Fully charging a 24 volt 220AH lead acid battery bank with a 60 amp alternator

[Paddingtonbear]

Stu gives very good advice but the regs and conditions on the US are different. I am certainly no expert(at anything) but as I always say in these situations your should consult Chris Gibson at Merlin. Knows a hell of a lot and almost deliberately refuses to sell anything to you as he obviously is so successful in other markets. http://www.smartgauge.co.uk/

 

[GHA]

Perhaps I should have asked the question elsewhere.....

Couple of links...

http://batteryuniversity.com/learn/article/charging_the_lead_acid_battery

http://www.powerstream.com/SLA.htm

 

[sailinglegend420]

..... your should consult Chris Gibson at Merlin. Knows a hell of a lot and almost deliberately refuses to sell anything to you ...

The last time I spoke with the MD of Merlin he told me Chris was locked in a secret room and not allowed out! He is working on top secret US and UK Military projects and is not allowed to communicate with the outside world.

 

[sailinglegend420]

To allow others to get a handle on info posted on here, perhaps you could reveal your own level of experience in the business. ....

That's a very fair question. Retired Electrical Engineer with 7 years full time Liveaboard in the Med. Writing a book on Power Systems Best Practice for Boats.

I would suggest you look at my Profile for more information - anytime you question peoples posts see how many posts they have, and how many per day on average, and then make up your mind if they seem to know what they are talking about. Every poster should be forced to add some sensible information before they are allowed to post. If they have 20,000 posts and a average of 20 posts a day you have to wonder have they got nothing better to do than cause disruption on these Forums? We definitely need better moderation here.

Thanks for posting some links.

 

[Tony Cross]

FWIW I know sailinglegend420, he's a well-respected CA member. When it comes to boat electrics he really does know what he's talking about. My advice would be to listen to him.

 

[GHA]

That's a very fair question. Retired Electrical Engineer with 7 years full time Liveaboard in the Med. Writing a book on Power Systems Best Practice for Boats.

Ta.

At the risk of being a little harsh it's comments like this which ring a few alarm bells....

A 220Ah battery on a boat needs a 55 amp charger, not a 14 amp as you suggest.

Which , in this case, seems too dogmatic and impossible to say without knowing more about the boats' situation. A day boat spending most of it's life tied up with power can easily live with a small charger, and probably have a longer battery life because of it.

For the benefit of others Chris Gibson explains better than i ever could...

http://www.smartgauge.co.uk/chargesize.html


Links as to *why* certain systems and settings work well can be very useful, I find.

Nothing is black and white, far too many variables and trade offs.

 

[cygnusv]

My original post has proved useful in that, as always, it has proved that any question asked can quickly become a minefield of differing opinions. It has also thrown up very useful links such as the smartgauge one. Taking what I consider to be an overall successful post, I now have a better idea of what I should be doing. Even armed with only a multimeter and a 'dumb' battery charger we've managed 4 years on this bank so far, and in excess of 5 years on the last. We are full time live aboards and have been since 2001. Most of our time aboard we have a shore hook up but operate the 24 volt side of things much of every day.

Two things in particular have been decided for me. Next year we will change the battery bank for more AH's, and I WILL buy a smart charger. If I dare ask, what thoughts are there on the option of a 24 volt, 40AH Sterling unit. Followed by the more dangerous question - Is there a more cost affective way of 'smartly' looking after our battery bank?

Many thanks.

 

[nigelmercier]

At the risk of being a little harsh it's comments like this which ring a few alarm bells....

A 220Ah battery on a boat needs a 55 amp charger, not a 14 amp as you suggest.

Which , in this case, seems too dogmatic and impossible to say without knowing more about the boats' situation.

Exactly. To specify that such a battery needs a certain charger is nonsense.

My suggestion was based on the info from the OP in Post #7, a reasonably priced charger that would do the job.

I've got 3 CTEK chargers on my boat, very pleased with them. For my 24V battery I've got a golf-trolley smart-charger, if it ever packs up, I will buy the one I linked to.

 

[sailinglegend420]

...If I dare ask, what thoughts are there on the option of a 24 volt, 40AH Sterling unit. Followed by the more dangerous question - Is there a more cost affective way of 'smartly' looking after our battery bank?
.

I'm glad you liked the Smartguage site - lots of good info there - and an I impossible amount of information for anyone to include on a post here. If you do some research all of your answers are here on PBO somewhere, or links to sites that will answer your questions.

So in response to your last post the Sterling charger at 40 amps is probably too small for a full time Liveaboard. One of the major comments of Sterling chargers is there maximum size at 60 a amps is too small!

My comment that "A 220Ah battery on a boat needs a 55 amp charger, not a 14 amp as you suggest" clearly demonstrates the difference in thinking. Most battery manufacturers suggest a 55 amp charger - 20% of the battery capacity +5% for boat loads? Only Trojan suggest 10%' but at this rate the charging will take much longer. 14 amps is just much too low for any kind of boat. The OP's original post was about how quickly a battery will fully charge. A Liveaboard that spends most of his time at anchor, cos we can't afford marinas, needs to know that one night in a marina will fully charge his bank. For that you need the largest charger your batteries will be happy with. It would be helpful if the OP Put more info in his profile so we knew he was a Liveaboard.

- Is there a more cost affective way of 'smartly' looking after our battery bank?"

IMHO you need to go for Best Practice in your situation - you can't afford to do it on the cheap - it will cost you more in the end. Look at an Inverter/Charger like the Victron, and get a Battery Monitor - see the SmartGuage site and go for their Smart Guage battery monitor that doesn't use a shunt and has proven to be much more reliable than conventional battery monitors. I could give you another link to Compass Marine who has just done an extensive test on the SmartGuage and doesn't even believe his own results. Conventional Battery Monitors get more and more inaccurate with age, SmartGuage gets better as it learns your system. Chris Gibson who designed it got so fed up working at Link that he dsigned a new product that really works. I have both types and the SmartGuage is magic.

Also get lots of Solar - about 600 watts will guarantee to keep you fully charged - but that's impossible on a monohull. 600 watts will give you 150Ah per day which is about what an average Liveaboard will use, much more when you are actually sailing. Some bright spark will shoot me down on these figures I'm sure. It's amazing how so many people say that by lunchtime there solar has fully charged their battery just because a little green light says "FULL" or their very inaccurate battery monitor says 100%!"...........

 

[GHA]

Two things in particular have been decided for me. Next year we will change the battery bank for more AH's, and I WILL buy a smart charger. If I dare ask, what thoughts are there on the option of a 24 volt, 40AH Sterling unit. Followed by the more dangerous question - Is there a more cost affective way of 'smartly' looking after our battery bank?

Many thanks.

I fitted a sterling pro charge ultra recently and very happy with it, most parameters are configurable. Having a manual equalise setting is nice, though it's buried in the setup and not in the manual.
Not to so sure about the arguments for a bigger charger, I've been full time livaboard for years now with a 20a rarely if every a need for more, it's either on all the time with shore power or not at all at anchor, nipping in overnight somewhere to get a charge just doesn't happen.
But everyone's situation is different.

A simple amp counter I find very useful, not so much as a "fuel gauge" but to keep an eye on how much is going out. (it's an aging BEP)

A smart gauge would be nice but on its own seems a bit limited long term.

Nearly all the info for longevity seems to point to getting them back to close to full charge as often as possible and get them back on charge as quickly as possible after a discharge. And equalise once in a while.

Not easy on a cruising boat

 

[[2574]]

A simple amp counter I find very useful, not so much as a "fuel gauge" but to keep an eye on how much is going out. (it's an aging BEP)

A smart gauge would be nice but on its own seems a bit limited long term.

I think I agree with this. I have had a look at the Smartgauge website and it seems to monitor voltage only and then apply "modelling" techniques to determine state of charge. It does seem limited in the information that it provides the user. We are told that the Smartgauge constantly does 2m calculations through several hundred models which is all fine and dandy but we seem to be left with only SoC.I wouldn't be without an ammeter as I too like to keep an eye on consumption and generation (via genny, solar and alternator) and have occasionally identified faulty kit through glancing at the ammeter as I walk past it.

It seems that we need both the Smartgauge and an AH counter such as the BEP?

 

[sailinglegend420]

.....It seems that we need both the Smartgauge and an AH counter such as the BEP?

You are right you need both, but a SmartGuage and a digital amp meter is a cheaper solution. I also have a BEP and the SmartGuage is always much more accurate. See this recent posting for a detailed "Discussion" on SmartGuage, including a link to the recent amazing test results by Maine Sail on my posting #72.

http://www.ybw.com/forums/showthrea...on-House-batts-necessary&highlight=SmartGuage

MAINE SAIL's post:

http://www.pbase.com/mainecruising/smart_gauge

 

[GHA]

I wouldn't be without an ammeter as I too like to keep an eye on consumption and generation (via genny, solar and alternator) and have occasionally identified faulty kit through glancing at the ammeter as I walk past it.

It's not just me then

I would very much miss the amp counting to check every morning what's happened overnight as well. Both would be nice, with the possibility of getting a rough idea of capacity by comparing soc from the smart gauge against amps used from something like a BEP.
The smart gauge seems to get a bit confused when charging as well, which is a pity, an accurate measure of how close to fully charged the batts are is one of the things we really want to know.

 

[JumbleDuck]

It seems that we need both the Smartgauge and an AH counter such as the BEP?

We need Li-ion (or other modern) battery technology to get cheaper enough that we can stop faffing about with bubbling vats of acid. Here's what my ancient laptop knows about one of its batteries:

$ cat /proc/acpi/battery/BAT0/info
present: yes
design capacity: 47520 mWh
last full capacity: 17390 mWh
battery technology: rechargeable
design voltage: 10800 mV
design capacity warning: 2376 mWh
design capacity low: 475 mWh
cycle count: 0
capacity granularity 1: 1 mWh
capacity granularity 2: 1 mWh
model number: IBM-08K8048
serial number: 1028
battery type: LION
OEM info: Panasonic​

 

[[2574]]

See this recent posting for a detailed "Discussion" on SmartGuage, including a link to the recent amazing test results by Maine Sail on my posting #72.

Matt,

Thanks for that. As you say, amazing results. Interesting that Maine Sail uses the phrase "snake oil" in his post which is what I thought after reading the website yesterday. However the facts seem to counter that perception. The Smartgauge website narrative is awful; leads one to think pure snake oil. However, the proof seems to be in the pudding.

Rob

 

[sailinglegend420]

.....Here's what my ancient laptop knows about one of its batteries...

3,807 posts ... 14 posts a day... so what's the point of this one?

Please try and be a bit more constructive in your comments!

 

[JumbleDuck]

The Smartgauge website narrative is awful; leads one to think pure snake oil. However, the proof seems to be in the pudding.

It's unfortunate that many manufacturers of marine 12V power equipment seem unable to write clear, friendly descriptions of their products. Aggressive hectoring seems to be the house style.

 

[JumbleDuck]

3,807 posts ... 14 posts a day... so what's the point of this one?

Please try and be a bit more constructive in your comments!

I was trying to be constructive, my dear chap, by pointing out that the undoubted problems of measuring the capacity of lead acid batteries will fade away as lead acid batteries fade away. It seems to be much easier to assess the state of Li-ion batteries, and when their prices are less eye-watering (and they are already approaching merely "expensive" rather than "stratospheric" per usable Wh) we will all be able to move across with, for the same weight, a lot more capacity.

The laptop battery was just an example of what pretty old Li-ion technology can do.