Thanks for advice

[Trevethan]

Thanks guys for the advice re: fuel filter change and bleeding. Bilge is half full of diesel.. well not quite, maybe lost a quarter pint in the effort. But engine is running sweetly and bilges haven't been de-dieseled, other than by washing up liquid from when most of the tank worked it way out through the fuel return pipe.

Much appreciated. and more stupid questions to follow... like if I put my multimeter on battery while engine is running, what sort of voltage should I expect? 13,6 seems to strike me as sensible... but I am showing just 13.3 at tickover. Does this mean its time to opt for an alternator booster?

 

[aztec]

SOUNDS OK TO ME, 14.8v TOPS THOUGH.

ahh say what you like.... what's done is done!

http://homepage.ntlworld.com/s.amos/index.html

 

[ccscott49]

When the engine is revving, the voltage should rise to 14v, but it may need a little time, 13.3 at tickover is fine.

 

[MedMan]

13.3v at tickover is fine - it is well above the voltage of a fully-charged, rested battery so it shows your alternator is working. At greater revs, and assuming your battery is reasonably well charged and that you have a standard automotive regulator rather than a so-called intelligent regulator, it is likely to rise to about 13.8v. However, if your battery is deeply discharged the alternator will not be able to hold such a high voltage at first so, even at higer revs, you might only get 13.3v. In these circumstances, the voltage will gradually come up to 13.8v as the battery charges up. If you have an intelligent regulator it is likely to rise rather higher, perhaps to 14.5v, but only when the battery is flat. Once the battery is fully charged intelligent regulators drop down to 13.8v like their automotive cousins.

 

[Paulka]

13.3 V at tick-over is O.K. It shows that your battery is reasonnably full. The voltage should, and most probably will, climb to 13.6 - 13.8 when you give some gas.
Unless the total capacity of all your batteries is higher than, say, 400 Ah, I think a "smart" regulator is not necessary.
And here is why : a battery, any battery, should be loaded at a current approx. 10% of its capacity; The alternators installed on most engines are rated at 55 A or more, thus sufficient to load (in theory) 550 Ah of batteries. Of course, a "smart" regulator will try to boost the current - at least temporarily - to more, or even much more than the 10%, loading a discharged battery much quicker. Pre-requisite is that the alternator can deliver the expected current!
A 55 A alternator can not, and will not deliver (much) more than 55 A, whatever the regulator! Or will be damaged, usually beyond repair.

Thus, as long as your total battery capacity is around 200 - 300 Ah as it is usual on "week-end" or "vacation" sail boat, and your alternator is rated at 55 - 90 Ah, there is no need for anything more than the standard regulator.

It's my opinion as electrical engineer, and it's how my own boat is equipped.

Paul

 

[ccscott49]

Paul,
I was thinking of uprating my 24 volt demestic bank from 330ah to 440 or even 550ah, as they need charging almost everyday at the moment. My alternators are 55a, I have a smart regulator on my staboard engine, which charges my domestics, I was thinking of uprating to a 95a alternator on this engine, I liveaboard, is this a sensible thing, or not? I also have a mains charger, an intelegent marine type, but it only puts out 35 amps, do you think it would be also wise to uprate this, to say 75a, as I want to limit the running time of my generator? Any advixce on this would be appreciated.
Colin.

 

[Trevethan]

And if I carry 2 x 200 amp hour batteries?

 

[vyv_cox]

Smart regulator

I thought the idea of a smart regulator was not to boost the output of the alternator but to delay the decay in the charging level that occurs with automotive alternators? Thus giving the initial charging rate for a longer period, as dictated by the requirements of the battery?

 

[Paulka]

Hi, Colin,

As mentionned, my previous post refer to "Week-end" sailboats.
Livaboards usually have different sort of expectations and needs, as well as more powerfull batteries. Yes, to cope with the expectations!

You have quite a big boat, probably with a lot of bells and whistles ;-)

This is confirmed by the fact that you need to charge your batteries on a daily schedule.
Of course, adding capacity to your batteries will help stretch the "charging schedule".
Of course, going up to 550 Ah, may force you to replace your 55 A alternator for a more powerfull one if this is your "main" charger.
I understand you have a generator as well, probably delivering 120 or 240 VAC, and a charger.

Basically, you have everything needed to be happy!

Maybe, one or the other link of your "electricity chain" is weak, but to find out which one, it's necessary to define some sort of philosophy.
- Do you rather sail, or motor?
- How much time do you spend at places where you can connect to the grid?
- If battery charging is needed when sailing, do you prefer to start the engine, or the generator?
- Is an additional source of power (solar panel, wind generator, water generator) an acceptable solution?
- And of course MONEY!

In my opinion, both solutions you propose (more powerfull alternator on your "domestics", and/or more powerfull charger) are O.K. If money is no thema, both, enthusiastically.
A new battery charger may be more expensive, but can be feed from the generator, as well as from the grid when in a marina (but not both at the same time!).
A powerfull alternator can probably be found at a reasonnable price at a lorry (because of the 24 V) demolition workshop (is this the right word?). Your present smart charger will do, but you may have to double the belt, and of course the pulley on the engine.

I understand you are somewhere in Spain, or even in the Balearics.
What about a chat about all the above around a fresh beer?

Cheers.

Paul

 

[ccscott49]

Paul,
Beer! now you're talking my language!! I'm anchored in St.Antonio bay Ibiza, right now, well the boat is, I'm in Norway right now! but will be back aboard around the 15th of August, are you in that area? I will be going on up to Mallorca shortly after arriving home, say a week. My vessel is power hungry, I motorsail most of the time, Englander needs a fair breeze to make her sail effectively!! Solar and wind are out of the question, too expensive and of limited value on Englander. I am not normally in marinas during summer and prefer to use the genny to charge, mainly because I can superfreeze the freezer when the genny (230v) is on and it uses less from the batteries when on the inverter, (It's mains). I will get my brother to look out for a bigger alternator for me, I'm already double belted. But I think a bigger output charger is on the cards, any ideas where and which to get? Anyway, that beer sounds good, lets see if we can't meet! Thanks for your input.
Colin.

 

[Paulka]

Re: Smart regulator

Hummm!

Maybe you're right!
Actually, none of the "smart regulator's" manufacturers really tell what their "baby" really does, except that it charges your battery better than any other one!

Thus, it's anybody's guess.

Nevertheless, all of them claim your battery will be charged more rapidly than with a "car type" regulator.
To me, this means that for some time, usually at the beginning of the charging process, there will be some sort of "boosting" phase.
Boosting (or bulk charge) means pumping high current into the battery.
How high the current?
3 times the normal charging current (that's 30% of capacity) is usually accepted as a maximum, for a limited period of time (20 to 30 minutes).
2 times being more reasonnable in my opinion, nevertheless still 20% of the capacity, still for a limited period of time (up to 1 1/2 to 2 hours).

You'll find a pretty good explanation of the charging process in the current delivery (August) of PBO, page 40. This one applys to the mains charger, but the charging process is exactly the same. The battery doesn't know where the current comes from. ;-)
.... And a pertinent remark about "smart regulator", and how to build your own at virtually no cost in the July PBO, page 34.

Enjoy your sailing.

Paul

 

[Paulka]

.... That's 400 Ah.
Thus, "normal" charging current 40 A.
What's the rating of your alternator?
Check the voltage of the battery after motoring a long time (two or more hours), and the engine still running more than tick-over, and all consumers off. It should be 14.0 - 14.4 V.
This means that your battery is fully charged, and everything O.K.
If your battery doesn't reach 14.0 V, try charging it with a charger from the mains. Just to make sure the problem doesn't lie with the battery. It should reach 14.0 V as a minimum 14.4 V being better. Be patient, it could need 24 hours!

Check all the connections between the alternator, the regulator (if separate) and everything else. (See PBO July, page 34 - 35)

Really, unless your boat is equipped with all sort of gimmicks (fridge, radar, freezer, autopilot, heater, SSB radio, etc.) you should be O.K. for week-ends and vacations. Of course, if you live aboard, you may need some few additional equipments to cope. (see my post to ccscott49)

Good luck.

Paul

 

[Trevethan]

Thank you for the advice! I will be fiddling this weekend.

 

[Gunfleet]

Re: Smart regulator

How interesting. THere's an American website which tells you how to build a Galvanic Isolator for a few quid. I'm beginning to wonder just how much of this very expensive kit is worth more than a fiver! I haven't built he isolator, by the way, because I'm so electrically incompetent I'd kill someone. I suppose that's what the other couple of hundred quid is for....

 

[jfkal]

Go for the booster. worth every penny. I get 51 AMPS on a 55 AMPS alternator at tick-over. Voltage settles nicely at 14.4 )))

 

[Paulka]

Great!
Which make?
And how much battery capacity connected at the time of the measurement?

Thanks for the feed-back.

Paul

 

[jfkal]

Sterling power. Battery cap. 160 Ah.
Good luck.

 

[boatone]

A Little Trick.........

......given to me by a certain manufacturer of power management systems.

If with engine running you meter between the POSitive terminal of the alternator and the POSitive terminal of the battery the reading will be the voltage drop in your charging circuit due to cable resistance, split charge diodes and anything else in the route. With a standard machine sensed alternator any significant drop will reduce its ability to recharge the batterries fully. Any drop more than about 0.2 volts needs to be looked at if you want good charging. Solution may be as simple as replacing battery cables with heavier duty=lower resistance. If you have split charge diodes fitted for dual battery charging the diode itself will take at least 0.8 volts or so.
On my P32 the voltage drop is only 0.2 volts, I have no sophisticated charging systems. I assume that batteries will never charge above 85% and should not be discharged below 50% so 3 x 110AH batteries in the domestic circuit let me run for 2 days without running engine at all and that includes a fridge running 24 hours/day .

<A target="_blank" HREF=http://www.arweb.co.uk/argallery/mobochat> My P32 and Boaters Picture Gallery</A>