"Geoff Schultz" wrote

What you need is a regulator that runs in diverter mode. In this mode it
senses the voltage and when it goes above the level that you've set, it
diverts some of the wattage to a resistive load (in my case, a water
heater
element in my hot water tank). There is absolutely no loss when running
in
this mode. This regulator controlls both my solar panels and my wind
generator.

I would suggest looking at charge controllers from MorningStar. I went
through several Trace/Xantrex and finally scrapped it. It seems that once
they started buulding the units in China that the reliability went to
hell.
I went with MorningStar TriStar unit and have been very happy with it.

Geoff,

I have been looking at the Tristar but couldn't figure out what to divert
to. How did you wire up the water heater to isolate the Tristar from the AC
shore power?

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"Glenn Ashmore" wrote:


"Geoff Schultz" wrote

What you need is a regulator that runs in diverter mode. In this mode it
senses the voltage and when it goes above the level that you've set, it
diverts some of the wattage to a resistive load (in my case, a water
heater
element in my hot water tank). There is absolutely no loss when running
in
this mode. This regulator controlls both my solar panels and my wind
generator.

I would suggest looking at charge controllers from MorningStar. I went
through several Trace/Xantrex and finally scrapped it. It seems that once
they started buulding the units in China that the reliability went to
hell.
I went with MorningStar TriStar unit and have been very happy with it.

Geoff,

I have been looking at the Tristar but couldn't figure out what to divert
to. How did you wire up the water heater to isolate the Tristar from the AC
shore power?

We divert the excess solar power (and wind power) to little fans that
run in the cabins and keep the air circulating. We can tell when the
batteries are charged if the fans start to run. If the boat is on the
hard and we aren't aboard, it helps to have the air circulate. YMMV

"Glenn Ashmore" wrote

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com


I like the idea of diverting to the water heater, but most of us do not have
the option to add a second 12V element to our existing heaters.

One thought, would be to add a second heater in an external loop around the
water heater - something like the add-on heaters that are sold for cars in
lieu of a block heater. This site has the elements:

http://www.realgoods.com/renew/shop/...204/ts/1025078

But, if the solar panels put out, say 150 watts for 8 hours, what happens
when the water becomes too hot? With a small boat type water heater say 6 or
10 gal, this could happen quite quickly. Maybe then we throw the towel?

GBM

"GBM" wrote in
:


"Glenn Ashmore" wrote

I'm building a 45' cutter in strip/composite. Watch my progress (or
lack there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com


I like the idea of diverting to the water heater, but most of us do not
have the option to add a second 12V element to our existing heaters.

One thought, would be to add a second heater in an external loop around
the water heater - something like the add-on heaters that are sold for
cars in lieu of a block heater. This site has the elements:

http://www.realgoods.com/renew/shop/...1204/ts/102507
8

But, if the solar panels put out, say 150 watts for 8 hours, what
happens when the water becomes too hot? With a small boat type water
heater say 6 or 10 gal, this could happen quite quickly. Maybe then we
throw the towel?

GBM

You can get elements that have both 120V AC and 12V DC feeds. See
http://www.svhotwire.com/divert_loads.html

-- Geoff

I used diverted power from my solar regulator to run fans throughout the
boat.


"Geoff Schultz" wrote in message
6...
"GBM" wrote in
:


"Glenn Ashmore" wrote

I'm building a 45' cutter in strip/composite. Watch my progress (or
lack there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com


I like the idea of diverting to the water heater, but most of us do not
have the option to add a second 12V element to our existing heaters.

One thought, would be to add a second heater in an external loop around
the water heater - something like the add-on heaters that are sold for
cars in lieu of a block heater. This site has the elements:

http://www.realgoods.com/renew/shop/...1204/ts/102507
8

But, if the solar panels put out, say 150 watts for 8 hours, what
happens when the water becomes too hot? With a small boat type water
heater say 6 or 10 gal, this could happen quite quickly. Maybe then we
throw the towel?

GBM

You can get elements that have both 120V AC and 12V DC feeds. See
http://www.svhotwire.com/divert_loads.html

-- Geoff

"Gerald" wrote in
:

I used diverted power from my solar regulator to run fans throughout the
boat.

Just how many watts do your fans draw?

-- Geoff

At initial outfitting time, I had a separate 12V fan curcuit installed with
outlets throughout over bunks, heads, galley, eating area, chart table. I
installed HELLA fans primarilly because they would give a reasonable breeze
..... for a 12 V fan and have minimal current draw --- for an electric fan..
So when I wanted to operate on the cheap (electrically cheap) I could have
my breeze without eating the batteries. When I installed solar panels, I
discovered the controller I selected(morningstar) had the ability to divert
as the batteries topped off. Rather than do nothng with all the free
electrons, I hooked it up to the fan circuit.


"Geoff Schultz" wrote in message
6...
"Gerald" wrote in
:

I used diverted power from my solar regulator to run fans throughout the
boat.

Just how many watts do your fans draw?

-- Geoff

"Geoff Schultz" wrote

You can get elements that have both 120V AC and 12V DC feeds. See
http://www.svhotwire.com/divert_loads.html


That's great, but:
- how is the water temperature controlled? Temperature should not exceed
49C to prevent scalding (used to be 60C)
- Once water reaches maximum temperature, what do you do then?

Seems to be of limited value if engine is also used to heat water. Our hot
water gets up to about 45C after an hour of motoring at low speed. It is
self limiting because of engine thermostat.

GBM

"Geoff Schultz" wrote

You can get elements that have both 120V AC and 12V DC feeds. See
http://www.svhotwire.com/divert_loads.html


GBM wrote:
That's great, but:
- how is the water temperature controlled? Temperature should not
exceed
49C to prevent scalding (used to be 60C)
- Once water reaches maximum temperature, what do you do then?

Seems to be of limited value if engine is also used to heat water. Our
hot water gets up to about 45C after an hour of motoring at low speed.
It is self limiting because of engine thermostat.

Just curious because I'm not familiar that with them - do marine water
heaters have any sort of provision whereby you can insert a temperature
sensor, which can then be hooked up to a limiting circuit?

Sailaway wrote:
"Geoff Schultz" wrote

You can get elements that have both 120V AC and 12V DC feeds. See
http://www.svhotwire.com/divert_loads.html


GBM wrote:
That's great, but:
- how is the water temperature controlled? Temperature should not
exceed
49C to prevent scalding (used to be 60C)
- Once water reaches maximum temperature, what do you do then?

Seems to be of limited value if engine is also used to heat water. Our
hot water gets up to about 45C after an hour of motoring at low speed.
It is self limiting because of engine thermostat.

Just curious because I'm not familiar that with them - do marine water
heaters have any sort of provision whereby you can insert a temperature
sensor, which can then be hooked up to a limiting circuit?

Marine water heaters typically have two heating devices in one package.

The first is a standard 110V electrical heating element, connected thru
a thermostat mounted on the tank, more or less just like your standard
domestic water heater.

The second heating device is a coil of tubing inside the tank thru which
you can circulate your engine coolant. There is no thermostat in the
water heater for this circuit. But the engine has a thermostat which
controls the temperature of the engine coolant which is circulating in
it. This means that the hot water temperature will approach the engine
thermostat set temperature with prolonged engine run times.

bob