Battery Question

[SanMarzano]

So who knows batteries? I have the stock interstate cranking battery (Deep Cycle) and an interstate deep cycle for the stereo . They are not holding a charge so I want to swap out........Does the starting battery need to be deep cycle??? I believe my stereo head unit is connected to it but all amps etc are on the other battery. I do sit and play music for a few hours..... What should I get? And how many cranking amps are needed and will more cranking amps than what I have today hurt the system?

[Boonejeepin]

Limited knowledge here.

I think it is preferred to have identical batteries in a bank.

Blue top optimal have always proven to be reliable.

[wolfeman131]

Limited knowledge here.

I think it is preferred to have identical batteries in a bank.

Blue top optimal have always proven to be reliable.

Yes, it's best to have them matched and the blue tops have always been mentioned as top notch. Pricey, but top notch.

[maxpower220]

I replaced my battery this year. Like each time I have had to do this, I got a marine battery from Walmart. Their price is good and their return policy/warranty is excellent. YMMV, but I expect to have battery issues when a boat doesn't get "normal" car-like use.

[SanMarzano]

Identical in a bank when connected through an isolator? I thought identical when in parallel or series

[Boonejeepin]

I have hear - If they ever charge ( are connected at the same time) you want them identical as both batteries can take on the performance of the weakest battery.

Someone please confirm or deny this statement. I am not an electrical guru.

[lsvboombox]

I replaced my battery this year. Like each time I have had to do this, I got a marine battery from Walmart. Their price is good and their return policy/warranty is excellent. YMMV, but I expect to have battery issues when a boat doesn't get "normal" car-like use.

+1 they have 2 year warranties and are priced right

[zabooda]

If the batteries are isolated when the engine is off then having two different batteries doesn't matter. If they are connected with no charging then the batteries are no stronger than the weakest battery.

[MLA]

SanMarzano,

For the main starting battery, all you need is a quality marine group-24 starting battery. For your house bank, I would suggest at a minimum, a group-24 marine deep-cycle. Your stereo design and how you use it will ultimately determine what battery size and how many, would be best. I often tell people to buy the biggest that you fit in the given space and that your wallet can handle. As an example, a typical Group-29 will have around 100+ Ah, which is about 2x the Ah of a Blue-top, yet the group-29 is half the cost and is far easier to maintain and less likely to be left undercharged by your alternator.

In RE to mixing battery types: This is referring to the construction type of the battery as in lead-acid wet cell, AGM, Gel-cell, etc. Its perfectly fine to use a wet cell starting and deep-cycle in a dual bank setup. It is also ok to use wet-cell starting and an AGM if the banks are isolated. If you are building a battery bank with 2 or more wired together, they must be the same type. Its also a good idea to have them the same age and condition as well.

[Cigars n scotch]

MLA, when you say build a battery bank what do you mean? Is a bank just 2 or more batteries? How would you isolate them typically: perko switch? All this dual battery talk has confused the hell out of me and caused me to hold up on getting a 2nd until I feel like I definitely have what I need.

When you say "amperage hours" what does that really mean in our terms? Meaning those of us installing stereo systems and a second battery to play off of. I assume the more Ah the better but does that mean how many hrs until depletion or something else?

Just trying to wrap my head around all of this as I've gotten like 50 different opinions on what to do. I have an interstate deep cycle group 24 starting battery now; would getting the interstate group 29 serve me well?

Should I be charging my batteries in between weekends? I don't have an onboard charger and can't get one now, maybe next year, but I've never charged my starting battery before during the season. I generally only have the stereo on for max 2 hrs without the motor running while we raft up. I see that others charge their batteries, but they also may use their systems different than I and have more speakers and amps.

Any guidance or advice is very much appreciated.

Justin

[MLA]

MLA, when you say build a battery bank what do you mean? Is a bank just 2 or more batteries? How would you isolate them typically: perko switch? All this dual battery talk has confused the hell out of me and caused me to hold up on getting a 2nd until I feel like I definitely have what I need.

When you say "amperage hours" what does that really mean in our terms? Meaning those of us installing stereo systems and a second battery to play off of. I assume the more Ah the better but does that mean how many hrs until depletion or something else?

Just trying to wrap my head around all of this as I've gotten like 50 different opinions on what to do. I have an interstate deep cycle group 24 starting battery now; would getting the interstate group 29 serve me well?

Should I be charging my batteries in between weekends? I don't have an on-board charger and can't get one now, maybe next year, but I've never charged my starting battery before during the season. I generally only have the stereo on for max 2 hrs without the motor running while we raft up. I see that others charge their batteries, but they also may use their systems different than I and have more speakers and amps.

Any guidance or advice is very much appreciated.

Justin

If a boat only has a single battery, the term "bank" really wouldn't apply. If you wired 2 batteries together, they in a sense, become 1. So again, we wouldn't use the term bank. But, when we have 2 separate batteries, each set a side for a primary purpose, now we have battery banks. In boats and motor homes, we typically call one the "starting" bank and the other the "house" bank. Now, we can have multiple batteries wired together within each bank, but they are still a bank. Some large twin screw cruisers will have a 3rd bank that would be the secondary starting bank. This gives you another battery to start the engines off of in case the primary starting battery is dead.

Main starting: Typically carries the loads of the engine management and gauges, etc. In a typical boat, especially a tow boat, run-about, etc, we only need a single starting battery. It doesnt need to be a large high capacity battery, just sufficient to start the engine. A Group-24 (group sise is how a battery is sized) is the most common. Its pretty middle of the road in terms of physical size and CCA's.

House bank: This is where the fun begins. The house bank can be one or more batteries wired together and thier function is to carry everything else not on the starting bank....stereo, LEDs, Fog machine, motorized dancer pole, AC/heat water pumps, etc. Basically any load that we want to run for an extended time without drawing down the starting bank. There are soooooo many variables here that there is no single design or setup. This is where we have to take into account the loads draw and how long we want to run that load before the battery depletes. Then we can estimate the number of Ah's (battery amp hours) we will need to reach that goal. Then we need to decide how large a battery(s) we can fit and how many we will need based on the projected Ah draw.

Isolation: When we two or more battery banks in a boat, or motor home, we need to have a means of isolating the banks from each other. This prevents house loads from drawing down the stating bank when the engine is off. This is typically done with a manual multi-battery switch such as the mentioned Perko. The switch also allows us to combine the banks for emergency starting or recharging the house bank once the engine is restarted. From here, we can way deep into the design based on the stereo, the size of the bank and how its used. We can add in an ACR (auto combiner relay) which will automatically combine the banks when the engine is running and isolate the banks when the engine off, all while leaving the manual switch in one position. With some large house banks, we will even use an ON/OFF switch to isolate all but one house battery, thus allowing the alternator to recharge only one depleted house battery instead of dropping 2, 3 or 4 dead house batteries on the alternator like a ton of bricks. Once the isolated house battery has recovered, we can then bring the others in line. This allows the house loads to still be used when the engine is running, even though the bank was getting low when the engine was off.

There is no one size fits all battery scheme, but there are some best practices that will apply to just about every battery setup depending the design, the switch and ACR used, etc.

Yes, the Ah is a rating given to the battery based on how long it will carry a given load before depletion. So go with as big a battery as you can fit and your budget will allow when looking for a house battery. When I say "as big" rule of thumb is that the more Ah's the battery has, the larger is will be. Thsi is due to the surface are of the lead plates. More surface are = more Ah's. And they cost more as well.

Im an interstate dealer. I carry Group-24 (24M-XHD) starting and Group-24 Deep-Cycle (SRM-24) and Group-29 (SRM-29) Deep-Cycle. These are the ones I use most. They are quality batteries, but there are plenty on good solid wet-cell batteries out there. The technology has been around sicne 1859, so most battery manufacturers have it down. I also use some AGM (absorbed glass mat) batteries and on occasion, 6V golf cart batteries.

Yes, you should recharge at least the house bank after each trip, especially if you are one that drops anchor at the party spot and plays for hours on end. You can not rely on the alternator to recharge a dead battery. An on-board shore charger is not always a must. If you boat sleeps at your house, then a small portable recharger will do. Getting one that is a multi-step smart charger is a bonus. It will taper off the rate of charge as the battery is coming back up.

[parrothd]

I have hear - If they ever charge ( are connected at the same time) you want them identical as both batteries can take on the performance of the weakest battery.

Someone please confirm or deny this statement. I am not an electrical guru.

:)............

[SanMarzano]

great info thanks guys

[jjerrod]

Fog machine, motorized dancer pole, .

Can we get a DIY on this?:)

[NCSUmoomba]

MLA, That is an excellent write up. Very informative.

Here is my setup if anyone is curious:

I have a group 24 marine starting battery plus a group 27 marine deep cycle house battery. These are wired up with a Blue Sea Systems switch and ACR. ALL of my stereo equipment is wired to the house battery side (even the head unit).
I also have a small portable trickle charger from Sears (about $20) that I keep connected to my house battery when the boat is at home. My boat has the factory alternator, which is I think like 50 amps or so.

I have 3 amps totalling about 1000 watts RMS and I have enough battery power to average about 8 hours (maybe, rough guess) of boat and/or stereo usage. After which time, there is not enough power left in the battery and there stereo will turn itself on and off. This has never really been an issue, since my boat is basically out of gas at about 6 hours, we are ready to get out of the sun, and the wally's are out.

[MLA]

Can we get a DIY on this?:)

You build it, i'll dance around it :cool:

[Cigars n scotch]

Thank you MLA and ncsumoomba. Extremely helpful.

Ncsumoomba, any pictures of your setup to help me visualize? The more I see the more I learn.

[bzubke1]

I got about 2-3 hours of playtime on the interstate group 24 deep cycle's that came with the boat. I had it playing on only one battery and at a pretty decent volume and it started fine when we were ready to leave. I did start the boat and let it run for 10 minutes once just to see if it would start after an hour and a half. I get a kick out of people who run the battery down for a while and start there boat to see if it will start let it run for 3 seconds then turn it off.

[cab13367]

So who knows batteries? I have the stock interstate cranking battery (Deep Cycle) and an interstate deep cycle for the stereo . They are not holding a charge so I want to swap out........Does the starting battery need to be deep cycle??? I believe my stereo head unit is connected to it but all amps etc are on the other battery. I do sit and play music for a few hours..... What should I get? And how many cranking amps are needed and will more cranking amps than what I have today hurt the system?

I see a lot of people spending a ton of money on expensive batteries which I've never understood. Do yourself a favor and go to Wal-Mart or Costco and get their group 27 or 29 deep cycle marine batteries. They will do everything you need them to do and won't cost you a fortune. I would rather spend my extra money on other things than expensive batteries when these work perfectly fine. That's just me though.

And no, buying a battery with more cranking amps than you need won't hurt anything.

[NCSUmoomba]

Here are some photos of my setup.

[mmandley]

I see a lot of people spending a ton of money on expensive batteries which I've never understood. Do yourself a favor and go to Wal-Mart or Costco and get their group 27 or 29 deep cycle marine batteries. They will do everything you need them to do and won't cost you a fortune. I would rather spend my extra money on other things than expensive batteries when these work perfectly fine. That's just me though.

And no, buying a battery with more cranking amps than you need won't hurt anything.

I agree 100% AL

I have been running for 4 seasons on my 3 group 24s lol. I run 2 as my battery bank and 1 as my house battery. Trust, me anyone who has been with me knows how much i abuse my volume button when rolling, im almost full tilt on my stereo all the time when driving and theres no way my Alternator is keeping up.

What i do that makes my batteries last season after season is a computer digital charger/maintainer. When the boat goes in the garage or parked for the night, i plug it in. It stays pluged in all the time.

I use an ACR and several times ran my stereo bank down due to one issue or another but the boat always starts right up.

Bigger bateries only get you 1 thing, longer play time between charges. If you party cove a lot, or you go places where electricity isnt around for days on end then you might want to spend a lot more on your batteries to ensure they last, or take a few hundo and buy a better alternator.