I have a situation that I am not sure if the two batteries are having
problem or the on-dashboard voltmeter doesn't work reliably in cold
weather. After I had fully charged the batteries (that were left on
the boat in cold winter like 32-degree), the needle in the on-dashboard
voltmeter would show exactly 12-volt. But after the batteries had sat
there doing nothing for a couple hours later, it showed at something
like 11.5-volt to 11-volt. I am sure that the batteries were not
supposed to have been used because I had turned the battery switch to
OFF. I recharged it anyway. Strangely, after I had recharged the
batteries for less than a minute, the recharger would stop recharging
and indicate that the batteries were fully recharged. I checked the
batteries with a portable mult-meter, and I found that both batteries
were fully charged (with 12.99 volt).

Seem like the batteries are really fully recharged and they are good
because of these facts (1) The recharger had stopped recharging the
batteries and indicated that the batteries were fully charged. (2)
Nothing was using the batteries. (3) The mult-meter also said that the
batteries were fully charged.

I am wondering may be the on-dashboard voltmeter doesn't work that well
in cold weather considering the fact that the on-dashboard is being
left in the cold for a long time. The multmeter still worked well when
I used it in the boat because I brought it out from room temperature,
and it was still warm when I used it to check the batteries.

Is my understanding correct? If my understanding is correct, I will
have to stop using the on-dashboard voltmeter to check the batteries
during winter, and I should use a multmeter instead. If my
understanding is not correct, does this mean that the on-dashboard
voltmeter is no good and it should be replaced?

Thanks for any info in advance.

Jay Chan

It's not uncommon for boats to have connection resistance. How old is your
boat? Corrosion is the common cause. The dash voltmeter may be correct,
you might only be seeing 11.5 volts at the dash. Try your multimeter on the
terminals of the dash voltmeter and see what it says.

wrote in message
oups.com...
I have a situation that I am not sure if the two batteries are having
problem or the on-dashboard voltmeter doesn't work reliably in cold
weather. After I had fully charged the batteries (that were left on
the boat in cold winter like 32-degree), the needle in the on-dashboard
voltmeter would show exactly 12-volt. But after the batteries had sat
there doing nothing for a couple hours later, it showed at something
like 11.5-volt to 11-volt. I am sure that the batteries were not
supposed to have been used because I had turned the battery switch to
OFF. I recharged it anyway. Strangely, after I had recharged the
batteries for less than a minute, the recharger would stop recharging
and indicate that the batteries were fully recharged. I checked the
batteries with a portable mult-meter, and I found that both batteries
were fully charged (with 12.99 volt).

Seem like the batteries are really fully recharged and they are good
because of these facts (1) The recharger had stopped recharging the
batteries and indicated that the batteries were fully charged. (2)
Nothing was using the batteries. (3) The mult-meter also said that the
batteries were fully charged.

I am wondering may be the on-dashboard voltmeter doesn't work that well
in cold weather considering the fact that the on-dashboard is being
left in the cold for a long time. The multmeter still worked well when
I used it in the boat because I brought it out from room temperature,
and it was still warm when I used it to check the batteries.

Is my understanding correct? If my understanding is correct, I will
have to stop using the on-dashboard voltmeter to check the batteries
during winter, and I should use a multmeter instead. If my
understanding is not correct, does this mean that the on-dashboard
voltmeter is no good and it should be replaced?

Thanks for any info in advance.

Jay Chan

Jay,
I do not think an analog voltmeter will be affected by the cold. I
would check the wires. How far from the battery? There could be a
voltage drop. What size are they? They may need to be bigger to
compensate for distance. Is there corrosion on the terminals? This will
affect the reading. Does the meter have a calibration screw on it? If
it does adjust it so it matches the reading of the digital at the
batteries.

Hope this helps.


Paul


wrote:
I have a situation that I am not sure if the two batteries are having
problem or the on-dashboard voltmeter doesn't work reliably in cold
weather. After I had fully charged the batteries (that were left on
the boat in cold winter like 32-degree), the needle in the on-dashboard
voltmeter would show exactly 12-volt. But after the batteries had sat
there doing nothing for a couple hours later, it showed at something
like 11.5-volt to 11-volt. I am sure that the batteries were not
supposed to have been used because I had turned the battery switch to
OFF. I recharged it anyway. Strangely, after I had recharged the
batteries for less than a minute, the recharger would stop recharging
and indicate that the batteries were fully recharged. I checked the
batteries with a portable mult-meter, and I found that both batteries
were fully charged (with 12.99 volt).

Seem like the batteries are really fully recharged and they are good
because of these facts (1) The recharger had stopped recharging the
batteries and indicated that the batteries were fully charged. (2)
Nothing was using the batteries. (3) The mult-meter also said that the
batteries were fully charged.

I am wondering may be the on-dashboard voltmeter doesn't work that well
in cold weather considering the fact that the on-dashboard is being
left in the cold for a long time. The multmeter still worked well when
I used it in the boat because I brought it out from room temperature,
and it was still warm when I used it to check the batteries.

Is my understanding correct? If my understanding is correct, I will
have to stop using the on-dashboard voltmeter to check the batteries
during winter, and I should use a multmeter instead. If my
understanding is not correct, does this mean that the on-dashboard
voltmeter is no good and it should be replaced?

Thanks for any info in advance.

Jay Chan

wrote:
I have a situation that I am not sure if the two batteries are having
problem or the on-dashboard voltmeter doesn't work reliably in cold
weather. After I had fully charged the batteries (that were left on
the boat in cold winter like 32-degree), the needle in the on-dashboard
voltmeter would show exactly 12-volt. But after the batteries had sat
there doing nothing for a couple hours later, it showed at something
like 11.5-volt to 11-volt. I am sure that the batteries were not
supposed to have been used because I had turned the battery switch to
OFF. I recharged it anyway. Strangely, after I had recharged the
batteries for less than a minute, the recharger would stop recharging
and indicate that the batteries were fully recharged. I checked the
batteries with a portable mult-meter, and I found that both batteries
were fully charged (with 12.99 volt).

Seem like the batteries are really fully recharged and they are good
because of these facts (1) The recharger had stopped recharging the
batteries and indicated that the batteries were fully charged. (2)
Nothing was using the batteries. (3) The mult-meter also said that the
batteries were fully charged.

I am wondering may be the on-dashboard voltmeter doesn't work that well
in cold weather considering the fact that the on-dashboard is being
left in the cold for a long time. The multmeter still worked well when
I used it in the boat because I brought it out from room temperature,
and it was still warm when I used it to check the batteries.

Is my understanding correct? If my understanding is correct, I will
have to stop using the on-dashboard voltmeter to check the batteries
during winter, and I should use a multmeter instead. If my
understanding is not correct, does this mean that the on-dashboard
voltmeter is no good and it should be replaced?

Thanks for any info in advance.

Jay Chan

The responses about a voltage drop between the battery and the meter
are probably excellent starting points for tracking down the problem.
Bad connection, undersize wire, etc,etc,etc------check all the usual
suspects.

In addition, you're not adequately charging your battery. Is your
converter ("recharger") properly set up? Is there a selector switch to
designate wet cell vs. AGM?
You battery voltage should reach 2.2 volts per cell while recharging
(2.2 times 6 equals
13.2) and should still read at least 2.1 volts per cell (12.6) hours or
even days later if there isn't a load on the battery. If your charger
shuts off at 12.99 volts, instead of 13.2, you are slightly
undercharging your batteries.

Obviously you had the key on when monitoring the voltmeter. You may
have something drawing current through the ignition switch that isn't
occuring to you. (If simply running the guages and dash lights is
drawing you battery down that quickly, you need a new battery).
Whatever may be drawing current with the swtich on might not be a
problem with the engine running so that the alternator can take over
the load.

If you're seeing 11 volts with the engine *running* and it isn't a
corroded connection, etc, you would want to take a close look at the
alternator.

It's not uncommon for boats to have connection resistance. How old is your
boat? Corrosion is the common cause. The dash voltmeter may be correct,
you might only be seeing 11.5 volts at the dash. Try your multimeter on the
terminals of the dash voltmeter and see what it says.

The boat is from 1995, around 10 years old.

Thanks for pointing out that the connection between the battery to the
dashboard voltmeter may have too much resistance. I will check the
voltage at the terminals of the dashboard voltmeter to see if it is
reading the same low voltage as the voltmeter. If this is the case,
this means I definitely need to do something about the wiring in this
boat that I intend to do anyway when the weather becomes warmer.

Jay Chan

I do not think an analog voltmeter will be affected by the cold.

Great to hear this. This means I may not need to replace the voltmeter
on the dashboard, and can save some money. I thought the voltmeter
might be affected by cold temperature because the instruction manual of
the multmeter tells me not to use it when temperature is too cold.

I would check the wires. How far from the battery? There could be a
voltage drop. What size are they? They may need to be bigger to
compensate for distance. Is there corrosion on the terminals? This will
affect the reading.

Honestly, I didn't even think of checking the connection between the
battery and the on-dashboard voltmeter until you guys have pointed this
out. You guys are probably right in saying that the wiring may be
undersized because I recall that most of the wires inside the
batteries/wiring compartment are kind of thin like those light gauge
wires. I will document all the wiring inside the boat when the weather
becomes warm. For now, I will check the voltage in the voltmeter
terminals to see if the voltage is as low as what is being shown in the
voltmeter.

Does the meter have a calibration screw on it? If it does adjust
it so it matches the reading of the digital at the batteries.

Thanks for this tip. I didn't know that there is such a thing in a
voltmeter. I will find out when I get back home.

Jay Chan

In addition, you're not adequately charging your battery. Is your
converter ("recharger") properly set up? Is there a selector switch to
designate wet cell vs. AGM?

If I remember this correctly, I have setup the charger to the correct
battery type that is "wet cells". I will double check when I go home
anyway just to be sure.

You battery voltage should reach 2.2 volts per cell while recharging
(2.2 times 6 equals
13.2) and should still read at least 2.1 volts per cell (12.6) hours or
even days later if there isn't a load on the battery. If your charger
shuts off at 12.99 volts, instead of 13.2, you are slightly
undercharging your batteries.

Yes, you are probably right. The boating book also says that I should
see the voltage above 13-volt (I don't remember the exact number).
What's the significance of slightly under-charging the batteries? Does
the charger undercharge the batteries to avoid boiling the batteries?

Obviously you had the key on when monitoring the voltmeter. You may
have something drawing current through the ignition switch that isn't
occuring to you. (If simply running the guages and dash lights is
drawing you battery down that quickly, you need a new battery).

I don't think there is anything else that is drawing power from the
batteries other than the gauges and the dash lights. The boat doesn't
have any fancy electronic device other than the gauges (voltmeter, rpm
meter, motor temp gauge) and a bilge pump that doesn't seem to be
working.

I hope the batteries are fine. I did a load test on the batteries
using the electric starter of the motor as a load. And the batteries
were fine. Honestly, I don't know how old the batteries are. I will
have to do a load test on the batteries one more time when I
recommission the boat in the spring.

If you're seeing 11 volts with the engine *running* and it isn't a
corroded connection, etc, you would want to take a close look at the
alternator.

Actually, I saw the voltmeter showing something like 12.7-volt or above
when I was running the motor. This means the alternator was running
fine.

What this means is that I should make sure the connection between the
batteries and the voltmeter is fine in order to establish a good base
line before I do anything else (anything else means things like doing a
load test on the batteries, like checking the voltage when the
alternator is checking). Otherwise, any number that I get from the
voltmeter is questionable.

Jay Chan

Jay,

I would take the batteries to a place that can do a load test on the
batteries with a real load. Autozone, Pepboys and walmart should be
able to load test. A starter running with no load is really no load on
a battery. For $20.00 you can buy your own load tester.
http://www.harborfreight.com/cpi/cta...emnumber=90636

for $60.00 you can really drain a battery.
http://www.harborfreight.com/cpi/cta...emnumber=91129

Paul

On 6 Dec 2005 11:03:42 -0800, "Paul" wrote:

for $60.00 you can really drain a battery.
http://www.harborfreight.com/cpi/cta...emnumber=91129

===================================

That's kind of funny, a 500 amp load with 4 guage hook up cables. Not
for too long I hope unless you like the smell of burning PVC.

Thanks for pointing out that the connection between the battery to the
dashboard voltmeter may have too much resistance. I will check the
voltage at the terminals of the dashboard voltmeter to see if it is
reading the same low voltage as the voltmeter. If this is the case,
this means I definitely need to do something about the wiring in this
boat that I intend to do anyway when the weather becomes warmer.

Last night I tried to check the voltage at the terminals of the
voltmeter. But I was totally confused by the various wiring at the
voltmeter. I think I will check it again _after_ I have documented all
the wiring in the boat. By that time, I will understand the wiring at
the voltmeter better. For now, I just have to continue using the
multmeter to check the voltage of the batteries instead of relying on
the voltmeter on the dashboard.

Jay Chan