Battery Selection?

[sabray]

Adhere to the charge schedule of the batts. My lifelines have done well. Solar charged and minimal deep drain. 7 years now and still holding. I will go lipo batts next go round. Then my charge gear will be ready for upgrade and the system will need all the next gen stuff. Right now this has worked well and doesn't need replacing. Thinking ahead. I did zip mntc except checking leads and changing how the connections were arranged.

[mitiempo]

Originally Posted by TxCoastSailor

OK all you battery wizards talk to me about Gel cells. Do they offer the tolerance to undercharging of flooded batteries in a maintenance free package???

Gels are one of the longest lasting of the conventional 3 types available. They seem to have become rare though, Agm's being the hotter choice for many. Their charge profiles are different, lower voltage for bulk charging and higher float voltage (13.8). Make sure you have a 3 stage reg for the alt set properly. Originally developed by Sonnenshein in Germany.

More info here Charging
They are made by Deka in the US now.

[mitiempo]

Originally Posted by rw58ph

What ever battery, do not discharge below 50% or 12.4 volts as that will shorten the battery live. We get 7+ years.

Agree about 50% being the lowest you should discharge to but 12.1 volts is 50% SOC. Trojan chart below

[smac999]

no one has mentioned the biggest difference of agm. safety and cleanness. flooded batteries are just plain nasty. and if it was up to me I'd never install or have to remove another one in my life.

I pulled some agms out of a boat today. lifted them out sideways out of the box. held them up on my lap, then moved them to the salon carpet. totally dry and clean.

[jongleur]

You must add the cost of the clothes you ruin
when you lean on the FLA batteries to the
cost of those batteries.

[mitiempo]

Originally Posted by jongleur

You must add the cost of the clothes you ruin
when you lean on the FLA batteries to the
cost of those batteries.

HaHaHa!

I was looking at smac's post and wondering what to say - you beat me.

I have installed battery banks large and small of each type. Most recently 4 Lifeline 8D's. My choice is flooded for their bang for the dollar, tolerance of under (or over) charging, and reliability if treated properly. I am definitely not a fan of Agm's - too many seem to die young in all kinds of systems. Gel can be a good choice if charging is properly set-up and can be very long lasting but are not as common as they once were.

Golf carts in series/parallel will be my next bank. If I had a larger boat and the budget that goes with it I would still pick flooded, but they would be Rolls/Surrette traction batteries.

"Generally, Gel and Agm batteries have about 20% less capacity, and cost about 2 times more, and have a shorter cycle life than comparable flooded lead acid batteries. However Gel and Agm batteries do not need watering, are safer (no acid spilling out), can be placed in a variety of positions, have a slower self discharge characteristic, and are more efficient in charging and discharging than flooded batteries. Gel batteries are more suitable for deep cycling applications whereas Agm batteries are more for light cycling and engine starting applications."

This is a quote from the Trojan Battery Company - they produce all 3 types.

[sailinglegend]

Originally Posted by mitiempo

...."Generally, Gel and Agm batteries have about 20% less capacity, and cost about 2 times more, ........Gel batteries are more suitable for deep cycling applications whereas Agm batteries are more for light cycling and engine starting applications."

This is a quote from the Trojan Battery Company - they produce all 3 types.

This is also often quoted by Maine Sail - but note that the Para starts with the word "Generally".....

If you look at the benchmark for AGM batteries - LIFELINE - then the Trojan statement does not make any sense.

"Generally" the uniformed make the mistake of buying the wrong kind of AGM, maybe because they go for the cheap option that is "..more for light cycling and engine starting applications" - and then don't install the proper charging regime!

Trojan say charge their batteries at C/5 whereas Lifeline say you can charge up to C x 5.

Trojan say AGMs should not be equalized - unlike Lifeline who recommend regular equalization.

So with Trojan it would seem you are not getting the full benefits of GOOD AGM technology, so you have to take their comments with this in mind.

A new AGM technology that is worth looking at is LEAD CRYSTAL batteries which use a new kind of AGM separator and a crystal electrolyte. They have all the same benefits of good AGMs but claim over 1000 cycles at 80% DoD - that's a 20% State of Charge, can repeatedly go down to zero SoC, and sulfate much less so over a much longer life cycles that FLAs and AGMs. There is another thread on this forum which is a getting a bit bogged down through lack of reliable information - but it has already had a lot of viewers.

[Seman]

In my experience as a full time cruiser, no marinas, running the batteries down to 50 / 60% & not fully charging them, & a lot of my cruising friends, have found that AGM's, doesn't matter what brand, die within 2 years ( my Trojans lasted 14 month ) Cheap wet cells last about the same time.

[sailinglegend]

Originally Posted by Seman

....a lot of my cruising friends, have found that AGM's, doesn't matter what brand, die within 2 years ( my Trojans lasted 14 month ) Cheap wet cells last about the same time.

As a full time cruiser for the past 7 years who rarely goes in a marina except for the winter, my Lifeline AGMs have lasted 10 years. They weren't particularly well looked after for the first three years through ignorance. I only have a 100 amp alternator, 140 watts of solar, and a 280 amp DC genny that has only done 400 hours so doesn't get used that much. The secret is a 1050 Ah bank that doesn't cycle too low.

[Maine Sail]

Originally Posted by sailinglegend

A new AGM technology that is worth looking at is LEAD CRYSTAL batteries which use a new kind of AGM separator and a crystal electrolyte. They have all the same benefits of good AGMs but claim over 1000 cycles at 80% DoD - that's a 20% State of Charge, can repeatedly go down to zero SoC, and sulfate much less so over a much longer life cycles that FLAs and AGMs. There is another thread on this forum which is a getting a bit bogged down through lack of reliable information - but it has already had a lot of viewers.

Sounds similar to the claims originally made by AGM makers when they entered the marine market, most all of which have drastically changed over time? 80% DOD, they don't sulfate yada, yada, yada. Now it is 50% DOD for optimal cycle life, they can and do sulfate etc... I will be very curious to see how this new technology pans out just as I am with LiFePO4.

If you keep AGM's topped up, charged correctly, temp compensated, equalized if Lifelines, they can do fine (marina). If you don't provide proper care and feeding they can be very expensive.. Those acceptance rates also quickly fade off as they sulfate and they pretty much turn into wet cells with regard to acceptance.

I still install LOTS of AGM's but I do not sell them on more cycle life than FLA or GEL and owners know and are educated as to how best to treat them so they can continue to the the fast charging performance they paid for.....

I have a bank of four 6V Lifelines sitting in my shop today that have been kept topped up by solar, temp compensated equalized, charged at close to .3 "C" etc. and they are currently accepting current like flooded batteries and have been for approx two years. They are about 5-6 years old and equalizing has not worked.. They are going through a re-conditioning charge in a few weeks and we'll see if things change...

AGM's can be good but it has to be done as a system not just a battery swap out for it to perform at its best.. There are only two "premium" brands IMHO and those are Lifeline and Odyssey... Still I have never seen anywhere even close to half the face value factory cycle life ratings from either brand when cruised off grid..

Originally Posted by sailinglegend

The secret is a 1050 Ah bank that doesn't cycle too low.

Bingo! Any LA battery will last longer when shallow cycled. I have 8 year old Wal*Mart batteries still putting up 93% of capacity under a 20 hour load test. They were rarely ever cycled below 70% SOC. Total bank cost was about $230.00..... I can buy a few t-shirts for that...

The big issues with MOST AGM installations or any battery installations I come across:

*No idea what SOC the batteries are at, EVER
*Improper charging systems
*Improper charging voltages
*Allowed to sit at less than full for too long
*No temp compensation
*Never equalized (Lifeline)
*In hot engine rooms


That said I have a number of customers with GEL's well past 10 years that do cycle deeply and those batts are still putting up a good fight. The oldest at 14 years old...

[Stu Jackson]

You have an M25 engine. So do I. There are more things you need to do to that engine to make it useful for charging: Make sure you have done the alternator bracket upgrade, the wiring harness connection replacement, getting rid of the ammeter in the cockpit panel. Getting a larger 3 inch HX wouldn't hurt either.

In addition to Maine Sail's points, you could learn a lot from these, since our boats are almost identical:

http://c34.org/bbs/index.php/topic,5078.0.html

Electrical Systems 101 http://c34.org/bbs/index.php/topic,5977.0.html

The best bang for your buck is still either three or four wet cells or 4 golf carts. Learn more about battery technology, use these for now and then make your own informed decision before you head offshore.

This has a ton of M25 engine information: Diesel Engine - C34 It includes sources for HX upgrades.

Good luck.

[TxCoastSailor]

Maine Sail,

I saw your most recent post where you mentioned you have customers with gels that are 14 years old. Are gels more tolerant to the chronic undercharging and deep cycling that appears to be wide spread in the cruising environment than AGMs?

I currently have gels for both starter and house bank but will probably need to replace them before beginning an extended cruise in about 2 years. I'm leaning to going back with gels but I don't want to spend a bunch of extra money on gels vs. flooded and then trash them. I really don't want to have to motor or run my genny for hours on end to get the batteries to 100% SOC. I'm planning to put as many Sobian solar panels as I can get on my bimini but still I don't think the batteries are going to spend a lot of time at 100% SOC. I'm guessing the batteries are going to spend most of their time cycling between 50% and 90% or so SOC but rarely up to 100%. Will gels stand up to that?