StripersOnline › SurfTalk › Stripers Online Forums › Boating Forum ›  Battery group ?? What the heck is it?? Experts?? Help!
New Posts  All Forums:Forum Nav:

Battery group ?? What the heck is it?? Experts?? Help!

post #1 of 19
Thread Starter 
I have a 98 Merc 150 duel batteries. One is a gonner. Both are group 24.
What does that mean? Can I use a different group?
Both are starting / deep cycle. Im leaning towards one of each assuming the starting kills the deep cycle. Dead Battery was primary used for starting.
Electronics.

Any experts care to educate me??
post #2 of 19
No expert, but the group indicates the physical size of the battery.
post #3 of 19
"group" is an indicator of size and power of a battery. grp 24 is the smallest (typically) used in a boat. 27 is bigger/more powerful, so if you have lostsa electronics and/or conumption of battery power during eac outing, then go for a bigger size. I can't answer the 24-and-27-together part of yer question, but I would say the safest/simplest answer is to replace both; and prolly go to a bigger size.
post #4 of 19
Group means battery physical size, ie group 24 and group 27 as mentioned earlier. Its CCA/MCA rating that counts. I have two batteries, one is 1000 cca's the other is 600 cca's (cold cranking Amps). The 1000 is the starter battery, the 600 runs accessories and is a back up starter. The higher the CCA rating, the more starting power you have. This is oversimplifying it but it gives you an idea of what a battery rating means.
post #5 of 19
Thread Starter 
OK great info thanks simpler than I thought.

I can assume then that my alternator will charge with no ill effects? I thought group may have needed to be specific to a charging system
post #6 of 19
Previous posts are correct in that group numbers refer to the physical case size of the battery. There are overlaps in storage capacity between case sizes, in that a better quality group 24 may have more amp hours than a lesser quality group 27.

The CCA ratings are significant for motor cranking applications. The reserve capacity number is significant if you are using a battery for house banks, bait well pumps, trolling motors and such. The reserve capacity number is a measure of how long a battery will provide a constant 23 amp load in minutes.

A starting battery will usually have a higher CCA rating but lower Reserve capacity than a Deep Cycle battery of the same group number from what I have observed.

A deep cycle battery will perform as well as a starting type battery in most applications but you may need to jump up a group size to get the same CCA rating. However, the starting battery will expire more quickly if you are using it under heavy sustained loads such as a house bank or trolling motor power.

Then there are the AGMs! They perform like deep cycle batteries, but self-discharge more slowly and can be recharged more quickly, but at a price premium!
post #7 of 19
Quote:
Originally Posted by The Knife View Post

OK great info thanks simpler than I thought.
I can assume then that my alternator will charge with no ill effects? I thought group may have needed to be specific to a charging system

1st, Think of "group" as Horsepower for starting any motor, they are Group 24, 27, 29, 31 along w/ 4D & 8D (4 and 8 are huge, mostly for Trucks and big Diesel's,

On a regular boat, it's better to use a Dual Purpose Marine Deep Cycle Battery, Wal Mart has them for about $100 for a Group 27 if it will fit in your battery boxes. Never mix deep and regular on the same charging circuit. Deep cycle holds the max. power curve longer then drops off quick to being dead.

Charging is the same as long as you have an Alternator, but some Gel Cell Batteries "sometimes" need special voltage regulators so stay away from that type.



Personally, I use 1 4D deep cycle to run everything in my live-aboard Cruiser and am adding another soon. it has 1625 CCA and 225 Amp Hours capacity but also weighs 137 lbs..
post #8 of 19
Thread Starter 
Awesome. Appreciate the help.
Tight lines!
post #9 of 19
You ever want advice on batteries let me know, if you REALLY want to know what to look for and how they work, I could probably write a book on it. It is not by any stretch a simple topic.

The best thing any boat owner can do for their boat in terms of batteries is have the boat wired PROPERLY, and use two identical types and years of battery. Either of those 2 variables are off, and they will die quickly, no matter the type of quality.

I find that anything with the word MARINE on it costs a LOT more, for no specific reason. I have never purchased a battery that said marine, and I have had all my deep cycle batteries last me 5 years+, no charger, left on the boat all winter.

The biggest tell of a batteries quality, is the weight. Lead is incredibly heavy. Deep cycle batteries use very thick plates, so the higher the quality deep cycle(less pores in the lead) the heavier the battery. As a referance, the above mentioned 8d weighs 137 lbs. Rolls Surrette, which cost almost $1,000 for an 8d, weighs right near 300 lbs. Thats double the lead in the same housing. Granted it costs a lot more, and there are more plus's to the surrette brand, but that's a tell of quality. You can go get a group 27 deep cycle marine and it will weigh 50 lbs. Then go get a tractor deep cycle 27 and it will weigh 70 lbs. Thats 20lbs extra lead, which leads to longer power provided, so long as the draw is low.

IMO, for you, go to napa, and grab 2 group 27 deep cycle batteries, should run you about $180, and properly cared for, should last 5-6 years. When you go out, start motor and drive TO your spot on Batt. 1, start motor again and return HOME on Batt. 2. That way you use and re-charge each battery every trip.
post #10 of 19
I like to only use only one of two batteries on any given day. The strategy being that you always have one fully charged battery as a backup. Switching batteries during an outing could kill both batteries and leave you stranded in the event that your engine's charging system "cooks" the batteries. The rule of thumb for any backup system is to have at least one fully redundant functioning system as a backup.

If you need to switch batteries during the day, you need to buy bigger batteries with more CCA's and/or RC.

I have a lot of electronics that I run all day long and radar at night with the engine off and I can still start my engine. I use two group 31 AGM batteries and have an on board charger that is plugged in when not in use 24/7 365 days a year. I've never had to switch batteries during the day except for when the boat was brand new and Parker did not use a heavy enough gauge wire when I requested that the batts be installed in the console instead of the bilge - which I did because I knew that I would be using large/heavy batts and wanted better weight distribution.
post #11 of 19
Wayne, I actually do the same, BUT, I use my boat all the time. Most people in the NE use their boat AT MOST one day per week. Many only use their boat once every 2 weeks. If you only charge one battery each time you are out, that means Batt1 used week one, Battery2 used week3, Battery 1 used week 5. That puts 4 weeks between charges. If you have ANY wiring drains, that won't cut it.
post #12 of 19

Group size has been answered, but what you should get for replacement has not.  Rule is, when replacing batteries, replace all batteries in a multiple battery system at once, and do so with matched sized batteries.  Reason being, if you use an old 24 with a new 24, a new 24 with a new 27, or worst of all, an old 24 with a new 27, the smaller or older battery will always exert parasitic draw off the newer or larger battery, as the system is looking for equilibrium.  Replace both batteries.  I use 2 27's, but group size requirement depends largely on your power needs and desire for extra reserve capacity.  I run my running lights (always on), halogen deck lights (when needed), fishfinder/GPS (always on), and a 1200 gallon per hour livewell pump (always on) off my system, and a 1.5 million candle power halogen spotlight (when landing fish, or running in the bays for finding the cans) sometimes all night without restarting, and have yet to encounter a problem with not enough reserve. 

 

Also, the fella who recommended AGM's is right, they are fantastic, significantly smaller and lighter for a given group size/CCA/AH rating than a typical flood design, are leak proof, are low gas, can be mounted literally any way you want, including upside down, and have a longer overall service life, all wins.  Cost is the issue, however, as AGM's will typically run 2-5X more expensive than others.  Stay away from gels, unless you have a specific need for their performance benefits and have expert consulting. 

 

Whatever you go with, make sure they are SECURELY mounted and tied down in the boat, and not with those plastic jobby clips that come with the battery box that break on the first choppy day you have to pound through on the way to or from the fishing grounds.  Get a couple nice stainless mounts, and a good tie down.  This is especially important for smaller boats that tend to pound over largest boats that tend to cut.  The most common cause for physical battery failure, ie something breaking inside the battery, is vibration and shock damage to the plates and cells.  Vibration is inevitable in any moving vehicle, and in a boat we're way behind the eight ball as we have no shocks and dampers like a car/truck.  So the pounding a battery takes on a boat is bad enough to begin with, don't exacerbate the problem by have a broken or non existent battery tied down so the battery can just levitate on the way off the top of every wave and slam down after impact.  Not so hot for the deck of the boat, either, to have 30 or more pounds crashing down over and over in the same spot.

 

Get those batteries replaced and mounted and enjoy a great season!!! 

post #13 of 19

          Sorry, failed to address the starting or deep cycle part of your question:  Use two marine batteries, combo of starting and deep cycle.  Sounds like that is what you had on there before.  There are pretty much no circumstances in which a starting only battery is desirable in a marine application.  Starting does not kill the deep cycle, though it does slightly deplete it, anywhere from 2-5% on a normal start.  That is quickly regained by the functioning of the alternator on the boat, however, so this effect is negligible.  Also, to combat this problem, most marine class batteries have a deeper amp hour reserve to draw from that a similar sized starting battery.  The problem is actually the reverse, you see deep cycling kills the starting only battery.  Here's why:

 

          Starting batteries do not have deep cycle capability, in essence the ability to be discharged and recharged many times over without any negative effect on the performance or life of the battery.  A starting battery is meant to start the motor, plain and simple, using that 2%-5% of it's reserve I mentioned above, and then immediately be topped off by the alternator.  If you run electronics and lights and accesories off a starting battery while the motor is NOT running, and drain the battery down and then recharge it, it will fail after as few as 20 or 30 repetitions of this "deep cycle".  A deep cycle battery, on the other hand, can be draw off 80% or more of it's total capacity, and then be recharged time and time again, with no ill effects on it's performance or life. 

 

          So, if you mounted a starting battery and a marine (starting/deep cycle combo) battery together, say on a 1/2/all battery switch, you would have to start the boat on "all" then, after you have stopped, you'd have to change just to the battery with deep cycle capability, and then back again for starting and running, and so on and so forth, or risk swift and permanent damage to the starting battery, which would then start to pirate charge from the other battery in the system, eventually causing both batteries to fail well before their expected service life.  there is only one way you could run this type of system without damage to the batteries: leave the motor running all the time, so it never deep cycles, but with the price of fuel these days I'm not thinking you'll want to go that route wink.gif

 

So, the answer remains: get 2 new Marine (starting/deep cycle combo) batteries in the appropriate Group Size/CCA/AH for your particular power needs.

 

And again, enjoy a safe and fruitful season!

post #14 of 19
Quote:
Originally Posted by Chief2 View Post

Wayne, I actually do the same, BUT, I use my boat all the time. Most people in the NE use their boat AT MOST one day per week. Many only use their boat once every 2 weeks. If you only charge one battery each time you are out, that means Batt1 used week one, Battery2 used week3, Battery 1 used week 5. That puts 4 weeks between charges. If you have ANY wiring drains, that won't cut it.

I understand where you're coming from but your method assumes that your batteries are being fully charged by your engine. I know for a fact that mine are not always brought to full charge - even when running for hours after having been significantly discharged.

Your best bet is to always charge them on a good charger after each use. The good on board charges even keep track of the number of charge cycles and runs a conditioning cycle after 30 or so cycles, which enables the batts to take more of a charge.
post #15 of 19
Quote:
Originally Posted by catfish9797 View Post

          Sorry, failed to address the starting or deep cycle part of your question:  Use two marine batteries, combo of starting and deep cycle.  Sounds like that is what you had on there before.  There are pretty much no circumstances in which a starting only battery is desirable in a marine application.  Starting does not kill the deep cycle, though it does slightly deplete it, anywhere from 2-5% on a normal start.  That is quickly regained by the functioning of the alternator on the boat, however, so this effect is negligible.  Also, to combat this problem, most marine class batteries have a deeper amp hour reserve to draw from that a similar sized starting battery.  The problem is actually the reverse, you see deep cycling kills the starting only battery.  Here's why:

 

          Starting batteries do not have deep cycle capability, in essence the ability to be discharged and recharged many times over without any negative effect on the performance or life of the battery.  A starting battery is meant to start the motor, plain and simple, using that 2%-5% of it's reserve I mentioned above, and then immediately be topped off by the alternator.  If you run electronics and lights and accesories off a starting battery while the motor is NOT running, and drain the battery down and then recharge it, it will fail after as few as 20 or 30 repetitions of this "deep cycle".  A deep cycle battery, on the other hand, can be draw off 80% or more of it's total capacity, and then be recharged time and time again, with no ill effects on it's performance or life. 

 

          So, if you mounted a starting battery and a marine (starting/deep cycle combo) battery together, say on a 1/2/all battery switch, you would have to start the boat on "all" then, after you have stopped, you'd have to change just to the battery with deep cycle capability, and then back again for starting and running, and so on and so forth, or risk swift and permanent damage to the starting battery, which would then start to pirate charge from the other battery in the system, eventually causing both batteries to fail well before their expected service life.  there is only one way you could run this type of system without damage to the batteries: leave the motor running all the time, so it never deep cycles, but with the price of fuel these days I'm not thinking you'll want to go that route " rel="http://files.stripersonline.com/images/smilies/wink.gif">wink.gif

 

So, the answer remains: get 2 new Marine (starting/deep cycle combo) batteries in the appropriate Group Size/CCA/AH for your particular power needs.

 

And again, enjoy a safe and fruitful season!


Another benefit of AGM batteries is their ability to resist degradation due to shock. AGM's were originally developed for military use in aircraft where the requirements were that they be able to be mounted in any position and be resistant to G-forces and vibration.
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Boating Forum
StripersOnline › SurfTalk › Stripers Online Forums › Boating Forum ›  Battery group ?? What the heck is it?? Experts?? Help!