Solar and AGM'S

[sailinglegend]

Originally Posted by colemj

....... a constant current will increase the voltage on a battery. If done like Lifeline recommends, the battery voltage will climb to over 15V over that one hour. If left on for more than that hour, you will damage the battery....

You clearly didn't read ALL the manual, nor have taken on board the many postings on here about Lifeline batteries. Lifeline recommend equalising their batteries at 15.5v for 8 hours, and they recommend you should do this once a month if you haven't manage to recharge them to 100%. I equalise mine at least twice a year, and they are now 10 years old after a full time Liveaboard life for the last 7 years.

Your posts are full of opinions with no supporting links. I try and provide reference data which you then interpret your own way.

Originally Posted by colemj

.....Look, I am really not interested in debating this stuff with you. I will post what I do and leave it to others to consider. They can differentiate between correct and incorrect knowledge. ....

Then stop spoiling another post by confusing readers.

[Wotname]

Originally Posted by goboatingnow

Of course , the industry has promoted AGMs as a kind of "super" LA

AGM Positive
Low self discharge, rarely useful on a boat with shore power these days
High C charging, few have the equipment to to just that
Sealed - well if you boat is upside down , a little acid spillage may not be your first concern
Charge efficiency , in reality with the difficulty of returning to 100% this is not attainable

AGM Negatives
Charging Profile - more sensitive to having a particular charging profile
100% recharge - often requiring a return to 100% which is difficult
Sealed - as per all sealed batteries

The fact is the benefits can rarely be accessed and the negatives are typically always present.

I cannot see any reason to buy them , but please put forward one.

dave

Hmm... clearly AGM's don't suit you and perhaps many others

but

They suit me very well, especially the low self discharge and that they are sealed.

I accept the disadvantage of cost and requirement of 100% recharge to get the above positives.

[goboatingnow]

I'm interested in this.

Why is self discharge important. Does your boat spend large amounts of time with no charge source whatsoever and all loads disconnected ?

Dave

[Wotname]

Originally Posted by goboatingnow

I'm interested in this.

Why is self discharge important. Does your boat spend large amounts of time with no charge source whatsoever and all loads disconnected ?

Dave

Yes...

[Ex-Calif]

Originally Posted by goboatingnow

I cannot see any reason to buy them , but please put forward one.

dave

The overwhelmingly predominant reason is they are "maintenance free"

FLA is a pain in the butt... Always has been, always will be.

For the person who doesn't have a job and lives on their boat - they make sense - you have time to maintain them, monitor them etc.

For those of us unfortunate enough to still have to work 50 hours a week. I want to go step on the boat Friday afternoon, flip on the reefer and step off Sunday night.

So I am using 400 amps a week - that's less than 50 a day on average - but the average doesn't matter. I am using 150 a day for 2.5 days. I have 4 1/2 days for the batteries to top up.

With a reasonable amount of solar, a shore charger perhaps - I don't see why an AGM bank won't go 6+ years. I "deep cycle them" a couple of times a week. (Saturday and Sunday. Mine have...

Oh - and I've never done it but they can be installed on their side, apparently...

[sailorboy1]

Seems like this thread lot of extra worry being spent to getting a little more life out of a battery bank.

Maybe time to stop thinking that batteries are made of gold and just go ahead and "use & abuse" the batteries and lose 1-2 years of life from them because of it. What would that cost, $100/yr? Isn't losing $100/yr worth more than all this batteries are made of gold stress?

[Ex-Calif]

Originally Posted by goboatingnow

I'm interested in this.

Why is self discharge important. Does your boat spend large amounts of time with no charge source whatsoever and all loads disconnected ?

Dave

Originally Posted by Wotname

Yes...

Me too...

I can't believe all the cruisers have forgotten what it is to be a weekend warrior? Did you all get "born" living on a boat in the Carribean? - LOL...

Do I try to sail every week? - heck yeah. Do I get to? Heck no!

I can go 6 weeks off the boat if work and life get in the way. I may leave the charger (when I get one) plugged in weekend to weekend. But more likely the solar is going to keep things up to scratch for me. I would never feel comfortable with A/C power on the boat and me out of country or gone for 4+ weeks.

If I end the weekend with a 150 amp deficit I am OK letting the system take care of it self.

[sailorboy1]

Originally Posted by Ex-Calif

The overwhelmingly predominant reason is they are "maintenance free"

FLA is a pain in the butt... Always has been, always will be.

I check the water in my batteries once every month or so and it takes maybe 5 minutes. If this is too much maintenance time you should rethink having a boat I feel!

My boat sits out on a mooring all week with the refrigerator running and a 290W solar panel taking care of the batteries. The beer always being cold is worth a lot more to me than the 5 minutes every month or so.

[Wotname]

Originally Posted by Ex-Calif

The overwhelmingly predominant reason is they are "maintenance free"................
Oh - and I've never done it but they can be installed on their side, apparently...

Not only on their side etc but also right in the middle of your accommodation area

[impi]

Originally Posted by tedsherrin

Thanks everyone for your help.

I've decided and source four 120amp Fullriver AGM batteries which I can get for $330 each seeing I'm buying four. I'm also going to get two replacement 125 watt solar panels to replace the single 80amp I have.

Now someone suggested I also put a separate alternator regulator on as well? Not sure why. I have a 90amp Alternator that I had serviced only last year.

Why do I need a new alternator regulator?

I purchased 8 x 210 AH AGM lifelines about 1 year ago ... I have a very good charging system onboard the boat and record performance ... have not been happy at all! Had an electrician check everything out and write a report ... all wiring is terrific, the charging systems are behaving like they should and we just find they do NOT hold the voltage the same way our EXIDE deep cycle gel batteries did and we had less of them installed.

At huge cost, we are now working out a way to replace them with the EXIDE deep cycle gels again simply because we live on our boat and cannot accept the added weight for less performance.

I am not sure how deep cycle gels perform in these climates, but I can tell you that right up to the time we changed out the Gels in the USA after 4 years and still going strong at that stage (did it because we thought the USA was a great place to do this before heading for the pacific)... we HAD a great system, and after just 3 weeks we reported the AGMs were not performing. Now 1 year later and having done extensive tests at cost we are going back to the gels ...

Lifeline tell me I nee to equalise ... done that ... done everything ... paid the price and got the T-shirt ... I will NEVER have AGMS in a cruising yacht again!

[colemj]

Originally Posted by sailinglegend

You clearly didn't read ALL the manual, nor have taken on board the many postings on here about Lifeline batteries. Lifeline recommend equalising their batteries at 15.5v for 8 hours, and they recommend you should do this once a month if you haven't manage to recharge them to 100%. I equalise mine at least twice a year, and they are now 10 years old after a full time Liveaboard life for the last 7 years.

Your posts are full of opinions with no supporting links. I try and provide reference data which you then interpret your own way.

Then stop spoiling another post by confusing readers.

Pleases go back to my post and point out to me which of those 5 points I posted were my opinion and not taken directly from the Lifeline manual.

Yes, I am fully aware of the need to equalize Lifeline AGM's - the need of which directly contradicts one of the advantages of AGM's, BTW.

However, you again have misread the information presented by Lifeline. In point #5, Lifeline is suggesting a constant current charge to a short equalization every time the batteries are charged (if they are routinely discharged below 50% and you cannot charge them fully with high %C current) - not just a couple of times/yr as routine maintenance.

They also recommend periodic equalization as a matter of course regardless of depth of cycling - as you point out.

These are two different conditions and recommendations that you have conflated.

I apologize that you are confused and hope this helps.

Mark

[sailinglegend]

Originally Posted by Ex-Calif

The overwhelmingly predominant reason is they are "maintenance free"....

For me it is definitely the faster charge, even without a rediculously large charge source. You need to get your head around why and how the charge efficiency does charge AGMs faster.

Originally Posted by Ex-Calif

Oh - and I've never done it but they can be installed on their side, apparently...

Lots of batteries are 'maintenance free' but my starter battery is a very small 'Red Flash' AGM that has been lying on its side under the floor, untouched for 10 years. 37Ah starting a 56 HP Yanmar.

[colemj]

Originally Posted by tedsherrin

And apparently a 120 ah AGM battery is the equivalent of a 130ah wet cell. That's what I've been repeatedly told by people quoting me on AGM's this week.

Quoted by salespeople? I wouldn't put any weight into that one.

Cost? I keep hearing on CF that there much more expensive than wet cell. Well, I'm not convinced that's true. Compared to a car battery, well yes AGM are dearer. But comparing AGM to 'Marine' wet cell, deep cycle batteries there relatively the same price unless going to the upper high industrial AGM's. I'm looking at 120ah AGM's. Because I'm buying four of them, I can get them for $330 each. Wet cell Marine wet cell battery prices for 130ah $280 to $340 for an optima. So for the sake of going maintenance free it would seem the AGM are ahead.

This is probably location dependent. In the US for example, 220Ahr of Lifeline AGM's cost 3x the price of equivalent Trojan FLA's.

Now, because I want 'maintenance free' and leak and gas proof, AGM seem to be the way to go. But I'm also aware that I can get 'maintenance free', wet cells. But, when I've asked about them, for the purpose of a boat, the shop attendants have suggested not a good idea for a sail boat and their longevity is no where near as good as an AGM.

Here you got good advice - "maintenance free" wet cells are not a good choice for a boat.

So, this has led me back to AGM's again. I'm not really picking up 'any' real practical reasons not to have them but I see lots of positives. You have suggested two 'negatives', one being charging profile to which they are sensitive to. Ok, but from what I'm picking up as long as I have a big enough bank for my use, the upgrade in solar and my 90amp alternator will suffice. I think that's what I'm picking up. Your second negative is that they require 100% recharge. Ok, so for a 480ah bank (4x 120), I'm still picking up that my two 120watt solar panels and 90amp regulator (obviously for boosting) would bring them up to 100%?

And my vessel lives on a mooring so I don't have the luxury of shore charging. Though my boats set up for 240v with a marine shore charger. The mooring makes this not possible.

You will be fine on a mooring with solar panels and an OEM alternator. For the time they sit idle, they will be fully charged and mostly on float. When you use them hard on weekends, they will easily recover during the week.

However, you don't require AGM's for this type of usage - FLA's will perform the same too. Even the business of watering them will be greatly reduced with your type of usage (maybe once or twice/yr?), so FLA's will be almost maintenance free too.

In your case, if price is taken out of the equation, there is no practical difference between AGM and FLA in your decision, so AGM's won't be a bad choice.

Mark

[Ex-Calif]

Originally Posted by sailorboy1

I check the water in my batteries once every month or so and it takes maybe 5 minutes. If this is too much maintenance time you should rethink having a boat I feel!

My boat sits out on a mooring all week with the refrigerator running and a 290W solar panel taking care of the batteries. The beer always being cold is worth a lot more to me than the 5 minutes every month or so.

Good on ya!

I have to take out 20 screws, remove the panel that covers the cockpit floor, tip myself upside down in the bilge (two of 3 are aft of the opening), I don't even know if I could really reach the top of my batteries with out unstrapping them and taking them out.

I am not advising anyone to do anything different than what they wanna do. I have no skin in your game - I just know what's worked for me as an admitted weekend warrior for 6 years and doing fine...

201 a/h bank, 70 amp alternator and 40 watts of solar - changing as we speak...

[sailinglegend]

Originally Posted by colemj

Pleases go back to my post and point out to me which of those 5 points I posted were my opinion and not taken directly from the Lifeline manual....

So let me summarize what you have been misinterpreting.

1. (this is a direct quote from the text) "Charging Lifeline AGM batteries is a matter of replacing the energy removed during discharge plus a little extra to make up for charging inefficiency".

Exactly what I have been saying - only a 'little extra charge - 102% to 110% to make up for charge inefficiency. This is a lot lot less than FLAs. I clearly didn't misinterpret this one!

2. Lifeline states that their batteries should be fully charged regularly or they will suffer shorter lives.

Nowhere do they use the word 'regularly' they say 'return the battery to a fully charged condition as soon as possible'


3. The charging current during bulk charging should be as high as possible because that means a faster recharge time. They mention that at 0.25C it will take 4hrs to recharge and at 0.1C it will take 7hrs.

Where have I ever misinterpreted this? It is such an obvious statement.

4. If full recharge is not achieved because the charging time is too slow, then the battery SOC will "gradually walk-down" as it is cycled continually. This will lead to shorter battery life. Again, Lifeline recommends that their batteries be regularly brought to full charge - this is different from FLA's.

Refer to 2 above, and nowhere do they say this is different to charging FLAs. In fact if you read Morganscloud.com Justin Godber from Lifeline specifically says that AGMs are no different to FLAs, they are all lead acid batteries and need to be fully recharged to avoid sulfation build up on the plates. Batteries should not be left uncharged.

5. For repetitive cycling below 50% DOD (this is deep discharging and most attempt to avoid it), they recommend an output current of at least 0.2C or "the cycle life of the battery may be negatively affected". If this is not practical, they recommend a low current be applied for a long time after the end of the absorption stage.

That's called a float voltage!

...This has everything to do with Lifeline recognizing that AGM's are uniquely fragile in the LA world when it comes to deep discharges without full recharges - they are telling you to fully recharge them.

That's your interpretation - nowhere do they say this!

Also on the Morganscloud.com site Justin laid out 4 scenarios where batteries last from 1-9 years depending on how they were charged and whether they were equalised. Maine Sail has quoted this on many of his posts, but people have taken this as applying to Lifeline AGMs only. In the same post Justin says what I have quoted above - AGMs GELs and FLAs are all lead acid!