AGM vs Flood cell

Ardea · **Joined:** 19 Mar 2007 16:40 **Posts:** 195

I've been using 4 Trojan T-105s since we bought Ardea. The current set is 4 1/2 years old and my charger is disqualifying the bank because is detects a problem with at least one battery. Most of them are visibly sulfated so that's must be why they call it a smart charger. Prices have skyrocketed since I bought this set so I'm looking for more longevity out of the next set. AGMs are looking good to me for a number of reasons (no gassing, no spilling, no watering, no maintenance, etc.) at about a 50% increase in price over the T-105s. I think I could have gotten a little more life out of the T-105s had I equalized them periodically. I buy them from a local outfit that supplies golf courses and the golf courses replace them every two year so for them equalizing is something they don't do. For this reason I think they told me not to equalize them but I think I get stratification of the electrolyte from light or non-use (a daysail doesn't use much power). Soooo, I've been eyeballing a couple of 4D AGMs to replace them with and was wondering what kind of life people are getting out of AGMs and what if any special care you give them.

-Jim

Velera · **Joined:** 29 Dec 2006 09:38 **Posts:** 656

I would say that going to AGMs is not going to solve whatever electrical problem you have if your flooded cells are spent after 4 years. I have used flooded golf cart batteries for the last 19 years (on my third set) and really never had to replace them, just did it because I was told that they are not reliable beyond 6 years. I am not sure where you are getting your batteries or information, but Jim Ramos at American Battery in Hayward is a live aboard and knows more about batteries and charging than any person I have every met. He told me not to equalize them as this is a process for other kinds of industrial batteries (which he sells and services as well). My current flooded batteries are 6 years old, worked for a couple years and many many cycles of tropical cruising and show very little sulfation, I am deliberating whether to replace them but there is no real reason to do so.

Ray

Tortuga's Lie · **Joined:** 27 Oct 2006 10:32 **Posts:** 827

Ray,
Out of curiousity, which brand of golf cart batteries did you go with? I have always heard that Trojan is the best, but I went cheap and I am trying the Werker brand from Battery Warehouse. I figured I would field test them and so far so good. I have only 3 years on them so far, but time will tell if saving money is worth it.

Tom

Ardea · **Joined:** 19 Mar 2007 16:40 **Posts:** 195

Most retailers rate the T-105s for 2 to 7 years. I have 4 1/2 years on them. I get the batteries from the Trojan dealer in San Jose and get my info from all over but mostly from Nigel Calder. The dealer I bought them from replaces them in golf carts after 2 years and some retailers rate them from 2 to 7 years. I would assume 7 years would be in a home solar system. They don't become unreliable but lose capacity until there is not enough capacity to run the boats electrics for a reasonable amount of time. It's not an instantanious process. I'm at a loss to understand why some one would recommend not equalizing the trojans but it's ok for other flooded cell industrial batteries. Or for that matter what harm it would do the Trojans. I'd be curious to hear the explanation.

My charging system is state of the art. I suspect they sulfate due to non use. In 2009 we didn't hardly use the boat at all. Cycling them keeps the electorlyte mixed up. Ever wonder why you charge them before taking a hydrometer reading? It's because the acid ends up in the bottom of the cells and the water at the top. I probably should be equalizing them periodically for that reason. In any case it's not only the life span as no maintenance and no gassing aspects that appeal to me in the AGMs. So perhaps some one will chime that is using AGMs.

Ardea · **Joined:** 19 Mar 2007 16:40 **Posts:** 195

Just to avoid any confusion here is what Trojan has to say about equalization of batteries:

"Many experts recommend that batteries be equalized periodically, ranging anywhere from once a month to once or twice per year. However, Trojan only recommends equalizing when low or wide ranging specific gravity (+/- .015) are detected after fully charging a battery."

This sort of goes without saying as the first step in equalizing a battery is to record the specific gravity reading taken from each cell with a temperature compensated hydrometer. If at that point the numbers indicate that an equalization charge is warrented then you have at it. Without the hydrometer readings it would be akin to abitrarily putting air in you car tires. The hydrometer is also used to determine when to end the equalization process. It's not just a time thang. This is another reason for me to consider AGMs. I really hate this process as it's messy and usually takes me all day.

Velera · **Joined:** 29 Dec 2006 09:38 **Posts:** 656

Jim--

I use the cheap golf cart batteries offered by American Battery. I, too have been told how superior Rolls, Trojan and others are, but I would be hard pressed to spend the extra cash based on my experience. My standard batteries have lasted (actually there was only a modest reduction in their capacity at the end--I pre emptively replaced them to avoid future problems) six years. The current ones measure only slightly reduced in capacity (sp. gr) after 5 years, two seasons of which were when I was cruising in the tropics and running my old Adler Barbour refrigerator, running my autopilot and computer and lights a lot. I admit that I take very good care of them, cycle them in a shallow manner, charge them with the best systems you can buy, and keep them in distilled water:

1. I have two banks of 220 ah each that I always run as one 440ah bank to minimize the depth of discharge of each cycle. The only reason I have two banks is in case there is a dead cell, I can isolate it from the system--otherwise I would only have one bank. I have no starting battery as you can let batteries sit for a while and an nearly dead battery will come back enough to start the engine--I think the modern thing in robust systems is to leave this out. I like simple and cheap. So my batteries were rarely down more than 25% before being recharged.

2. I have an Ample Power smart regulator with a high output alternator that brings things up really fast and floats the system well. Along with a 40 amp three step shore charger and a 65 watt solar panel on the top of my dodger. I think that, unless you are tied to a first class shore charger most of the time, you need a first class system to recharge fully---I think a lot of problems cruisers have with battery life is: not having enough capacity and drawing them too far down on a regular basis (which kills them) and not having sophisticated systems to fully recharge them (virtually impossible without running the engine many hours because the last bit charge requires a lot of time to be accepted without a sophisticated alternator controller).

I have had awfully good luck with this system over the years. The last time I bought these batteries I think they were about $85 a piece or $320 for the whole bank.

Jim Ramos at American Battery in Hayward is, IMHO, a premier resource on all things having to do with battery systems.

Ardea · **Joined:** 19 Mar 2007 16:40 **Posts:** 195

Well I made up my mind and went with another set of these.

Attachment:

T-105s.JPG [ 104.08 KB | Viewed 0 times ]

I really wanted the 4D AGMs but it was going to turn into a new project to modify the battery box to accept them. But I think the biggest consideration was that I can't lift the 4Ds. The T-105s can be easily...well maybe not easily... installed by yours truly. I'm not sure how many cases of beer it would cost to get the 4Ds installed. Cheers

So I'll just keep watering batteries for a few more years.

Jim

curriernh · **Joined:** 14 Jul 2011 07:14 **Posts:** 60

The PO of my boat said the T-105's are 8 years old and are still going strong. I hedged on that....maybe we'll get more life but I struck a deal with my offer which covered roughly 50% of the replacement cost.....

I think he kept the boat on shore power most of the time except for a few week or two trips here and there.

I haven't checked specific gravity but the smart shore charger isn't complaining about anything when I've plugged it in (I keep her on a mooring so need to figure out a solar solution). I've got 4 house batteries so am looking at roughly $500 to replace them. I'll try to squeeze out another season if I can; who know, maybe I'll be one of the lucky ones who see's them last 20 years Smile

Ardea · **Joined:** 19 Mar 2007 16:40 **Posts:** 195

Keep in mind that specific gravity won't give you an indication of the capicity left in the batteries. For that you need a load test. My old batteries were charging fine and the specific gravity as checked with a hydrometer was good and even cell to cell but I had greatly reduced capacity. If you don't have refrigeration of other power hogs then the batteries my last some time longer.

BTW I bought my last set from an outfit in AZ. You pay them with credit card and then pick the batteries up at the Trojan dealer nearest you. It was the best price I found and they were $131 each,

Tartan37.com

AGM vs Flood cell

Who is online