Very helpful advice re: battery charging

[tomandsophie]

This might seem very elementary to many of you long-time-liveaboards out there, but for those of us (like me) who have only been living aboard a short time so far, this could be very useful knowledge.

We moved aboard our boat 6 months ago now (loving every minute!), and we were advised to run our engine for around 2 hrs per night (winter) to keep out 4x100ah batteries charged up. We did this and found it to be fine. A bit heavy on the diesel though (£25 - £30 a month). We always ran it at tickover (Beta 43 Greenline - around 850rpm) and did alternate nights in gear and in neutral.

I was recently advised that this may not be the best rpm for charging our batteries. So I phoned Beta Marine (very helpful) and asked them what we should be doing. They suggested around 1400 rpm and running in neutral (only need to run in gear every couple of weeks or so to clear out any carbon deposits). This I duly did and have now found that we only have to run the engine for around 40 minutes each night to keep our batteries topped up (running lights, pumps, laptop, stereo, 1800w inverter). Genius

[DHutch]

Alternatively, you could see about geting a larger pulley to drive the alternator.

- So it was spin at a high speed when the engine was it tick over?

 

 

Daniel

[tomandsophie]

Hmm... interesting...

[khaffra]

Alternatively, you could see about geting a larger pulley to drive the alternator.

- So it was spin at a high speed when the engine was it tick over?

Daniel

 

This is ok as long as you don't overrev the alternator while you are actually using the boat at higher rpm's

[bottle]

Hi

 

Personally I would stick with the advice from Beta. They should know.

[stuart]

Do you use any more/less fuel by running the engine for 40mins @ 1400 rpm rather than 120mins @ 850rpm ?

[tomandsophie]

Do you use any more/less fuel by running the engine for 40mins @ 1400 rpm rather than 120mins @ 850rpm ?

 

Apparently no. The engineer I spoke to at Beta said that the fuel consumption should be nearly the same at 1400rpm as it is at 850rpm. Obviously it would be slightly higher, but not proportional to the length of time we're now running the engine. Still, we'll find out when we next refill the tank

[bottle]

Do you use any more/less fuel by running the engine for 40mins @ 1400 rpm rather than 120mins @ 850rpm ?

 

Stuart

 

Go here Beta marine you can find graphs for there engine fuel consumption.

 

According to the graph the consumption for 850 and1400 rpm are very similar (about two litres an hour) so as the engine runs for less time the overall consumption would be less.

 

 

 

 

 

a lot of consumption in this

[bottle]

(edit.......This I duly did and have now found that we only have to run the engine for around 40 minutes each night to keep our batteries topped up (running lights, pumps, laptop, stereo, 1800w inverter). Genius

 

 

I am constantly amazed that people who pay many thousands of pounds for a narrowboat will not spend £10 on a multimeter. If anyone thinks that more revs means more charge should take 5 minutes to test the hypothesis..............................................(edit)

 

 

Well John, please explain why Tom and sophie now run their engine less.

 

Surely alternators have an optimum speed, if not why then do engine marinisers put smaller pulleys on the domestic one to make it spin faster.

[Guest]

I'm getting a stange feeling of deja vous.......

[DHutch]

This is ok as long as you don't overrev the alternator while you are actually using the boat at higher rpm's

Yeah, i guess you would have to check the max rpm rating of the alternator, and try not to exced that too often i guess.

 

I am constantly amazed that people who pay many thousands of pounds for a narrowboat will not spend £10 on a multimeter.

I very much agree with you there, to me, its very odd that people like tom dont have a meter on the alternator. So i they dont even know if it working, or what rate its charging.

 

If anyone thinks that more revs means more charge should take 5 minutes to test the hypothesis.

I also very deffonatly agree with this. I would have done by now!

 

HOWEVER, your clearly trying to sugest the the revs make no diffrence, which is clear utter rubbish.

- We've been round this loop before. (see catwesals comment - haha!)

 

 

Daniel

Edited February 9, 2006 by dhutch

[dor]

Run my engine at 1500 rpm, charge rate is double that at the 900 rpm tickover.

 

Not waffling nonsense, but actual, incontrovertible fact.

 

And I don't for a minute believe that my system is any different to most others.

 

Yes we've been here before, with the same opinions made.

 

So how about some FACTS being discussed, rather than just dismissing other people's real experience as nonsense.

[Liam]

In our old boat we had a Lister SR2. We also had 4 batteries, 1 being a starter, and the other 3 being leisure batteries, and the charging rate was absolutely crap.

 

Some guy I know also on the moorings also has an SR2, and.. wait for it.. also has charging problems. The alternator was connected to a pully wheel which is not only small, but only turns at half the speed of the engine.

 

My uncle gave us the tip of putting a larger pulley wheel on the boat, which would in turn make the alternator spin faster. As soon as the guy on the moorings fitted this, there was a mega change.. he was putting more charge into his batteries -- how do I know? Simply because they lasted alot longer than they did when the alternator spinned faster. We didn't change ours, and eventually sold it.

[DHutch]

Rather than do this again, can you just read this thread again john.

 

http://www.canalworld.net/forums/index.php?showtopic=2996

 

For thoese who didnt take part in the last thread, it basicaly consisted of john saying it was not possable that high revs could give higher outputs, and people should mesure it and see that they where wrong

- And then a load of the people saying that they had mesured it, and that they also didnt get full output at tickover.

 

 

Daniel

[Bones]

T & S - an excellent tip! I was told by the owner of my first boat (which I borrowed off him) that charging the batteries should be done as you have suggested. I'm certainly not knowledgeable enough, nd scatty enough not to think of quantifyingly measureing input of charge over a variety of engine speeds, so your advice is a top tip for the novice. I didn't have to charge my batteries very much because of the windmill, but it all certainly makes sense to me now you have demonstrated the charge so well!

 

The other element of good news is that you will be reducing your monthly bills too - !

[tomandsophie]

Thank you Bones! It's nice to see that somebody read my post for what it was meant to be. I was simply sharing my experience with others so they might benefit from it - higher revs (as suggested by a Beta engineer, not just anybody on the street) has cut our charging time by more than half. Take it or leave it, it worked for us.

[Lesd]

Its this type of info that makes this such a great site for the novice like myself, I know there are always differing views and there always will be, but this is a great tip, one I had pondered many times and niow one I hope to test out for myself in due course. Thankyou Tom and Sophie !

 

Thank you Bones! It's nice to see that somebody read my post for what it was meant to be. I was simply sharing my experience with others so they might benefit from it - higher revs (as suggested by a Beta engineer, not just anybody on the street) has cut our charging time by more than half. Take it or leave it, it worked for us.

[DHutch]

Thank you Bones! It's nice to see that somebody read my post for what it was meant to be. I was simply sharing my experience with others so they might benefit from it - higher revs (as suggested by a Beta engineer, not just anybody on the street) has cut our charging time by more than half. Take it or leave it, it worked for us.

Yeah, deffonatly.

- It is good advice, and could easly reduce people fuel comsumintion and running hours, which is good allround.

 

I was just adding, that for £20/30 you could get a ampmeter fitted between the alternator and the batterys, which would show you how much the alternetor was puting out. (it would have told you, for instance, that you wherent geting anywhere near the full charge rate at tick over...)

 

 

Daniel

[Guest]

I don't know about the engine concerned, but I can say that Vetus don't recommend letting the engine run for more than "a few minutes" at idle. On the rare occasions that we use the engine to charge batteries when moored we tend to run it at about 1100rpm, sometimes in gear sometimes not. Furthermore the water in the calorifier warms up much faster at the increased revs.

[dor]

Pontification should come a bad third, you would do well to keep them in that order.

 

Hmmmmmm.......

 

Pot.

 

Kettle.

 

Black?

[khaffra]

If you have a multimeter or even use the voltmeter on the control panel, If the voltage goes up as you increase the revs then you will be putting more current into the batteries, If it stays the same the alternernator has already reached its voltage output limit and will not output any more. The amount of charge in your batteries and the size of your battery bank will greatly affect the amount of revs you need to use to attain max charge.

Basically if you have flat batteries your alternator will try and output a lot but will need to be running faster to do so.

If your batteries are full your alternator will not need to output much to attain its voltage cut off therefore charge rate may well not change with revs.

 

I don't know if this will make sense to anyone but I am sure there are people who will disagree with it.

 

Basically I would reccomend running your engine at the minimum revs that allow your voltmeter to read its highest.

[Guest]

If you have a multimeter or even use the voltmeter on the control panel, If the voltage goes up as you increase the revs then you will be putting more current into the batteries, If it stays the same the alternernator has already reached its voltage output limit and will not output any more. The amount of charge in your batteries and the size of your battery bank will greatly affect the amount of revs you need to use to attain max charge.

Basically if you have flat batteries your alternator will try and output a lot but will need to be running faster to do so.

If your batteries are full your alternator will not need to output much to attain its voltage cut off therefore charge rate may well not change with revs.

 

I don't know if this will make sense to anyone but I am sure there are people who will disagree with it.

 

Basically I would reccomend running your engine at the minimum revs that allow your voltmeter to read its highest.

That sounds like the voice of common sense to me. I agree that a voltmeter gives a reasonable indication and is useful, but still think you can't touch an ammeter and a voltmeter combined for indicating what is happening.

Edited February 11, 2006 by Guest

[John Dixon]

That sounds like the voice of common sense to me. I agree that a voltmeter gives a reasonable indication and is useful, but still think you can't touch an ammeter and a voltmeter combined for indicating what is happening.

 

 

Forgive me if I mess up my first posting. Having just finished 9 years of ocean cruising, I thought you might be interested in the general set-up of many cruising yachts. The most popular wind generator is the Kiss, made in Trinidad. Best output at moderate wind speeds (10-15kts) and is pretty quiet. However, ALL wind generators are annoying to nearby neighbours and the use of them in tight communities often will lead to less than friendly discussions. The most popular solar panel (best output per real estate) and probably the most efficient is the Siemens 75W panel.(I think Siemens may have been taken over and trading under a different name). Golf cart batteries are still the most cost effective, but AGM batteries are pretty well indestructable when it comes to charging - you can almost throw any amps at them, which brings me to my last point. If you have a large house battery bank and you are a power hungry boat, then more often than not you will either have to accept long charging times or never fully charge your batteries. The problem is that the battery voltage will come up pretty quick causing the regulator to cut back on the charging amps. Not what you want when you are trying to recover (and bank) many used A/hrs. (Although called a voltage regulator, in reality it is a current regulator). A cheap fix to this is to remove the internal alternator regulator completely and replace it with a small external panel on which you mount 3 resistors and a simple switch to place a variable resistance in the generator field to fool it and thus run the alternator at, say three settings including maximum output. You also buy, but at a price, commercial external regulators to do the same thing. Making mine cost me less than a fiver. However, you must monitor what is going on to prevent battery damage or alternator burn out. A good interface panel is a must displaying volts, amps, a/hrs etc, but this is a good bonus, anyway.

John Dixon

[ChrisPy]

A cheap fix to this is to remove the internal alternator regulator completely and replace it with a small external panel on which you mount 3 resistors and a simple switch to place a variable resistance in the generator field to fool it and thus run the alternator at, say three settings including maximum output. You also buy, but at a price, commercial external regulators to do the same thing. Making mine cost me less than a fiver. However, you must monitor what is going on to prevent battery damage or alternator burn out.

 

sounds like a manual version of an alternator controller which costs a couple of hundred quid. cheap. but expensive if you forget ........

[anhar]

...but AGM batteries are pretty well indestructable when it comes to charging - you can almost throw any amps at them, which brings me to my last point...

Oh dear John. You've heard of a can of worms I presume?

 

You'll have the horse drawn narrowboat lobby down on you like a ton of bricks for making a suggestion like that. No matter that you have many years of experience to back it up.

 

On another thread a while a back I suggested such a thing simply because I want the minimum maintenance possible for all the various equipment on my boat, plus AGM batts. charge much quicker because of the higher rate they can stand.

 

Wot? Maintenance free batteries? Are you nuts? Everyone knows that the best batteries are those filthy things that you have to keep topping up with distilled water, which if you forget are ruined, are the best! And as for charging those disgusting AGM things, well, you have to regulate it very carefully don't you know. It's not true that you can charge them at a huge rate. Forget what Mastervolt tell you, wotdotheyknow? They're filthy corrupt capitalists only trying to sell you their stuff.

 

However, I remain totally convinced of the huge benefits of AGM or other mf batteries. Glad to have your opinion in support based on actual experience.

 

regards

Steve

Edited February 12, 2006 by anhar