No charging system on boat

smcg71

Cadet
Joined
Nov 7, 2002
Messages
20
Hi all, I have a fishing boat and I would like to put an electric trolling motor on it. The problem is my 40HP Merc Sea Pro doesn't have any type of internal magneto/alternator for charging the battery. From what I've read in previous posts, an electric motor will drain my battery in no time. What are my options? I've read about charging systems you can add but I think they need to be plugged in to 110V when you get home which doesn't do me any good when I'm on the water. Also, I know it depends on size of motor and battery but roughly how long does it take a 36lb. electric motor to drain a battery? Thanks in advance
 

cuzner

Senior Chief Petty Officer
Joined
Feb 14, 2004
Messages
771
Re: No charging system on boat

Hey sheephead, I'm not to farmiliar with them, but every bass boat I've been does not have the trolling motor batteries hooked up to the boats electrical system. I was in a bass tournoment on lake st claire Sat. we used the trolling motor for about 4 hours in high winds and waves,and had plenty of juice left. Just make sure you buy a good charger and you should be o.k.,I would suggest you use a seperate battery also.<br /><br /><br /> Jim
 

dakotashooter2

Petty Officer 2nd Class
Joined
Jun 10, 2003
Messages
125
Re: No charging system on boat

Somebody else will hopefully give you a more complete answer but marine cranking batteries and deep cycle batteries are different beasts. While some are advertized as both as a general rule you want a deep cycle for running your troller. A starting battery will not give you the extended power as you suspect. There is also some debate as to which is better way to charge a deep cycle a slow low amp charge or fast high amp.
 

TELMANMN

Chief Petty Officer
Joined
Jun 9, 2003
Messages
465
Re: No charging system on boat

Even though my motor does have an alternator I keep my deep cycle seperate from the starting battery. <br /> A friend just purchased a new combination battery(minkota mk-31 deep cycle/starting battery) From the stats it states 14 to 25 hours of charge for typical fishing conditions.<br /> Batteries list amp hours for capacity. So if your battery is listed as 100 amp hours with a 1 amp draw it would last 100 hrs.(perfect world) So if you know what the amp draw is for diferent speeds of your trolling motor you could figure out how long you could fish.<br /> I would get the best deep cycle you can afford, a good charger and a battery maintainer to put on at home when not in use. This should get you 3 to 5 years of use(if using battery maintainer probobly more)
 

jtexas

Fleet Admiral
Joined
Oct 13, 2003
Messages
8,646
Re: No charging system on boat

Sheephead, my outboard charges the cranking battery, but not the trolling motor battery. I can use it pretty much all day. If it's particularly windy it might start getting weak in the afternoon. Just make sure you charge it up after every use, and every 2-3 weeks when you're not using it.
 

rpddoc

Cadet
Joined
Jun 20, 2004
Messages
27
Re: No charging system on boat

Plenty of bass boats and bay boats over here in southeast Texas. Most of them have one or two deep cycle batteries to run nothing but the trolling motor. I have one cranking battery (also runs the bilge pump), one deep cycle trolling battery and one deep cycle battery that runs the nav lights, depth finder, aerator, spot light (duck hunting season) and acts as a back up battery for the trolling motor. My cranking battery is a group 24 dual purpose battery. My deep cycles are group 27. My engine charges only the cranking battery. However, I always put a portable charger on all my batteries upon returning home from the lake and the night before fishing or hunting. For the money and weekend angler, Vector (can be purchased at Wal Mart) makes some decent chargers. Good luck and happy fishing.<br /><br />TakeEm
 

DeFeet63

Cadet
Joined
Jun 28, 2004
Messages
21
Re: No charging system on boat

This is what I understand...the Optima deep cycle for your trolling motor. Keep it separate from your cranking system. Deep cycle batteries are made to be taken down below 10volts. Normal batteries would not recover many times if taken down that low. Optima recommend an 8-amp charger for recharging the battery. Go to http://www.optimabatteries.com/ <br /><br /> My outboard has a STATOR that generates AC from the motor and then it sends back to the battery through the rectifier as DC...7 amp output back to the battery. Good luck
 

duck-n-pond

Petty Officer 2nd Class
Joined
May 27, 2003
Messages
124
Re: No charging system on boat

You can check with your dealer and you may be lucky enough to find a coil set that has the charging coils, and add a battery isolator such as in a RV if you are headstrong in doing so and got the $$$$$. But it may not be a good way to charge deep cycle batteries as stated above. If you are so concerned about how long the charge lasts use the KISS method; it seems to me the simplest/cheapest solution is to have 2 deep cycles for your electric. Will cost bucks to build a good charging system, and you may still be dismayed with results.
 

kd6nem

Chief Petty Officer
Joined
Jul 25, 2003
Messages
576
Re: No charging system on boat

I don't think any type of deep cycle will last as long if it is discharged much beyond half its amp/hour capacity. You can do it, but the more it is done the sooner you'll need a new one. Keep it stored all charged up and it will be a happy battery. When the voltage is dropping off much it may be a bit too long for maximum life, since the voltage drop off tends to happen pretty far into the depletion process- batteries try to maintain their voltage until the bitter end. Generally a fully charged 12 v battery should read about 12.7 volts. When it hits only 12.0 volts (no load) it ought to be about 50% used up, and ready to head home for a recharge. Most manufacturers should have some good technical details online about the specifics for their products. Consult that before routinely running down to 8 volts. It might be cheaper to pay the extra for two batteries or one higher capacity battery so you don't have to drain it quite that much.<br /><br />Optima is indeed a great way to go if you have the extra bucks. By the way. Optima batteries have very little self discharge- they maintain their charge while being stored much better than most batteries. Many other advantages like spill proof and enhanced safety, too.<br /> Deep cycle FAQ
 
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