Charging Batteries via a Generator

[Nick-Now]

I'm a bit confused but maybe you can help?

On my recently purchased boat, there is installed a "Victron Easy Plus. 12v, 1600va inverter with 70 amp charger"  

 

My question is this.. because it not only an inverter  it also has a built in 70amp charger. 

 

1.) Would I only need to connect a generator directly to the Victron by means of the land line electric hookup socket?

 

2.) How long does the generator need to run to charge battery banks? ( I know this is how long is a piece of string type question, but in people experiences, are they having to run the generators for hours and hours to top up the batteries?)  

 

I will be looking into solar later on this year but it will be the flexible type as I really think the big flat panels are very ugly. I would rather have extra flexis to make up the shortfall.

[BEngo]

Yes it does both.

Connect your generator to the Victron and it should charge, provided of course that your generator is big enough.  70 Amps at about 14.V is near enough 1 kW, so your generator will need to be a bit bigger than that because of the losses in the inverter charger.

 

The answer to the how long is very much dependent on your battery bank ( size and age) , your power consumption and how much time you actually can run the generator under the 8am to 8pm license condition.    You will typically need to run the generator 2-4  hours a day and for 8 hours or more at the weekends.  Getting some charge into Lead Acid batteries is quite quick.  Getting them full takes ages.

 

N

[Alan de Enfield]

Yes - you need to hook-it-up to a mains supply (either generator or bollard)

 

Just like with a car fuel tank - how much it takes to fill depends on how much you have taken from it, and how big the tank is.

Taking you battery from 50% SoC (state of charge) to 100% SoC could take 8 hours.

 

How many batteries do you have, what size are they (Ah) how old are they, and the size of battery charger. ?

 

Because you have (say) a 70 amp charger does not mean that it will charge a battery that needs 70Ah in one hour.

 

It is a very complex chemical reaction to charge a battery.

It is the battery that decides how much charge it will take, it is not the battery charger that says I can put in 70 amps, so that's what you get.

Initially the battery may take 70 amps, after a few minutes it may drop to 50 amps, another few minutes 40 amps and after an hour maybe 25 amps.

This continues to gradually reduce until after 6-8 hours you may still be putting in 3 or 4 amps.

Once you are charging at 1%-2% of battery capacity (ie if you have 400 Ah battery bank and are charging at 6-8amps) for one hour without it reducing any further you can consider the battery to be charged.

Edited February 16, 2020 by Alan de Enfield

[Alan de Enfield]

Do you have any battery monitoring equipment to show Ah used, SoC, voltage, and charging current ?

[Nick-Now]

i am not sure, I will know more on Thursday when I boat is handed over to me

[Alan de Enfield]

1 minute ago, Nick-Now said:

i am not sure, I will know more on Thursday when I boat is handed over to me

Did the surveyor not make any notes in the 'equipment' section of the Survey ?

[OldGoat]

Petrol generators  are one of the many Inventions of the Devil and 'should be avoided  at all costs' - but how you generate your power may be the subject of a further post / thread...

[Nick-Now]

From the report:

 

The electrical system comprised of 2 alternators on the engine charging four 110 amp hr lead acid cabin batteries and a single 110 amp hr starter battery. Main electricity was provided vi a shoreline socket or an inverter powered from the cabin batteries and then supplied to the cabin via a consumer unit. The 12volt power was connected to the cabin via a trip panel.

[Alan de Enfield]

42 minutes ago, Nick-Now said:

From the report:

 

The electrical system comprised of 2 alternators on the engine charging four 110 amp hr lead acid cabin batteries and a single 110 amp hr starter battery. Main electricity was provided vi a shoreline socket or an inverter powered from the cabin batteries and then supplied to the cabin via a consumer unit. The 12volt power was connected to the cabin via a trip panel.

 

Have a look when you get the boat for any monitoring / management systems (might be called something like Smart gauge, but others available).

You WILL need someway of deciding when to start charging and when to stop charging otherwise you are wasting fuel.

 

You (ideally) should replace any power used immediately, any use / recharging reduces the life of a battery and deeply discharging a battery can cause irreparable damage, leaving a battery partly charged causes problems (sulphation) so it is best to get as much charge back in every day and then do a full (100%) charge once a week.

 

Until you get the hang of managing electricity expect to probably have to replace the batteries twice in the 1st year.

 

Ate you planning to liveaboard or weekend / holiday / leisure use ?

[grahame r]

Are you planning on living on the canal side (constantly cruising) or in a marina? If this is your first boat then a marina for a few months might be worthwhile while you get the hang of power supply etc.

If in a marina, simply plug in the landline into the bollard and the Victron will look after your batteries.

If you are constantly cruising then running the engine regularly will also charge the batteries directly fro the alternator(s), but insufficiently unless you are cruising 5+ hours a day. Additional charging can be by simply running the engine whilst tied up but charging this way will never get the bateries back up to 100% which is what you are aiming to do. Attaching a generator to the Victron will make a much better fist of charging to 100% but you really do need a good battery monitoring system to keep you informed of the state of charge, Everyone has a view as to the best Battery Monitoring System but hopefully I won't start a riot by saying that a "Smartgauge" (reasonably priced and easy to install) will give you a good idea of when the batteries need charging and a monitor to tell you the charging current and therefore when the batteries are approaching 100%, as described by Alan de Enfield, post 3, shouid suffice.

Petrol generators have to be treated with respect. Apart from sizing, as descibed by BEngo in post 2, they are potentially very antisocial if not properly silenced and dangerous, don't even think of putting one in the engine room and remember that all engines, if not being used for propulsion, are banned between 8pm and 8am.   

 

Sorry crossed with AdE's reply, same message different words! I'll butt out!          

Edited February 16, 2020 by grahame r
Clarity.

[Alan de Enfield]

6 minutes ago, grahame r said:

Petrol generators have to be treated with respect. Apart from sizing, as descibed by BEngo in post 2, they are potentially very antisocial if not properly silenced and dangerous,

A very good point.

Just to re-inforce Grahame's comment - DON'T run a generator on board (lift it off and put it downwind of the boat) and don't mess about modifying it and putting it in the engine 'hole'.

 

A family died on board , the person who installed the generator was a 'gas safe' registered installer.

 

SYNOPSIS On Monday 1 April 2013, the emergency services attended the motor cruiser Arniston on Windermere, Cumbria, where a mother and her daughter had been found unconscious. The    two    females    were    taken    by    air    ambulance    to    Lancaster    Royal    Infirmary    where    they    were pronounced deceased. A postmortem concluded that the cause of death was carbon monoxide poisoning.

 

The    subsequent    MAIB    investigation    identified    that:

 

• The carbon monoxide poisoning had resulted from the inhalation of fumes emitted from a portable generator installed in the boat’s engine bay.

• The    external    exhaust    system    fitted    to    the    portable    generator    had    been    modified    to    incorporate    a    silencer    that    had    become    detached    from    both    the    generator and the outlet pipe to the vessel’s side.

• The    portable    generator’s    engine    exhaust    fumes    filled    the    engine    bay    and    spread through gaps in an internal bulkhead into the aft cabin where the mother and daughter were asleep.

• The portable generator was not intended by its manufacturer to be installed into    an    enclosed    space,    nor    was    it    intended    to    be    modified    in    any    way.

• The improvised exhaust system attached to the generator was constructed from materials and using methods that were not appropriate for this application.

• The boat’s occupants were not alerted to the danger because two carbon monoxide    sensors    fitted    to    the    boat    at    build    were    out    of    date    and    had    been    disconnected from the power supply.

 

https://assets.publishing.service.gov.uk/media/56a20e2040f0b667ce00002b/MAIBInvReport_2_2015.pdf

[David Mack]

If this is a liveaboard you will probably need a mains connection or generator, unless you are VERY frugal with your use of electricity.

But if this is a cruising boat and you travel a few hours most days when you are on board, then engine charging and solar will be more than sufficient for about 9 months of the year (and solar will keep the batteries topped up while you are not on board).

For 3 months in the winter, with shorter boating days, longer evenings with the lights on and virtually no solar, you may need to run the engine or a genny to keep the batteries topped up. But if you turn the fridge off and keep perishables outside you will significantly reduce your electricity usage.

[Nick-Now]

Thank you all for your input. Much appreciated.

[Dr Bob]

1 hour ago, Nick-Now said:

Thank you all for your input. Much appreciated.

Will you be a liveaboard? If not, how much time will you spend on the boat? They are important questions when asking about power.

[Chewbacka]

1 hour ago, Nick-Now said:

Thank you all for your input. Much appreciated.

The batteries true capacity will depend upon how will they have been looked after since fitting, so possibly they are already well past their best.  See how you get on - fingers crossed.....

[Dr Bob]

4 hours ago, Nick-Now said:

I'm a bit confused but maybe you can help?

On my recently purchased boat, there is installed a "Victron Easy Plus. 12v, 1600va inverter with 70 amp charger"  

 

My question is this.. because it not only an inverter  it also has a built in 70amp charger. 

 

1.) Would I only need to connect a generator directly to the Victron by means of the land line electric hookup socket?

 

2.) How long does the generator need to run to charge battery banks? ( I know this is how long is a piece of string type question, but in people experiences, are they having to run the generators for hours and hours to top up the batteries?)  

 

I will be looking into solar later on this year but it will be the flexible type as I really think the big flat panels are very ugly. I would rather have extra flexis to make up the shortfall.

Generators are the work of the devil. I hate it when you find a nice quiet place to moor and then some plonker comes in, moors 2 ft from your bow and then commences to start their noisey (most cheap ones are) genny and run it for hours belching out smoke and CO which then get blown in your cabin. Noise is something we try and avoid by being on canals.

 

Solar is a much better idea but no use for 3-4 months in winter. I would go for rigid panels everytime. Too many failures of the floppy ones. Ugly...yes, but functional.

[WotEver]

7 hours ago, Nick-Now said:

How long does the generator need to run to charge battery banks? ( I know this is how long is a piece of string type question, but in people experiences, are they having to run the generators for hours and hours to top up the batteries?)  

Have a read of this post:

 

[Chewbacka]

3 hours ago, Dr Bob said:

Generators are the work of the devil. I hate it when you find a nice quiet place to moor and then some plonker comes in, moors 2 ft from your bow and then commences to start their noisey (most cheap ones are) genny and run it for hours belching out smoke and CO which then get blown in your cabin. Noise is something we try and avoid by being on canals.

 

Solar is a much better idea but no use for 3-4 months in winter. I would go for rigid panels everytime. Too many failures of the floppy ones. Ugly...yes, but functional.

Solar good, gennie bad is good advice, but the basic question is how to charge the batteries for the few months that solar is no use???

[MtB]

8 hours ago, Nick-Now said:

2.) How long does the generator need to run to charge battery banks? ( I know this is how long is a piece of string type question, but in people experiences, are they having to run the generators for hours and hours to top up the batteries?)

 

If by "top up" you mean "fully charge", it takes typically 12 hours to fully charge from 50% discharged, using an appropriately specified battery charger. (This also depends on exactly what you might take "fully charged" to mean  )

 

But you are right it depends on how long the piece of string is, and what type of string too. And the colour. 

 

WotEver's battery charging primer he just linked to is well worth ploughing through if you have the time, it's not as heavy reading as it first appears. Or if you don't have the time and inclination, the money to keep replacing your batteries  

 

 

[DandV]

The Victron combis in default setting are fairly fussy over the quality of input power, frequency, voltage, and wave form that they will accept before they will activate charging mode. They have no difficulty passing power through though via the bypass relay.

For ours, there was a culture clash between the precision Dutch Victron and a agricultural open frame Chinese Generator. 

No we were not on the cut but in a remote isolated area of New Zealand coping with a week with no sun on the panels, a fridge full of food and no road access. 

But they a still a thing of the devil! 

Resolved when we changed  the internal Victron setting away from UPS on to off. (or was it the other way round?) This needed to be done from a lap top via the optional R232 interface, dip switches did not cut it. We also took the generator power through a suitably sized isolating transformer which considerably improved the wave form.

Edited February 16, 2020 by DandV

[Richard10002]

3 hours ago, Dr Bob said:

Solar is a much better idea but no use for 3-4 months in winter.

 

What do you use to charge yours during this part of the year?

[MtB]

25 minutes ago, DandV said:

We also took the generator power through a suitably sized isolating transformer which considerably improved the wave form.

 

Now there's a most interesting idea I've never seen mentioned before, and well worth investigating further. For all manner of cases where electronics get fussy about waveforms, e.g. washing machines.

 

 

[Dr Bob]

1 hour ago, Richard10002 said:

 

What do you use to charge yours during this part of the year?

When out and about, we run the engine for one to two hours a day. We need to run for at least an hour to heat the water. This winter though we have spent more time than last winter in the marina hooked up to shore power. Solar is just about coming back now though and we've seen a few days with >50Ahrs in the last week.

[Dr Bob]

1 hour ago, Chewbacka said:

Solar good, gennie bad is good advice, but the basic question is how to charge the batteries for the few months that solar is no use???

As above in my response to Richard........the engine.....but that only works if you have lithiums. When I run the engine I get 50A in each hour regardless of how full the batteries are and I don't have to take them to any set figure of SoC. Without LIthiums then I guess I would be running the engine for 30 hrs a week. Hence lithiums are a better investment than solar if you are technical enough to look after them.

[DandV]

8 hours ago, Mike the Boilerman said:

 

Now there's a most interesting idea I've never seen mentioned before, and well worth investigating further. For all manner of cases where electronics get fussy about waveforms, e.g. washing machines.

 

 

The initial reason for passing the generator output through an isolating transformer was, the supplied house switchboard was wired for a future mains connection with a conventional earth to neutral bond at the switchboard. Phase at 230v to earth/neutral. But I found  the generator was actually centre tapped to earth, that is a two phase 110v to earth, 220 v between phases, and I wanted the ability to completly  remove the Inverter if it failed and needed to be removed for servicing. An isolating transformer between meant I did not need to get involved in modifying the generator by snipping the centre tap and earthing on side on the output of generator unsure as I was of the safety implications. The isolating transformer though does filter the  generator  output as a welcome by product when the sun goes into hiding for a few days.

A 2.5kva isolating transformer is some brick.