Daily battery charging

[Jstupot]

Hello, and I will start by saying sorry, as I'm sure this question has been asked many times before. My partner and I are moving into a a narrow boat this month. We are really not sure how often we should charge the batteries on a daily basis with general living aboard in mind.... 12v fridge, lights(all LED), small use of mains with 240v inverter, charging laptop, little bit of t.v, and so on.

We have a 58ft with a beta marine 43 engine. One battery for starting the engine and 3 large batteries for power.

Could someone please have the courtesy of helping a couple of newbies please, and no smart ass comments.

Also is it fine to just have the engine running idle or does it need a bit of juice then charging?

[rusty69]

You will likely need to charge on a daily basis depending on your usage and have the ability to determine when your batteries are charged (or charged enough).

 

You will need a way to determine when you need to start charging your batteries, and when you can stop charging them.

 

An Ammeter and Voltmeter are useful tools to determine this.

Edited November 8, 2016 by rusty69

[Jak]

There will be no end of experts along soon I'm sure, but on such a boat you will probably want to consider significant solar. At least in the summer you can reduce all of that engine running.

[MtB]

You will likely need to charge on a daily basis depending on your usage and have the ability to determine when your batteries are charged (or charged enough).

 

You will need a way to determine when you need to charge your batteries, and when you can stop charging them.

 

An Ammeter and Voltmeter are useful tools to determine this.

 

 

I disagree with the last bit. An ammeter is moderately useful for determining when a battery is fully charged but a voltmeter is as good as useless. My recommendation is to get a SmartGauge which monitors SoC admirably. You'll need to know when to start charging as well as when stop, and only a SmartGauge can tell you this with any accuracy. An ammeter is handy if funds allow, but by no means essential. If you get both then the SG is best for telling you when you need to charge (i.e. state of charge approaching 50%) and the ammeter tells you most accurately when the charging is finished (tail current falling to about 2% of nominal battery capacity, and stopped falling for 30 minutes).

 

Search this forum for "SmartGauge" for endless threads about what they do and how good they are.

Edited November 8, 2016 by Mike the Boilerman

[Phil Ambrose]

As Rusty says, you will need to run your engine for at least 2 hours or even 4 hours a day to maintain a reasonable state of charge in your batteries. Some form of battery monitor is an essential bit of kit, Smart gauge is one which many people swear by.

You also need to do an energy audit, as precisely as possible, its no good saying a bit of TV or a couple of lights on for a bit, once you have some form of monitoring and a precise energy audit you will then be in the position to establish a battery charging regime.

Check out the search function top right of home page, there are loads of items ref battery charging and management.

Phil

[rusty69]

 

 

I disagree. An ammeter is moderately useful for determining when a battery is fully charged but a voltmeter is as good as useless. My recommendation is to get a SmartGauge which monitors SoC admirably, and then an ammeter too if funds allow.

 

Search this forum for "SMartGauge" for endless threads about what they do and how good they are.

A voltmeter is pretty useful to determine when the batteries need charging (interpret soc). It wasn't too long ago you were advising me not to spend other peoples money by recommending a Smartgauge.

[MtB]

A voltmeter is pretty useful to determine when the batteries need charging (interpret soc). It wasn't too long ago you were advising me not to spend other peoples money by recommending a Smartgauge.

 

Well I've changed my mind! Anyway in this case it is appropriate advice. It probably wasn't when you were telling someone to get one.

[rusty69]

 

Well I've changed my mind! Anyway in this case it is appropriate advice. It probably wasn't when you were telling someone to get one.

I see.

[Athy]

.

Could someone please have the courtesy of helping a couple of newbies please, and no smart ass comments.

 

Well-dressed donkeys rarely comment in this forum, don't worry.

[MtB]

Well-dressed donkeys rarely comment in this forum, don't worry.

 

 

How do you know what the donkeys commenting in this forum are wearing?

[Chris-B]

Hes is making ASSumptions !

[Athy]

Ee, yore funny.

[MtB]

Well this is going well isn't it? Gibbon the OP's demand that there are no smart ass comments.

 

 

Oops, wrong genus!

[Athy]

Well this is going well isn't it? Gibbon the OP's demand that there are no smart ass comments.

 

 

Oops, wrong genus!

Although many of us willingly offer advice and the fruits of our experience when we can (in this particular case, I can't as I'm not a liver bored), some of us do not care to be told, not even asked, how we should couch our comments.

[zenataomm]

................ and no smart ass comments.

 

Why?

[MtB]

Why?

 

 

My guess would be because they can result in a long series of answers which have nothing to do with the topic of the thread...

 

As if that would ever happen!!!

[Athy]

 

 

My guess would be because they can result in a long series of answers which have nothing to do with the topic of the thread...

 

As if that would ever happen!!!

Heaven forfend!

[MtB]

Heaven forfend!

 

 

Interesting turn of phrase, that.

 

Until about 15 years ago, everyone used to say "Heavens forbid", then suddenly it changed and "heaven forfend" became trendy instead. Any eye dear why?

[Mac of Cygnet]

Interesting turn of phrase, that.

 

Until about 15 years ago, everyone used to say "Heavens forbid", then suddenly it changed and "heaven forfend" became trendy instead. Any eye dear why?

Is it trendy now, then? Better tell the dictionaries, which say "archaic, if not obsolete". (Referring I think to the word, not the user).

[ditchcrawler]

Ee, yore funny.

I didn't notice him posting in this thread

[MtB]

Is it trendy now, then? Better tell the dictionaries, which say "archaic, if not obsolete". (Referring I think to the word, not the user).

 

 

Yes it is. I, like the dictionaries, always considered 'forfend' to be an archaic word but suddenly everyone seems to be using it. EG post 17.

[Athy]

 

 

Interesting turn of phrase, that.

 

Until about 15 years ago, everyone used to say "Heavens forbid", then suddenly it changed and "heaven forfend" became trendy instead. Any eye dear why?

I certainly used it before that - picked up, I think, from Private Eye magazine who used to use it to show that they weren't being serious.

[Tony Brooks]

Whilst two to four hours engine running MIGHT be sufficient to get enough electricity back into the battery to last the night it is very unlikely that it will fully charge it. With just the alternator you will need to run for at least 8 hours at least once a week and much of that time you will be pitting very little charge into your battery. If you do not fully charge regularly the batteries will gradually sulphate and that means they will lose capacity. Livaboards who do not fully charge their batteries regularly can wreck a set in weeks.

 

This is why significant solar is so good. In the middle of summer you may not have to run the engine. In winter you can do the four hours charge and for the rest of daylight the solar will help to get the batteries fully charged. having said that in the depths of winter the solar contribution is likely to be small.

 

I agree with the ammeter and voltmeter comment as the bare minimum of battery monitoring you will need but you MUST learn how to use them to make fairly accurate inferences about the state of charge. A Smartguage just makes deciding when to start charging easier. There is much for you to learn here if you want to maximise your battery life but we can advise on that later when you have digested this lot.

 

There is no point in running the engine on idle until the later stages of charging. An ammeter will allow you to run at whatever revs are needed to keep the alternator output as high as it will go. This speed will gradually reduce as the charging progresses. In the early stages of charging the alternator load on the engine may well be higher than the load when canal cruising and keeping a diesel under load is always good.

 

The alternator will be charging once the "ignition" warning lamp goes out. This may need a bit of a rev but as long as it stays out some charge will be produced.

 

There is much you have not told us about your boat like how many alternators and their rated output. Also the battery bank size in Ah. You probably do not know this but you really need to find out. I guess you have two alternators and three x 110Ah batteries but it is only a guess.

 

Finally I do not like people assuming that I and others who reply seriously will take the mickey, even if the way a question is presented invites some smart replies. You will note someone else has also said as much. If you upset people I assume that you would not expect much help.

[johnmck]

A Smartguage would give you an easy means of, at a glance, seeing your state of charge. Using this and depending on your demands, will give you a fair idea of how long you need to run the engine. It will be longer than you imagine I would guess.

[Tony Brooks]

As the Smartguage is acknowledged to be up to 10% out when charging a far better indication of fully charged batteries is what is know as the tail current - that is the very small current towards the end of charging. Relying on the Smartguage may not get the batteries fully charged, maybe to only 90% and that implies a slightly faster loss of capacity.