I would like to wire up the inverter on my boat to be very simple to
switch on and connect into the boats mains wiring. Ideally I want just
one switch. I am happy for this to be a big battery switch. I want the
plugs and other mains appliances (microwave, some lights etc) to just
work when I flick the switch. This is further complicated by the need to
not run other things - the battery charger is the only one that comes to
mind - from the inverter.

I am thinking about using a relay which will automatically disconnect
the inverter from the internal cct breaker and fuse panel if shore power
is connected. The same relay can also connect up the shore power only
circuits.

To do this seems simple... I use a 3 or 4 pole DT relay which is
energised by the shore power feed and will connect the feed to the fuse
panel input. When shore power is removed the relay will switch the
inverter output to the fuse panel input and disconnect the battery charger.

Does anyone see a problem with this? The only worry I had was that there
could be an issue with voltage spikes when the mains is unplugged and
some motor or coil gets connected to the inverter as its field collapses
(which may or may not be actually on). Presumably the inverter is
protected against such things cause by the DC power vanishing but having
the relay there means that the voltage switched on to the inverter when
the contacts eventually close could be quite high. Do inverters normally
have protection against such transients?

Alternatively, a 12VDC energised relay could be used that is on the same
switch as the inverter power. It would then disconnect the shore power
if the inverter is on. This has a couple of draw backs. 1) I need to run
the relay whenever the inverter is to be used (ok I know it is
insignificant but... well - you know!..) 2) I don't get an option for
automatic fail over if shore power fails. Which may be a good or bad
thing but at least it is an option. 3) the big spike could end up on the
shore power plug but I don't think will be any worse than when you
unplug the shore power by pulling the plug out.

Thanks in advance,

Steve

Steve wrote in :

I would like to wire up the inverter on my boat to be very simple to
switch on and connect into the boats mains wiring. Ideally I want just
one switch. I am happy for this to be a big battery switch. I want the
plugs and other mains appliances (microwave, some lights etc) to just
work when I flick the switch. This is further complicated by the need
to not run other things - the battery charger is the only one that
comes to mind - from the inverter.

Aren't your lights 12V? How big is this boat?

The microwave is easy. Just run it on a dedicated cable plugged into the
inverter all the time, even at the dock. I have ours wired this way and it
works great. I installed separate outlets in the galley and at the nav
station (41' ketch) for small appliances and our nav computer/printer's AC
dongles. Noone can accidently plug the shore power into the inverter when
they're not hooked together.


I am thinking about using a relay which will automatically disconnect
the inverter from the internal cct breaker and fuse panel if shore
power is connected. The same relay can also connect up the shore power
only circuits.

Quick, contact your INSURANCE agent! Ask him about installing non-code,
homemade AC power modifications. I was going to do the same thing until
they told us it would void our insurance policy.

In order to satisfy the insurance company, we would have had to install an
NEC-approved genset transfer panel and transfer switch like:
http://www.4lots.com/index.asp?PageA...ROD&ProdID=493
It will do what you want. You must buy the 50A model to service your 50A
shore power connection. The unit must be a commercial, approved unit to
satisfy your insurance boys.

If you don't have insurance on the boat....what you've written will work
great if you use a 50A relay with 50A wiring. Have at it.

A quick word on inverter remote control......

We're using a 1000W Radio Shack inverter to power
computer/printer/microwave and small appliances on Lionheart. Having the
fan running inside the living space wasn't much of an option because of the
noise it makes. If you open any of the inverters, you'll see the power
switch is a very low current little switch, because it only switches the
electronic drive on and off, not battery DC at 100A. To connect a remote
control to mount it in the engine compartment, next to the batteries, I
soldered a small, 2-conductor cable across the inverter's internal power
switch and pulled the wire to our nav station where a previous owner had a
hole we needed to fill. At the panel I installed a little aluminum plate
over the hole with a simple SPST mini switch hooked to the other end of the
cable, simple on-off. Next to the miniswitch, there is a neon indicator
light that runs off the nearby AC power outlet hooked to the inverter. The
light lets you know, yes the inverter is on and it's putting out AC power.
Just flick the little switch on and cook dinner...even at the dock...

Steve wrote:
I would like to wire up the inverter on my boat to be very simple to
switch on and connect into the boats mains wiring. Ideally I want just
one switch. I am happy for this to be a big battery switch. I want the
plugs and other mains appliances (microwave, some lights etc) to just
work when I flick the switch. This is further complicated by the need
to not run other things - the battery charger is the only one that
comes to mind - from the inverter.

I am thinking about using a relay which will automatically disconnect
the inverter from the internal cct breaker and fuse panel if shore
power is connected. The same relay can also connect up the shore
power only circuits.

To do this seems simple... I use a 3 or 4 pole DT relay which is
energised by the shore power feed and will connect the feed to the
fuse panel input. When shore power is removed the relay will switch
the inverter output to the fuse panel input and disconnect the
battery charger.

Does anyone see a problem with this? The only worry I had was that
there could be an issue with voltage spikes when the mains is
unplugged and
some motor or coil gets connected to the inverter as its field
collapses (which may or may not be actually on). Presumably the
inverter is protected against such things cause by the DC power
vanishing but having the relay there means that the voltage switched
on to the inverter when the contacts eventually close could be quite
high. Do inverters normally have protection against such transients?

Alternatively, a 12VDC energised relay could be used that is on the
same switch as the inverter power. It would then disconnect the shore
power
if the inverter is on. This has a couple of draw backs. 1) I need to
run the relay whenever the inverter is to be used (ok I know it is
insignificant but... well - you know!..) 2) I don't get an option for
automatic fail over if shore power fails. Which may be a good or bad
thing but at least it is an option. 3) the big spike could end up on
the shore power plug but I don't think will be any worse than when you
unplug the shore power by pulling the plug out.

Thanks in advance,

Steve

We have a 3-way switch (Off, Inverter,Shore Power) on our Beneteau 50. This
is the first switch we use on entering the boat. The battery charger is
wired to only operate when the switch is on Shore Power. Seems to work OK.

Dennis.


----
Remove *nospam* to reply.

Larry W4CSC wrote:
Aren't your lights 12V? How big is this boat?
Thanks for the reply.
Most the lights are 12V but there are a number of 240V units also. I am
in the process of removing them and replacing with IRC halogen units
although I am tempted to put a big mains florescent tube unit in the
engine room.

Its only a 40' cutter.


The microwave is easy. Just run it on a dedicated cable plugged into the
inverter all the time, even at the dock. I have ours wired this way and it
works great. I installed separate outlets in the galley and at the nav
station (41' ketch) for small appliances and our nav computer/printer's AC
dongles. Noone can accidently plug the shore power into the inverter when
they're not hooked together.
I really don't like this idea although I can see that simplicity is
good. It doesn't seem very elegant to have the microwave and some points
driven the the inverter and others not.


Quick, contact your INSURANCE agent! Ask him about installing non-code,
homemade AC power modifications. I was going to do the same thing until
they told us it would void our insurance policy.
You are kidding right? If not, what specific code are you referring to?
I think my insurance says you need a electrician to certify it.


In order to satisfy the insurance company, we would have had to install an
NEC-approved genset transfer panel and transfer switch like:
http://www.4lots.com/index.asp?PageA...ROD&ProdID=493
It will do what you want. You must buy the 50A model to service your 50A
shore power connection. The unit must be a commercial, approved unit to
satisfy your insurance boys.
Wow! That is a lot of cash to do the job of a relay! I can buy a rail
mounted 240V relay for just a few bucks.


If you don't have insurance on the boat....what you've written will work
great if you use a 50A relay with 50A wiring. Have at it.
50A! I only have 20A wiring but then it is for 240V. Does that mean you
don't think that the voltage spike will cause a problem to the inverter
when the mains is unplugged?

A quick word on inverter remote control......

We're using a 1000W Radio Shack inverter to power
computer/printer/microwave and small appliances on Lionheart. Having the
fan running inside the living space wasn't much of an option because of the
noise it makes. If you open any of the inverters, you'll see the power
switch is a very low current little switch, because it only switches the
electronic drive on and off, not battery DC at 100A. To connect a remote
control to mount it in the engine compartment, next to the batteries, I
soldered a small, 2-conductor cable across the inverter's internal power
switch and pulled the wire to our nav station where a previous owner had a
hole we needed to fill. At the panel I installed a little aluminum plate
over the hole with a simple SPST mini switch hooked to the other end of the
cable, simple on-off. Next to the miniswitch, there is a neon indicator
light that runs off the nearby AC power outlet hooked to the inverter. The
light lets you know, yes the inverter is on and it's putting out AC power.
Just flick the little switch on and cook dinner...even at the dock...

Interesting but it makes sense that only the control is switched I
guess. My inverter is so cheap it doesn't have an on off switch.

Larry W4CSC wrote:
Aren't your lights 12V? How big is this boat?
Thanks for the reply.
Most the lights are 12V but there are a number of 240V units also. I am
in the process of removing them and replacing with IRC halogen units
although I am tempted to put a big mains florescent tube unit in the
engine room.

Its only a 40' cutter.


The microwave is easy. Just run it on a dedicated cable plugged into the
inverter all the time, even at the dock. I have ours wired this way and it
works great. I installed separate outlets in the galley and at the nav
station (41' ketch) for small appliances and our nav computer/printer's AC
dongles. Noone can accidently plug the shore power into the inverter when
they're not hooked together.
I really don't like this idea although I can see that simplicity is
good. It doesn't seem very elegant to have the microwave and some points
driven the the inverter and others not.


Quick, contact your INSURANCE agent! Ask him about installing non-code,
homemade AC power modifications. I was going to do the same thing until
they told us it would void our insurance policy.
You are kidding right? If not, what specific code are you referring to?
I think my insurance says you need a electrician to certify it.


In order to satisfy the insurance company, we would have had to install an
NEC-approved genset transfer panel and transfer switch like:
http://www.4lots.com/index.asp?PageA...ROD&ProdID=493
It will do what you want. You must buy the 50A model to service your 50A
shore power connection. The unit must be a commercial, approved unit to
satisfy your insurance boys.
Wow! That is a lot of cash to do the job of a relay! I can buy a rail
mounted 240V relay for just a few bucks.


If you don't have insurance on the boat....what you've written will work
great if you use a 50A relay with 50A wiring. Have at it.
50A! I only have 20A wiring but then it is for 240V. Does that mean you
don't think that the voltage spike will cause a problem to the inverter
when the mains is unplugged?

A quick word on inverter remote control......

We're using a 1000W Radio Shack inverter to power
computer/printer/microwave and small appliances on Lionheart. Having the
fan running inside the living space wasn't much of an option because of the
noise it makes. If you open any of the inverters, you'll see the power
switch is a very low current little switch, because it only switches the
electronic drive on and off, not battery DC at 100A. To connect a remote
control to mount it in the engine compartment, next to the batteries, I
soldered a small, 2-conductor cable across the inverter's internal power
switch and pulled the wire to our nav station where a previous owner had a
hole we needed to fill. At the panel I installed a little aluminum plate
over the hole with a simple SPST mini switch hooked to the other end of the
cable, simple on-off. Next to the miniswitch, there is a neon indicator
light that runs off the nearby AC power outlet hooked to the inverter. The
light lets you know, yes the inverter is on and it's putting out AC power.
Just flick the little switch on and cook dinner...even at the dock...

Interesting but it makes sense that only the control is switched I
guess. My inverter is so cheap it doesn't have an on off switch.

I did look at three way switches but could not get one with enough poles
to do everything I wanted. I would need 2 for the live and neutral, one
for the battery charger and then I would also have need something to
turn on the DC power to my inverter (probably an electronic battery
switch driven by another pole). I am guessing that you have something
very flash and expensive which I will wish I had spend money on in a few
years when my stuff is playing up.

Thanks for the reply.

Steve

Dennis Pogson wrote:


We have a 3-way switch (Off, Inverter,Shore Power) on our Beneteau 50. This
is the first switch we use on entering the boat. The battery charger is
wired to only operate when the switch is on Shore Power. Seems to work OK.

Dennis.


----
Remove *nospam* to reply.

Steve wrote:
I did look at three way switches but could not get one with enough
poles to do everything I wanted. I would need 2 for the live and
neutral, one for the battery charger and then I would also have need
something to turn on the DC power to my inverter (probably an
electronic battery switch driven by another pole). I am guessing that
you have something very flash and expensive which I will wish I had
spend money on in a few years when my stuff is playing up.

Thanks for the reply.

Steve

Not really, it's a circular 3-way DC switch with a pointer/knob which turns
left, right, and straight up. AFAIR our +/- battery leads (massive) go
straight to the inverter via the main master switches (2,+/-), and there is
an on/off switch on the inverter itself. With the 3-way switch off, turning
on the inverter's on/off switch does nothing, with the 3-way switched to
shore power, the battery charger and all the 12-volt systems are activated,
but the inverter is still out of circuit. Only when the 3-way is switched to
inverter is it possible to activate the inverter and the 240-volt ring main
et al. The only remote switch we have is the gas solenoid in the cockpit gas
locker, actuated by a contact-breaker switch on the main saloon panel. It's
all manual, and all very simple.

Dennis.

Steve wrote in :

You are kidding right? If not, what specific code are you referring to?
I think my insurance says you need a electrician to certify it.


Unless you are in some third world country, your country will have an
ELECTRICAL CODE, like the NEC (National Electric Code) in the USA. All
electrical components must be NEC components.

Your question was about something home-made. If it ever caused a fire and
were "Not To Code", the insurance company would simply disallow the claim.

An example happened to a country church I used to fix the Hammond organ
for....

Instead of buying proper in-floor 115VAC recepticals, those round brass
floor outlets you see in a mall store all over which have flip-top covers
or screw covers to protect the sunken outlets noone can step on and break,
the church decided to save a few bucks by installing wall outlets in the
stage floor on either side of the pulpit and putting a metal outlet cover,
no protection at all, on them. This is NOT to CODE. They are WALL
outlets.

Well, someone stepped on one and cracked open the plastic outlet, but it
didn't immediately arc and catch the wooden stage on fire. That happened
some time between Sunday night service and Wednesday prayer service. Being
isolated way out in the country, noone saw it go up in flames. The
insurance company found out about the Not to Code wiring and disallowed the
claim for the fire.

Don't blame me....ask your insurance guy if you can put a home-made relay
in your AC line and be insured by his underwriters.....

Steve wrote in :

50A! I only have 20A wiring but then it is for 240V. Does that mean you
don't think that the voltage spike will cause a problem to the inverter
when the mains is unplugged?


Proper transfer equipment OPENS the circuit between the time it disconnects
from one AC source and connects to the other. There are no spikes. Break
before make it's called.

You'll notice a little dark period between when the AC line disconnects and
the genset connects when the transfer switch is thrown, automatic or
manual.

Larry,

Yes America is universally accepted as the king of all the nanny states.
NZ is getting there but still has a long way to go.

home-made relay

I am sorry if I gave the impression that I was intending to buy
something from radio shack and cobble it up with insulating tape and
solder or worse wind my own. This isn't quite what I have in mind.... I
was going to use a rail mounted relay? They are designed and made for
switching mains electricity. They have a base socket that mounts on a
standard rail within the fuse panel (the same rail that RCD and cct
breakers are attached to). Have a look at
http://ecb.omron.com.sg/product/c-relaygp.asp I can buy the LY series
from any local electrical supplier. As far as I can find out these are
sold to be used in mains connected systems and they are approved for use
connected to the mains.

My feeling is that using such an approved relay in a system will not
violate the regulations BUT it is a good point that is worth checking so
thanks.



Larry W4CSC wrote:
Steve wrote in :


You are kidding right? If not, what specific code are you referring to?
I think my insurance says you need a electrician to certify it.



Unless you are in some third world country, your country will have an
ELECTRICAL CODE, like the NEC (National Electric Code) in the USA. All
electrical components must be NEC components.

Your question was about something home-made. If it ever caused a fire and
were "Not To Code", the insurance company would simply disallow the claim.

An example happened to a country church I used to fix the Hammond organ
for....

Instead of buying proper in-floor 115VAC recepticals, those round brass
floor outlets you see in a mall store all over which have flip-top covers
or screw covers to protect the sunken outlets noone can step on and break,
the church decided to save a few bucks by installing wall outlets in the
stage floor on either side of the pulpit and putting a metal outlet cover,
no protection at all, on them. This is NOT to CODE. They are WALL
outlets.

Well, someone stepped on one and cracked open the plastic outlet, but it
didn't immediately arc and catch the wooden stage on fire. That happened
some time between Sunday night service and Wednesday prayer service. Being
isolated way out in the country, noone saw it go up in flames. The
insurance company found out about the Not to Code wiring and disallowed the
claim for the fire.

Don't blame me....ask your insurance guy if you can put a home-made relay
in your AC line and be insured by his underwriters.....