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Gavin17

Batteries

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Gavin17

I'm getting some new batteries but can't decide what to do.  My stereo has a jl 250w amp on the sub, jl 300w amp on the boat speakers and a syn4 on the rev 10 tower speakers. 

 

Currently I have two group 24 batteries, one is a cranking and one is deep cycle.  After I installed a stereo we started leaving the switch on both to have one big battery. I was going to get a pair of dual purpose batteries and leave the switch on both.  I'm also going to install an on board battery charger to charge the boat each night.  

Originally I was going to install a relay to isolate one battery when not running but because of what the stereo can draw I decided against that.  I have a jump box on board just in case but have never had to use it.  If we're stopped and swimming I only use the tower speakers at a lower volume. 

Should I just get two more group 24 batteries and call it a day?

Should I replace the battery boxes with larger ones and try to fit some group 29 or 31 batteries in there?  I can't decided if this is worth the time/ money/ effort.  Plus I'll give up some storage. 

Are the Agm batteries worth it?  In the past I've just used regular lead acid batteries and keep them fresh. 

 

If I'm keeping the batteries in parallel and the switch on both should I get a one bank battery charger or two?

 

 

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Gavin17

I'm still brainstorming.  It looks like with 3 amplifiers at 100% my stereo could pull about 115 amps.   But I never do that. 

For wakeboarding we do tower speakers 100%

Swimming: tower speakers at 40% or lower

cruising: boat speakers 40%, sub 40% tower speakers 30%

The percentages are just estimates but I was curious how much power I was drawing and thought it would help pick the best batteries.  

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minnmarker
12 minutes ago, Gavin17 said:

Swimming: tower speakers at 40% or lower

Since your engine-off drain will not be so much I would recommend keeping one of your 24s for starting and get a Group 29 Deep Cycle at Walmart for $99 to power your stereo.  Put an ACR between them and a single bank charger on the stereo battery.  Some will say get a dual bank charger, but your starter battery will never need charging since it's not being drained when the engine is off...  Loose the switch IMHO.  It's just one more thing to forget to manage with all the other stuff you do as Captain.  This way you will never get stranded.  AGM not worth the $$ unless you want to mount them on their side.

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Lees23

I had the dealer install 2 group 31 AGM's and a 20amp, dual bank charger at delivery.

I shouldn't have any starting issues.

Edited by Lees23

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Steve B.

I used to change the switch as we lounged. Then about 2 years ago I started just leaving it on both. No issue. My amp draw is probably similar, and we hang for sometimes 2 hours or so with the party going. If I was rich and famous I'd get one of those auto switching dual bank charging units.

Steve B.

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formulaben
5 hours ago, Gavin17 said:

I'm getting some new batteries but can't decide what to do.  My stereo has a jl 250w amp on the sub, jl 300w amp on the boat speakers and a syn4 on the rev 10 tower speakers. 

 

Currently I have two group 24 batteries, one is a cranking and one is deep cycle.  After I installed a stereo we started leaving the switch on both to have one big battery. I was going to get a pair of dual purpose batteries and leave the switch on both.  I'm also going to install an on board battery charger to charge the boat each night.  

Originally I was going to install a relay to isolate one battery when not running but because of what the stereo can draw I decided against that.  I have a jump box on board just in case but have never had to use it.  If we're stopped and swimming I only use the tower speakers at a lower volume. 

Should I just get two more group 24 batteries and call it a day?

Should I replace the battery boxes with larger ones and try to fit some group 29 or 31 batteries in there?  I can't decided if this is worth the time/ money/ effort.  Plus I'll give up some storage. 

Are the Agm batteries worth it?  In the past I've just used regular lead acid batteries and keep them fresh.

Yes. Get a Blue Seas ACR, 2 Group 29 batteries and you'll be fine if you're using it as above. Don't waste your time or money on AGM batteries.

https://www.walmart.com/ip/EverStart-Maxx-Group-Size-29-Marine-Battery/20531539

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The Hulk

Spend some jack and get some LiFePo4 batteries.. pure awesomeness.. and expensive but nothing compares.. bad for ballast weight though due to being so light ha. Or just get one for stereo it will handle your power/amps fine and u can leave one for starting.. 

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The Hulk

FYI when the low battery alarm sounds it's kind of like the boat is rubbing it in..u are being warned that you can NO Longer start your boat! Well when you level it on 1+2 at least.. 

 

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semi

Using a deep cycle battery to start your boat is probably not that great of an idea. It will start the boat, but it doesn't do that kind of battery any favors. Deep cycles are not good for short power bursts, they are for long drawn out draw. So if you have two different batteries and your starting with both, you are shortening the life of the deep cycle. 

If it were me, i would get 2 group 27's or 31's, and make them either starting, or preferrably multi purpose. Install a 2 bank 10amp per bank onboard charger. 

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MLA
21 hours ago, Gavin17 said:

Originally I was going to install a relay to isolate one battery when not running but because of what the stereo can draw I decided against that.

You already have a means to isolate, its your manual battery switch. Simple and effective. 

 

21 hours ago, Gavin17 said:

After I installed a stereo we started leaving the switch on both to have one big battery

This is ok when engine running, but I dont suggest it of you drop anchor. You run the risk of running your cranking battery down.

21 hours ago, Gavin17 said:

It looks like with 3 amplifiers at 100% my stereo could pull about 115 amps.

Likely half, in reality, but a good number to use for calculating the needed Ah for a house bank at anchor. 

 

21 hours ago, Gavin17 said:

I can't decided if this is worth the time/ money/ effort.  

It is if you are seeking more play time at anchor. Only way to get that is more Ah. This is goin gto be either through larger or more batteries. 

 

21 hours ago, Gavin17 said:

I'm still brainstorming.  It looks like with 3 amplifiers at 100% my stereo could pull about 115 amps.   But I never do that. 

For wakeboarding we do tower speakers 100%

Swimming: tower speakers at 40% or lower

cruising: boat speakers 40%, sub 40% tower speakers 30%

The percentages are just estimates but I was curious how much power I was drawing and thought it would help pick the best batteries.  

All of this indicates you are just looking for whats needed for cruising. Thats simple, one group-29 or similar cranking will get it down. In reality, dont even need a 2nd battery bank, if you dont play on the hook. 

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formulaben
3 hours ago, semi said:

Using a deep cycle battery to start your boat is probably not that great of an idea. It will start the boat, but it doesn't do that kind of battery any favors. Deep cycles are not good for short power bursts, they are for long drawn out draw. So if you have two different batteries and your starting with both, you are shortening the life of the deep cycle. 

If it were me, i would get 2 group 27's or 31's, and make them either starting, or preferrably multi purpose. Install a 2 bank 10amp per bank onboard charger. 

It is my understanding that a deep cycle battery may be used for starting, but a standard starting battery may NOT be used for deep cycles...I see no harm in using a deep cycle (and higher capacity) battery as a starting battery.

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Gavin17
Just now, formulaben said:

It is my understanding that a deep cycle battery may be used for starting, but a standard starting battery may NOT be used for deep cycles...I see no harm in using a deep cycle (and higher capacity) battery as a starting battery.

I've always been told not to do this. But I'm not sure why.  Does anyone know?

 

Currently I'm leaning toward 2 dual purpose batteries now and then if I don't have enough ah for our use then I'd add a third starting battery and a relay.  Lots of good idea's and info here, thanks.  A starting battery and a big deep cycle house battery would work fine too but I'd have to buy and switch the battery boxes.  I need to take some measurements and see what I can fit.  

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semi
24 minutes ago, formulaben said:

It is my understanding that a deep cycle battery may be used for starting, but a standard starting battery may NOT be used for deep cycles...I see no harm in using a deep cycle (and higher capacity) battery as a starting battery.

incorrect. Let me explain. Deep cycles are made with larger plates. They are meant for continual use not high freq bursts. It can be done, but it contributes to the battery going bad much faster. They are not starting batteries. Its why they are made different. You would never see anyone put a deep cycle in their car or truck. They are aren't designed for that type of use. They are designed to last longer under continuous current. 

Starting batteries are meant for higher bursts or cranking amps.. Thats why they are rated that way. CCA/MCA. You don't see that rating on deep cycle for a reason. A starting battery can be used for continuous current like a radio with little harm to the battery it just drains faster and needs to be recharged more often. I would go with 2 starting batteries and one deep cycle for the radio. Or a mix of deep and starting with the switch on deep when running the radio and switch to the starting battery when starting. 

Edited by semi

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formulaben
Gavin17

I guess I'm going to re-wire everything.  I pulled the batteries tonight to test them and take measurements for the new ones.  

Currently the amps are bypassing my perko switch so I want to fix that.  The amps are wired directly to the battery and one isn't even fused.  

Shouldn't every positive cable go to the common terminal on the perko switch? Then I'd  wire the positive sides of the batteries to the switch.  I think I'll used a fused distribution block for all the amp wires. 

What should I do with the grounds?  Should they go to the batteries individually like they are now or should I use a distribution block for all the grounds too?

 

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MLA
Just now, Gavin17 said:

Shouldn't every positive cable go to the common terminal on the perko switch?

I agree

Just now, Gavin17 said:

What should I do with the grounds?  Should they go to the batteries individually like they are now or should I use a distribution block for all the grounds too?

A trunk line reduces the overall number of terminals stacked on a battery post.

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TallRedRider

To really confuse the discussion, I believe that if you are going to be having the batteries connected with either a perko switch or charging at the same time with a combiner, you should have 2 of the same type of batteries.    As FormulaBen pointed out, using a deep cycle for a starting application will work fine, but don't use a starting battery in a deep cycle application.  I only read the link to the Trojan battery site, but they confirmed it is OK to use deep cycle for starting.  

I would get 2 deep cycles so that you do not have 2 batteries connected together with varying rates of charge and discharge and different resting voltages, that leads to premature death of one of them.  

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Gavin17

I was going to use 2 similar deep cycle batterys and wire everything thru the perko switch.  But I just talked to a mechanic friend at the Nautique dealership and he says not to wire the amps thru the perko switch because it will introduce noise to the system.  He said to instead leave the amps going directly to the battery which is how most new stock systems are and make sure that the head unit power goes thru the perko switch so nothing can be turned on if this switch is off.  My headunit currently has power that bypasses the switch so If I turn my switch off I can play the stereo normally.  This is bad. 

I  also want to make sure the bilge pump bypasses the perko switch.  It may be like this already but I haven't tested.  

Since he recommended me not fully wire everything thru the perko switch now I'm leaning toward an ACR to separate my starting battery. 

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MLA
20 minutes ago, Gavin17 said:

not to wire the amps thru the perko switch because it will introduce noise to the system.

Could not disagree more

21 minutes ago, Gavin17 said:

He said to instead leave the amps going directly to the battery which is how most new stock systems are

Not in my world, and i get the opportunity to see boats of all ages and brands. One tow boat that goes by two letters, does it this way, and is prone to noise and other audio issues 

21 minutes ago, Gavin17 said:

and make sure that the head unit power goes thru the perko switch

Basically, this and the first quoted statement are the prime ingredients for noise, not the prevention. 

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semi

I worked in the battery industry for a few years. Trust me when i say you shouldn't use deep cycles as a starting battery. Also, Tallredrider is correct that both batteries should be the same. Again, you can start with a deep cycle battery, it will work, but it will degrade the life of a deep cycle battery. A good deep cycle that is maintained and charged after use should last for 5-6 years or more. Once you introduce starting into the mix, it will cut its life. They are not meant to start engines. That's why there are different kinds of batteries. Thats why there are starting (cranking) batteries with specific CCA/MCA ratings. Deep cycles don't usually have those ratings. Get multipurpose at least. 

 

if you look at the interstate link above it specifically states MULTI purpose battery, and NOT deep cycle or Starting battery. this is right from the trojan site posted above. So NO, it is not okay to use a deep cycle battery for starting. 

 

What is the difference between a deep cycle battery, a starting battery, and a dual-purpose battery? 
A deep-cycle battery has the ability to be deeply discharged and charged many times during its service life. It is designed specifically for powering electrical equipment for long periods of time. An automotive or starting battery is designed for brief bursts of high current and cannot withstand more than a few deep discharges before failure. This is why it is unable to start your car if you accidentally leave the lights on more than a couple of times. For applications where both engine starting and light deep cycling are required, a dual-purpose battery is often used. This type of battery is neither a starting nor a deep-cycle battery but rather a compromise between the two so it performs both functions adequately. 

Edited by semi

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Gavin17

Thanks for helping MLA.  I think I'm going to try it your way first.  All it will cost me is a few feet of wire and time.  I'd rather have 2 multi purpose batteries in parallel with a working switch than the ACR because 2 batteries and my existing switch is the lowest cost and highest amp hour option. (I still have the jump pack for emergencies)  If I get more noise I'll troubleshoot from there.  Currently my stereo has a tiny bit of alternator whine when the engine is running.  I was hoping that grounding the head unit directly to the amp grounding location would get rid of the noise.  

 

I haven't taken my Perko switch apart yet but since so many things are not running thru it currently I hope there is enough room on the Perko terminals to add everything. 

 

Thanks for all the help everyone! 

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minnmarker

KISS, that's my MO if at all possible.  @Gavin17 are you glad you asked the question?  If the objectives are to make your boating life simple, not drain your starting battery, have some good amp hour capacity to hang at the sand bar, and not introduce noise into the stereo system then:

Buy a regular old group 29 deep cycle battery, hook ALL your stereo stuff to it with dedicated fused positive (either direct or through a buss) and ground wires to your HU, amps, and a switch on the dash if desired - so there is no connection between stereo and other boat electrics.  Then connect your two batteries with a nice heavy ground and an ACR.  Put a single bank charger on the deep cycle only, or a dual bank to both.  There are those that say the single bank is not a good idea on one side of an ACR but I say nay.  YMMV.  The only connection between the stereo and other stuff is through the ACR.

And no switch. They are not necessary with an ACR and will only mess up your fun, or charging, or starting if you leave it in the wrong position.  If you must have a switch then get 2 - one for the starting battery and one for the stereo battery.

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shawndoggy
26 minutes ago, minnmarker said:

KISS, that's my MO if at all possible.  @Gavin17 are you glad you asked the question?  If the objectives are to make your boating life simple, not drain your starting battery, have some good amp hour capacity to hang at the sand bar, and not introduce noise into the stereo system then:

Buy a regular old group 29 deep cycle battery, hook ALL your stereo stuff to it with dedicated fused positive (either direct or through a buss) and ground wires to your HU, amps, and a switch on the dash if desired - so there is no connection between stereo and other boat electrics.  Then connect your two batteries with a nice heavy ground and an ACR.  Put a single bank charger on the deep cycle only, or a dual bank to both.  There are those that say the single bank is not a good idea on one side of an ACR but I say nay.  YMMV.  The only connection between the stereo and other stuff is through the ACR.

And no switch. They are not necessary with an ACR and will only mess up your fun, or charging, or starting if you leave it in the wrong position.  If you must have a switch then get 2 - one for the starting battery and one for the stereo battery.

LOL @minnmarker you and my kids are the only people who find the concept of an on off switch to be complicated.  

And the kicker is that the only "complication" it adds is that if you leave the switch on, the ACR still works exactly the same way that you are advocating.

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MadMan
22 minutes ago, shawndoggy said:

LOL @minnmarker you and my kids are the only people who find the concept of an on off switch to be complicated.  

And the kicker is that the only "complication" it adds is that if you leave the switch on, the ACR still works exactly the same way that you are advocating.

Count me in that group too....

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minnmarker
5 minutes ago, shawndoggy said:

LOL @minnmarker you and my kids are the only people who find the concept of an on off switch to be complicated.  

And the kicker is that the only "complication" it adds is that if you leave the switch on, the ACR still works exactly the same way that you are advocating.

If your kids and I are allowed in the same boat things could get messy!  Perhaps we are confusing the Blue Sea ACR switch with a regular old A,B,A+B,Off switch?

Yep, I'm pretty dim about some things. :crazy:  It's not the on/off issue I am concerned with, it's the A,B,A+B issue that concerns me.  Leaving things connected when they should not be (and draining both batteries) - or connecting two batteries in vastly different charge states - that kind of thing.  There's really no need for a switch that I, in my intellectually diminished state, can understand except for the possibility that you somehow drain your starting battery (which is isolated by the ACR) while listening to your stereo which is being powered only by your stereo battery.  I think the scenario where I (or your kids) leave the batteries connected (by either A/B or Blue Sea switch) and then drain both batteries while listening to the stereo is much more likely.

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