15-15.5 volts too much?

[gargoyle_house]

I bought a new battery (Interstate brand) and just because I'm curious, I hooked up a meter to the negative terminal on the battery and the positive/red cable coming from the fuse block (the cable that goes to the pos terminal on the battery -- couldn't reach the terminal on the battery with my type of meter clips).

When I'm riding, the voltage climbs to 14.9 or so but then when I'm going about 80 (which I do often on the wide open Vermont Interstate on my way to Canada) - the voltage will climb to about 15 or 15.5 volts. Am I frying my battery? I am surprised at this since I read on here how often the voltage regulators don't give enough volts and mines giving a lot. Is it possible mine is about the die, too?...just wanted your thoughts...thanks.

[Bonz]

14.9 seems about right, not sure about a bit higher in the 15.5 range?

[motoman]

I bought a new battery (Interstate brand) and just because I'm curious, I hooked up a meter to the negative terminal on the battery and the positive/red cable coming from the fuse block (the cable that goes to the pos terminal on the battery -- couldn't reach the terminal on the battery with my type of meter clips).

When I'm riding, the voltage climbs to 14.9 or so but then when I'm going about 80 (which I do often on the wide open Vermont Interstate on my way to Canada) - the voltage will climb to about 15 or 15.5 volts. Am I frying my battery? I am surprised at this since I read on here how often the voltage regulators don't give enough volts and mines giving a lot. Is it possible mine is about the die, too?...just wanted your thoughts...thanks.

You definitely have poor electrical connections in system, BUT the regulator doesn't know that and continues to charge at an overly high rate.........and yes, poor electrical connections IS a good way to overcharge a battery which WILL cause you to need a new battery....again.....very soon.

BTW, the ideal charge rate in the automotive world is 13.8v-14.2v. Unfortunately, over the decades in the motorcycle world, the regualtors charge rate has charging voltages at 14.5v-14.9v. This kinda charge rate definitely reduces life of wet cell batteries!

[TopCatGr58]

Hey there Gargoyle,

As stated, the Reg/Rect measures system voltages, and then allows current to flow thru the ALT's field coil, the stronger the magnetic coil field, the more power will be created. IF there are bad connections where volts are being lost before they get to the REG/RECT, then it thinks there isn't enough power being created, and will then allow more current thru the field coil. SO...as Brant/Motoman suggested, clean ALL of your harness connectors, or at least the ones involved in the charging system, the grounds, the wires to the housing of the Reg/Rect, the ALT connectors BEHIND the fuse panel mounting plate, etc.!

And then first test the charging at idle, should be close to only 12 V, then rev to 2500 and hold, should then be about 14.5 V. IF you still then see the 15+V, then the Reg/Rect may be on it's way out??

T.C.

[motoman]

Hey there Gargoyle,

As stated, the Reg/Rect measures system voltages, and then allows current to flow thru the ALT's field coil, the stronger the magnetic coil field, the more power will be created. IF there are bad connections where volts are being lost before they get to the REG/RECT, then it thinks there isn't enough power being created, and will then allow more current thru the field coil. SO...as Brant/Motoman suggested, clean ALL of your harness connectors, or at least the ones involved in the charging system, the grounds, the wires to the housing of the Reg/Rect, the ALT connectors BEHIND the fuse panel mounting plate, etc.!

And then first test the charging at idle, should be close to only 12 V, then rev to 2500 and hold, should then be about 14.5 V. IF you still then see the 15+V, then the Reg/Rect may be on it's way out??

T.C.

I majority of the time get really lazy explaining speciifices......but can pretty much count on you to chime in with details.