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>Boat-Trolling Motor< Battery Re-Charge: How long??


kyle johnson's Avatar
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05-01-13, 03:51 PM   #1  
>Boat-Trolling Motor< Battery Re-Charge: How long??

I've got the battery on slow charge for 4 hrs....so for. How long do I "slow charge the battery for the trolling motor???
How long do I slow charge the regular motor that starts the boat??
I've got the charger on 2 amp/ 12 volt....is that correct?
How long??

 
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chandler's Avatar
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05-01-13, 03:56 PM   #2  
Are the batteries deep cycle batteries? The two amp charge may take a day or so. Why not use the standard charging rate for a lesser period of time. A quality charger will tell you when the charge is complete. A cheap one is a crap shoot.

 
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05-01-13, 06:56 PM   #3  
I think they are deep cycle.
The two amp slow charge will give it a better longer charge.
I could put it on a quicker charge....6 amp.

 
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05-02-13, 03:21 AM   #4  
You're in Alabama and are wasting time with a slow charge while there are fish in Lake Eufala calling your name I think a quicker charge would get you going, and a trickle during the week when the fish are asleep is a good thing. This is all in jest, you know, but it takes a while for a trickle charge to fully get the job done.

 
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05-02-13, 06:02 AM   #5  
The charging rate and how long to charge depends on the size of the battery and how discharged it is. It's sorta like asking how much gas to put into the tank when you don't know how full it is.

Is your charger an older model with a needle gauge on the front or a more modern digital, self regulating type where you select the type of battery? Modern chargers are quite good and are safer to leave connected to a battery for longer periods while older chargers you do need to worry more about the charging rate and time.

If you've got a decent sized deep cycle you should be able to use a rate higher than 2 amps but 2 amps is nice and easy on the battery and will help it last a long time. What was the charging rate when you started charging and at the end of 4 hours? If it was still taking more than a trickle after 4 hours it probably needs more charging. Also, if your battery is a wet cell make sure you check the levels in every cell especially if you forget and leave it hooked up to a dumb charger for a day or two.

 
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05-02-13, 08:18 AM   #6  
Yes ... my charger is an older model with a needle gauge on the front

 
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05-02-13, 12:08 PM   #7  
I think they are deep cycle.
"Thinking" doesn't cut it, you need to KNOW if they are starting and ignition service (common automobile battery), Marine (hybrid starting and ignition vs. deep cycle) or true deep cycle as they all have different charging and discharging characteristics.

The two amp slow charge will give it a better longer charge.
I have no idea where you came up with this little tidbit of misinformation but it is patently wrong. The rate of charge is dependent upon two major factors, the capacity of the battery and the percentage of charge left in the battery. Speaking VERY generally the rate of charge in amperes should be approximately one third of the total ampere-hour capacity of the battery. This is tempered by whether or not a constant voltage source is used for the charging or if a "tapering voltage/rate" source is used. The battery should be charged until the cells are freely gassing and then the rate lowered about 20% or just below the gassing point for another hour or so for final charging. These are generic instructions and should be modified in light of any additional or contrary instructions from the battery manufacturer.

 
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05-02-13, 12:34 PM   #8  
Hey Furd... You seem like you are a smart aleck.....No... I know you are a smart ass... I don't think!!

 
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05-02-13, 12:46 PM   #9  
Actually Kyle...Furd gave you very good advice based on his knowledge and experience. Slower charges are not always better. Just like the old saying "more is not always better", less is not always better either.

His comments may not be to your liking...but I'll bet money they are accurate.

Advice is worth what you pay for it.......and the rudeness of your reply was not necessary.


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05-02-13, 02:32 PM   #10  
If dealing with someone that mentioned a 2 amp current and asked about slow charging and has not given specifics about the battery (size or temperature) I'm going to advise the safer approach. 2 amp charge rate is better for the life of the battery because it's extremely difficult to harm a battery of any size with a 2 am current even if it's being charged in the sun in Alabama and you happen to forget it and don't turn off the charger till the following day. Yes, it could take a long time at 2 amps but it's not going to overheat the battery or boil it like a 1/3 rate.

The wording about a 1/3 the battery's amp capacity charge rate should be changed from "should be" to "maximum rate" and most of what I've read calls for a more conservative 25% maximum rate. I prefer a maximum charge rate of about 10% the battery's 20 hour amperage capacity. If I'm in a hurry 10% of it's 10 hour amperage capacity but you get more gassing requiring closer monitoring of the levels in the cells and battery temperature.

 
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05-10-13, 02:19 PM   #11  
Correct me if I am wrong.......

The amount of time a battery needs to be re-charged, generically speaking, is based upon it's amp hour rating. Example: a battery with a 640 amp hour rate charged at a rate of 2 amps (per hour) will take 320 hours to fully re charge. Less time if battery is less then fully discharged.

Amp hour charging rate (2) divided into the batteries amp (640) hour rate. Equals 320 hours. Battery may not even fully re-charge at a rate of 2 amps!...

Best to use full charge rate until battery is fully re-charged and then switch to 2 amps to maintain a full charge, if the charger has this option manually or automatically. Manual mode requires you to know rate of discharge battery is at before re-charging. An automatic charger will automatically go to 2 or less amps to maintain the full charge.

Very likely the trolling motor battery is a deep cycle battery. If it is not, it should be since it's not likely being charged during usage. Additionally, most boat batteries are also deep cycle types. If not, they should be too. Personally never seen a non deep cycle battery used in a boat unless owner did their own battery replacement without knowing why deep cycles are used.

Why boats use deep cycle batteries? Most have optional accessories that use power while boat engine may not be running! Optional accessories may be AM-FM radio, CD music players, stereos, VHS radios, bait tank pumps, lights, etc.

My Two Cents....


 
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05-11-13, 06:06 AM   #12  
My boat has two 720AH deep cycle marine/RV batteries and one standard starting battery. The 720s are used for house power when the boat is not connected to shore power. They are charged from the port engine (when running) and a charger (shore power).

The charger is capable of delivering 30 amps to each of the three batteries. My guesstimate is that the refrigerator, stereo, and intermittent use of lights & other 12-volt electrical devices will draw about 30 amps. It therefore takes roughly the same amount of time to recharge as it does to use them without the engine running. It's more complicated than that, though, because the port engine is dedicated to charging those batteries when it is running. After the batteries are fully charged the charger's meter slows to less than an amp to trickle-charge them.

The starboard engine is dedicated to the starting battery but can be switched to the port as a booster. The starting battery is never used for house duties. (Using as a deep cycle will severely reduce its use life.)

I never run the batteries down all the way. It isn't good for them to drain below 10.5 to 11 volts. When the volt meter shows them getting close I run the engine to quick charge them. The alternators are 140-amp on each engine.

 
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05-11-13, 08:10 AM   #13  


Hi: Rick

Your boat is a house boat. Type unknown. usually fresh water lake variety. As such, not very likely anchored far off shore (deep sea) with engine(s) not running for days at a time. Therefore, dual deep cycle batteries while house boat is in use for day trips (engine not running) is correct set up.

Reason why the deep cycle batteries are mostly recharged more fully while at dock or in a port. Mostly meaning priority recharging is directed to the non deep cycle engine starting and running battery. Once that battery is fully recharged the remaining charging from the alternators is directed to the deep cycle batteries. A complex system granted but it works well when it is working as designed and intended.

One standard non deep cycle for engine starting and running is all that is required for the intended and usual usage of a house boat. That battery is isolated from the deep cycles so it will not be drained of power to restart propulsion engines. Recharged only during engine running times just like a land based motor vehicle.

Some smaller boats have a manual switch to direct charging. Multiple positioning switch. ALL, One or two etc. Larger boats have an automatic sensing and switching component that handles all recharging... No owner/user input required.

In regards to member Kyle's question, a house boat is not likely in question. Not the type one would usually use on a lake with a trolling motor for fresh water fishing but can be used for such. Just not a very common set up. More likely to be a day use fresh water lake fishing boat.

Care to clarify any of the above Kyle? Use the reply button to due so. Thanks.


 
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