Batteries and High Ambient Temps.

[Pelagic]

I am on my 2nd set of AGM batteries.

8 x TROJAN 8D-AGM 12V 230Ah Series/Parallel = 920 AH @ 24v

They seem to only last 4 years

I can already tell that the Trojans are getting week as the voltage drops quickly and rises fast on recharge

Not sure exactly what i am doing wrong.
I'm using smart monitoring and smart charging with a Victon Multipluss following the manufactuers parameters.

Perhaps it is because I live in the Tropics and the battery compartment temp can be high
probably + 34°C at times

This comparison by Victron seems to suggest I should switch to Gel longlife

Any other thoughts or ideas?

[smac999]

Consider ditching the 8d format for a deep cycle battery size. That is a huge bank. Look at the L16 size of you have height.

[noelex 77]

High temperatures will significantly shorten the life of lead acid batteries. Unfortunately, higher than desirable battery temperatures are unavoidable for a yacht in tropical waters. Installation location is important.

Good gel batteries are excellent in deep cycle applications. I have achieved up to 17 years service with Sonnenschein gel batteries in a yacht house bank.

Even with lots of abuse (the previous owner of our second yacht thought gel batteries needed to be drained down to flat frequently to avoid a memory effect ) the lifespan was over 15 years. This is with 12v gel batteries. Good quality 2v gel deep cycle batteries are reportedly significantly better again.

However, these batteries are expensive and cost per year may not be lower despite the long service life. They also need to be good quality batteries, there are only a few companies that seem to be capable of producing gel batteries worth buying.

Sonnenschein and Hoppecke have excellent reputations.

[Pelagic]

Originally Posted by smac999

Consider ditching the 8d format for a deep cycle battery size. That is a huge bank. Look at the L16 size of you have height.

Hi smac
Height is an issue unless I choose a new location.

What do you mean by Deep Cycle Size?

The 8D AGMs (first Fullriver, now Trojan) are called "Deep Cycle Marine Batteries"?

When I bought the boat in 2004 it had 400ah of FLA 8D's no solar and a new interior with a heavy halogen lighting plan and inefficient fridges.
Took lots of water and the Generator was working overtime to keep the batteries up.
Solar was too expensive then, so I thought increasing the capacity with "sealed" AGM's was the best options, which I installed in 2 levels

Now I have lots of Solar, I just need to figure out if AGM was the wrong choice for the Tropics and what the best alternative is?

[Pelagic]

Originally Posted by noelex 77

High temperatures will significantly shorten the life of lead acid batteries. Unfortunately, higher than desirable battery temperatures are unavoidable for a yacht in tropical waters. Installation location is important.

Good gel batteries are excellent in deep cycle applications. I have achieved up to 17 years service with Sonnenschein gel batteries in a yacht house bank.

.... Sonnenschein and Hoppecke have excellent reputations.

Hi Nolex....In the 90's I also had great service +10 years with Sonnenschein on super yachts as start and Emergency batteries
They could handle the engine room temps.

What batteries are you using on your present yacht?

[john61ct]

Originally Posted by Pelagic

I am on my 2nd set of AGM batteries.

8 x TROJAN 8D-AGM 12V 230Ah Series/Parallel = 920 AH @ 24v

They seem to only last 4 years

Well first off, Trojan just like Deka make great FLA, but their AGM lines barely qualify as deep cycling.

That said, 4 years is not that bad for AGM at high temperatures.

FLA is both cheaper and last longer, sure you can't go back that way?

If not, then Lifeline, Northstar or Odyssey are what you want.

Agree with the above about 6V models generally being much better than 12V, and automotive sizes like 8D / rarely perform well.

GEL can last well but finicky to care for, easy to damage by overcharging, either voltage or C-rate.

And at least as susceptible to damage from frequent overtemp

[john61ct]

BTW for AGM Full River is OK, not saying great but likely better than Trojan & Deka.

All a big step down from the top three mentioned though.

[noelex 77]

Originally Posted by Pelagic

What batteries are you using on your present yacht?

We have Mastervolt gel batteries.

The 2v Hoppecke batteries were part of the discussions, but supply, delivery and cost problems etc made these not viable.

I don’t expect the Mastervolt gel batteries to be as good, but our battery bank is large (600Ahrs@24v) so I think the life will be good, although not anywhere close to the numbers I indicated in my first post.

When replacement is needed, the correct charging and management practices for lithium will be clearer, as will their lifespan in the real world. With a boat relying predominantly on generator power I think Lithium is a no brainier, but for a boat such as mine producing virtually all power from solar, gel batteries have a lot of appeal.

[noelex 77]

Originally Posted by Pelagic

Hi Nolex....In the 90's I also had great service +10 years with Sonnenschein on super yachts as start and Emergency batteries
They could handle the engine room temps.

I have cruised with gel batteries in high ambient temperatures (Australia and the Med), but the batteries were always installed in relatively cool locations. Therefore I can only speculate about the effect of engine room temperatures.

My suspicion is that gel batteries are not any better, and are perhaps even worse in the percentage of lifespan that is retained at higher temperatures. The difference is the maximum lifespan for the gel batteries is much longer.

So an owner that installs a typical flooded deep cycle lead acid battery that may achieve 6-7 years under optimal conditions finds the shorter 3-4 year lifespan achieved at high battery temperatures is frustrating. 2v gel batteries that may have a 20 year life under optimal conditions still deliver a usable 10-12 year life at high battery temperatures. The percentage loss in both cases is the same, but the gel battery option avoids the problem of trying to replace batteries as frequently.

[Paul L]

Not to contradict the learned JohnCt with actual experience....

I have 3 Rolls AGM batteries as our house bank. They are about 9 years old with heavy use in the tropics. Still are very strong.
Previously I had two Northstar AGMs that failed in a year with terrible factory support.

You definately want a temp sensor on the batteries and a charge controller that effectively uses it.

[ranger58sb]

Originally Posted by Pelagic

Hi smac
Height is an issue unless I choose a new location.

What do you mean by Deep Cycle Size?

The 8D AGMs (first Fullriver, now Trojan) are called "Deep Cycle Marine Batteries"?

Apparently "deep cycle marine" sometimes really means "dual purpose". You might check with MaineSail about the Trojan 8Ds.

Anyway, if 6V L16 batteries would be too tall -- probably not uncommon -- more normal 6V GC2s might fit in the same space. They're usually only a tad bit taller than 8Ds. Usually 3x will fit in the same horizontal space as one 8D, and also individual weight is much friendlier than an 8D.

If you want to stay with AGMs, Lifeline's GPL-4CT 6V GC2-equivalent batteries might be a good choice for you.

-Chris

[sailorboy1]

Car batteries live in a hot environment and don't seem to suffer short life.

[noelex 77]

This is some data from Hoppecke. The numbers are only specific for this battery, but they do at least give some idea of the relationship between temperature, discharge depth and battery lifespan (in cycles) for good quality lead acid batteries.

I would caution against placing too much weight on the actual numbers. Battery performance measured in laboratory controlled conditions is often vastly different to numbers achieved in real life.

These numbers are at least from a reputable battery company. I suspect some manufacturers just ask the marketing department to make up their technical details .

[Pete7]

Originally Posted by sailorboy1

Car batteries live in a hot environment and don't seem to suffer short life.

Hmm, we average about 5 years on ordinary car batteries. However, a car battery is only delivering a short burst of power to start the engine, not being discharged and then charged up again.

Back to the discussion on engine room blowers, perhaps it would be better to blow cool air in over the batteries and alternator rather than trying to remove hot air. Another job to ponder over and add to the list for next winter.

Pete

[Siggiland]

Hi,
if also the second set of batteries is dying premature I would check their "environment" that will be most likely responsible (charger, alternator, power consumption, etc.)
If you want to educate yourself go on YouTube and search for Pacific Yacht Systems. Jeff is an in depth expert (that is also doing consulting) and puts his electrical seminars on YouTube.
Regards
Siggi