Gel or not?

[Terra Nova]

mac--local sailing; Xantrex 2kw inverter/charger.

[BobnCamie]

I just talked to the solar power people I am ordering my set-up from. He said as long as I vent the flooded batteries, there would be no problem, he recommends flooded,in fact. The gel and gam work good, and will last as long as any other, so why spend the money for them. I know from personnel experience that a good deep cycle battery that is taken care of and not discharged below the 50 percent mark will last many years. Mine are now on their 7th yr. and going strong. Will continue to use them. As salesman told me, if you want to spend the money on agm/gell batteries, go ahead. If doing so just to spend money, send it to him and he will enjoy it himself. Break it down over 10 yrs. and. Look at what it cost you to buy the latest and greatest. I just as soon have the money in my pocket than someone else's for the same function. Just my thoughts

[sailinglegend]

Originally Posted by Vasco

Agms are the worst batteries a cruiser could get. If they are not charged right up every time they will die in a couple of years.

This is often quoted on these forums but nobody has really come up with a reason or proof that this is true. Maine Sail has suggested that AGMs he sees fail earlier than FLAs, but I suspect that is due to undercharging - they need a MINIMUM charge rate of 20% of C, whereas that is a maximum rate for FLAs. So a 500Ah bank needs a 120 amp alternator and shorepower charger(5% extra to supply boat loads). If you can't charge them properly don't waste your money.

AGMs are wet lead acids just like other batteries but Lifeline are one of the few manufacturers who have come out and said that all batteries will behave as you suggest, Lifeline are no different - but the good thing about Lifelines and Fullriver AGMs is they can and should be equalized if they are abused.

My Lifelines have lasted 10 years - 7 years as a fulltime liveabord in the Med and only going on shorepower for the winter. I find shorepower once a month to charge to a guaranteed 100%. I have only 140 watts of solar, a 400w wind gen and a 280 AMP DC genset.

The big advantage of AGMs is their faster charge time, even with solar, because of their much better charge efficiency. Add very big shorepower charger and you AC genset runtimes will be much less.

[Vasco]

My Agms died after two winter seasons of cruising. No marinas and they seldom got fully charged. Others I know had the same experience. Expensive lesson. If you live in marinas they'll be fine. I'm back to flooded Trojans and couldn't be happier.

[sailorboy1]

Originally Posted by sailinglegend

The big advantage of AGMs is their faster charge time, even with solar, because of their much better charge efficiency. Add very big shorepower charger and you AC genset runtimes will be much less.

Yes and this was said at the beginning of the thread.

[sailinglegend]

Originally Posted by Vasco

My Agms died after two winter seasons of cruising. No marinas and they seldom got fully charged.....

Not all AGMs are the same - some are designed as standby Solar or Telecoms and not designed to go regularly down to 50%C or fall of 3 metre waves!!!!

I'm interested to know which brand did you had and what charging - alternator - solar - etc.? Did you charge them at greater than 20% of their capacity? Did you ever equalize them? Do you equalize your Trojans?

[sailinglegend]

Originally Posted by sailorboy1

Yes and this was said at the beginning of the thread.

But I think you were only talking about "charge acceptance rate" not "charge efficiency" which is different. I quote:

Originally Posted by sailorboy1

The advantage of Gel or AGMs are:
- faster charging acceptance....
.....So if your charging system is high output, meaning it has been upgraded, you could reduce the time of running your engine.......

My point was that you don't have to upgrade the charging system - they will even charge faster with Solar. "Charge efficiency" of Lifelines is 98%, wet cells can be as low as 75% - search the net for these figures.That means with Lifeline's high charge efficiency very many LESS Ah need to be put in a battery to raise the actual stored Ah capacity. This could mean between 20-40% faster charging.

Of course you SHOULD upgrade to get even more advantage, and if you double the size of your charging sources then the "Charge Acceptance Rate" means more current going into your battery and charge times can come down even more dramatically.

[sailorboy1]

I can go with it. It isn't enough of an advantage for me to spend all the extra cash for a set of batteries and then be a slave to having to be sure they always get fully charged, but of course people get the AGMs so they must believe.

I have 6V golf cart house batteries after my research when I needed to replace them. They were inexpensive and survived their first 1.5 years where I abused them. Now I have solar and batteries are doing fine and performing same as when I got them. Far I'm concrned a $500 set of wet cell batteries that last 6+ years is not worth all the worry people spend on them.

[ullar]

Originally Posted by ranger42c

Just FWIW, usually can't mix gel and LA/AGM chemistry on the same charger, though.

-Chris

Good point, therefore "may be". I don't know if there are any gels that are good for starting, and if there are do they have the similar charging characteristics to "normal" house gel batteries. Separate chargers for house and starting banks will solve the problem of course.

Also, I've got an impression that good open deep cycle lead-acid batteries still have a better cycle-life then best gels. That on the expense of higher maintenance level and the possibility of acid spill when accidentally turned over.

[sailorboy1]

Originally Posted by Shantih

Being not very electrics savvy and as I'm about to replace 3 x 145Ah 12v batteries I would appreciate comments regarding the merits or otherwise of sealed gel as opposed to open type requiring occasional top up with distilled water.
Thanks

So between this thread the other one you started about batteries, what are you going to do???????????????

[Pete7]

Hmm, shake his head in dis-belief, how hard can it be to choose a battery, after all they have been around for 2000 years

Then go to the local chandlers or order 3 batteries on line. They should arrive by Friday and be in the boat Saturday morning, KISS approach and job done.

Pete

[Terra Nova]

Originally Posted by ullar

... I don't know if there are any gels that are good for starting, and if there are do they have the similar charging characteristics to "normal" house gel batteries...
I've got an impression that good open deep cycle lead-acid batteries still have a better cycle-life then best gels...

On small boats, I feel gel or AGM battery banks can be considered dual purpose, easily handling starting duty for an auxiliary. Though it is wise to provide a separate start battery.

Not cycle life, but bang for the buck generally goes to flooded batteries because of their ordinarily lower cost.

[BobnCamie]

My thoughts,too, on the flooded batteries. Cost effective is somewhat paramount for me. I would really like to replace the 12v. Batteries for 2 more 6v. batteries, but due to room constraints, will go with the 2 deep cycle I have and if or when they need replaced, will look at them then. I am also carrying a eu-2000 gen. for the just in case we need 120v. so will have charging option since there is a batt. charger on board. Sounds like a bank of 6v. would be best, but back to the cost effective problem.

[d design]

If money is not a barrier, go for Lifepo4

[ranger58sb]

Originally Posted by Terra Nova

On small boats, I feel gel or AGM battery banks can be considered dual purpose, easily handling starting duty for an auxiliary. Though it is wise to provide a separate start battery.

I think chemistry isn't limited to any specific role. Lifeline, for example, makes 6v Deep Cycle golf cart batteries... and they're AGMs. Trojans are FLAs. And probably somebody makes 6v gel GCs, too.

Our dual-purpose batteries are Odyssey AGMs, but everybody and their brother makes an FLA or gel version of same.

Et cetera.

-Chris