Hi Wim
THanks for the response

Yes, great, I will make the measurement on the battery after one hour of
charging (while charging it) at 10amps to see if it measures greater than
14.8 volts. That may answer my concern.

If it remains under the 14.8v mark should I just keep it charging? My
charger is the automatic style that shuts off when it knows the battery is
fully charged. It has the meter on the front and always starts off near the
red then goes through the yellow part of the meter then when in the green
part of the meter it shuts off and the green light comes on. If left like
this the charger will cycle back on after a while for very short time then
off then on, etc etc, does that mean it is losing its charge just sitting
there? Is that ok or the sign of a dead or dying battery? Recently it just
doesn't shut off and stays charging. I will measure its voltage at this
stage.

I will also measure to see if it is holding the voltage after a few days of
nothing. I have a digital volt meter and can measure that easily.

Thanks

Tom







"Wimpie" wrote in message
abel.net...
El 10-05-13 15:26, Tom escribió:
Hi again

Sorry, I know I asked this question a couple years ago or a similiar one.

I am stumbled again and I don't want to ruin my batteries so I thought
I would ask the pros again.

I have two Marine deep cycle 750 A Nautaulis Canadian Tire Batteries.
225min/115 ah model number is 10-3199-0. These are the bit bigger
batteries about 40 lbs.

I also have the 10am/2am Automatic Canadian Tire 11-1567-0 battery
charger.

I have had these batteries in my garage all winter and about once
every month or 50 days I would bring them up to full charge. Takes
about 25 or 30 hours at 10 amp charging until that GREEN light comes
on and automatically shutting off.

My problem is now that the green light isn't coming on. They are just
sitting there bubbling away, I actually had to put about a litre or
two into each of Reverse Osmosis water in to them because I could see
they were low. But the green light will not come on and they keep
charging. About 3 days now.

I took both batteries down to Canadian Tire and the chap used a little
hand tool electronic device that pumped me out a receipt thing
(EXP800) and this battery test told me that the batteries are GOOD.
Voltage is 12.63 for one and the other was 12.68 for the other. They
measured 922 CCA and 684 CCA (both rated for 750A) so he said they are
good. Temp was 19C


I asked him why the green light doesn't come on and the charging stop
but he said because the batteries are fully charged and good that the
charger must be good. And it is good because I used it on another deep
cycle battery I have and the green light came on and it stopped when
fullly charged.

I see the needle is close to the green on the meter but just not
moving over and continues charging at 10 amps with the bigger
batteries in question.

Batteries are almost 4 years old.

Any ideas or comments? Should I stop the charging? or continue until
that green light comes on like it used to? I would like to get a few
more years from these batteries . All coments are appreciated, cheap
or otherwise, I appreciate your expertise very much. Sorry the
question is OFF Topic, but I know you folks have the answer better
than the boating groups. thnx

Best regards and thanks

73s


Hello Tom,

Can you measure the voltage when the charger is charging the batteries
(after charging your full batteries for an hour or more)? When it reads
14.8V, your charger is only generating gas and you are reducing the
service life of the battery (and you need to add demi water).

You may also measure the battery open load voltage after leaving it some
days without any load (no charger connected). When it reads the values you
mentioned (12.68V), there is no leakage in one of the cells and the
battery is fully charged.

I have no idea about the charge modes of your charger, maybe some voltage
or current setting changed over time. For example when the charging
voltage drifts up during aging, the charge current remains relatively high
so that the charger thinks it still needs charge. Some chargers have a
current measurement. Once the current drops below a certain value, the
charger changes to maintenance charge (that means it reduces the charge
voltage to avoid/reduce gassing).


--
Wim
PA3DJS
www.tetech.nl
Please remove abc first in case of PM