GC wrote:
I'd like to get a new battery for my boat... I don't know exactly how old
the current battery is as the sticker which should show the date doesn't
really have a makr on the year... although it seems to have a small smudge
on 00.
Check into desulphating your old battery instead. It may add years of
life to the battery. Many smart chargers have this feature.
So anyway, I'd like to get a new battery and just keep this current one for
my electronics... I'd like to get one a little bit more powerful for
starting... I have an old Johnson 90HP (about 20-25 years old)and I need a
bit more time to get it started sometimes... Probably is I don't know a lot
about batteries and the curent one doesn't have a rating written on it....
What I did get from it...
Brand: Ample
Model: N70ZZ
Size: 300mm X 200mm X 170mm
Most boat batteries are sized by their casing group; ie Group 24, Group
27, Group 31, etc etc. It sounds like your battery may be a car battery.
I looked up that part number and I got a few different brands listed but
they don't have an Amp rating (like the new batteries do in the shops).
One of them was Marshall, 600CCA, 130 RC.
And found another cheap one that was 640CCA.
Buying the cheapest battery is usually expensive in the long run. What
you want is to get the cheapest *power* which requires a battery of good
capacity & good service life... a good charger will extend the service
life of the battery too.
First question what is CCA?
"Cold Cranking Amp" This is the number of amps the battery can deliver
in total in a short time (IIRC 1 minute) at 0 degrees.
Comparing the size to the newer batteries.... The same sized batteries are
anywhere from 70Amperes to 100Amperes.
Batteries are built for two seperate functions... 1- to deliver a big
wallop of juice for starting an engine, then recovering slowly over a
long period of time... 2- delivering moderate amounts of power over a
long time frame and being recharged quickly. These two functions are
almost mutually exclusive. If you want a battery for power on board
(lights, electronics, etc etc) then you want a deep cycle battery. It's
rating in amp-hours will tell you how much it is capable of. If you want
a battery for starting, you want a starting battery which is constructed
differently, and the important rating is CCA or MCA (marine cranking amps).
Is getting a fully sealed battery worth the extra $100+??
Not IMHO. It's better to get plain old fashioned flooded cell battery,
check it fairly often, and use a smart charger.
Another question, I just got a little portable emergency jump starter which
says it can do 600Amps, 900Amps peak. Is this too weak to give my current
battery a boost? How much does a motor of this age normally draw??
I don't know but it sounds like this booster should be able to start the
motor all by itself. This is just my own personal taste but I'd be leery
of depending on such a gizmo regularly. A nice emergency back-up though.
A reliable battery bank is kind of old fashioned and boring low-tech but
it's the way to go IMHO.
Hope this helps
Doug King
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