Another one for the electrickery experts

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FrankieJ

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Our Bav.42 which lives in Greece, is a bog standard,cooking variety, ex charter yacht.
It has shore power but it does [--word removed--] all, except heating the water. ( water in the boat that is)
We would like a battery charger and a AMS so that we can keep the beer cool. As we can't budget this year for such luxuries, we thought we may be able to temporarily use a car battery charger to top up the batteries and run the fridge at the same time.I personally think it may not be so simple as just to plug in and go without disconnecting things. I hope it is. I am sure some of you out there will know,as I have been very impressed with the advice that has been previously given on many topics.
Frank.
ps the word removed began with B and ends with R.
 
I'm very surprised that the charter company or Bavaria would have shore power on the boat without a built in battery charger. Are you sure that thereisn't one, but merely broken.

You can use a car type battery charger but it is very awkward because the cheaper ones just keep charging all the time no matter how charged the batteries are, I have also found car battery chargers became quite noisy therefore needed to be plugged and unplugged.

Having fitted shorepower myself last winter along with a 3 stage Sterling battery charger (admittedly bought 2nd hand) I think it was well worth doing.
Are you serious that you've got a Bav 42 in Greece and can't afford £150 for a charger and £100 or less for other parts for the shorepower - less I expect as you have probably got many of the parts you need already. /forums/images/graemlins/laugh.gif

Regards
 
Thanks Andrew. There may have been charger at one time, I don't know. But there isn't one now. Our syndicate has a budget for luxuries each year and this year we have overspent as we are buying a new dinghy, and it was voted that a new charging system was not a priority and could wait until next year. If it was my own boat I would buy it now.
Frank.
 
I agree there MUST be one somewhere but a fuse may have blown or a switch needs switching somewhere. It may be hidden so all you can do is follow ALL the cables from the battery and the alternator to see if there is another cable going somewhere.

Auto parts and assessories on a boat are never a cost effective solution because in the end the salt air will eventually kill them and let you down - usually when you need them most. Is that Sod's Law or Murphys Law
 
Odd lot you are where you consider a dinghy a luxury. Mind you the water of the Med is warmer than the Kyles....

Nowt queer as folk, right enough....

Donald
 
" Odd lot you are where you consider a dinghy a luxury."
What I intended to say AJA, was - we have overspent our budget and are buying a new dinghy as well.
Allthough I refer to it as a luxury budget, it really is a wish list.
Anyway, when the two of us are cooped up in the cramped confines of said Bav. 42. Why shouldn't a leg stretch in a dinghy now and again be a luxury??? /forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gif
 
You would be able to put a car battery charger across the battery terminals and its power output would help run the fridge. However, car battery chargers are mostly very simple devices with no protection against overcharging so if you were to inadvertently leave it connected you could fry the batteries.

Given how cheap a proper charger is ...........................
 
Halfords do an automatic charger for a very reasonable price - £30 - 40.

I have had one on my batteries for over a year now without any problems.

Basically they just bring the voltage up to fully charged and then give an occasional pulse of juice to maintain the charge.

Whether they would run the fridge as well I don't know. It depends of course on how many amps the fridge draws and what is its duty cycle.

If you know these figures then fairly easy to calculate how many amp/hrs you are putting in/out of the battery.
 
As others have said, it is unusual not to have some kind of charger on board, but if so, then if you are summer holidaymakers maybe you seldom need one? If you are at anchor most of the time and moving from anchorage to anchorage you would seldom use a charger except at the beginning of the holiday.

If you don't want to keep the charger on all season or year then why not go for a cheap car one, as Jim suggested, at €30? Just connect it across the battery with croc clips supplied and plug it in. You don't have to be too clever just because it's a boat /forums/images/graemlins/wink.gif Be careful to check the volts before leaving it unattended for ages. For an ordinary flooded battery, 14.4 V is good for getting the battery nice and full and let it stay at that for half an hour or so AFTER the current has fallen to a few amps or less, then fall back to around 13.3 ish.
 
"Halfords do an automatic charger for a very reasonable price - £30 - 40."
It was one of these that we had in mind and When I looked at them it said on the box "max. 70A." Does this matter?
 
My boat has an inverter that has obvioulsy the 12V dc input and also the shore power 230Vac input. it powers the fridge (230V fridge) and one additional socket at the Nav station only.

It only works as an inverter when on DC and has internal bypass when on shore power, it does not have battery charger.

This is also an ex charter yacht.

This year I intend to alter the shore supply to feed into a small breaker box, this will then feed as before into the fridge inverter system. second circuit will then power any additional 230Vac circuits that I want plus a battery charger.

Will be looking for a regulated charger, the ones that boost then drop down to trickle charge.
 
Car battery chargers come in a variety of types. The old type just have a transformer and rectifier and provide 50 hertz pulses of power into the battery The current is limited by the transformer design and the charge in the battery. But they can cook a battery if left on 24/7 with no services being used. More modern styles have a regulator so it provides 14V to the battery so current into the battery depends on the charge state ad the services being used. this type emulates an engine driven alternator/regulator. The latest type use a voltage sensing algorythm to charge hard then slow down to tri9ckle with the battery becoming charged. They will hopefully then increase the current o provide for the fridge etc.

Now you can use any sort of charger. If you have large batteries and the fridge on full time a current of 3 or 4 amps continuous would not cook the batteries. This can be of the crudest type charger.
You may even have one of those power packs rated at 12 or 13volts used for electronic gadgets. One of these may give you some usefull continuous charge like .5 amps. But that may not keep the battery up with fridge running.
If you go for a cheap option you nneed to use an ampmeter or multimeter to find what current is actually going into the battery. (no load) If the charger has a metal case and or 3 wire power connection. (an earth connected) it would be well worth using your multimeter to ensure there is no connection from the mains earth pin to the negative or positive output leads.
This connection if it is there can lead to mains earth current going to the sea via your propeller etc accelerating corrosion. This is a special concern if it is lkeft connected to the mains 24/7.
You should also invest in an inline fuse with a fuse of suitable rating fitted in the +ve wire but near to the battery to minimise any chance of fire through wires shorting. Sit the charger (especially a crude type) on a ceramic tile in a place where it can burn with minimum chance of seting fire to the boat. I might even want to disconnect power when leaving the boat. (nervous nelly) olewill
 
Just a general reply - there is nothing unusual about shorepower without a battery charger - we don't have one "built in" either (but she has always been a private vessel so kit hasn't had to be standard) ... we just use a slightly intelligent battery charger - it shows on the front how much it is chucking into the battery ... can be quite handy if we want to run the eber during the winter but not run the engine to re-charge the battery ... but we do unplug and disconnect if the battery is nearly charged.
 
A big THANK YOU to all who took the trouble to share your valued knowledge.
Long live the forum and it's valuable participants.

Cheers Frank. /forums/images/graemlins/smirk.gif
 
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