Best deep cycle battery

[beat taco]

I have plenty of friends charging their dual 6v batteries off the stock alternator. I was offering an explanation as to why some people use high quality a/c chargers and choose to separate their house batteries from the alternator.

Another option would be to upgrade your alternator. That's what I did once my stock unit failed.

[PDXVLX]

Based on what I've found, I still don't see dual 6V batteries offering longer running times than dual 12V batteries do. In terms of capacity, if you get a couple of really good 12 volt, group 27 or higher, batteries then the runtime that you'll get out of the two systems is longer with the dual 12V batteries. It's documented here using the dual parallel 12V connection approach (pick dual Interstate SRM-29's for example for 420 RC): http://www.trojanbattery.com/BatteryMaintenance/gettingstarted.html

The main advantage of using two 6 volt batteries connected in series is long life. They generally last about two times longer than 12 volt batteries. This is because 6 volt batteries have bigger and thicker plates that can better withstand the effects of deep cycling. The main advantage of using two 12 volt batteries connected in parallel is backup. If one battery goes down, you will have the other battery to keep your system running. With two 6 volts, if one goes down then your entire 12 volt system is down.

I'd be interested in seeing a link to a dual 6V series battery connection that provides more than 420 RC if anyone can find one, I couldn't.

[Bill_AirJunky]

I have plenty of friends charging their dual 6v batteries off the stock alternator. I was offering an explanation as to why some people use high quality a/c chargers and choose to separate their house batteries from the alternator.

Another option would be to upgrade your alternator. That's what I did once my stock unit failed.

Yea, I don't claim to know what I'm talking about on this particular topic. Which is why when it was time for me to buy batteries, I got a pair of 12V DieHards......KISS. If I have problems in little podunk towns, I know I can get a replacement easily. And I know the stock alternator will charge them without any issues. The idea to run the on-board charger was really to get them thru the winters here (I've had a couple of batteries freeze) and maybe get a few years out of them.

One of the guys I ride with is a high voltage electrician for Boeing & he runs a couple of 6V golf cart batteries in his LSV. He charges with a golf cart charger that cost him like $500. They last for about 3 or 4 days without any issues, and he's running a stupid amount of watts driving 2 big NVS tower speakers. But he can't leave the boat in the water for more than that 4 days or he won't have a stereo any more.

Another guy I ride with looked into 6V batteries for his LSV last summer & came to a similar conclusion as PDXLSV. He keeps his boat on the lake for long periods too so he ended up going with 1 Deka starter & 2 group 27 Deka deep cycles driving a big Exile system. He has an on-board charger for when it's the in the garage & the stock alternator for when it's being kept on the dock all summer. His batteries have a ton of reserve (I don't recall how many hours). The only downfall is if one fails when we're on a week long trip at Shasta, he might have a tough time getting a replacement easily. Whereas I can get one from any DieHard dealer (Sears or Kmart).

[PDXVLX]

It seems that two 6V Interstate GC2-XHD-UTL Deep Cycle batteries in series offer 474RC/232AH vs. two 12V Interstate SRM-29 Deep Cycle batteries in parallel that offer 420RC. They also offer more deep cycles and can use a standard 12V charger if charged together: http://www.youtube.com/watch?v=sN2mkvUOL5E. I do notice that at lighter loads the 6V setup (54.5Hr@5A) can run longer than the 12V setup (42Hr@5A). It seems the 6V setup might have an slight edge.

[Greeko]

Yea, I don't claim to know what I'm talking about on this particular topic. Which is why when it was time for me to buy batteries, I got a pair of 12V DieHards......KISS. If I have problems in little podunk towns, I know I can get a replacement easily. And I know the stock alternator will charge them without any issues. The idea to run the on-board charger was really to get them thru the winters here (I've had a couple of batteries freeze) and maybe get a few years out of them.

One of the guys I ride with is a high voltage electrician for Boeing & he runs a couple of 6V golf cart batteries in his LSV. He charges with a golf cart charger that cost him like $500. They last for about 3 or 4 days without any issues, and he's running a stupid amount of watts driving 2 big NVS tower speakers. But he can't leave the boat in the water for more than that 4 days or he won't have a stereo any more.

Another guy I ride with looked into 6V batteries for his LSV last summer & came to a similar conclusion as PDXLSV. He keeps his boat on the lake for long periods too so he ended up going with 1 Deka starter & 2 group 27 Deka deep cycles driving a big Exile system. He has an on-board charger for when it's the in the garage & the stock alternator for when it's being kept on the dock all summer. His batteries have a ton of reserve (I don't recall how many hours). The only downfall is if one fails when we're on a week long trip at Shasta, he might have a tough time getting a replacement easily. Whereas I can get one from any DieHard dealer (Sears or Kmart).

I disagree with your comment about easily replacing one battery in a parallel circuit when one fails.

Each battery will have a specific output when purchased. This is why you buy batteries at the same time and same model when used in parallel. Batteries seeing similar service will degrade on a similar level. When one battery dies, the other one won't be far off. If you install a brand new battery in parallel with an old battery, it will wear out the new battery very quickly. This is because the new battery sees this old battery as a load. It will try to "charge" up the old battery..

[MLA]

Yea, I get that. But every guy I know who runs 6 volt batteries uses some really high end, expensive charger to keep them charged up. Many are not being charged by the boat's system or won't charge them fully.

Once a pair of 6V GC's are wired together in series, they become one 12V battery. So you would choose the proper charger for them, same as you would any other shore charger.

The alternators ability or lack there of, to recharge a house battery bank, will hing more on the size of the bank in terms of total amp hours and not the type or actual number of batteries and how deeply that bank is discharged while at anchor. The larger the bank gets, the more you would need to depend on shore charging and less on the alternator. Alternators make for poor battery chargers, and will struggle to recharge a depleted battery, regardless of type and Ah. A larger bank just compounds the problem.

I think you guys are missing the point. A lot of these boats don't have access to shore power. The alternator has to do the job for weeks or months on end. The only time the boat sees AC for the on-board charger (in my case) is winter, or maybe a few times during the season if I'm out of town.

Not having access to A/C shore charging doesnt change my reply above. But not having access to A/C does change the question. Having 2 6V wired in series or 2 12V wired in parallel makes no difference. All the alternator knows is the load. The load is the stereo or other accessories and the depleted house bank. It doesnt know if thats made up of two 6V GC's wired in series to 12V or two 12V wired in parallel to combine their Ah. All it know is load. Running 2 6V GC's will not make you any more dependent on shore charging then running two 12V batteries in parallel. How the system is uses on a regular basis and the size (total Ah) of the battery bank, will make you more or less dependent on shore charging.

Now, for those with moderate to large stereo system, moderate to large Ah battery banks and spend a great deal of time playing the system while at anchor, will need to depend more on shore charging.

For those fall into the above category and do not have access to A/C, have a unique challenge. Upgrading the alternator to a large hi-output alternator will help replenish the batteries quicker then the typical stock alternator, but they are expensive and its not safe to run the engine at anchor due to CO. Even then, recharging a large dead battery bank is a task.

If you do not spend considerable time playing at anchor, then a large battery bank is not needed and you will likely not need to rely on shore charging as your batteries will likely no be depleted at the end of a day riding.

[Try2paz]

I ran two 6v batts in my last boat and loved them.

225 ah vs 55 is a no brainier if you have the space and don't mind a little maintenance.

http://www.altestore.com/store/Deep-Cycle-Batteries/Batteries-Flooded-Lead-Acid/Trojan-T-105-6V-225AH-20HR-Flooded-Lead-Acid-Battery/p1771/

I'm looking at the Deka agm for the new boat as the location is limited on height and I won't be able to run a batt box.

[Wake jumper]

The absolute best that anyone can put in a boat for a serious stereo is XS D3100. They are $369 each but well worth the money.

110 AMP hours per battery. Not bad.

[justgary]

The other reason to use a shore charger even if you don't have to is that different battery chemistries have unique charging profiles. The one-size-fits-all regulator in your boat is not sufficient if you want to optimize the capacity and lifetime of your batteries.

As for me, I have no need for an extra battery bank in my boat, but I do use 6V golf cart batteries in an off-grid solar charging system. They are not maintenance free, so I have to check the water level, they outgas, etc., but I get much better life out of them than I would with 12V batteries. Like others have said, if you just run your equipment while the engine can charge the batteries, it won't matter much what you do. If you really need deep cycle performance between charges, the series 6V batteries are probably a better choice.

Regards,

- Just Gary

[PDXVLX]

I have since learned that 6V batteries are the way to go, that's why all the motorhomes and golfcarts use 6V for their deep cell bank. My local golfcart dealer said that 6V batteries use more lead in their batteries due to the larger/deeper plates and as a result can achieve more deep cell cycles than 12V batteries with shorter plates. In addition, with dual 6V's on a 12V charger both batteries can be charged to their peak potential. With dual 12V in parallel, one of the batteries will be a drain on the peak perfomer due to the differences in profiles (even if identical). I picked up a pair of Trojan T105s with 225AH/447RC for $116 each from pnwyamaha. The Trojan T145s @ 244AH/530RC would have given me more juice but the cost of the T105s was a great deal. The golfcart dealer mentioned that they tried US Battery, Interstate, etc and none of them could achieve then number of deep cell cycles that the Trojan batteries could. Take a look around the camping and golf cart forumns, you may reach the same conclusion I did. Hope this helps.

[Bawshogg]

Regardless of 6v or 12v batteries, a good charger is a must have if you have a large bank of anything with any kind of decent AH ratings.

The big stereo systems are taxing on batteries in the marine environment and you should never rely on just the alternator to charge them. Your are asking for a shortened life span without a decent charger in the mix.

Edited January 4, 2014 by Bobby Bright

[Greeko]

Regardless of 6v or 12v batteries, a good charger is a must have if you have a large bank of anything with any kind of decent AH ratings.

The big stereo systems are taxing on batteries in the marine environment and you should never rely on just the alternator to charge them. Your are asking for a shortened life span without a decent charger in the mix.

I'm with bobby on this one. With a stereo bank of 200ish and house bank of 50-100 you can get away with a promariner20. If you call pro marine directly they will sell u one for $115. This is what I have used to keep the batteries charged up. It's not the high end dry mount charger but it still works well... Just takes a little longer. I think the rule of thumb is use a charger that is 8-10% the current size of your ah.. So 200 ah = 16-20 a charger.

I keep my boat in the water for the summer but I still pull it out every 3 weeks to scrub the bottom and top up the batteries with the charger...

[JohnnyDefacto]

I run two Kinetiks HC1800

x2 I run 2 of these (HC2000's) in my boat since 2007. I got a screaming deal of $480 for both delivered to my door (normally about $400 each). I have had them in my old boat, and moved them to my new boat. 6 full seasons and not a single issue. I use them as you would use 2 12 volt optima's, have them on a perk switch and are charged by my alternator. I have tended them in the winter for a couple months if I was not using my boat, but other than that, they are maintenance free. They are sealed and can be mounted anywhere, sideways, upsides down….etc. I have completely killed one battery on accident one time on the water, started the boat on the other battery, switched to "both", ran around for a little bit, and was able to start the boat on either battery again. They are competition audio batteries for cars (audio systems or hydraulic systems) and are true deep cycle, not hybrids, that are meant to be cycled really low.

When and IF these things ever go bad, I will gladly pay $800 to do it again.

[JohnnyDefacto]

killer deal right here….

http://www.rakuten.com/prod/kinetik-khc1800-vehicle-battery-81000-mah-sealed-lead-acid-12-v-dc/202695406.html?listingId=-1

[PDXVLX]

I forgot to add that if you use a flooded battery, this site provides two additional benefits the 6V batteries have over 12V flooded batteries due to the taller height:

http://www.pbase.com/mainecruising/flooded_battery_orientation (scroll down to the middle section).

[nwwakesurf]

I know this is an old thread but I found it while researching AGM options for boat. I had an Interstate flooded battery explode in a dock box on my dock. We were right next to it in the boat. It was really loud and spewed out a toxic plume of gas and acid. I have nightmares thinking about what would have happened if my kid was standing next to it. And I had my face right over that battery the day before. So I am a bit paranoid about keeping two Interstate flooded batteries on my boat. Anyway be careful with them and keep those battery boxes secured.