Poss Ferked Battery or Reg

[1sportyrich]

1998 Sportster 1200

The battery on my sportie has been losing charge over the last couple of weeks. Went out to start it before my dayshift and nothing, just the starter turning over, no oomph to get the bugga going.

Done a search on here and got Kiwidaves' "Measuring Battery Voltage" & " Troubleshooting your Charging System" threads.

Bought a voltmeter from Halfords.




Checked the battery voltage this afternoon and it was at 12.16. Tied to start the bike but same as before.


The values that I took this afternoon are


Battery - Ignition off 12.16v. The Meter was set at 20
Battery - Ignition on 11.6v. The Meter was set at 20

Regulator Pins - 4.5. The Meter was set at 200m
Regulator Pins - 3.3. The Meter was set at 200m

So is it my battery that is ferked, or the possibly the regulator?

[Mantis]

if it was your regulator you would notice the lights going dim and then bright, its either your battery and/or the charging system, your generator might need rewinding. Its not expensive to sort out, but your need to get the generator sent off to have it rewound, all in all it should cost no more than £160 to sort. Which include them taking it out and having the work done and putting it back read for you.

What will happen if it isnt the battery is that you will replace the battery it will seem fine then slowly the bike will get harder to start or it will not start at all.

If the battery is old it wont hurt to replace it, as killing it would be enough to kill the cells in an old battery.

BTW I'm not great with electrical stuff, and name of parts are proberly wrong.

[Drew]

At 12.1v your battery is dead.

A 12v battery should be around 13.5v or slightly higher in some cases. What confuses most people is that extra 1.5v isn't just 1.5v its the main power and bol-ocks / staying power behind the battery.

With it going down to 11.6v when the ignition is turned on suggests its beyond recharging i.e. the cells are dead and wont hold any charge greater than lighting up the neutral / oil light.

If its the original battery its done well

[Roger]

Battery is low. 12.16v is virtually flat. 11.6V - that wont start the bike.

You need to fully charge the battery before you test it out. When you've done that, take the charger off and leave it an hour to cool down. Check the Voltage - Should be close to 12.9V

If it's not, either your battery is goosed or you've got something drawing current.

If it is more than 12.6V, turn on the ignition, it should hardly drop. Start the bike and measure again. Should be 13.5V ish if it's charging.

[dodgyloner]

What Roger said - charge battery off bike, leave for an hour or two or overnight then check.

Suggest you also check regulator properly or get someone to do it for you. I had a reg that slowly overcooked batteries so they died after about eight months.

While your checking all this run a separate earth wire from the reg casing to the engine earth or back to the battery neg terminal - then you know its earthed properly.

[Mantis]

change, charge battery, it isnt the regulator, my money is on the charging system.

If it was the regulator the lights would go bright and dark.

[Roger]

Originally Posted by Mantis

change, charge battery, it isnt the regulator, my money is on the charging system.

If it was the regulator the lights would go bright and dark.

Mine's on the battery

[1sportyrich]

Battery is now charged, will check on it in the morning and report back.

Thanx for the replies.

[Mantis]

Originally Posted by Roger

Mine's on the battery

If he knew how to test it, or took it to a shop he would find out within 5 mins.

Could be battey sounds more like charging system. Like I said though before electrics I'm not great with.

[panheadpete]

If the battery is fully charged it should read at least 13.2v on a meter, ie 2.2v per cell.
A fully discharged battery will be 10.8v or 1.8v per cell.
You can test the capacity of a battery by giving it a full charge, leave it for an hour as Roger said, give it a shake to dispel the bubbles then measure the voltage. If you get 13+ volts then connect a lead light of 21watts (indicator bulb) for ten hours (giving a 1.75 amp/hour discharge rate) then measure the voltage again; it should be above 10.8 volts. Another way of looking at it is, if you have no meter, the light should still be bright. You need to re-charge the battery immediately after this test or it will be screwed.
There's a heck of a lot more to it; does one cell bubble more than the others when charging? Can you see any grey areas through the case? Does the voltage rise quickly when charging or at a stable rate? Eek.
Cheers,
Pete