I did some rough math and it looks like you'll need ~38Ahrs of power for a 15 minute shower. Your inverter will be drawing 150amps through the supply wires and your alternator would have to recharge that amount. With the stock alternator (35amps) it would take over and hour. I do think I remember you having an upgraded alternator. Of course the assumption was that the hot water was at full flow for the 15 minute duration.
The instant waterheater is just a resistive load. It would be more efficient and possibly safer to eliminate the inverter from the picture. It would take some electrical and electronics skills to re-engineer the unit to run on 12v instead of 120v. That new water heater really is shockingly smaller. You'll have to let us know how it turns out. Josh Muckley S/V Sea Hawk 1989 C&C 37+ Solomons, MD On Aug 31, 2015 10:15 AM, "Edd Schillay via CnC-List" <cnc-list@cnc-list.com> wrote: > My hot water tank was failing as well and I’m in the middle of putting in > a replacement — the hard part was getting the old one out of the tight > space under the galley. > > I decided to go with an on-demand water heater which will either be > powered by shore power or an inverter (2000W) while the engine is running. > Here’s the one I picked: > http://m.rakuten.com/product/263816304?listingid=337903396&adid=29963&sclid=pla_google_Zoro > > > And here is old and new side-by-side: > https://dl.dropboxusercontent.com/u/15162917/ENTERPRISE/heaters.jpg > > I’ll try to finish it up over the next couple of weeks, but if not, it’ll > be a quick winter project. > > > All the best, > > Edd > > > Edd M. Schillay > Starship Enterprise > C&C 37+ | Sail No: NCC-1701-B > City Island, NY > Starship Enterprise's Captain's Log <http://enterpriseb.blogspot.com/> > > > > > On Aug 30, 2015, at 11:13 AM, Josh Muckley via CnC-List < > cnc-list@cnc-list.com> wrote: > > In most of the little hot water tanks the anode is part of the hot water > outlet nipple. Follow the link for pictures of the tank rebuild I did. > > https://drive.google.com/folder/d/0B8pEh5lnvP1ydEpoMU1MWmx6Qms/edit > > Josh Muckley > S/V Sea Hawk > 1989 C&C 37+ > Solomons, MD > On Aug 30, 2015 10:26 AM, "phorvati . via CnC-List" <cnc-list@cnc-list.com> > wrote: > >> And make sure you have zinc anodes. Electrolysis will eat something. >> On Aug 29, 2015 8:51 PM, "Jim Watts via CnC-List" <cnc-list@cnc-list.com> >> wrote: >> >>> Put a meter on it and read what kind of voltage you are getting. 110V AC >>> does not generally give little shocks. >>> >>> Jim Watts >>> Paradigm Shift >>> C&C 35 Mk III >>> Victoria, BC >>> >>> On 29 August 2015 at 16:15, Michael Crombie via CnC-List < >>> cnc-list@cnc-list.com> wrote: >>> >>>> >>>> I'm working my way down my project list and finally got to my hot water >>>> tank. The PO just told me that it didn't work. I was getting 120V at the >>>> heating element so I checked the element and it was fried. >>>> >>>> I installed a new element and turned it on for a test. Got hot water >>>> after about 10 min, so I went to close everything up. But when I was doing >>>> that I touched the pressure relief valve and got a small shock. >>>> >>>> The green ground wire runs to one of the mouting bolts on the heating >>>> element and also to the water tank frame. So that seems ok. I also checked >>>> for continuity between the hot and neutral wires and the relief valve or >>>> frame and got none. >>>> >>>> So i'm puzzled. The shock wasn't big, but i definitely felt something. >>>> Any ideas??? >>>> >>>> Thanks, >>>> >>>> Mike >>>> Atacama 33 mk ii >>>> Toronto >>>> Sent wirelessly from my BlackBerry device on the Bell network. >>>> Envoyé sans fil par mon terminal mobile BlackBerry sur le réseau de >>>> Bell. >>>> _______________________________________________ >>>> >>> > > _______________________________________________ > > Email address: > CnC-List@cnc-list.com > To change your list preferences, including unsubscribing -- go to the > bottom of page at: > http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com > > >
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