battery problems

since last week when i installed led indicators, k and n air filter, cut out air box. My battery has been playing up. It really labours to turn on a morning but after a ride fires up perfectly. I dont think the mods have anythiing to do with it other than i left ignition on for long periods when doing indicators.

Do you think a night on a optimate charger will help or should i simply get a new battery?

Sounds like time for a new battery. Putting it on the charger may squeeze some more time out of it though you may park it one day, let it sit for a few hours and have to mpush start the bike.

Once a lead acid battery gets below 50% they are pretty much on a fast decline toward dead and will never properly hold a charge again. Once they hit 30% of a charge they are done for fast. It's the nature of the materials. The gel cel are usually much more forgiving and can be almost completely discharged and brought back. Sounds like ti's time for a new battery.

The good news? Your DR doesn't need the battery to run, your gauges will just flicker and you'll have to bump-start it. I found that out when I had catastrophic battery failure 40+ miles back into the woods!

Time for a super start kit from eddie.:thumbsup:

You have the symptoms of a bad battery.

My rule of thumb is; after a good ride the battery voltage at a fast idle should be 14V + or – 0.5V. You can get more variability depending on the capability of the charging system, the load on the system and the temperature. This will indicate that your charging system is working.

Turn the engine off and check the “no load – open circuit” battery voltage. In case your bike has some other hidden fault, I would keep the battery disconnected for the next 24 hours.

Check the “no load – open circuit battery” voltage again in 24 hours.

Compare the two voltage readings to the chart below. This will indicate the battery state of charge, but will not show the battery’s cranking capacity. If I had less than 12.4V I would probably opt for a new battery.

The next step would be to take it to a shop to have a load test done. At this point I probably would look at the age of the battery, remember the number of times I had let the battery go flat and just buy a new one.

Open circuit Volts - Charge %

< 11.7V - 0%

< 12V - 25%

< 12.2V - 50%

< 12.4V - 75%

> 12.6V - 100%

One more thing, you should really have a voltage monitor on your bike. Signal Dynamics makes a nice one.

thanks for replies, don't call me lazy but i think ill just buy a New battery. Anyway my bike still has warranty so they might sell me a battery at trade cost. Ill ask them for a free one but wont hold my breath....

i realised that i had warranty on my bike from the dealer and although the warranty does cover batteries the parts guy refused to change it after charging it and it stayed at 12.8 all night. Although the day after it was 12.7 then day after (today) 12.6. So as its losing .1 a day in a warm room disconnected would this suggest it no good?

I have no idea how quickly or slowly it should run down though.

OD - Where did you chart come from? I would expect a AGM battery to be higher voltage.

Noble - I do not know if an AGM battery would be higher. I pulled the chart from my Jeep's shop manual.

I have seen similar charts for other vehicles. From memory, they seem to vary by a 0.1V or so.

Here is the same voltage / state of charge chart from Harley. They use AGM batteries (and for the wise guys out there - this is one of the few changes Harley has made since 1903.)

O.C. Voltage - State of Charge

12.7V - 100%

12.6V - 75%

12.3V - 50%

12.0V - 25%

11.8V - 0%

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