On 5/10/2013 8:26 AM, Tom wrote:
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


Hi Tom.

What you want is a 3 stage charger. The guy who said the old "clunk",
relay based, chargers are best is way off base.

A decent 3 stage charger lets you set a number of things, all of which
are tailored to your specific battery string.

I have a set with an 80 AH and an 160 AH AGM 12V battery. I charge
using a 200W solar array through a maximum power point 3 stage charger.
The MPP part isn't relevant for you, but the 3 stage adjustments plus
a battery temperature sensor are. You can set battery finish voltage
per manufacturer specs at a specific temperature and then the sensor
drives the rest based on current temperature. The 3 stages finish the
charge the correct way and don't overcharge the string or cause
excessive water loss.

tom
K0TAR