it this normal

[oldyam80sg]

Ok i took a voltage reading with bad battery-11.5 volts.I turned key to on position and voltage dropped to 10 volts.Should the voltage drop like that when you turn key to on?Any electric gurus-or anyone.

[bikerphil]

Well, with a good battery, I get about 1V drop with the key on. My reading might be more of a drop 'cause my headlight also comes on with the key. Couldn't tell you with a bad battery, but I'd assume it would drop even more.

[The Lorax]

If the battery does not have sufficient charge or capacity to handle the load, it is not uncommon for the voltage to drop somewhat significantly when a load is applied to it. the battery has X volts and Y amps that it has available to supply to a given circuit, when that battery is no longer good, the amount of current it have available diminishes, the load will then take what it can and the voltage drops as a result. at least that's how I understand it to work, my nomenclature may be a bit off but that it the general jist of it. have a nice day and ride safe

[oldyam80sg]

Thanks bikerphil-yes the bad battery would drop and as soon as i turned key off it would go up-only to 11.5volts.New battery is on the battery tender and it is fully charged.
Thanks The Lorax!

[skids]

11.5 volts is not too good really. Of course if your bike hasn't been charged-up in a while, it is understandable. On the other hand, if you have charged it, it is not so good. Your ignition box may shut down spark to the coils at a bit over 10 volts, leaving you stranded... The only way to test a battery is to give it a complete charge and then load-test it.

[oldyam80sg]

When i took old battery to Auto Zone it was only reading 9.9volts on their machine-Could not get the bike to start at those low volts.When they hooked it up to their machine battery was charging but when they put a load on it-battery voltage dropped significantly.Test took 20 minutes to perform.Have had good luck with the Wal-Mart batteries.