# How to best care for a deep cycle battery?



## Spawn Sack (Jul 8, 2013)

I recently bought an electric trolling motor and 12V deep cycle battery. I also bought a charger that has deep cycle as well as conventional mode. In addition it can charge on 2V, 12V, or battery start.

I want to care for the battery so it will last as long as possible. The guy at NAPA, where I bought the battery, said whenever possible to charge the battery the same way I drain it. In other words, use the 2V trickle charge.

I have found that after a day's fishing the battery is at about 50%. Overnight on the 2V charge almost always brings it back up to 100% and it's good for the next day's fishing.

I've heard that when not in use it's advisable to leave such a battery on the trickle charge. I suppouse this makes sense as if you decide to use the battery with minimal notice it will be fully charged and ready to go. Is there any other reason why you would want to leave a battery hooked up to a trickle charge when not in use? And yes mine does have an auto shutoff feature so it will not overcharge. It will kick back on once the charge starts to drop.

I've also heard thay it is wise to recharge your battery within 24 hours of using/discharging it. Is this true? If so can someone please explain to me why?


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## JMichael (Jul 8, 2013)

[url=https://www.tinboats.net/forum/viewtopic.php?p=321626#p321626 said:


> Spawn Sack » Today, 16:57[/url]"]I recently bought an electric trolling motor and 12V deep cycle battery. I also bought a charger that has deep cycle as well as conventional mode. In addition it can charge on 2*V*, 12*V*, or battery start.
> 
> I want to care for the battery so it will last as long as possible. The guy at NAPA, where I bought the battery, said whenever possible to charge the battery the same way I drain it. In other words, use the 2*V* trickle charge.
> 
> ...


I think you're getting V / volts confused for A / amps. But based on what I think I've learned over the years about batteries, yes, it is better for the battery to charge them at a lower rate like 2amps if using a 2amp rate will get it charged in time for your next use. And yes, it is good to keep a float charger or maintainer type charger connected to a battery when it's not in use. Especially over the winter months if the battery is not stored in a heated area. You would not want to leave any sort of charger connected to a battery for prolonged periods if it didn't have an auto shutoff or float/maintainer circuit that it switches to once the battery reaches full charge.


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## sawmill (Jul 8, 2013)

If you leave a regular charger hooked up for an extended period of time your battery may go boom. I had one that was completely dead and was slowly bring a charge to it and after a couple of days in the middle night I was woke up by a big boom. Next morning I went out and had parts of the battery all over my pole barn and acid all over my tractors and new lawn mower. Now the battery goes outside when charging


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## Quackrstackr (Jul 8, 2013)

Yes, you want a battery minder... not left on trickle charge. That will boil your battery.

A battery minder only gives it a slow charge whenever the voltage drops below a certain setting, then shuts itself back off and goes into monitor mode again.


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## Spawn Sack (Jul 9, 2013)

Thanks for the tips guys! JMichael, yes I means amps, not volts, opps! :roll: So yes the charger can be set to 2A, 12A, and 75A to jump-start a dead battery. I double checked the manual and yes it does say that once the battery reaches full charge it will stop charging and switch to "maintainance mode." Once the charge falls a bit it will kick on/off to keep it fully charged.

Alright so I will leave it hooked up to the charger on the 2A charge when not in use.

A few other random thoughts:

1- Has anyone heard of this "make sure you recharge it within 12-24 hours after using" business? In other words, after you come basck from fishing charge it up ASAP rather that leaving it partially or fully discharged for several days or weeks. If this is true I'm curious why(?)

2- My battery is the servicable type that needs to be topped up with distilled water. Any idea how often one needs to check the water level? Any good rules of thumb. I've heard just top it up to the top of the bars, no higher


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## JMichael (Jul 9, 2013)

[url=https://www.tinboats.net/forum/viewtopic.php?p=321670#p321670 said:


> Spawn Sack » Yesterday, 22:34[/url]"]
> 1- Has anyone heard of this "make sure you recharge it within 12-24 hours after using" business? In other words, after you come basck from fishing charge it up ASAP rather that leaving it partially or fully discharged for several days or weeks. If this is true I'm curious why(?)


True. You don't want to leave a battery sitting or stored in a discharged state as it sometimes causes them not to accept a full charge the next time you try to charge them. I don't know the science behind it but I have seen words to this effect made by more than one manufacturer. 



[url=https://www.tinboats.net/forum/viewtopic.php?p=321670#p321670 said:


> Spawn Sack » Yesterday, 22:34[/url]"]
> 2- My battery is the serviceable type that needs to be topped up with distilled water. Any idea how often one needs to check the water level? Any good rules of thumb. I've heard just top it up to the top of the bars, no higher


I try to check mine 2 or more times through the season and always in the spring before I take it out the first time. This applies to all my batteries on my boat/motorcycle/mower/etc. I know most will say get an AGM battery and you won't have to worry about it. I've paid the extra $ for an AGM battery twice, and both died in less than 2 years. The one on my ATV died before 1 year so I'm done with AGM. Besides, it's no big deal to add a little distilled water to a battery from time to time. I keep a big 2 oz. syringe with a 12" piece of small fuel line attached to the end just for the purpose of adding water to batteries. And as you stated, add *distilled water only* as batteries don't like the minerals in tap or bottled drinking water.

As for how high to fill them, most batteries have a tube with a slot cut down the side of it that extends downward about an inch from the cap/plug. Fill each cell until it touches the lower portion of that tube.


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## chevyrulz (Jul 9, 2013)

QuackerStacker makes a great point, i love my Battery Tender brand trickle charger. it was about $75 for the built in style marine one on amazon, but there's cheaper & more expensive versions available. it's a charger and a "maintainer" in that it charges fast, but then it senses when the battery needs to be charged & tops it off with just enough charge, so it turns itself on & off & regulates the charge to maximize your battery life. so unlike other chargers, a maintainer can be left hooked up to the battery all the time. On my old ski boat, i had it installed in the engine compartment, and connected to the battery with ring connectors, and hooked to a regular 110v outlet on the boat, so when the boat was parked, i just plugged it into the wall with an extension cord. this makes the battery last pretty much forever. i kept it when i sold that boat, & now i just hook it to batteries using alligator clips

ideally, a battery needs to stay full, not be over charged or left undercharged. the problem is sometimes referred to as "battery memory", in that the battery can be discharged for long enough time, that it reduces the capacity of the battery, so if you leave your battery @ 50% charge long enough, then when it's fully charged, it's only @ 50% of it's original capacity. 


this is the battery tender i have:







https://www.amazon.com/Battery-Tender-022-0157-1-Waterproof-Charger/dp/B002DU3S9A/ref=sr_1_22?ie=UTF8&qid=1373394024&sr=8-22&keywords=battery+tender


but this one costs 1/2 as much & does the same thing:





https://www.amazon.com/Battery-Tender-800-Waterproof-Charger/dp/B000CITKCE/ref=sr_1_1?ie=UTF8&qid=1373394195&sr=8-1&keywords=battery+tender+marine


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## DanMC (Jul 9, 2013)

I have a few chargers around the house from the digital type to the old school type like the Battery Tender and the one that I'm most happy with is the Battery Tender !....the more specialized chargers if there is a power bump they (chargers) get confused....don't know or remember their setting.I use an Optima Blue Top AGM and it stays on trickle charger 7 months (Canadian winter!) without any issues.It does know when the battery is charged and just maintains it !,my .02$


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## JMichael (Jul 9, 2013)

[url=https://www.tinboats.net/forum/viewtopic.php?p=321743#p321743 said:


> chevyrulz » Today, 12:23[/url]"]
> 
> this is the battery tender i have:
> 
> ...



You may want to rethink that statement about 1/2 the cost and does the same thing. Lets say you have a 100ah battery and you discharge it 50% during a days fishing. If my calculations are right, your charger with a max output of 5 amp will recharge that battery in 10-12 hours depending on efficiency loss. The 800 Automatic has a max output of 800 milliamps and to recharge that same battery in the same condition would take it around 72 hours. Don't get me wrong, I like Battery Tender, and own 3 Battery Tender Jr models for my ATV, motorcycle, and lawnmower. But for recharging a battery that gets heavy use like a trolling motor battery, you might want to get one that has the ability to charge at 5-10 amps in case you come in at dark and want to be back on the water first thing the next morning. Of course if you only go fishing once a week then you might consider something smaller.


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## Zum (Jul 9, 2013)

I charge my battery at 12 amp,only time I put it on the 2amp trickle charge is if I havn't used it in awhile(winter).
Like you I asked questions and read stuff on the web.
I remember one article saying you should get the battery charged up as soon as possible but don't go over 10-15% of the amp hours of your battery.
All I can say is I have good results doing it this way...batteries always have lasted atleast 4+ years.
Never have to add water,figure if you start doing that the battery is on it's way out.


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## TNtroller (Jul 9, 2013)

My boat (Tracker PT 175) has a 2 bank charger and I use it when I return from the water to charge the batteries back up quickly, then I hook up a "Battery Minder" maintanence type charger that also "desulfates" the batteries as well. I had a HD motorcycle with a weak battery and hooked one of these Battery Minders up to it over the winter as a test to see if it would "re-vive" the weak battery and the next spring the battery started the bike up w/o issues. I continued to use it on the bike during the week when I was not able to ride, and never had a problem with the bike not starting. 

The cranking battery in my boat was made May 2006, and spins my 60 2 smoke fine, and runs all of my electronics while trolling, a HDS 8 w/ SS, and a color gps/2d HB on the bow for 4-6 hrs or more, and will start my 60 with ease. I use a Battery Minder on the TM battery as well during the week, and I troll for 4-6 hrs/trip using a MK Terrova 55 with IP. The TM battery is 2 yrs old, and is usually only 25% discharged when I get home, maybe 50% discharged if windy or I have to troll faster than 1.3 mph to suit the fish. Both batteries are from wally world. If I get 3 or 4 yrs from a TM battery I've gotten my $$ worth out it imo. Maintanence is the key to keeping a battery for a long time.


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## chevyrulz (Jul 10, 2013)

[url=https://www.tinboats.net/forum/viewtopic.php?p=321774#p321774 said:


> JMichael » Yesterday, 18:30[/url]"]
> 
> You may want to rethink that statement about 1/2 the cost and does the same thing. Lets say you have a 100ah battery and you discharge it 50% during a days fishing. If my calculations are right, your charger with a max output of 5 amp will recharge that battery in 10-12 hours depending on efficiency loss. The 800 Automatic has a max output of 800 milliamps and to recharge that same battery in the same condition would take it around 72 hours. Don't get me wrong, I like Battery Tender, and own 3 Battery Tender Jr models for my ATV, motorcycle, and lawnmower. But for recharging a battery that gets heavy use like a trolling motor battery, you might want to get one that has the ability to charge at 5-10 amps in case you come in at dark and want to be back on the water first thing the next morning. Of course if you only go fishing once a week then you might consider something smaller.


what you're saying is correct, but for the OP, he already has a quick charger if he needs to be out on the water in a hurry, so I was merely referring to the "maintainer" features of the 2 different battery tenders being identical, so he may as well go w/ the cheaper one


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## Spawn Sack (Jul 20, 2013)

Thanks for all the tips guys! What's I've learned is...

1- Charge your battery up ASAP after a days fishing. Best to use a trickle charge (2A on my charger) and charge a deep cycle battery the same way you discharge it. Low and slow!

2- When not in use leave it on the charger on 2A. Make sure your charger kicks on/off once the battery is charged.

3- Keep the water level topped up with distilled water.

That's all I can think of.

One other thing. I bought a 2.4A solar trickle charger that I plan to use occasionally on the boat if I think there is a risk I might run the battery too low. I don't see why I can't have the electric motor hooked up to the wing-nut terminals powering the motor, and *at the same time* have the solar charger hooked up to the other terminals (the ones the clamps connect to) charging the battery at the same time it is being discharged.

Is there any reason why I couldn't charge and discharge at the same time???


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## drum (Jul 22, 2013)

I have a motorcycle agm battery as a backup, it says 1 amp for 10 hours charge. 
I charge mine at 2 amps for 5 hours or less if I don't use it.
my main battery is a stowaway 1000 ca/ 800 cca, and I charge at 10 amps to maintain for 1 hour a day.
and this may not be the pefered way but it works for me, I check the cells add distilled water when needed.
I do feal me battery to make shure it is not hot.


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## bcbouy (Jul 22, 2013)

i have 2 deep cycles wired in parallell.i run them down between 60 and 80 percent and i charge them on 40 amps all the time.were talking at least 2 times a week between april and october. sometimes as much as 4 times a week.they're 6 years old now.on a side note,i just replaced my battery in my f 150. its the original mastercraft.its at least 10 years old.it still works but it wont charge all the way and was really working my alternator so out it went.i'm going to run it thru a maintenance cycle on my smart charger and see what happens.


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## chevyrulz (Jul 23, 2013)

[url=https://www.tinboats.net/forum/viewtopic.php?p=323044#p323044 said:


> Spawn Sack » 20 Jul 2013, 12:07[/url]"]
> 
> One other thing. I bought a 2.4A solar trickle charger that I plan to use occasionally on the boat if I think there is a risk I might run the battery too low. I don't see why I can't have the electric motor hooked up to the wing-nut terminals powering the motor, and *at the same time* have the solar charger hooked up to the other terminals (the ones the clamps connect to) charging the battery at the same time it is being discharged.
> 
> Is there any reason why I couldn't charge and discharge at the same time???


nope, that's fine. you'll wanna be sure your power wires are fused to prevent damage to the electric motor or to the solar charger


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