charging battery from generator

richievtu

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I know the answer is here somewhere but cant find it!
Must I use a sinewave generator to power my battery charger?
My current generator is a 750w yanmar 4 stroke which I dont think is sinewave due to its age but may be wrong?
The charger is a ctec type clone, smart type charger. I dont want to connect them together if something is going to break.
Also I know the battery leads are supposed to be disconnected when connecting up to the charger, but is this necessary?
thanks
 

BGW

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I know the answer is here somewhere but cant find it!
Must I use a sinewave generator to power my battery charger?
My current generator is a 750w yanmar 4 stroke which I dont think is sinewave due to its age but may be wrong?
The charger is a ctec type clone, smart type charger. I dont want to connect them together if something is going to break.
Also I know the battery leads are supposed to be disconnected when connecting up to the charger, but is this necessary?
thanks

If it's that old, is it an inverter generator? - If not it will be fine.
 

capetown

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Would have thought if your genny produces 230/240 volts @ 50 Hz, is it not the same as your 13 Amp mains supply at home. Or am I missing something?

I have a similar charger and have charged my batts from a genny.
 

William_H

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AC Generators

The older style AC generator (alternator) produced the AC from passing a magnetic field past stator coils. The speed of rotation defining the AC frequency. The shape of the magnetic field and its passing the stator coils giving the sine wave. So the sure indication of a proper AC generator with sine wave output is that the engine must run at a definite speed. ie 3000 RPM gives 50 turns per second or 50 hertz AC. (for a direct coupled gen.)
The inverter types also generate AC but the frequency is of no concern as the AC is converted to DC which is then converted to AC 50 hertz. The inverter types can run at low engine speed and engine power for low loads increasing in speed with load. It is the inverter types that often have bad waveform.
Don't confuse more exhaust noise with more load on an old gen with higher engine speed with load on an inverter type.
good luck olewill
 
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richievtu

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ok
So essentially the alternator type has a more stable current than the newer inverter type generator?
My only concern was that the power it produces may fluctuate too much for the type of charger im using, I have just purchased a new charger as the old one suddenly expired after connecting it up to the genny and I would like this one to last a bit longer, but if I understand the above correctly all should be ok.
thanks all
 

VicS

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So essentially the alternator type has a more stable current than the newer inverter type generator?

I think you will find that it is the wave form that is the problem.

An alternator will generate a pure sine wave. An inverter does not , maybe something closer to a square wave ?? but they modify and convert the output to a near sine wave.

The closer the output is to a true sine wave the better for some things.

That's my brief understanding anyway but its a subject I've not looked into in depth.
 

mjf107

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Most of the small generators that I have experience with are the magnetic type as described by William H. The output from these is similar to the mains with one big difference, the neutral is not referenced to earth. This may well cause a problem with the electronics in your charger. You can install link at the output connections between neutral and earth to overcome this, but for safety reasons you need to incorporate an RCD into the circuit which would disconnect the output wiring in the event of an earth fault (shock risk). I have no experience of the more modern inverter type so I cant comment on these. You would also have to check what you plug into the generator can cope with a less well regulated supply, the voltage and frequency will fluctuate more than the mains.

Edit The above only points out the likely differences between the mains and a portable generator, its not meant as a 'How to do it guide'. Professional advise should be taken before any modifications are undertaken or installing a fixed generator This site gives more information http://www.tb-training.co.uk/MarineE11.html#Isolation transformers
Michael
 
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contessaman

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for what its worth I have a sterling prodigital 40 amp charger. As this cost about 400 hard earned bucks I too was concerned about damaging it by running of a genny. I have a 'wolf' 1000w 4 stroke one which looks like a chinese jobby as I have seen the same one badged as other brands. I called sterling and asked them. they said it should be fine BUT start the genny first and let it stabilise THEN plug the shorepower into it. like wise unplug before switching off. This makes sense to me. The voltmeter is all over the place at first during/after starting. it soon settles.

It seems the charger can cope with mild fluctuations but perhaps not the big ones whilst starting.

The other thing that occured to me; if my genny is running and I then turn on a drill or mrs m puts her hair straighteners on then the engine sort of stutters to take up the load and once again the volts take a momentary dip so in the interests of maintaining the wiggy volts as stable as poss I would suggest you dont draw anything else of significant load whilst using it to charge thrugh your shorepower.

I guess the other option if youre really concerned is to buy a cheapo but quite high current car battery charger off ebay and use that with the genny. save yuor digital charger for on the shorepower. Also some gennys -my wolf one does- have a dc charge feature but alas its only about 7 amps.
 
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