I am looking to buy a deep-cycle battery to run a 55 lb trolling
motor (45A max/12V) which will be used as the only motor for an
inflatable boat for fishing.

I am converging so far on Optima D34/78 (gives you 120 min reserve
at 25A, so it should run motor for 1 hrs at highest power).
It can be had for 144 $

What do you say:

- Can I get a better battery or similar one for
better price?

- Is the battery sized properly for this motor/usage (its my first one,
so I dont know).

Regards,
Evgenij
--

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On Thu, 12 Feb 2004 15:55:24 -0600, Evgenij Barsukov
wrote:

I am looking to buy a deep-cycle battery to run a 55 lb trolling
motor (45A max/12V) which will be used as the only motor for an
inflatable boat for fishing.

I am converging so far on Optima D34/78 (gives you 120 min reserve
at 25A, so it should run motor for 1 hrs at highest power).
It can be had for 144 $

What do you say:

- Can I get a better battery or similar one for
better price?

- Is the battery sized properly for this motor/usage (its my first one,
so I dont know).

I had two of them on my Ranger for the trolling motor and one for
starting. I was less than impressed with them as a long life trolling
motor supply. (This was in a 24 volt situation - maybe it's better
with a 12 volt operation).

I now have Interstate Megatron Lead Acid deep cycle batteries and
based on their performance last year, lasted longer, recharged quicker
and in general performed better than the Optimax.

I know some other guys who used these and had similar discharge
problems that I had.

Later,

Tom
S. Woodstock, CT
----------

"To the fisherman born there is nothing
so provoking of curiosity as a fishing rod
in a case."

Roland Pertwee, "The River God" (1928)

Evgenij Barsukov wrote:
I am looking to buy a deep-cycle battery to run a 55 lb trolling
motor (45A max/12V) which will be used as the only motor for an
inflatable boat for fishing.

By far the most bang for the buck is golf cart batteries. Looking at the
cost per 12V amp-hour, they are about 2/3 the cost of car batteries and
1/2 the cost of marine batteries. Of course, they are 6V so you have the
trouble of wiring them in series, but that isn't difficult.

For our boat, I bought a pair of Exide Gr 31 dual purpose batteries from
Agri-Supply
http://www.agri-supply.com/catmain/1200005.htm
I don't know what the reserve rating is but their amp-hours are about
115 so one of those would certainly drive your motor at full power for 1
hour, and the cost is about $65

Remember that the power extracted from the battery follows a curve, so
that if you have 1 hour at full throttle, you have more than 2 hours at
half throttle and possibly 6 hours at 1/4 throttle etc etc.

Hope this helps

Doug King

Short Wave Sportfishing wrote:
Evgenij wrote:
I am converging so far on Optima D34/78 (gives you 120 min reserve
at 25A, so it should run motor for 1 hrs at highest power).
It can be had for 144 $
..............

I had two of them on my Ranger for the trolling motor and one for
starting. I was less than impressed with them as a long life trolling
motor supply. (This was in a 24 volt situation - maybe it's better
with a 12 volt operation).

I now have Interstate Megatron Lead Acid deep cycle batteries and
based on their performance last year, lasted longer, recharged quicker
and in general performed better than the Optimax.

I know some other guys who used these and had similar discharge
problems that I had.


Thanks for the hint. I looked at interstate batteries, and there is
SRM-24 with same 46 lb weight, but larger reserve capacity 140 min vs
120 with optima (so no wonder it lasts longer). But best of all, it
costs twice less ! (75 $)
I will probably go with it, unless some other good ideas come by.

Regards,
Evgenij
--

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DSK wrote:

Evgenij Barsukov wrote:
I am looking to buy a deep-cycle battery to run a 55 lb trolling
motor (45A max/12V) which will be used as the only motor for an
inflatable boat for fishing.

By far the most bang for the buck is golf cart batteries. Looking at the
cost per 12V amp-hour, they are about 2/3 the cost of car batteries and
1/2 the cost of marine batteries. Of course, they are 6V so you have the
trouble of wiring them in series, but that isn't difficult.

For our boat, I bought a pair of Exide Gr 31 dual purpose batteries from
Agri-Supply
http://www.agri-supply.com/catmain/1200005.htm
I don't know what the reserve rating is but their amp-hours are about
115 so one of those would certainly drive your motor at full power for 1
hour, and the cost is about $65

Are you sure it is Ah and not reserve time? If it is really 115 Ah, it would run
my motor for 2 hrs at max power! (115Ah / 45 A )
Well, actually somewhat less considering the curve you mentioned, as Ah rating
is for 20A load.

But another issue for me is weight. What would be the weight of the
2 batteries you mentioned?
It is an inflatable boat (through it has wooden bottom-plate) so
I would not like to place anything about 50 lb into
it (I have also to carry the battery from car to boat every time).

Regards,
Evgenij

--

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*science&fiction*free programs*fine art*phylosophy:
http://sudy_zhenja.tripod.com
----------remove hate_spam to answer--------------

"Evgenij Barsukov" wrote in message
...
I am looking to buy a deep-cycle battery to run a 55 lb trolling
motor (45A max/12V) which will be used as the only motor for an
inflatable boat for fishing.

Any idea how long you would need to run the motor at full thrust?


I am converging so far on Optima D34/78 (gives you 120 min reserve
at 25A, so it should run motor for 1 hrs at highest power).

No, not likely.

Forget the "reserve" rating, it is meaningless for this discussion. What
you need is the amp-hour rating, which on this battery is 55 amp-hours.

Now, here is the rub: The amp-hour rating is specified at a low draw rate,
typically a 20 hour rate. Thus, this battery would be able to provide 2.75
amps for 20 hours. The available amp-hours drops dramatically as the
discharge rate goes up. I suspect that at a 45 amp rate you would probably
get around 1/2 of the 20 hour rate, or only 27.5 am-hours, which would
provide you with around 36 minutes of operation.

You may also find that as the battery voltage drops, the current the motor
draws will increase. This could seriously degrade your run time even
further.


It can be had for 144 $

Seems like a fair price.

- Can I get a better battery or similar one for
better price?

Define "better".

As another person said, the best price/performance will be obtained from a
pair of golf cart batteries, referred to as either T-105 or 2200. Here is
a link to Trojan: http://www.trojanbattery.com/GolfDC.asp?Product=51

I have bought a number of the 2200 series batteries that I use in a deep
cycle application. These things are rugged, you can expect 6 years or more
of life from them. I pay around $55 each for them.

You need two to get 12 volts, but you will have 220 amp-hours of battery
when you are done. Since your battery is so much larger, the 45 amp draw
will not represent nearly as large of a load percentage wise and the impact
on discharge rate won't be quite so bad. So, for less money ($110) you get
four times the battery capacity compared to the Optima.

The draw back is that these batteries weigh over 60 pounds apiece, so you
will be adding 120 pounds to your little boat. They also need to be kept
upright or they will spill. The spill factor is a major advantage of the
Optima battery.

- Is the battery sized properly for this motor/usage (its my first one,
so I dont know).

It all depends on how much run time you need/expect.

Rod

On Fri, 13 Feb 2004 10:08:29 +0000, Evgenij Barsukov wrote:

DSK wrote:

Evgenij Barsukov wrote:
I am looking to buy a deep-cycle battery to run a 55 lb trolling motor (45A
max/12V) which will be used as the only motor for an inflatable boat for
fishing.

By far the most bang for the buck is golf cart batteries. Looking at the cost
per 12V amp-hour, they are about 2/3 the cost of car batteries and 1/2 the
cost of marine batteries. Of course, they are 6V so you have the trouble of
wiring them in series, but that isn't difficult.

For our boat, I bought a pair of Exide Gr 31 dual purpose batteries from
Agri-Supply
http://www.agri-supply.com/catmain/1200005.htm I don't know what the reserve
rating is but their amp-hours are about 115 so one of those would certainly
drive your motor at full power for 1 hour, and the cost is about $65

Are you sure it is Ah and not reserve time? If it is really 115 Ah, it would run
my motor for 2 hrs at max power! (115Ah / 45 A ) Well, actually somewhat less
considering the curve you mentioned, as Ah rating is for 20A load.


Actually, if they're similar to the golf-cart batteries I have in Far Cove, the
Ah rating is closer to 230.

But another issue for me is weight. What would be the weight of the 2 batteries
you mentioned?

(picture me pointing at my nose) You got it! These batteries are EACH heavier
than a Group 27, and there's 2 of them. Over 120lb total. Not for carrying
around. I'd say get a good deep-cycle Group 27. Even THEY are pretty heavy - I
use a Group 24 in Near Cove, but that's just a 33-lb thrust motor (runs at
"cruise" all afternoon).

My notes say:
"Golf Cart": weight 120 lb (total), 225 Ah, $250 Cdn (total)
Group 27: weight 50 lb, 115 Ah, $120Cdn
Group 24: weight 39lb, 65 Ah, $80Cdn

(The Ah is the "20 Amp" rate - probably less at higher currents)

Lloyd Sumpter
"Near Cove" Walker Bay 8

On Fri, 13 Feb 2004 20:46:04 -0800, "Lloyd Sumpter"
wrote:
My notes say:
"Golf Cart": weight 120 lb (total), 225 Ah, $250 Cdn (total)
Group 27: weight 50 lb, 115 Ah, $120Cdn
Group 24: weight 39lb, 65 Ah, $80Cdn

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

Those numbers sound about right except for the high Canadian prices.
Golf cart batts are commonly available in the US for $60 to 70 USD.
To me the golf carts have several big advantages:

High amp-hours for the price;

Longevity - these batteries can really withstand repeated deep cycling
that kills ordinary batteries in no time at all;

Weight manageability - not light weight, but the fact that each
battery individually is only about 60 pounds and much easier to handle
than a single 120 pounder.

"Lloyd Sumpter" wrote in message
...
On Fri, 13 Feb 2004 10:08:29 +0000, Evgenij Barsukov wrote:

DSK wrote:

Evgenij Barsukov wrote:
I am looking to buy a deep-cycle battery to run a 55 lb trolling
motor (45A
max/12V) which will be used as the only motor for an inflatable boat
for
fishing.

By far the most bang for the buck is golf cart batteries. Looking at
the cost
per 12V amp-hour, they are about 2/3 the cost of car batteries and 1/2
the
cost of marine batteries. Of course, they are 6V so you have the
trouble of
wiring them in series, but that isn't difficult.

For our boat, I bought a pair of Exide Gr 31 dual purpose batteries
from
Agri-Supply
http://www.agri-supply.com/catmain/1200005.htm I don't know what the
reserve
rating is but their amp-hours are about 115 so one of those would
certainly
drive your motor at full power for 1 hour, and the cost is about $65

Are you sure it is Ah and not reserve time? If it is really 115 Ah, it
would run
my motor for 2 hrs at max power! (115Ah / 45 A ) Well, actually somewhat
less
considering the curve you mentioned, as Ah rating is for 20A load.


Actually, if they're similar to the golf-cart batteries I have in Far
Cove, the
Ah rating is closer to 230.

But another issue for me is weight. What would be the weight of the 2
batteries
you mentioned?

(picture me pointing at my nose) You got it! These batteries are EACH
heavier
than a Group 27, and there's 2 of them. Over 120lb total. Not for carrying
around. I'd say get a good deep-cycle Group 27. Even THEY are pretty
heavy - I
use a Group 24 in Near Cove, but that's just a 33-lb thrust motor (runs at
"cruise" all afternoon).

My notes say:
"Golf Cart": weight 120 lb (total), 225 Ah, $250 Cdn (total)
Group 27: weight 50 lb, 115 Ah, $120Cdn
Group 24: weight 39lb, 65 Ah, $80Cdn

(The Ah is the "20 Amp" rate - probably less at higher currents)

Lloyd Sumpter
"Near Cove" Walker Bay 8


Stopped at Wal-mart today to get a Rubbermaid plastic tub. Walked past the
battery display and they have a Group 29 Marine Maxx battery. About $64 and
3 year warrantee. You will not run your motor on high for a long time. I
have a 24V 65# Minn Kota on my 21' jetboat. I have run it intermittently
for 3 days and then had to come in the last 2 miles because of lack of
gasoline in the fuel tank. This with dual Group 27 batteries (from Costco).
If you are not trying to go 10 miles in your inflatable, most good deep
cycle batteries should suffice.