Solar Hot (Warm) Water For Showering ?

[MikeH]

Has anyone done a solar hot water set-up for showering? ... beyond the solar shower bag on deck?

Most of my genset use is for water heating when at anchor. I've watched a bunch of YouTube videos for camper set-ups.

[chrishead]

Hey Mike - this is something on my wish list. Ideally, there would be a marine water heater that had two element-fitting ports. I don't think there is such a thing, at least for marine use. So it's my understanding that you must replace the 120 V element with a 12 V. Then use your excess solar to power the 12V element to heat the tank once the batteries are topped off, albeit slower than with the 120 V. I guess the answer lies in how much you anchor out versus in a slip with power. Here's a product that might work. https://www.green-yachting.online/ If you do this before we do expect us to stop by for showers when we see you in an anchorage!
Chris

[duetto]

i assume you have a) solar b) topped off batteries c) inverter ==> hot water .....not enough capacity? we have a 750w heater that'll make "hot enough" water in 25 minutes.

[MikeH]

Thanks Chris and John !

That looks like a great product ! ... and I didn't even know it existed. I've got a solar panel upgrade and new water heater coming up on my list, so this looks like a good solution. Certainly, simpler that trying to deal with a deck tank and solar collector.

I don't have enough guts to try the water heater on the 120v inverter (2000 watt Xantrex, 2010 model, expecting it to crap out any minute now...). On the genset, it takes about 10 to 15 minutes to make warm water for showering, depending on air/water temp.

For comparison, running the Mr. Coffee coffemaker on the inverter for 6 cups (4 minutes?), will reduce battery voltage readout by about 0.5 volts during operation, and "use up" about 0.1 volts total after the operation is done.

[MikeH]

John Cummings, damn if you are not right again !

It looks like by far the simplest route to go is to run the water heater off the inverter, which I'm already wired for.

Here's what I've found out so far, for those who are interested. If you Youtube search "solar dump load water heater" the RV'ers have a bunch of vidoes on this. Where they go down the rabbit hole (for me) is on the electronic control systems (sorry Brian Webb).

I don't need the electronic controls since I'm flipping the water heater switch on and off to operate it now.

Like Chris Head writes, ideally there would be a dual voltage water heater 120v and 12v. I could wire the 12v side to the batteries, and flip the switch "on," during sunny afternoons when the solar panels are maxed out. Or, if powering off the inverter, having dual wattage elements - a high watt for genset and shore power, and a lower watt for inverter use to help decrease battery drain and use the "solar dump load", which for me should be in the range of 400 watts.

My water heater is a Kuuma 6 gal 1500 watt element, mounted aft, with engine water heating.

The other option I'm considering is installing a 3 gal 12v water heater behind the shower, with a diverter valve so that the shower can pick up on either the 12v heater or the main heater.

I'll post again when I'm further down the road (or further down the ICW).