New battery: which parameters to check?

[hpotez]

Hello, I need to change my batteries (x5) and I^'m still not clear which parameters to check to be sure it's a good one.. For example, what about the Vetus AGM 100ah? I found cheap's ones. Thanks for your advices

[Pete7]

Welcome to CF.

Before the forum recommends something;

1. Do you know what sort of batteries you have at present and how long did they last?

2. Was this acceptable and would you be happy with similar performance?

3. Were is the yacht?

4. Does it spend most of its time in a marina on shore power? any solar?

5. Are there any limits on battery size, particularly height? many of the European yachts struggle to fit some of the more popular American sized golf cart batteries.

6. Do you live on board for long periods or is it used for weekend and holiday sailing?

7. Are you happy to maintain by topping up regularly or is maintenance free a requirement?

[ranger58sb]

Originally Posted by hpotez

Hello, I need to change my batteries (x5) and I^'m still not clear which parameters to check to be sure it's a good one.. For example, what about the Vetus AGM 100ah? I found cheap's ones. Thanks for your advices

Start batteries? Or house batteries?

-Chris

[Pete7]

The Vetus Direct shop has them for £279, which looks expensive.

https://www.vetusdirect.com/batterie...vesmf-9-sizes/

Pete

[hpotez]

Hi,
Thanks Pete for your questions, here are a few more details:
I'm talking about my house batteries (x4)

I have now regular PbCalcium batteries (maintenance free) for 3 years. Was quite happy but now they loose power too fast.
The boat is located currently in the Canaries and we plan to go to Brazil, Argentina, Chili.
I have 440W solar panels & a hydro-gen.

I'm limited by the size (330x117x220)
I'm looking for good new maintenance free batteries and AGM seems the good technology for me.
So, which specification should I pay attention to, when choosing new batteries?

[ranger58sb]

House batteries are about capacity, so the usual most meaningful spec for "deep cycle" batteries is the Ah rating, usually the 20-hour version, when comparing candidates.

And then weight might help compare between two supposedly "deep cycle" batteries, the heavier one being more likely closer to "deep cycle" capability.

Often 6V golf cart batteries (BCI Group 2) are deep cycle batteries, whereas 12V batteries labeled as being "deep cycle" are more often "dual purpose" (start + house) batteries. Lifeline deep cycle 12V AGMs are said to be an exception to that last, and I think the Odyssey 12V AGMs we've used certainly have lasted as long as deep cycle batteries would have.

I've had good luck with good (expensive) AGMs, but from reading, they're not for everyone. The maintenance-free part is good, of course, but then for longest life they should be fully recharged quickly and often after use.

IOW, they don't tolerate partial state of charge (PSOC) operations all that well (unless you looks specifically at the even more expensive Firefly Carbon Foam AGMs), so they don't do so well on cruisers who seldom visit a dock or who don't have solar.

Your solar may be a deciding factor.

-Chris

[GordMay]

Battery capacity measurements are commonly expressed in Amp-hours (Ah) and Reserve Minutes. Amp-hours measure the total amount of energy that a battery can deliver for 20 hours at a constant rate of discharge, before the voltage drops to 10.5 volts.

Cycle life is measured as the number of discharge/charge cycles the battery can provide at a specified percentage of its rated capacity. Battery manufacturers measure longevity by discharging full batteries at a temperature of 80°F until their voltage drops to 10.5 volts. The batteries are recharged under controlled conditions, and the process is repeated until the battery fails to hold half of its rated capacity.

Look for IEC and third-party test results. Select a battery manufacturer that employs outside testing companies to ensure the accuracy and validity of cycle life data. Testing to the IEC 61427 standard ensures the batteries meet the rigors of the deep discharge and recharge cycles of renewable energy applications.
See ➥ https://www.trojanbattery.com/pdf/RE...7_Standard.pdf

[Pete7]

Hp, given that you will using these and living aboard please spend a couple of evenings reading back through the threads on CF about batteries, particularly AGM etc. As Ranger 42c said, they don't like partial state of charging (PSOC), for example 50% to 80% which is pretty common living on board. You can help by running the engine or a genny early in the morning to get a good charge, then let the solar top up even further and you may get close to 100% this way.

I don't think you will get a 6v deep cycle flooded lead acid (FLA) battery with that height restriction. I have the same problem so its 12v batteries for me.

The one parameter I would look at is the number of cycles a battery has. 200 is poor and likely an engine start battery now labeled "leisure". 500 is better and likely the best you will achieve. 1000 is FLA golf cart batteries and Gel batteries. Problem with Gel is they need lower voltages than FLA so charging takes longer. Also very easy to make a mistake and destroy a set of expensive Gel batteries. Have a read of this website, though I am not suggesting buying from them. They have taken the time to say how many cycles a battery is suitable for before end of life (EOL).

https://www.alpha-batteries.co.uk/

What ever you choose I think you need one of the main stream makes like Trojan given your cruising plans. Availability in the Canaries will be another issue made easier with a main stream make. Good quality flooded lead acid will be a safe bet and take the usage and occasional abuse, if you don't mind topping up every few weeks. Measure again the battery box and see if Trojan 27-TMXs will fit. They also do a similar AGM sized battery.

Pete

[a64pilot]

I have Lifeline AGM batteries and so far they have been good, but I’m meticulous about fully recharging them.

My next set of batteries will likely be Gel, but good ones are hard to find apparently.

Your charge sources may also decide what type of battery, some are more tolerant than others, Gel it’s my understand require exact voltages, a charger that isn’t adjustable may not work well with Gel.

[ranger58sb]

Ah. Cycle life. Yep, forgot to include that one.

Realizing manufacturers predictions are based on lab cycles...

-Chris

[Emouchet]

My next batteries will be either carbon foam based or LiFePo4, assuming money will not be a question, and delivering will be possible where the boat will be at that time.

Those technologies are now mature enough I believe.

Firefly Oasis Batteries are carbon foam and they support very well PSOC.

[wrwakefield]

Hpotez,

We went through the same exercise in mid 2014: What batteries are available where we are at the time of need, and what is the best choice.

Our house bank is difficult to access for routine maintenance, so I was leaning toward 'maintenance free' AGM batteries. They were a ~50% premium at that time compared to flooded lead acid [FLA] batteries.

I next researched how to water FLA batteries in a remote location, and discovered centralized battery watering systems. [The battery dealer knew nothing of them at the time...]

We ended up with a new bank of cost effective FLA batteries and a centralized watering system. It takes less than a minute to top up the water in all 8 batteries in the bank— including retrieving and stowing the jug of distilled water. I couldn't be happier.

I mention this because often— just as I had— FLA batteries are rejected because of the watering hassle...

In case it is of interest, there are more details and links to the remote watering systems I found on this page detailing that project.

Best wishes with your project.

Cheers! Bill

[CarinaPDX]

Are you sure the width isn't 170mm instead of the 117mm you stated? That seems too narrow. If it is 117mm then you are going to be limited as to choice.

Choosing the "best" battery is not really that simple. Start with your electrical skills and inclinations: do you want cutting edge performance, requiring some extra effort? Or perhaps something that requires very little maintenance? Greatest longevity? Bang for the buck? What are you charging sources and do they support 3-step charging, and if so, is it adjustable or just selectable?

Flooded (liquid electrolyte, FLA) are inexpensive and robust, with the minor disadvantage of needing to occasionally add water. If you don't have a smart charger and a smart alternator regulator, and don't wish to invest in same (highly recommended that you do), then this is a good choice.

AGMs are good for leaving the boat idle due to low self-discharge rates, and perform well for power delivery and charge times. It is essential to have smart charging due to the requirements to do 100% charging and to drop to a low float voltage once charged; leaving an AGM on 13.8+V after full charge will damage it. Sealed.

Gels are my favorite, and in Europe you can source the Sonnenschein batteries - best in class. These have better longevity than FLA and AGM batteries, have very low self-discharge, and are excellent for house batteries. They need to have the charge voltage limited. Smart charging is strongly recommended as with AGMs. Sealed.

Carbon foam is a new technology. The few cruisers that have used them have generally had good reports. IIRC they are only available in 2 sizes, and are constantly back-ordered several months. Not a chance they will fit even if you could source them.

Lithium is for those wanting the best performance and have the skills and disposition to deal with bleeding edge technology. Oh, and lots of money. You will know if this is you...

If you don't have smart charging I would stick with FLAs. Do get quality deep cycle if available in your size. But do consider installing a smart charger and smart alternator regulator, and if you have them then FLA, AGM, and gel will all be good choices. If the 117mm width was not a mistake then you aren't going to have a lot of choices that will physically fit.

Greg

[hpotez]

Hi Greg,Thanks for the follow-up. I'm currently on my boat so connection is not easy.
You are right for the size. It was a typo. width is 170...
I think I currently have a standard + set-up... Smart Charger (Victron Quattro), a good alternator, Solar Panel, Watt&Sea & Gen. Production of electricity is not so an issue for me. But I'm a bit lost to understand what makes a good battery...
In term of technology, for me, Lithium is too expensive, Gel is too sensitive, FLA too risky so AGM has my perference but my question is: What makes a good AGM? Can you help me on that?
Many thanks, Herve.

[ranger58sb]

Originally Posted by hpotez

In term of technology, for me, Lithium is too expensive, Gel is too sensitive, FLA too risky so AGM has my perference but my question is: What makes a good AGM? Can you help me on that?
Many thanks, Herve.

FLA aren't generally considered risky... unless you're thinking about service issues? Even then, I suspect the only normal problem is about whether you do the periodic servicing or not.

Can't say "what makes a good AGM" battery, but I can say I've gotten very good service from Odyssey AGMs. I'm currently also using Lifeline AGMs, also said to be top-notch, but I don't have long experience with those yet. Northstar are said to be good, no experience. Firefly Carbon Foam AGMs are said to be good, ditto no experience. Don't know if any of those are available where you are. There may well be other brands, maybe nearer you, that I just haven't heard of or read much about (Vetus, for example).

Inexpensive AGMs are said to be only average.

You might find it useful to read about battery stuff on Maine Sail's site.

-Chris