Did I make a mistake?

[Brian66D]

I just purchased two identical deep cycle marine batteries for my boat. I also purchased a switch. The switch has OFF, 1, 2, BOTH.

My 3.0L mericruiser bayliner 1750 is what these will be going into.

My plan is to use one battery for starting, and one battery to listen to music sitting in coves (we usually sit for hours at a time). My plan is once the battery I was using for music goes dead I can start the boat with the other battery and once it is running then I can switch to the dead battery to charge back up.

I was talking to one of my relatives recently and he said that on his boat he has the same setup but uses a starting battery and a deep cycle.

Was I wrong in buying two of the same deep cycle batteries? Will my boat be okay to start off of the deep cycle?

Also is there any certain way I should wire them up? I did a bunch of searching but couldn't find a specific situation similar to mine.

I use the boat for wakeboarding, and sitting. I would get a starting battery and a deep cycle but from what I understood it was always smart to get two of the exact same battery....which is why I went out and bought two identical ones.

I can post pictures of whatever you need to see in order to help me out. Thank you very much in advance!

 

[Silvertip]

Re: Did I make a mistake?

No you didn't make a mistake although you will likely get a number of conflicting views on this topic. There are many owners who start much bigger engines than your on a deep cycle battery so do not concern yourself with this.

 

[sschefer]

Re: Did I make a mistake?

No you didn't make a mistake although you will likely get a number of conflicting views on this topic. There are many owners who start much bigger engines than your on a deep cycle battery so do not concern yourself with this.

100% Correct don't let anyone tell you any different. Starting/Deep Cycle combo batteries are typically less expensive and a more common choice as a single battery installation. It's an attempt to satisfy both needs in a single battery and that's all, nothng more.

 

[Brian66D]

Re: Did I make a mistake?

thank you both very much.

I'm not sure if the batteries I purchased are deep cycle/starting....I think they are just deep cycle.

I was skeptical but after reading a thread here about how F&F batteries are made by Johnson Controls i went with them....I purchased two of these...

http://www.farmandfleet.com/products/040563-marine_rv_battery.html#.T44XyO0gus8

Cold Cranking Amps: 550A
Group Size: 24MDC
Power: 12V
Height: 9-1/8"
Width: 6-3/4"
Length: 11-1/16"

 

[glenn property of pam]

Re: Did I make a mistake?

550 cold cranking its all good

 

[Scott Danforth]

Re: Did I make a mistake?

pure deep cycle batteries have thinner plates (and more of them) compared to an SLI (Starter, Lights, Ignition) battery. using a deep cycle battery for starting you may shorten the life of the battery because it tends to warp the plates due high current draw from starting. however if you have a cca rating, the battery is most likely a combination battery and you should be ok.

 

[Brian66D]

Re: Did I make a mistake?

I guess i could rotate which battery i use for music and which one i use for starting to try to reduce damage to the plates.

Is it going to be bad to run one battery dead, then switch to good battery to start, then switch back to dead battery for drive in to recharge...

I'm in a boat club and keep my boat in my hoist 99% of the time down there....so access to a trickle charger or anything like that isn't really an option....thoughts?

 

[Silvertip]

Re: Did I make a mistake?

You need to understand that "running a battery dead" is a sure way to kill it permanently. A battery 11 volts is essentially dead. That is worse for it than using it as a starting battery. What kind of an audio system do you have that routinely runs the battery dead? Any battery needs to be charged immediately after use so unless that battery gets FULLY charged immediately after use, you had best plan to buy a new one frequently. A ten minute run back to the dock does not fully charge a battery. Again -- stop worrying about the deep cycle as a starting battery. It simply is not a problem. But you do need to find a way to keep that house battery topped off.

 

[mark1905]

Re: Did I make a mistake?

I use 2 x 29 series deep cycle batteries for my 6 amplifier stereo system + starting and running with zero problems. No switches, no ACR, just permanently wired up in parallel.

You're fine.

 

[Brian66D]

Re: Did I make a mistake?

You need to understand that "running a battery dead" is a sure way to kill it permanently. A battery 11 volts is essentially dead. That is worse for it than using it as a starting battery. What kind of an audio system do you have that routinely runs the battery dead? Any battery needs to be charged immediately after use so unless that battery gets FULLY charged immediately after use, you had best plan to buy a new one frequently. A ten minute run back to the dock does not fully charge a battery. Again -- stop worrying about the deep cycle as a starting battery. It simply is not a problem. But you do need to find a way to keep that house battery topped off.

I do quite a bit of wakeboarding also so the boat definitely runs for at least 45 minutes at a time....I have never taken a battery completely "dead" because I have always been worried about it so I would turn the music of after 30 minutes and sit in silence for a while (awful). I don't want to leave a battery tender unattended plugged in on my dock which is at least a 10-15 minute drive from my house.

My audio isn't anything crazy...I just don't ever want to get stranded and I want to be able to listen to it at a fairly loud volume for an extended period of time. Sony CDX M30 marine radio running two no name brand marine 6" drivers in the passenger and drivers side foot-well areas. Then a 1000 watt marine amp running two kicker 6" drivers in the rear and two 8" bazooka tower speakers. I also have an 8" powered bazooka marine sub (100w maybe). I was throwing around the idea of incorporating two more 6" drivers in the side under the seats in the open bow area of the boat to get some more sound up there...

I use 2 x 29 series deep cycle batteries for my 6 amplifier stereo system + starting and running with zero problems. No switches, no ACR, just permanently wired up in parallel.

You're fine.

That makes me feel better....you've got a lot more going on than me lol. But how long do you usually sit without running the engine...

Do you think I should return the 24MDC batteries for the 29MDC? I went with them due to space constraints in my boat....but I could try to work something out if you think i need them?

 

[mark1905]

Re: Did I make a mistake?

I would use the absolute biggest battery that you can squeeze in there. 29 series will give you a good amount of juice. I actually only added the second battery after jumping from 3 amplifiers to 6.. and before that it was all sequential. I ran only 1 for a month or so, then added another, then another.. until it turned into a full on obsession/addiction to see how much I could cram in an 18' boat.

When I was running 1 amp.. you could honestly barely notice all that much of an extra draw on the battery as long as you started it for a few minutes every couple of hours and even then it was no biggie with the big battery. I would definitely recommend upgrading your charging system as well though.

- Upgrade to at least a 100A+ marine alternator
- Upgrade the charging and ground cable to and from the alternator to 6AWG marine cable
- Use only marine grade power wire and high quality battery/ring terminals for everything.. no exceptions

How long everything will last depends entirely on your volume level. Louder music = more drain. Even with my 6 amps, I can play at a reasonable level for an hour or so without starting.. and it cranks right over. I just don't push it. Modern, quality brand name stereo amplifiers are very well built and seem to be much more efficient than they used to be. Yet another reason to only use quality parts. Not sure what brand of equipment you're running, but those MB Quart marine amps are pretty much the best on the market and only around $110 shipped from Amazon.. and a true 60w x 4 RMS with crystal clear, full on stadium sound. You can't beat that.

 

[Brian66D]

Re: Did I make a mistake?

I would use the absolute biggest battery that you can squeeze in there. 29 series will give you a good amount of juice. I actually only added the second battery after jumping from 3 amplifiers to 6.. and before that it was all sequential. I ran only 1 for a month or so, then added another, then another.. until it turned into a full on obsession/addiction to see how much I could cram in an 18' boat.

When I was running 1 amp.. you could honestly barely notice all that much of an extra draw on the battery as long as you started it for a few minutes every couple of hours and even then it was no biggie with the big battery. I would definitely recommend upgrading your charging system as well though.

- Upgrade to at least a 100A+ marine alternator
- Upgrade the charging and ground cable to and from the alternator to 6AWG marine cable
- Use only marine grade power wire and high quality battery/ring terminals for everything.. no exceptions

How long everything will last depends entirely on your volume level. Louder music = more drain. Even with my 6 amps, I can play at a reasonable level for an hour or so without starting.. and it cranks right over. I just don't push it. Modern, quality brand name stereo amplifiers are very well built and seem to be much more efficient than they used to be. Yet another reason to only use quality parts. Not sure what brand of equipment you're running, but those MB Quart marine amps are pretty much the best on the market and only around $110 shipped from Amazon.. and a true 60w x 4 RMS with crystal clear, full on stadium sound. You can't beat that.

Thanks for the educated, quick response. You're helping me more than you know lol

My biggest concern for the batteries is space. They obviously have to be in boxes and im not sure if i could cram two 29 series batteries in there. If I can I will...if not you think the smaller ones i currently have will do the job reasonably well correct? I'm not trying to kill the fish in the water...but we usually have 30+ people in a cove so it is usually fairly loud. Most people take turns playing their boats for an hour or so then switching. I'd just like to have the ability to play for 3-4 hours safely and not have to worry about starting issues.

The amp I bought...I went el cheapo. Pyle marine...I'm sure it s pile o crap but I just want something reasonable...last year I ran the bazooka powered sub, and all the components off the headunit and it actually sounded pretty good. MB Quart is good stuff...I have some components mixed into my projection theater at my house. If this setup sounds 1/10th as good as I can only imagine how yours sounds I will be satisfied.

I'm fairly mechanically inclined as changing an alternator on a car is very attainable for me so I'm sure its just a bit more difficult on a boat....definitely something I will be thinking about doing in the near future but most likely not right at the start of the season....

I have a whole BUNCH of 8 gauge power cable from old vehicles and stereo systems. Have a bit of 0 gauge laying around as well....I should scrap this stuff and buy marine cable? Is there really a big difference....even in a freshwater environment?

 

[mark1905]

Re: Did I make a mistake?

Yeah.. even in freshwater, that soft auto sound system wire will corrode on you and you'll fry your amp and/or speakers.. and then have to spend more time and money replacing it. Search ebay/etc for the lowest prices and you'll be set. I so can't stress this enough to do it right the first time! The corrosion will literally creep all the way down the wire.. it's crazy. Trust meeeee...

The batteries don't have to be in boxes.. mine sit out with no problem. It's preferable.. but not required. The 24s will work.. but if you can switch up to bigger, then that would be the best case scenario.

FYI a 105A marine alternator is only $70 from DB Electrical and they work great. My 200A bad boy was $170 from PowerMax USA. Changing the alternator on a 3.0 is easy as pie.. it's all sitting right there. It should take you about 15 minutes.


I finally found the site I was looking for.. these guys have the best prices on marine cable online that I've seen: http://gregsmarinewiresupply.com/Zen/

 

[Scott Danforth]

Re: Did I make a mistake?

I would add a pulstech solargizer to the boat for when its on the lift to keep the batteries topped off when sitting on the lift. best thing I have ever added to my boats.

A group 31 will fit in your group 27 tray if you want the biggest battery to stuff into a location, however it wont fit in a group 24 tray.

 

[mark1905]

Re: Did I make a mistake?

Trying to find a decent group 31 battery though.. oy vey. Biggest I've seen readily available is a 29.. WalMart for $70+/-

 

[mark1905]

Re: Did I make a mistake?

I was throwing around the idea of incorporating two more 6" drivers in the side under the seats in the open bow area of the boat to get some more sound up there...

Sound up front = good

 

[Brian66D]

Re: Did I make a mistake?

Sound up front = good

View attachment 141795

hahaha that is wayyy more elaborate than the simple setup i was thinking about....looks NICE though....

I will buy the marine power wires. I am a firm believer that if you don't pay for it up front you'll pay more for it in the long run. For whatever reason the boat is the only thing I try to skimp on in my life lol

I will probably buy the 200a alternator and swap it out, makes the most sense to me.

On our lake...it is city owned, not state....so their boating requirements are more strict for whatever reason. The batteries on our lake have to be in boxes...not sure why but its a lake rule and you have to pass inspection at the begining of every season. No big deal just more of a pain for me to try and get both of the batteries crammed in there...

If my whole scenario is to use one battery for starting/backup if the other one is completely dead...could I:
return one of the batteries and get a larger one? Then use the switch the same as I stated before? Just use the bigger deep cycle for music...I don't ever plan on running the switch on the "BOTH" setting.

(this is purely due to space constraints....it is a TIGHT squeeze in there)

 

[Brian66D]

Re: Did I make a mistake?

I would add a pulstech solargizer to the boat for when its on the lift to keep the batteries topped off when sitting on the lift. best thing I have ever added to my boats.

A group 31 will fit in your group 27 tray if you want the biggest battery to stuff into a location, however it wont fit in a group 24 tray.

honestly never heard of one...what do they do?

 

[mark1905]

Re: Did I make a mistake?

Lol.. just stick with that 105A DB Electrical model.. it will do you just fine. It handled things great up until around the 4th amplifier mark. Make sure to upgrade the wiring though along with it.. 6AWG with nice set screw type ring terminals on all ends. You'll need to get a slightly longer screw for the ground post on the alternator since the ring terminal is thicker than normal.

How often do you get re-inspected during the summer? Not that I would ever suggest putting in the 24 just for inspection and then swapping it out after for the 29s after you're through. *cough*

If my whole scenario is to use one battery for starting/backup if the other one is completely dead...could I:
return one of the batteries and get a larger one? Then use the switch the same as I stated before? Just use the bigger deep cycle for music...I don't ever plan on running the switch on the "BOTH" setting.

Confused by this. If you can fit one, why can't you fit the other? If you're planning on battery longevity why wouldn't you use both at the same time?

..and the biggest question: What's so hard about just firing the motor every couple of hours for a few minutes to charge it up? I say if you really can't fit the bigger batteries, then go with dual 24 series MDCs and be done with it. Run both at the same time or just one until you get a feel for how much power you'll really be using for how loud and long you're playing and gain the confidence to just run both.

 

[lmuss53]

Re: Did I make a mistake?

Look at a Yandina battery combined/isolator, it connects the house battery and starting batteries together electrically when the starting battery is above about an 80% charge. It will drop the house battery from the circuit if the combined batteries fall below the 80% mark. This allows the starting battery's charging system to charge the house battery, but keeps the house battery from running the starting battery down. I've used them on my pontoon for years snd they will let you listen to your music all day without worrying about killing your starting battery.

I would keep a 24 for starting and get the biggest deep cycle you can for the house battery. Even if you keep both 24' s the yandina is the ticket for isolating one to keep for starting only use.

www.yandina.com/c100InfoR3.htm

I hope the link is allowed.