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-   -   Gel or Wet cell batteries? (http://www.sailnet.com/forums/gear-maintenance/35539-gel-wet-cell-batteries.html)

sailbear50 07-31-2007 12:56 AM

Gel or Wet cell batteries?
 
My Morgan 43 had (4) 6v wet cell bats and (1) 12v wet for the windlass. Would like to change the arrangement and have a separate starting bat, Suggestions, open to ideas more bats? There is a 8kw westerbeke on board also. Are the gel bats a good idea? Thanks

wind_magic 07-31-2007 01:15 AM

Opinions vary on this.

All I can tell you is what I'm doing.

For me it's driven by cost/benefit, and wet cells win. Too much of a premium on gel cells, and I don't like their charge characteristics. With a wet cell I know what I'm getting, and I like how much I'm paying for it.

Edit, and I will add this too. Arizona Wind and Sun is a big outfit that sells a lot of solar panels and systems for homes and other uses. Here is what they say in their Deep Cycle Battery FAQ about Gel Cells. See the bold print below (added for emphasis).

Quote:

Originally Posted by Deep Cycle Battery FAQ
Some other disadvantages of gel cells is that they must be charged at a lower voltage (2/10th's less) than flooded or AGM batteries. If overcharged, voids can develop in the gel which will never heal, causing a loss in battery capacity. In hot climates, water loss can be enough over 2-4 years to cause premature battery death. It is for this and other reasons that we no longer sell any of the gelled cells except for replacement use. The newer AGM (absorbed glass mat) batteries have all the advantages (and then some) of gelled, with none of the disadvantages.

And then later in their FAQ they say this ...

Quote:

Originally Posted by Deep Cycle Battery FAQ
Even with all the advantages listed above, there is still a place for the standard flooded deep cycle battery. AGM's will cost 2 to 3 times as much as flooded batteries of the same capacity. In many installations, where the batteries are set in an area where you don't have to worry about fumes or leakage, a standard or industrial deep cycle is a better economic choice. AGM batteries main advantages are no maintenance, completely sealed against fumes, Hydrogen, or leakage, non-spilling even if they are broken, and can survive most freezes. Not everyone needs these features.

Which pretty well sums up why I am using wet cells.

rewell6 07-31-2007 09:41 AM

The only time I bought anything other than wet cells was for a PWC. And I only bought AGM's because I knew it would spend some time upside down.:D :D

camaraderie 07-31-2007 10:38 AM

I would note that GEL cells really are not used much on boats these days and AGM's are the preferred type of "no maintenance" batteries.
While I would agree that wet cells are the most economical solution long term if you are NOT living aboard and at anchor much of the time....decent AGM's are actually more economical long term if you ARE living aboard for several reasons:
1. # of life cycles of recharging is several times greater than wet cells
2 the SPEED of recharging since you you can recharge at 100% of capacity rather tha 20% of capacity saves $$ in diesel since you can recharge fully in far less time.

As to the original question...many times a separate battery for the windlass is wired in to avoid long runs of necessarilly VERY thick and expensive power cables from far away. Consider this before you change your set up arrangements.
As to adding a separate engine start battery, there is no problem with that if you just add in another Perko switch (1-2-both-off).
Do NOT mix battery types...go all AGM if you are a full time cruiser or all wet cell if you are not (and don't need the maintenance free aspects). You may vary battery capacities as long as the type doesn't change.

Cruisingdad 07-31-2007 10:46 AM

If you are a laker or weekender, just buy a wet. If you are a cruiser, don't buy a wet. Buy a AGM (and not a gell - those are junk). I will never put another wet in my boat. Contact Lifeline or go directly to Deka. Lifelines seem to be better, but cost a lot more than Dekas. Cam put Dekas in his tub and they served him well. If he had put Lifelines in, he would have already sold his boat - keep that in mind. (smile).

- CD

PS If you want to go directly to Lifeline, PM me and I will give you contacts.

camaraderie 07-31-2007 10:59 AM

I would have put in Lifeline AGM's but finally decided to invest my cash in a seaworthy boat rather than an accessory platform!! :D:D:D:D:D

Cruisingdad 07-31-2007 11:05 AM

Quote:

Originally Posted by camaraderie (Post 173502)
I would have put in Lifeline AGM's but finally decided to invest my cash in a seaworthy boat rather than an accessory platform!! :D:D:D:D:D

HAHAHAHAHAHAAHHA!!!!!!

wind_magic 07-31-2007 11:17 AM

Quote:

Originally Posted by camaraderie (Post 173492)
While I would agree that wet cells are the most economical solution long term if you are NOT living aboard and at anchor much of the time....decent AGM's are actually more economical long term if you ARE living aboard for several reasons:
1. # of life cycles of recharging is several times greater than wet cells
2 the SPEED of recharging since you you can recharge at 100% of capacity rather tha 20% of capacity saves $$ in diesel since you can recharge fully in far less time.

Before I make comments let me say that Cam has more practical experience with AGM's than I do. So, though I disagree somewhat on his point #1, it is with respect that I do so.

#1 - I have not seen any data that shows AGM's last longer than wet cells, in fact, I have seen data showing that GOOD wet cells can outlast AGM batteries by up to 400%. AGM's do have a better lifetime than golf cart deep cycle wet cells but only by about 20%. This assumes properly maintained wet cells which is really big assumption, because wet cells are easier to kill if you don't take care of them (i.e. check water, etc). I have seen HYPE that says AGM's last longer than wet cells, and it sounds a whole lot like the same hype that said gel cells were going to take over the entire battery world.

#2 - Cam is right, AGM's can take a full on charge and wet cells can't, and that does matter when charging from a generator or alternator. That isn't an issue though when using wind and solar for most of your power generation, and it's less of an issue with a large battery bank. Depending on how you are charging batteries I think this could be a deciding factor.

Quote:

Originally Posted by camaraderie (Post 173492)
Do NOT mix battery types...go all AGM if you are a full time cruiser or all wet cell if you are not (and don't need the maintenance free aspects). You may vary battery capacities as long as the type doesn't change.

I don't think it's as simple as wet if the boat is sitting and AGM's for cruising. You can get more bang for the buck with wet. I agree if you have limited space (we all do) and you can only fit 8 batteries, or 10, or whatever, and you want the best bank you can get regardless of the money, then yes, buy the AGM. But if you are like me where space isn't the overall limiting factor and money does actually influence your decisions, then you can have a battery bank 2-3 times BIGGER if you buy wet over AGM, and that's not something to be taken lightly (it certainly will be hard to take it "lightly" when you have to carry all those freaking batteries LOL). Say that again, if you have 1000$us to spend, you can get 2 - 3 times the number of amp hours with wet cells as you can with AGM. With the cost of lead going sky high for wet cells, maybe AGM's will eventually make that less of an issue.

camaraderie 07-31-2007 11:39 AM

Hey Wind...All good points....but read this and you will have a better sense of where I get my opinions. Work out the graph on the last page for your own best solution!
http://www.vonwentzel.net/Battery/01.Type/index.html

Have to run...will chat more on this later.

wind_magic 07-31-2007 11:42 AM

Thanks for the link Cam, I'll give it a good read in a bit. I have to get out of here too and get some stuff done. :D


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