On Thu, 21 Aug 2003 10:33:24 +0000, BinaryBillTheSailo wrote:

On Wed, 20 Aug 2003 20:19:15 -0700, "Lloyd Sumpter" wrote:

On Wed, 20 Aug 2003 17:47:42 +0000, BinaryBillThesailo wrote:

On Wed, 20 Aug 2003 07:09:29 -0700, "Lloyd Sumpter"
wrote:


Actually, the motor will run identically between deepcyle/trolling and
starting.

Sorry Lloyd, but you are incorrect on that point.


Why? Does the deep cycle have different volts? Ohms law doesn't apply?


Same volts, but a different power output curve. The starter battery is designed
to output maximum amps for a short period. The trolling motor will gladly use
whatever is available, and the starter battery will quickly lose output if you
run the electric motor at full speed. The trolling motor will run like a
jackrabbit for a short time, and then will lose it's enthusiasm.

A deep cycle trolling motor will output lower amperage over a longer period.
Think of the difference between a sprinter and a marathoner. That's why there
are many different types of batteries. Different uses require different
characteristics.

BB

There's a difference between how much current a battery CAN supply and how
much the load is drawing. A 30-lb Endura pulls 30A at 12.5 V (approx) full
load. It's Ohm's Law, not the battery characteristics, that determines the
current. A fully charged battery, starting or deep-cycle, provides this: 30A
is not excessive even for a deep-cycle. The discharge curves are slightly
different, so the voltage drops differently between the two, but not
enough to notice. As I said, the difference in this case is the ability to
"come back" from a deep discharge.

If we were talking about 200A, you'd be right.

I've been running the exact motor he's talking about with a small starting
battery and have not seen what you describe: it just slowly runs slower as
the battery dies, over the course of several hours.

Lloyd