technology class?  Some technologies self-discharge faster than others (although none should self-discharge like this.)  Prefer you buy and AGM class sealed battery.

Would be nice to know where you are located so that someone nearby might assist or advise.

Patrick Hayes
Fremont CA

[gutzi]

So, I tried charging the battery.  I have a charger that is supposed to sense whether it is a 6v or 12v battery.  So i hooked it up and when it indicated "maintaining", the battery was only at 6.9 volts.  So I unhooked the charger, and rehooked it up.  Now it was displaying "charging at 12V" and took a long time to charge it up.  But it finally got there and now the battery is fully charged.  I started the bike and ran it up to over 3K revs, and the battery voltage was well above 13.5 v.  So, I presume the charging system is working properly.  Still wonder about a parasitic drain though.  In thinking back, I may have left the key in the "on" position for many hours last saturday, and maybe that is what discharged the battery.  I guess i will, by default, leave the charger on when not in use for extended periods.  Thanks for the comments.

[charlie b]

I would still measure the drain on the battery with switch off.  You can use one of the cheap ammeters for this.  There should not be very much.

Also, how long are you riding it once you start it?  Needs to be something like 20min or more of running (not sitting at stoplights) just to charge back what you used in starting it.

[Kiwi_Roy]

At idle the battery is still discharging, it doesn't go to the plus side until you reach about 2000 revs

You have a headlight that comes on and the fuel pump draws over 4 Amps, you may not of had that on your previous bikes.