Recommendation for Deep Cycle Batteries

[PowellBride]

Heading to the lake in a little over a week We are looking to replace the house batteries on our Houseboat this year. Any thoughts/preferences on a brand of deep cycle batteries? Also, do you feel that the marine grade is worth the additional costs?

Thanks in advance for any advice

 

[Randy Helzer]

This one of those topics that will probably have a lot of different opinions. If your house battery bank serves only as the house battery (does not start any type of engine) then I feel the 6 volt golf cart batteries from Trojan are the best choice. They have two sizes, 100 AH and 125 AH. We built our bank with the 125s (paired in series for 12 volt). I think they give you the best bang for the buck. With a quality smart charger we had some last in excess of 6 years (check water level weekly) it's been a few years since we bought any but it seems like the 125ah model was about $135 from Hensley in Denver.

 

[Ryan]

Almost all batteries are made by Johnson Control. Some are to different specifications depending on who they private label for.

I am of the opinion that this is one rare instance in life where you do not get what you pay for. When I buy batteries, I look to see who has the best price coupled with the best warranty. That is usually Walmart/SAM's, or Costco. Good luck.

 

[PowellBride]

We are currently set up with 3 deep cycle group 24 batteries that are trickle charged from our solar. Not sure I want to mess with it, as it is working. I'm really just looking to replace them, but see prices ranging from $80/battery to $200+ We haven't replaced these batteries in years (5+) and I'm embarrassed to admit we didn't maintain the water in them so it's probably our fault we have to replace them now

 

[Randy Helzer]

I am a true believer in "if it worked for you before, don't change it".

We went from the 12v deep cycles because we were only getting about two seasons out of them. There is some added cost to change over to the paired 6volt type system with needed additional cables and connectors.

I need to update, Hensley does not carry Trojan anymore. The new distributor carries the T105 (225ah) for about $145, the T125 size (240 AH) for about $175. He suggested another brand, US 2200 (235 AH) for about ($145).

If you are staying with 12 volt batteries I also have had good luck with Costco.

Now for starting batteries, not that you asked, I would always prefer Optima's.

 

[birdsnest]

I throw my hat in with R.H.. I am on my third set of batteries for my off grid solar system. I started with Trojan and they lasted 7 years. Next set I didn't want to spend the extra $35 each so bought U.S. Battery brand(4). In two years I had dead cell in one. Very disappointed. They only had one year warranty. I like the trojan brand. I check my batteries often with a hydrometer and equalize them as well. The maintenance is worth the trouble to me. They do manufacture their own batteries.

 

[birdsnest]

Six volt batteries are the only way to go for house systems. (in my humble opinion)

 

[Squirrel]

Powellbride, shoot me an email. [email protected]

 

[TR.]

Based on years past I will be in the minority here, however I love optima. Truck and boat going strong after four years.

TR

 

[Ringer]

I buy the blems on the group 31 AGM batteries from East Penn on the west side of Phoenix. They are the exact battery as Deka and also BPS. I buy the blems for $100 each and the people there said they are the exact same battery other than they only have the threaded posts and not the lead post. They have lasted 3 years in my bass boat and no water to add.

 

[Powelldreamer]

IMHO go with the AGM's if you can. Low maintenance and reliable.

 

[Endurance]

If a set of three Group 24 deep cycles gave you five years with spotty maintenance, I would guess that your battery needs are pretty modest. If that guess is right, there's no sense going hog wild and spending a lot of money.

If you pulled up at Sam's club today, here would be three choices:

Duracell GC-2 for $85 each. Two of them would give you a 215 Amp-hours (20 hour rating) at 12 volts. Total cost = $170/215Ah, or $0.79 per Amp hour.
Duracell HGC-2 for $118 each. Two of them would give you a 230 Amp-hours (20 hour rating) at 12 volts. Total cost = $236/230Ah, or $1.03 per Amp hour.
Duracell Group 24 for $80 each. Three of them would give you a 225 Amp-hours (20 hour rating) at 12 volts. Total cost = $240/225Ah, or $1.07 per Amp hour.

Each of these three choices has its merits. You will notice that two GC-2s give you the most bang for the buck at $0.79 per amp hour. If you can stand a little step down from the 225 Amp-hour battery bank that you are used to and can get by with 215 Amp-hours, spending $170 for a pair of the GC-2s is a solid choice. If you have always wanted to increase the size of your battery bank and have room for four batteries, four of these would cost you $340 but would give you a whopping 430 Amp-hours. That is a lot of power for a little money.

If you have no interest in stepping down a little or up a lot in battery bank size, you need to spend a little more per Amp-hour to "right size" your battery bank. Two HGC-2s at $1.03 per Amp-hour aren't a bad buy. You would need to make sure you have room for a little more height. I don't know what the "H" in HGC-2 stands for, but I always think of it as "high" because the HGC-2s stand a few inches taller than a regular GC-2. A pair of these meets your goal of "right sizing" your battery bank and even give you a nice little step up from 225Ah to 230Ah for less money than replacing what you have now.

The most expensive in terms of cost per amp hours is three Group 24s like you have now. At $1.07 per Amp-hour, they're the most expensive of the three. But if you ever have a motor battery die on you, you can grab one of these and replace your motor battery and limp through a trip. So while three of what you have now gives you the least amount of bang for the buck, they also give you the most flexibility.

Hopefully this gives you enough information to make a reasoned decision about what size batteries to buy. Whether to buy AGMs to replace your flooded lead acid is another matter. If I have a minute and no one else addresses the pros and cons of AGMs, I will try to add another post later when I can.

 

[ROSCOELAB]

we did the AGM 6 volt 230AH, we have gotten 6 seasons and going on 7 with 3 185w panels, a blue sky controller and a 2500w inverter with 8 battery bank. have replaced the cheep inverter every other season but the batteries are still going strong. with AGM there is no maintenance except cleaning terminals every spring.

 

[Endurance]

Once you decide on a battery size, you will want to think about what kind of batteries to buy. The biggest decision is battery technology. While things like lithium ion are really cool, they're still an emerging technology that is kind of expensive for what you get. For most of us, the action will be in batteries with lead and acid of some kind. The three basic types of lead acid batteries are wet cells (flooded lead acid), absorbed glass mat ("AGM") and gel. For whatever reason, the gels haven't really taken off as deep cycle storage batteries. My guess is that most deep cycle storage users that are interested in a sealed battery move to AGMs since they are a little more rugged than gel. So most of us don't really consider gels for house batteries.

AGMs are expensive. Usually, you will spend at least double the cost of a comparably-sized flooded lead acid to get AGM. To make matters worse for AGMs, the absorbed mats don't make power as readily available as a wet cell, which means that a same size AGM will have only 80% or 90% of the Amp-hour rating of a flooded lead acid.

Since AGMs cost more and deliver less, you would think they would be the dumbest thing in the world to buy, right? Probably, but I can think of at least two reasons why smart people buy them anyway. First is a safety reason. Flooded lead acid batteries give off gasses during normal operation. That gas contains hydrogen. As the passengers of the Hindenburg would tell us if they hadn't died in a ball of fire, hydrogen gas is flammable and dangerous. The sulfuric acid in batteries adds some other chemicals to the mix and make it not healthy to be around. AGMs don't off-gas during normal operation. If your batteries are inside your cabin or any enclosed space, you pay the money for AGMs and don't look back.

Another reason to buy AGMs is a "know thyself" proposition. If you are the kind of boater (or have an owner in your houseboat group) who you know will let flooded lead acid batteries run dry, you are a good candidate for AGMs. Since you never have to add water to AGMs, you can't cause them to suffer a premature death from going dry. If going dry is likely to kill your batteries in less than half of their normal life, paying double the price and getting AGMs puts you money ahead.

Since you got five years' life out of your last set of flooded batteries, you are still ahead of the game. Five years is more than half the life I would expect from a fancy set of AGM batteries. For your situation, I would roll the dice on another set of flooded lead acid wet batteries and promise myself that I will take a bottle of distilled water to the houseboat and use it from time to time.

There is still a little to consider, but this post is getting long. I will try to add some more later when I have a minute.

 

[BartsPlace]

We moved onto gel last year. So far, so good. I'm very interested to see how well they perform over time - and how long they last.

 

[PowellBride]

Really appreciate all the information!!!

 

[Endurance]

There are a few more things that matter in your purchase and also a few things that matter less. One thing that matters is that you want to buy deep cycle batteries and avoid starting batteries. All of the golf cart batteries are deep cycle since they are designed to be charged overnight then run down driving the golf cart around in the day. But 12 volt Group 24 batteries come in both starting and deep cycle batteries. Starting batteries have a lot of thin plates in them. That works great at delivering a big power surge at once like you need to turn a starter motor. But all those thin plates are terrible at standing up to the rigors of deep discharge and charge cycles. You might see so-called starting/deep cycle marine batteries. They claim to do both well but really are a compromise. They won't start as well as a dedicated starting battery and won't deep cycle as well as a dedicated deep cycle battery.

Brand names don't matter much either. Those in the battery industry joke that there is only one battery plant in the world somewhere in China that produces some batteries that get marked as Interstate, some as Sears Die Hard, and some as Exide. Like most jokes, this is an exaggeration, but like most jokes, it has a grain of truth to it. There are few battery manufacturers and some lesser-known brands like Deka are actually made by big companies like East Penn. I tend to think about name brands as more tied marketing and less an indicator of real differences.

Also in the category of mostly marketing are designations like marine grade. Marine grade might get you a different color case or handy lifting ropes on the ends of the battery, but inside they're still the same lead plates in wet acid, gel, or AGM configurations.

You will mainly want to pay attention to Amp hour ratings for the money. When you compare Amp hour ratings, you need to make sure that you're comparing apples to apples. Amp hour ratings are different depending on the length of time you are drawing down a battery. Batteries store then give off power through chemical reactions. It takes time for those reactions to take place and the longer time you can give a battery, the more chemical reaction takes place. For example, a common Trojan T-105 (GC-2 sized) battery has the following amp hour ratings for different times:

5 hour rating - 185 Amp hours
10 hour rating - 207 Amp hours
20 hour rating - 225 Amp hours
100 hour rating - 250 Amp hours

That's all from the same battery. Ideally, you want to use the hour rating that matches how you use the battery. If you run the batteries down overnight then charge them every day, a 5 or 10 hour rating makes sense. If you run them down over a weekend trip then trickle charge them between trips, a 20 hour rating is most relevant. If you gradually discharge over a 4 or 5 day trip, the 100 hour rating is the best indicator to compare batteries. But which rating you use is less important than that you use the same rating for all of the batteries you are comparing.

You might be wondering why you can buy a 6 volt golf cart battery that has 225 Amp hours but if you buy two of them you still have 225 Amp hours. The reason is that a single 6 volt golf cart battery does indeed have 225 Amp hours, but at 6 volts. Since most of us need 12 volts, we have to combine two of them in series to give 12 volts. The two 6 volt golf cart batteries in series gives you 225 Amp hours at 12 volts.

Another long post. Sorry about that. I will try to wrap this up in one more post later today.

 

[Powelldreamer]

There are a few more things that matter in your purchase and also a few things that matter less. One thing that matters is that you want to buy deep cycle batteries and avoid starting batteries. All of the golf cart batteries are deep cycle since they are designed to be charged overnight then run down driving the golf cart around in the day. But 12 volt Group 24 batteries come in both starting and deep cycle batteries. Starting batteries have a lot of thin plates in them. That works great at delivering a big power surge at once like you need to turn a starter motor. But all those thin plates are terrible at standing up to the rigors of deep discharge and charge cycles. You might see so-called starting/deep cycle marine batteries. They claim to do both well but really are a compromise. They won't start as well as a dedicated starting battery and won't deep cycle as well as a dedicated deep cycle battery.

Brand names don't matter much either. Those in the battery industry joke that there is only one battery plant in the world somewhere in China that produces some batteries that get marked as Interstate, some as Sears Die Hard, and some as Exide. Like most jokes, this is an exaggeration, but like most jokes, it has a grain of truth to it. There are few battery manufacturers and some less common brands like Deka are actually made by big companies. I tend to think about name brands as more tied marketing and less an indicator of real differences.

Also in the category of mostly marketing are designations like marine grade. Marine grade might get you a different color case or handy lifting ropes on the ends of the battery, but inside they're still the same lead plates in wet acid, gel, or AGM configurations.

You will mainly want to pay attention to Amp hour ratings for the money. When you compare Amp hour ratings, you need to make sure that you're comparing apples to apples. Amp hour ratings are different depending on the length of time you are drawing down a battery. Batteries store then give off power through chemical reactions. It takes time for those reactions to take place and the longer time you can give a battery, the more chemical reaction takes place. For example, a common Trojan T-105 (GC-2 sized) battery has the following amp hour ratings for different times:

5 hour rating - 185 Amp hours
10 hour rating - 207 Amp hours
20 hour rating - 225 Amp hours
100 hour rating - 250 Amp hours

That's all from the same battery. Ideally, you want to use the hour rating that matches how you use the battery. If you run the batteries down overnight then charge them every day, a 5 or 10 hour rating makes sense. If you run them down over a weekend trip then trickle charge them between trips, a 20 hour rating is most relevant. If you gradually discharge over a 4 or 5 day trip, the 100 hour rating is the best indicator to compare batteries. But which rating you use is less important than that you use the same rating for all of the batteries you are comparing.

You might be wondering why you can buy a 6 volt golf cart battery that has 225 Amp hours but if you buy two of them you still have 225 Amp hours. The reason is that a single 6 volt golf cart battery does indeed have 225 Amp hours, but at 6 volts. Since most of us need 12 volts, we have to combine two of them in series to give 12 volts. The two 6 volt golf cart batteries in series gives you 225 Amp hours at 12 volts.

Another long post. Sorry about that. I will try to wrap this up in one more post later today.

Awesome info Thanks for the long posts

 

[birdsnest]

there is alot to consider when choosing batteries so your post has to be long and is appreciated. As many years as I've been messing with batteries, it still is great to see information.

 

[Endurance]

To wrap this up, there comes a time to make a final decision. If this were my boat, I would drive to Sam's Club or Costco and buy four GC-2 golf cart batteries. Four of the Duracell GC-2s at Sam's Club at $85 each will run $340 and would have a 20 hour rating of 430 Amp hours at 12 volts. A similar Interstate GC-2 at Costco runs $84 each and has a 20 hour rating of 210 Amp hours. Four of them would run $336 and give you a 20 hour rating of 420 Amp hours at 12 volts. At prices of $0.79 per Amp hour at Sam's Club and $0.80 per Amp hour at Costco, they are a little more than half the price per Amp hour compared to what you would spend at a battery supplier.

For only $100 more than replacing the existing set of three Group 24 batteries, you end up with a lot more capacity. That capacity buys some peace of mind. You can feel free to run the stereo and lights into the night if the party just doesn't want to stop. You can leave the light on to help you find your way back to the houseboat after night fishing. You can let your nephew plug his iPad into the cigarette lighter to charge it if he wants to. In short, can relax your job of being the Power Consumption Sheriff.

You can also relax at the prospect of wiring series and parallel connections. You just need to follow this picture:

You will notice that this uses the same four jumper wires that you use on your current bank of three Group 24s. You will also notice that you pull positive from one side of the battery bank and negative from the other. That is the correct way of doing it. Even on your bank of three Group 24s, you should pull positive and negative from opposite ends of the bank to help keep you batteries in balance.

Oversizing your battery bank a little isn't as big a splurge as it seems. Because it is bigger, it won't have to work as hard and will last longer. Better yet, you will have less water evaporation, which eases your maintenance issues and adds even more life to your bank.

If you have never run short on power and can't imagine what you would do with a little more power, my second choice would be just two of the golf cart batteries from Sam's Club or Costco. Even though this is a boat and we all know that our job is to spend money on boats, there is no sense wasting it. So if a $170 solution works, I would grab it. You would wire two golf cart batteries like this:

Sure, you have to be a little frugal in your power use, but you can't beat the $170 total price.

Good luck!