A Question Regarding Excess Charge....

[hummingway]

When you're on shore power you leave it on continuously? I've always turned it on until water was hot then turned it off but I haven't been on shore power in a couple of years.

The specs I was looking through didn't mention thermostats and mine certainly doesn't have a variable control though maybe it has a thermocoupler of some type.

[monte]

yes its on continuously on shore power
the thermostat is a small screw next to the element under the same cover

[hummingway]

Originally Posted by monte

yes its on continuously on shore power
the thermostat is a small screw next to the element under the same cover

Well, I have to hang upside under the sole to get to mine so it could have one of those and I'll never know it without removing the whole unit!

This thread has me thinking of doing just that. I'm on on-demand propane in my float home and have thought of converting the sailboat but the idea of 12v using excess power is more attractive to me. That relay driver is quite cheap as are 12v replacement elements. I doubt that adding a relay to the wiring itself would add much to the cost, total conversion maybe $250. If I ran it off the battery instead of directly off the power source I could take advantage of all extra power, when the engine or generator is running as well as when the solar panels were making excess.

[Stu Jackson]

Originally Posted by hummingway

That looks like the answer.

I think I have a Seaward 6 gallon, 1500w 120v on my boat. It has a temperature pressure release valve but I don't think it has a thermostat. As far as I can determine most of them don't. Do you have to be concerned with the water overheating and venting into the bilge on a regular basis?

Yes, it's possible, although I never have had that problem. Some have reported it.

We counter that possibility by simply ONLY turning the hot water on for 15-30 minutes at a time, we never just leave it on all the time.

Once you run out of hot water, just turn it back on again. Although i don't recall having to do that except for the next day anyway. We try not to use too much water at all times. The Scanvik water wand is a great help.

[Lagoon4us]

Originally Posted by hummingway

Well, I have to hang upside under the sole to get to mine so it could have one of those and I'll never know it without removing the whole unit!

This thread has me thinking of doing just that. I'm on on-demand propane in my float home and have thought of converting the sailboat but the idea of 12v using excess power is more attractive to me. That relay driver is quite cheap as are 12v replacement elements. I doubt that adding a relay to the wiring itself would add much to the cost, total conversion maybe $250. If I ran it off the battery instead of directly off the power source I could take advantage of all extra power, when the engine or generator is running as well as when the solar panels were making excess.

Good one now every one is 'gettin it' lmao!!!

Yes def on thermostat otherwise if relief blocked we would have bombs in our bilges, ours is on whenever shore power is on, as in a house, it is left on UNLESS we leave the boat for more than 24hours.

Well done guys for the tech info.... true forum stuff! Cheers

[ArtM]

This has me thinking about water heaters I've used in Motorhomes in the past. Those systems were so well insulated, that there was never any concern about the water cooling off. I could easily see an overheating situation happening in a middle-of-a-sunny-day scenario where not only is the "excess power" diverted to heating the water tank, but it is also at the hottest time of day, and at the time of day you are least likely to be using hot water.

I think I would agree with the idea of turning on a water heater only when heat is needed. Use your excess power to recharge batteries and portable devices, and to generate water to replace your morning shower and lunchtime cooking usage. There are few greater luxuries while on the hook than being able to use as much water as you wish.

[Lagoon4us]

Originally Posted by ArtM

This has me thinking about water heaters I've used in Motorhomes in the past. Those systems were so well insulated, that there was never any concern about the water cooling off. I could easily see an overheating situation happening in a middle-of-a-sunny-day scenario where not only is the "excess power" diverted to heating the water tank, but it is also at the hottest time of day, and at the time of day you are least likely to be using hot water.

I think I would agree with the idea of turning on a water heater only when heat is needed. Use your excess power to recharge batteries and portable devices, and to generate water to replace your morning shower and lunchtime cooking usage. There are few greater luxuries while on the hook than being able to use as much water as you wish.

Your not getting it? The power diverts WHEN the charge rate is tapering off ie the batteries are near full....

All hot water systems are thermostat controlled, they are not a tank that simply boils because you switch it on. In a marina ours is on 24/7 it's a modern device.... Overheating doesn't happen....

And yes by flicking the 'CHOICE' of diversion the excess goes to either the HWS or the De-sal via an invertor if AC.......

Cheers

[monte]

Hows the Med weather now Frank? North of Spain is more like a Victorian Winter!

[Lagoon4us]

Ahhh we back in Australia about a week ago to see the Grandkids etc, its cold here, back to Croatia soon will likely head north for a month then get ready for Greece.......
Hows the boat going , sorting it out?

[monte]

AH nice one. Boats all sorted, just some minor things to sort but I'll always find some of those I'm sure

[Lagoon4us]

Taking one son and two squibs back for 5 weeks to all the fantastic places we've found there...
If you heading this way in future we have charts and pilots etc....

[ArtM]

Originally Posted by Lagoon4us

Your not getting it? The power diverts WHEN the charge rate is tapering off ie the batteries are near full....

All hot water systems are thermostat controlled, they are not a tank that simply boils because you switch it on. In a marina ours is on 24/7 it's a modern device.... Overheating doesn't happen....

And yes by flicking the 'CHOICE' of diversion the excess goes to either the HWS or the De-sal via an invertor if AC.......

Cheers

This is a discussion of a modification to add a heating coil to an existing water heater, if I understand it correctly, and specifically choosing to apply that energy to a water heater whether or not it is needed.

My point is that the middle of the day may not be the right time to be applying "extra" heat to a water tank.

I just ran into this very situation this week. A water heater designed with a primary heating system (thermostatically controlled) plus an auxillary electric heating element, overheated and shut down. It entered a "lockout" mode, refusing to start again until it was "reset" by turning off power and turning it back on.

My point is why go to the effort/expense of this modification to get "extra" power to a hot water tank, unless it actually needs that heat? Especially since there is a risk of overheating the tank, possibly creating a boilover, a burst tank, scalding hot water at the tap, or locking out the thermostat.

If, in fact, the water heater does happen to need heating at this time of the day, then no modification is needed. The heater system will apply the energy automatically.

[Lagoon4us]

Ah but it's not my intention to modify any part of the heater, it's simply a matter of changing the element to a 12volt unit, thermostat still in place.....

Using a regulator that dumps gives you the choice of heating/charging whatever. The concept is not new most isolated australian solar systems do the same...

Elements are available, they screw in giving you the choice of power 12volt 110 volt or 240 volt. only one element at a time........

Cheers