Generator on a boat to charge batteries?

In article <A3mPh.44$x4.13@newsfe4-gui.ntli.net>, Malcolm
<sweet.TakeThisOut@notworkingmail.com> writes
>On Fri, 30 Mar 2007 17:50:26 GMT, Malcolm <sweet.TakeThisOut@notworkingmail.com>
>wrote:

(snip)

>
>My needs are simple, as stated, and I think the Honda EU1i seems to
>fit the bill nicely.
>
>What would be nice, would be the occasional use of an 800w
>microwave/oven for a max of 30 minutes or so at a time. Would an
>inverter run this from the two 110 batteries, and if so, how much
>power would this consume from the batteries? How long to charge the
>batteries to capacity again?
>
>TIA

800W from a 12V supply can be considered roughly as 800 / 10 = 80 Amps
(allowing for losses in the inverter, etc), so you are talking about 40
amp-hours, a significant proportion of the total charge in the batteries

110 AH should not normally be taken below half-charge, so you've got
maybe 55 AH in each battery - so your microwave use looks like nearly
half the capacity. OK, so I've rounded down towards 'worst case' at
each calculation, but it's still a big chunk.

Charging from the outboard at 6 Amps would be a reasonable day's
cruising, without any allowance for running lights, etc. in the
evenings. On the other hand, if you started charging from your genny
before turning on the microwave, and left the genny running for the
whole time you used the microwave, then maybe 30 - 60 mins after that,
it should cover most of the loss.

--

Jeremy Nunns
Cambridge
Remove Chinese Ship to Reply
 >> Stay informed about: Generator on a boat to charge batteries? 

On Sun, 1 Apr 2007 17:40:18 +0100, Jeremy Nunns
<Jeremy.DeleteThis@junk.yours.demon.co.uk> wrote:

>In article <A3mPh.44$x4.13@newsfe4-gui.ntli.net>, Malcolm
><sweet.DeleteThis@notworkingmail.com> writes
>>On Fri, 30 Mar 2007 17:50:26 GMT, Malcolm <sweet.DeleteThis@notworkingmail.com>
>>wrote:
>
>(snip)
>
>>
>>My needs are simple, as stated, and I think the Honda EU1i seems to
>>fit the bill nicely.
>>
>>What would be nice, would be the occasional use of an 800w
>>microwave/oven for a max of 30 minutes or so at a time. Would an
>>inverter run this from the two 110 batteries, and if so, how much
>>power would this consume from the batteries? How long to charge the
>>batteries to capacity again?
>>
>>TIA
>
>800W from a 12V supply can be considered roughly as 800 / 10 = 80 Amps
>(allowing for losses in the inverter, etc), so you are talking about 40
>amp-hours, a significant proportion of the total charge in the batteries
>
>110 AH should not normally be taken below half-charge, so you've got
>maybe 55 AH in each battery - so your microwave use looks like nearly
>half the capacity. OK, so I've rounded down towards 'worst case' at
>each calculation, but it's still a big chunk.
>
>Charging from the outboard at 6 Amps would be a reasonable day's
>cruising, without any allowance for running lights, etc. in the
>evenings. On the other hand, if you started charging from your genny
>before turning on the microwave, and left the genny running for the
>whole time you used the microwave, then maybe 30 - 60 mins after that,
>it should cover most of the loss.

So practical then?
 >> Stay informed about: Generator on a boat to charge batteries? 

Hi Malcolm
I'm not familiar with your stated generator, but could you not power the
microwave off the mains side of the generator? - assuming it has this
facility.

Davy M.

"Malcolm" <sweet.TakeThisOut@notworkingmail.com> wrote in message
news:A3mPh.44$x4.13@newsfe4-gui.ntli.net...
> On Fri, 30 Mar 2007 17:50:26 GMT, Malcolm <sweet.TakeThisOut@notworkingmail.com>
> wrote:
>
>>Small cruiser (26 ft) with two 110 batteries, running up to 6 inside
>>lights, radio/cd player. Central heating fan for a Truma combi (LPG)
>>and maybe a laptop for a few hours per day. I really don't want a
>>generator, but if I am going out for a few days I don't want to be
>>caught short. I would rarely be using it anyway, as I imagine the
>>batteries would last two or three days easily, but if I did need to
>>charge them up, how long would it take with a small genny?
>>
>>Is it better to use 240 connected to a 12v charger and charge
>>batteries, or to use the onboard battery charger on the genny?
>>
>>What sort of fuel consumption would it use?
>>
>>Just a few general questions really, as to is it worth it etc?
>>
>>TIA.
>
> PS: I only have a 25hp outboard with minimal charging, about 6amps I
> think.
>
> **********************************************
>
> On further investigation I found more questions than answers!
>
> My needs are simple, as stated, and I think the Honda EU1i seems to
> fit the bill nicely.
>
> What would be nice, would be the occasional use of an 800w
> microwave/oven for a max of 30 minutes or so at a time. Would an
> inverter run this from the two 110 batteries, and if so, how much
> power would this consume from the batteries? How long to charge the
> batteries to capacity again?
>
> TIA
 >> Stay informed about: Generator on a boat to charge batteries? 

On Mon, 02 Apr 2007 10:54:12 GMT, "David Murray"
<DavyMurray DeleteThis @Hotmail.com> wrote:


>"Malcolm" <sweet DeleteThis @notworkingmail.com> wrote in message
>news:A3mPh.44$x4.13@newsfe4-gui.ntli.net...
>> On Fri, 30 Mar 2007 17:50:26 GMT, Malcolm <sweet DeleteThis @notworkingmail.com>
>> wrote:
>>
>>>Small cruiser (26 ft) with two 110 batteries, running up to 6 inside
>>>lights, radio/cd player. Central heating fan for a Truma combi (LPG)
>>>and maybe a laptop for a few hours per day. I really don't want a
>>>generator, but if I am going out for a few days I don't want to be
>>>caught short. I would rarely be using it anyway, as I imagine the
>>>batteries would last two or three days easily, but if I did need to
>>>charge them up, how long would it take with a small genny?
>>>
>>>Is it better to use 240 connected to a 12v charger and charge
>>>batteries, or to use the onboard battery charger on the genny?
>>>
>>>What sort of fuel consumption would it use?
>>>
>>>Just a few general questions really, as to is it worth it etc?
>>>
>>>TIA.
>>
>> PS: I only have a 25hp outboard with minimal charging, about 6amps I
>> think.
>>
>> **********************************************
>>
>> On further investigation I found more questions than answers!
>>
>> My needs are simple, as stated, and I think the Honda EU1i seems to
>> fit the bill nicely.
>>
>> What would be nice, would be the occasional use of an 800w
>> microwave/oven for a max of 30 minutes or so at a time. Would an
>> inverter run this from the two 110 batteries, and if so, how much
>> power would this consume from the batteries? How long to charge the
>> batteries to capacity again?
>>
>> TIA
>

>Hi Malcolm
>I'm not familiar with your stated generator, but could you not power the
>microwave off the mains side of the generator? - assuming it has this
>facility.

The Honda EU10i is only 1kw, so no, not enough to power a microwave. I
couldn't justify going to a 2kw just to power the microwave. The EU10
is very economical, but at £600 it's still a very expensive battery
charger!
 >> Stay informed about: Generator on a boat to charge batteries? 

In article <WW4Qh.21562$2F5.10277@newsfe5-win.ntli.net>, Malcolm
<sweet.DeleteThis@notworkingmail.com> writes
>On Sun, 1 Apr 2007 17:40:18 +0100, Jeremy Nunns
><Jeremy.DeleteThis@junk.yours.demon.co.uk> wrote:
>
>>In article <A3mPh.44$x4.13@newsfe4-gui.ntli.net>, Malcolm
>><sweet.DeleteThis@notworkingmail.com> writes
>>>On Fri, 30 Mar 2007 17:50:26 GMT, Malcolm <sweet.DeleteThis@notworkingmail.com>
>>>wrote:
>>
>>(snip)
>>
>>>
>>>My needs are simple, as stated, and I think the Honda EU1i seems to
>>>fit the bill nicely.
>>>
>>>What would be nice, would be the occasional use of an 800w
>>>microwave/oven for a max of 30 minutes or so at a time. Would an
>>>inverter run this from the two 110 batteries, and if so, how much
>>>power would this consume from the batteries? How long to charge the
>>>batteries to capacity again?
>>>
>>>TIA
>>
>>800W from a 12V supply can be considered roughly as 800 / 10 = 80 Amps
>>(allowing for losses in the inverter, etc), so you are talking about 40
>>amp-hours, a significant proportion of the total charge in the batteries
>>
>>110 AH should not normally be taken below half-charge, so you've got
>>maybe 55 AH in each battery - so your microwave use looks like nearly
>>half the capacity. OK, so I've rounded down towards 'worst case' at
>>each calculation, but it's still a big chunk.
>>
>>Charging from the outboard at 6 Amps would be a reasonable day's
>>cruising, without any allowance for running lights, etc. in the
>>evenings. On the other hand, if you started charging from your genny
>>before turning on the microwave, and left the genny running for the
>>whole time you used the microwave, then maybe 30 - 60 mins after that,
>>it should cover most of the loss.
>
>So practical then?
>

Yes - practical with the proviso I mentioned.

A 1Kw genny running while you use the microwave will significantly
reduce the drain during cooking, and pretty rapidly bring the batteries
back up to full charge afterwards.

It would be possible to run the inverter for that long without the genny
(if you are on a quiet mooring and don't want to disturb neigbours, for
example), but not recommended unless you are about to go on a long run,
not to do unless you have to.

--

Jeremy Nunns
Cambridge
Remove Chinese Ship to Reply
 >> Stay informed about: Generator on a boat to charge batteries? 

"Malcolm" <sweet DeleteThis @notworkingmail.com> wrote in message
news:ze6Qh.41581$Lz4.9499@newsfe7-gui.ntli.net...
> On Mon, 02 Apr 2007 10:54:12 GMT, "David Murray"
> <DavyMurray DeleteThis @Hotmail.com> wrote:
>
>
>>"Malcolm" <sweet DeleteThis @notworkingmail.com> wrote in message
>>news:A3mPh.44$x4.13@newsfe4-gui.ntli.net...
>>> On Fri, 30 Mar 2007 17:50:26 GMT, Malcolm <sweet DeleteThis @notworkingmail.com>
>>> wrote:
>>>
>>>>Small cruiser (26 ft) with two 110 batteries, running up to 6 inside
>>>>lights, radio/cd player. Central heating fan for a Truma combi (LPG)
>>>>and maybe a laptop for a few hours per day. I really don't want a
>>>>generator, but if I am going out for a few days I don't want to be
>>>>caught short. I would rarely be using it anyway, as I imagine the
>>>>batteries would last two or three days easily, but if I did need to
>>>>charge them up, how long would it take with a small genny?
>>>>
>>>>Is it better to use 240 connected to a 12v charger and charge
>>>>batteries, or to use the onboard battery charger on the genny?
>>>>
>>>>What sort of fuel consumption would it use?
>>>>
>>>>Just a few general questions really, as to is it worth it etc?
>>>>
>>>>TIA.
>>>
>>> PS: I only have a 25hp outboard with minimal charging, about 6amps I
>>> think.
>>>
>>> **********************************************
>>>
>>> On further investigation I found more questions than answers!
>>>
>>> My needs are simple, as stated, and I think the Honda EU1i seems to
>>> fit the bill nicely.
>>>
>>> What would be nice, would be the occasional use of an 800w
>>> microwave/oven for a max of 30 minutes or so at a time. Would an
>>> inverter run this from the two 110 batteries, and if so, how much
>>> power would this consume from the batteries? How long to charge the
>>> batteries to capacity again?
>>>
>>> TIA
>>
>
>>Hi Malcolm
>>I'm not familiar with your stated generator, but could you not power the
>>microwave off the mains side of the generator? - assuming it has this
>>facility.
>
> The Honda EU10i is only 1kw, so no, not enough to power a microwave. I
> couldn't justify going to a 2kw just to power the microwave. The EU10
> is very economical, but at £600 it's still a very expensive battery
> charger!


Beware - I think the EU10 is rated at 1000 kVA which is less than 1kW. It
all depends upon the Power Factor of whatever you have hooked up onto the
end of it. Probably best to assume about 850 W.

I could not get Honda to tell me the voltage available at the 12v output and
have a sneaky feeling its only about 12.7 volts. Unless you can get 13.8
volts from the 12v output drive a battery charger from the mains output,
however unless you start talking lots of cash I think you may find the mains
charger will only supply 8 to 10 amps.

I think the 800 watt load will have to go - however nice it is.


--
Tony Brooks
www.TB-Training.co.uk

Maintenance & Electrical training for ordinary boaters
 >> Stay informed about: Generator on a boat to charge batteries? 

On Fri, 13 Apr 2007 10:50:39 +0100, "Tony Brooks"
<tony DeleteThis @tb-training.co.uk> wrote:

>
>"Malcolm" <sweet DeleteThis @notworkingmail.com> wrote in message
>news:ze6Qh.41581$Lz4.9499@newsfe7-gui.ntli.net...
>> On Mon, 02 Apr 2007 10:54:12 GMT, "David Murray"
>> <DavyMurray DeleteThis @Hotmail.com> wrote:
>>
>>
>>>"Malcolm" <sweet DeleteThis @notworkingmail.com> wrote in message
>>>news:A3mPh.44$x4.13@newsfe4-gui.ntli.net...
>>>> On Fri, 30 Mar 2007 17:50:26 GMT, Malcolm <sweet DeleteThis @notworkingmail.com>
>>>> wrote:
>>>>
>>>>>Small cruiser (26 ft) with two 110 batteries, running up to 6 inside
>>>>>lights, radio/cd player. Central heating fan for a Truma combi (LPG)
>>>>>and maybe a laptop for a few hours per day. I really don't want a
>>>>>generator, but if I am going out for a few days I don't want to be
>>>>>caught short. I would rarely be using it anyway, as I imagine the
>>>>>batteries would last two or three days easily, but if I did need to
>>>>>charge them up, how long would it take with a small genny?
>>>>>
>>>>>Is it better to use 240 connected to a 12v charger and charge
>>>>>batteries, or to use the onboard battery charger on the genny?
>>>>>
>>>>>What sort of fuel consumption would it use?
>>>>>
>>>>>Just a few general questions really, as to is it worth it etc?
>>>>>
>>>>>TIA.
>>>>
>>>> PS: I only have a 25hp outboard with minimal charging, about 6amps I
>>>> think.
>>>>
>>>> **********************************************
>>>>
>>>> On further investigation I found more questions than answers!
>>>>
>>>> My needs are simple, as stated, and I think the Honda EU1i seems to
>>>> fit the bill nicely.
>>>>
>>>> What would be nice, would be the occasional use of an 800w
>>>> microwave/oven for a max of 30 minutes or so at a time. Would an
>>>> inverter run this from the two 110 batteries, and if so, how much
>>>> power would this consume from the batteries? How long to charge the
>>>> batteries to capacity again?
>>>>
>>>> TIA
>>>
>>
>>>Hi Malcolm
>>>I'm not familiar with your stated generator, but could you not power the
>>>microwave off the mains side of the generator? - assuming it has this
>>>facility.
>>
>> The Honda EU10i is only 1kw, so no, not enough to power a microwave. I
>> couldn't justify going to a 2kw just to power the microwave. The EU10
>> is very economical, but at £600 it's still a very expensive battery
>> charger!
>
>
>Beware - I think the EU10 is rated at 1000 kVA which is less than 1kW. It
>all depends upon the Power Factor of whatever you have hooked up onto the
>end of it. Probably best to assume about 850 W.

That's the sort of figure I thought reliably.

>I could not get Honda to tell me

Don't seem the best company for the general market. I also note from
reviews that if anything goes wrong out of warranty it's scrap! The
parts are horrendous.

Honda motorcycles had a great CS side.

>the voltage available at the 12v output and
>have a sneaky feeling its only about 12.7 volts. Unless you can get 13.8
>volts from the 12v output drive a battery charger from the mains output,

Would say a 30amp charger charge at 3x the rate of a 10amp charger ie
3x quicker?

>however unless you start talking lots of cash I think you may find the mains
>charger will only supply 8 to 10 amps.
>
>I think the 800 watt load will have to go - however nice it is.

Then we have space problems
 >> Stay informed about: Generator on a boat to charge batteries?