At what point is a vehicle battery charging or discharging? 12.6v ?

I have been thinking about installing a battery monitor on my
motorcycle to tell me when I'm draining the battery. I will have
several accessories on he auxillary lights, heated clothing, etc.
With the monitor I can tell when I've got too much stuff turned on.

The one I like uses a single LED to indicate status. It's green when
the voltage is 12v or above, amber when 11.5-11.9, and red when below
11.5. You can read it he http://tinyurl.com/2vpth

Now my understanding has always been that when a vehicle's charging
system is below 12.6 volts, it is discharging the battery. If this
were true it would make this device not very useful, I could be on a
trip riding down the road at 12.3 volts, discharging the battery and
never know it.

So is it 12.6v or does it vary with different types of batteries or
something? (Gel, lead acid, glass mat) I've emailed the battery monitor
manufacturer, too, but wanted to get some expert opinions here.
Thanks a lot,
-Ryan

On 27 Dec 2004 20:05:12 -0800, wrote:

>I have been thinking about installing a battery monitor on my
>motorcycle to tell me when I'm draining the battery. I will have
>several accessories on he auxillary lights, heated clothing, etc.
>With the monitor I can tell when I've got too much stuff turned on.
>
>The one I like uses a single LED to indicate status. It's green when
>the voltage is 12v or above, amber when 11.5-11.9, and red when below
>11.5. You can read it he http://tinyurl.com/2vpth
>
>Now my understanding has always been that when a vehicle's charging
>system is below 12.6 volts, it is discharging the battery. If this
>were true it would make this device not very useful, I could be on a
>trip riding down the road at 12.3 volts, discharging the battery and
>never know it.
>
>So is it 12.6v or does it vary with different types of batteries or
>something? (Gel, lead acid, glass mat) I've emailed the battery monitor
>manufacturer, too, but wanted to get some expert opinions here.
>Thanks a lot,
>-Ryan

The way to know for certain is to install an ammeter. Then
you know which way current is flowing, regardless of voltage.

wrote:
>
> I have been thinking about installing a battery monitor on my
> motorcycle to tell me when I'm draining the battery. I will have
> several accessories on he auxillary lights, heated clothing, etc.
> With the monitor I can tell when I've got too much stuff turned on.
>
> The one I like uses a single LED to indicate status. It's green when
> the voltage is 12v or above, amber when 11.5-11.9, and red when below
> 11.5. You can read it he http://tinyurl.com/2vpth
>
> Now my understanding has always been that when a vehicle's charging
> system is below 12.6 volts, it is discharging the battery. If this
> were true it would make this device not very useful, I could be on a
> trip riding down the road at 12.3 volts, discharging the battery and
> never know it.
>
> So is it 12.6v or does it vary with different types of batteries or
> something? (Gel, lead acid, glass mat) I've emailed the battery monitor
> manufacturer, too, but wanted to get some expert opinions here.
> Thanks a lot,
> -Ryan

12.6 volts is for 6 cells of a lead-acid battery.
(PbO2-Pb-PbSO4 reaction)
I don't know what your battery is made of.
The Fly is right: install an ammeter.

"None" > wrote in message
...
> wrote:
>>
>> I have been thinking about installing a battery monitor on my
>> motorcycle to tell me when I'm draining the battery. I will have
>> several accessories on he auxillary lights, heated clothing, etc.
>> With the monitor I can tell when I've got too much stuff turned on.
>>
>> The one I like uses a single LED to indicate status. It's green when
>> the voltage is 12v or above, amber when 11.5-11.9, and red when below
>> 11.5. You can read it he http://tinyurl.com/2vpth
>>
>> Now my understanding has always been that when a vehicle's charging
>> system is below 12.6 volts, it is discharging the battery. If this
>> were true it would make this device not very useful, I could be on a
>> trip riding down the road at 12.3 volts, discharging the battery and
>> never know it.
>>
>> So is it 12.6v or does it vary with different types of batteries or
>> something? (Gel, lead acid, glass mat) I've emailed the battery monitor
>> manufacturer, too, but wanted to get some expert opinions here.
>> Thanks a lot,
>> -Ryan
>
> 12.6 volts is for 6 cells of a lead-acid battery.
> (PbO2-Pb-PbSO4 reaction)
> I don't know what your battery is made of.
> The Fly is right: install an ammeter.

You are both wrong, a voltmeter is easier to install and will give a better
idea of what's going on. Below 12.6 volts is discharging and over 13 volts
is charging. I'd say the device the OP was talking about is completely
worthless.

There are amp meters that you can get, that read remotely with a shunt
resistor, two small leads from there to the amp meter. If you don't need it
all the time, you can get one that you just hold against the wire. Check
J-C Whitney's catalog.

Voltage, by itself, tells you very little. 13.8V could be perfectly normal,
or you could have a completely open battery.. An open-circuit battery won't
start or charge, but your voltage regulator will hold your system voltage
near this point, even with out a battery in the system (Though on some
motorcycles this varies, they do unusual things sometimes)

If current into the battery is positive, then you're charging.
If current out of the battery is positive, then you're discharging.
If the current is near zero, then you've charged the battery.

> wrote in message
oups.com...
> I have been thinking about installing a battery monitor on my
> motorcycle to tell me when I'm draining the battery. I will have
> several accessories on he auxillary lights, heated clothing, etc.
> With the monitor I can tell when I've got too much stuff turned on.
>
> The one I like uses a single LED to indicate status. It's green when
> the voltage is 12v or above, amber when 11.5-11.9, and red when below
> 11.5. You can read it he http://tinyurl.com/2vpth
>
> Now my understanding has always been that when a vehicle's charging
> system is below 12.6 volts, it is discharging the battery. If this
> were true it would make this device not very useful, I could be on a
> trip riding down the road at 12.3 volts, discharging the battery and
> never know it.
>
> So is it 12.6v or does it vary with different types of batteries or
> something? (Gel, lead acid, glass mat) I've emailed the battery
monitor
> manufacturer, too, but wanted to get some expert opinions here.
> Thanks a lot,
> -Ryan
>

Easier way to do it. Look up the specs on your bike and see how many
watts the alternator puts out. Then add up all the stuff using power and
see what you get. I can tell you from experience with older bikes you
WILL be discharging the battery with all the extras on at the same time.
Now if you have one of the newer 'Wings or a Beemer you might be OK,
they have higher output charging systems.

Hi Ryan,

If the charging system is not working and there is no load, the
voltage is a relative value to the State-of-Charge of the battery.
Notwithstanding the internal self-discharge of a lead-acid battery,
charging simply occurs when the voltage is increased to a point that
current is flowing into the battery and discharging is at a point
where current is flowing out of a battery.

Since most charging systems normally operate at a higher voltage than
the battery, the vehicle's electrical load is powered by the charging
system. Any "left over" power will be used to recharge the battery.
When the charging system's voltage is near or drops below that of the
battery, the electrical load shared between the battery and the
charging system. That is the reason why stop-and-go driving with a
heavy electrical load, might not recharge a starting battery. When
the charging system is not working, the electrical load is placed on
the battery until the battery can not handle it.

Please see Section 9 of the Car (including Motorcycles) and Deep Cycle
Battery FAQ on www.batteryfaq.org for more information on charging.

For troubleshooting battery and charging system problems, both an
ammeter and voltmeter are useful, if you know how to correctly
interpret the measurements..

Kindest regards and Happy New Year,

BiLL.........



On 27 Dec 2004 20:05:12 -0800, wrote:

>I have been thinking about installing a battery monitor on my
>motorcycle to tell me when I'm draining the battery. I will have
>several accessories on he auxillary lights, heated clothing, etc.
>With the monitor I can tell when I've got too much stuff turned on.
>
>The one I like uses a single LED to indicate status. It's green when
>the voltage is 12v or above, amber when 11.5-11.9, and red when below
>11.5. You can read it he http://tinyurl.com/2vpth
>
>Now my understanding has always been that when a vehicle's charging
>system is below 12.6 volts, it is discharging the battery. If this
>were true it would make this device not very useful, I could be on a
>trip riding down the road at 12.3 volts, discharging the battery and
>never know it.
>
>So is it 12.6v or does it vary with different types of batteries or
>something? (Gel, lead acid, glass mat) I've emailed the battery monitor
>manufacturer, too, but wanted to get some expert opinions here.
>Thanks a lot,
>-Ryan

Add a silicon diode in series with the monitor to reduce the voltage by about .7 volts. It will then indicate green when the voltage is 12.7 volts or higher.

wrote:
>
> I have been thinking about installing a battery monitor on my
> motorcycle to tell me when I'm draining the battery. I will have
> several accessories on he auxillary lights, heated clothing, etc.
> With the monitor I can tell when I've got too much stuff turned on.
>
> The one I like uses a single LED to indicate status. It's green when
> the voltage is 12v or above, amber when 11.5-11.9, and red when below
> 11.5. You can read it he http://tinyurl.com/2vpth
>
> Now my understanding has always been that when a vehicle's charging
> system is below 12.6 volts, it is discharging the battery. If this
> were true it would make this device not very useful, I could be on a
> trip riding down the road at 12.3 volts, discharging the battery and
> never know it.
>
> So is it 12.6v or does it vary with different types of batteries or
> something? (Gel, lead acid, glass mat) I've emailed the battery monitor
> manufacturer, too, but wanted to get some expert opinions here.
> Thanks a lot,
> -Ryan

--
Mike Walsh
West Palm Beach, Florida, U.S.A.

Mike Walsh wrote:
> Add a silicon diode in series with the monitor to reduce the voltage
by about .7 volts. It will then indicate green when the voltage is 12.7
volts or higher.

I was thinking of putting a resistor inline, but a diode is probably a
better idea.

The other idea is to make my own. I've found a schematic (see small
voltage alert at http://tinyurl.com/2tvnj). This way I could set the
point at which the indicator comes on. And it would probably be a lot
cheaper.

-Ryan

Dave VanHorn wrote:
> There are amp meters that you can get, that read remotely with a
shunt
> resistor, two small leads from there to the amp meter. If you don't
need it
> all the time, you can get one that you just hold against the wire.
Check
> J-C Whitney's catalog.
>
> Voltage, by itself, tells you very little. 13.8V could be perfectly
normal,
> or you could have a completely open battery.. An open-circuit battery
won't
> start or charge, but your voltage regulator will hold your system
voltage
> near this point, even with out a battery in the system (Though on
some
> motorcycles this varies, they do unusual things sometimes)
>
> If current into the battery is positive, then you're charging.
> If current out of the battery is positive, then you're discharging.


> If the current is near zero, then you've charged the battery.

Or you could have a completely open battery.. or the charging system
has gone out, but your current drain on the battery is low enough that
it's not visible on the ammeter..

Auto manufacturers have gotten away from ammeters and gone to
voltmeters.. in addition to many other reasons, voltmeters are much
easier to wire in. You can wire a voltmeter pretty much anywhere in the
harness to read voltage.. where do you wire an ammeter to monitor
current into and out of the battery?

Regards,

Jim