New Batteries

My boat came with three Optima Blue Top batteries that are supposed to be maintenance free. While I've only had the boat a short while the knowledgable guys at my boat house agree that they're some of the best marine batteries.
 
Norm - for a boat your size, I would recommend to go with Group 31 AGM batteries. Trojan has an excellent reputation. Lifelines are supposed to be good too. The above recommendation assumes that you have the standard 3 or 4 group 27 battery setup that Sea Ray generally uses and that your automatic charger is capable of handling AGM battteries.

Because of the horrendous battery accessibility on Reflection (you 310 owners know what I mean) I opted for 3 group 31's and did have to replace my charger to the tune of about $300. It was still worth it to NOT have to go through the midget contortionist routine just to check the :smt021 battery water level!
 
Chris,

Right-on about the 310 battery location.

I thought the fully automatic charger on Sea Rays would do AGM. How did you determine that it had to be replaced? Also, what did the batteries cost?
 
I have never used either the Liveline or the Optima batteries, but I have used AGM batteries for remote telecommunications sites.
I think either of these two mentioned batteries would be a good choice where you have limited access to the battery for adding water.

Below is a link for charging a Liveline AGM battery, also one for the Optima. If you do a search on the web you will find it is stressed not to overcharge an AGM battery.

AGM batteries are built so that the hydrogen and oxygen that is produced during charging are contained in the cell and recombine. Thus there is no water loss. The internal of the cell may be under slight positive pressure. Normally there is a relief valve hidden somewhere on the battery that relieves pressure if it builds up too much inside the battery. If this happens during charging, then you will lose hydrogen and oxygen, and thus water. This will cause the cell to dry out. So you want to limit your charging voltage so that you are not causing so much internal gassing in the AGM battery that some might be forced out. This is not an issue with a wet cell, you just add more water (except it can be VERY INCONVENIENT).

It is therefore important that you not exceed the recommended charge and float voltage for the AGM batteries. For whatever battery you choose, you should find out what that manufacturer specs for charging and follow it.

Note that Lifeline specifies about 2.23 volts per cell (13.36 volts overall) for floating the battery, and one volt above that for bulk charging. Normal float for a wet cell is 2.25 to 2.27 volts per cell.

For the Optima battery, the float voltage is listed as 13.2 to 13.8 volts, or 2.2 to 2.3 volts per cell. But then they qualify that by saying you have to limit the float current into the battery to 1 amp for long term floating. So to do that, you would need to be able to check the current into the battery during float, and verify it is not over 1 amp.

For reference, a fully charged cell normally measures about 2.13 --2.18 volts with no charger or load attached (12.8 to 13.1 volts overall). So in float you are applying about 0.1 to 0.15 volt per cell over the fully charged voltage. I see the Optima battery has lead-tin plates, and it lists an open circuit voltage of 13.1 volts, or 2.18 volts per cell.


If your charger can meet these requirements, then you don't need a new charger. Basically, you should have a three stage charger that has a setting for AGM batteries, and whose output voltage is temperature compensated (see the Lifeline float voltage chart). The charger may have a remote temperature senor that you can put near the battery so the charger will know what the temp at the battery is.


http://www.lifelinebatteries.com/marinegraphs.php
http://www.optimabatteries.com/publ...nfig/product_info/marine/technical_specs.html


Each cell in a battery is a separate critter, can be slightly different internal voltage, and each will have its own internal discharge rate. You need to apply enough voltage that the lowest voltage cell gets at least 2.15 volts applied across it, even if the others go a bit higher. Doing this will insure that you are applying enough current so that the cell with the highest internal discharge rate does not begin to drop below the fully charged level. So floating above the fully charged level a bit helps insure this.

Equalizing from time to time, where you apply a higher voltage for a few hours or a day, helps even more to bring each cell's voltage in line with the others (thus equalizing). What it primarily does is bring up any low cells. In batteries like we have in out boats with multiple cells per case, you can't measure the voltage of each cell, so you don't really know if a battery needs equalizing or not. In an AGM battery you also can't measure the electrolyte specific gravity to determine cell charge, so you just need to go carefully by the manufacturers recommendation.

One question you might have is how you can know what current is really going into the battery at various times. In my experience, a commercial AGM battery will have a float current of around 0.1 to 0.2 mA per amp hour of capacity. So for a group 31 battery, which is about a 50 amp-hr battery, I would expect the float current into the battery to dtop to about 5 to 10 mA. With the batteries I have worked with, when the float current gets to about 1mA per amp-hr capacity, or 50 mA for a 50 amp-hr battery, it is time to think about replacement. I don't know if this holds true for the Lifeline and Optima batteries, but I would suspect so.

Measuring currents like these, if you wish to keep up with what you battery is doing, requires special test equipment. The only clamp on ammeter that I know of that can measure these low levels of DC current with suitable accuracy is the Extech model 38042. I carry one of these on my boat, plus an accurate multimeter.

Sorry for the long post.

This thread belongs in the electrical section.
 
Thanks, Dave.


Any chance you could post a picture of the Glaspar?
 
Ron - sorry for the late reply - The newer chargers have a switch for AGM / Gel. I had the older version of Charles Industries C-charger that did not have the switch. Recommended by the local marine electrician that I just change it out. (The ampmeter was acting up too.)

I paid $182 each for Trojan Group 31's at a local battery shop. They aint cheap, but I'm not worrying about them anymore, either.
 
Thought I should do a reality check on all the stuff I wrote at midnight two days ago. My boat has been sitting in my shop for the last month plugged in to shore power. I have not done anything to it except add significant water to all the batteries about 2 or 3 weeks ago. By now the effect of adding water should be over.

My battery switch is in both. The SeaRay provided converter is turned off. All batteries are being charged by the Xantrex inverter/charger. I have two start batteries connected in parallel on position 1 of the battery selector switch. I have two sets of Exide GC3 golf cart batteries connected in parallel on position 2 of the selector switch. So in both, all these batteries are connected together, and were being floated by the Xantrex inverter. I measured the float voltage, plus each batteries float current. Here is what I found.

Float voltage was 13.39 volts, or 2.232 volts per cell. A conservative low number, I think.

Golf cart battery set 1, Exide GC3, manufactured July 2004, 200 amp-hr capacity roughly. Drawing 70 mA of float current. This is then about 0.35 mA per amp hr capacity, which fits nicely in with the numbers I posted I used as a guide for AGM battery aging.

Golf cart battery set 2, same info as above, was drawing 90 mA, or 0.45mA/amp-hr.

Rear start battery, a Stowaway ST27DP700 (group 27, dual purpose, 700 cramking amps) with Reserve Capacity of 160 (160 min discharge at 25 amps = 2 2/3 hrs at 25 amps = 66 amp hrs at 25 A). Probably close to an 80 amp-hr battery at low discharge rate, manufactured Sept 02. This battery was drawing 70 mA, about 0.9 mA/amp-hr.

Front start battery, same type, was drawing 90 mA, about 1.1mA/Amp hr capacity.

So the two start batteries, which are deep cycle/start dual purpose batteries which are normal wet cell, not sealed, are at what I would use for a limit for AGM batteries for float current. But I have no idea if this parameter even applies for normal wet cell batteries. These batteries are now 4 years old, so if I keep track of things, maybe I will find out.

http://www.classicglasspars.com/index.php?option=com_content&task=view&id=79&Itemid=46
 

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i replaced the two deep cycle 27s that were connected in parallel with deep cycle 31s from sams club (stoaway - $69.00). these are for house duties and to start the stbd engine. they worked like champs all season and when i took them out this fall after a week on land (and no charging) they were steady at 13.04 volts. my other single battery (a 27 Ever-Start) is a purely a starting battery - and serves the port engine and genny. it's stamped H-1 (august of 2001). it came with the boat and continues to perform admirably and it too holds a charge at over 13v.

maybe someone can enlighten me, but i dont see the lure of the above mentioned super-expensive batteries, unless you are on a mooring and dont have the ability to continually trickle charge your batteries.
 
I pretty much like the old style lead acid batts the best. Cheap to replace and they last for about four to five years in tha boat ( I never remove them) with being excercised and on the battery tender all the time. I feel no need to spend the extra money for Optimas or other AGMs ...
 
It all depends on what your needs for a battery are, and maybe what your perspective is. I come from the telecom world, where our batteries were guaranteed for 20 years, and it was not uncommon for them be last 25 years. These were wet lead-calcium batteries. Then the company started replacing them with AGM batteries, also guaranteed for 20 years. They started failing at 9 to 10 years, and were very high maintenance compared to the wet cell batteries. So we learned our lesson about that and began replacing the AGM with wet cell lead-calcium again. Our requirements were for a battery that would last a long time, and number of deep cycles was not important as they did not sustain many discharge cycles.

For a boat there are two or three basics types of need. One is a start battery only. For that, a sealed lead-calcium battery with low internal discharge and a designed life of maybe 5 years or so is a good fit. The lead-calcium means that the battery does not gas much, so does not lose water very quickly. Discharging this type of battery to only 20% charge or so frequently will kill it in a hurry, but that does not happen with a start battery if properly maintained. This type of battery typically has thin plates, and lots of them, so you have high surface area for lots of cranking amps. It is pretty much the same application as an auto battery, except it may need to be more rugged.

A second application is as a house battery, paired with an inverter. This system would provide 120V AC and maybe 12V DC while not on shore power. This configuration has much the same use as a generator, except with much more limited kWhr capacity. For this application you would expect to cycle the battery, down to at least 50%, and maybe more. And do it a lot of times. For this, you don't want a thin plate lead-calcium battery, but want a thick plate wet cell lead-antimony or an AGM battery. The wet cell, if properly maintained, will likely outlast the AGM, but the AGM does not require the addition of water. So that really fills the bill for the original question in this long topic.

Or go with the AGM batteries. I suspect you get what you pay for. You might buy cheaper ones that last a few years. If you pay a lot, you might end up with something with a 10 year or more guarantee.

The third thing would be a dual purpose start and house battery. You probably won't get by well with a normal start battery, it won't tolerate deep discharges. So you need an RV type battery, at least. But a typical golf cart battery that is wet cell, if large enough to crank your engine, will work as well or better. And they are cheap. You just need to add water, because the antimony causes higher water loss than calcium. You also need to make sure you charge them frequently, as they have a ligher self-discharge rate.

With the Optima or other AGM battery you get freedom from watering the battery. I am sure that for some, that is reason enough. If you can't reasonbly get to the top of you battery to add water, then AGM seems a simple choice. Looking at a link to the Optima battery, I see they claim it loses less than half a volt when stored for six months. This means you can leave it in your boat over the winter, with the load removed, and not have to worry about charging it. It won't suffer a deep discharge like a wet cell lead-antimony battery would. Some people have their boats stacked inside in the winter, and may have to pay extra for keeping the batteries charged.

With the Optima construction, the lead is not formed in plates that have to have another metal added to make them strong enough. The plates are rolled up, and supported by the case. So as I read their web site, they don't need to add the antimony that causes water loss and self discharge, nor the calcium that causes poor deep cycle performance.

One issue with some AGM batteries is that they are more temperature sensitive than the other style batteries. Much over 100 dgrees and they start to degrade rather quickly (ones with tin may be the exception). So if you lived in the desert southwest, and your boat were commonly exposed to 115 degrees, I think AGM batteries might not last well. And you would not want them to be on charge at that temperature, that only raises the battery above ambient temperature. As the cell temperature goes up, the cell voltage goes down. If you have a charger attached that does not sense battery temperature and compensate for it, then it will try harder to keep the cell voltage up. That will make the cell even hotter, the cell voltage lower, and on and on, maybe until something gives.

Here is a link that talks about thermal runaway. It points out that using nearly pure lead with a small amount of tin, (I think no calcium or antimony) will go a long ways towards preventing this unlikely but not impossible scenario. I think I remember reading that the Optima uses tin. It can do this because the spiral wound constructon does not require the plates to be strong enough to be self supporting.

http://www.enersysinc.com/defense/pdfs/Thermal runaway paper for BATTCON 2005.pdf

So I think it mainly is a matter of what you need your battery to do. You need to answer that question first, then you can make better choices. So the first step is to understand the different issues with the different types of batteries so you understand what questions you need to be asking yourself about what your battery requirements are.

I am currently in the cheap, reliable if maintained, wet cell deep cycle category, especially for the house battery. Also guilty of an overly-long post again. :smt018
 
Chris,

thanks. I'll look for an AGM switch on the charger. Probably did not have them back in 1999. If not, I will stick with lead-acid.
 
Dave,

Interesting Glaspar design. I did not see any like that when I was growing up on Long Island. However I recognized some from the web site. We had a Winner runabout.
 
The other issue that keeps me away from Optimas and AGM is the fact that both, Optima and AGM have had their significant share of problems with early failure. Further when AGMs fail, they do on the spot from godd to no power. They do not "annouce" their failure like lead acid batteries
 
Like Ron had mentioned before, I have used lead-acid batteries exclusively. For me, they fit my needs nicely. I use 3 group 31's (combo start/deep cycle). I currently have 2 Excide Gold group 31's from 2000 ($120 at Boaters World) and they are still going strong. The other is a Sam's Club Stow-away (same spec's as the Excides) which cost me $69 last year (Sept 2005). Unless this new one fails prematurely, I plan to replace the excide golds with the Stowaways and save $60 each. I have to check the water level mid-summer and they typically dont need anything but a top off (probably dont even need that, but while I'm in there...) :wink:

Again, I dont have any crazy requirements for deep cycling or starting, but they have never failed me yet. I also keep the charger on 24x7.
 
Consumer reports is a great source for unbiased battery quality tests ... unfortunately they only test starter batteries. I had good luck with Interstate, even though they do not test that well in CR.
 
Alex D said:
The other issue that keeps me away from Optimas and AGM is the fact that both, Optima and AGM have had their significant share of problems with early failure. Further when AGMs fail, they do on the spot from godd to no power. They do not "annouce" their failure like lead acid batteries
Click to expand...

I believe AGMs can be load tested at the end of the season or prior to the start of boating and this will give you an indication of the likely remaining life. At least that is what my yard is saying. Tiara just switched back to flooded batteries because of the high cost without added life of AGMs. The value was not there. Many of their boats are sold in Florida and heat could be the culprit. I plan to stay with AGMs and test them because it is very difficult to get to my batteries. Having to check them monthly would be a real PITA.
 
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