Water heater with inverter ?

wellbuilt

Hi all , how do you guys feel about mounting a on demand water heater on the out side wall of my utility room. 

 The wall is 6’6” wide and my inverter is on the left side I wanted to save the right side of the wall for my utility power but it dose not look like that will ever happen . 

It doesn’t get very hot in there now 75o would be warm .
 I had planed to locate the heater 10lb away on the other side of the room but things don’t seam to be working out 
 my batterys are in the garage on the other side of the wall and the room is vented to the garage
 thanks for the reply .         John 

wellbuilt

The battery’s are not on the floor they are to the right of the wall in the garage and vented out side 

mike95490

A water heater has to be vented out doors.   There is a lot of moisture in the exhaust, and some heaters also need a drainage line for acidic water.

icarus

I assume that you are talking about a gas (or LP) fired demand water heater?  Two things to consider.  First, most modern demand water heaters (Rinnai/takagi/Noritz ) are sealed combustion unites that draw outside air in, and directly vent exhaust out, so it shouldn’t be an issue.  Assuming your batteries are well vented to outside, there is little risk of combustion from off gassing due to the water heater.

Second, the water heater will only add a little bit of heat to the room, given the basic efficiency of the unit.  If it were to run 24/7 that might be an issue, but for normal duty cycle it certainly isn’t.

Finally, if you are going to run an old fashioned, standing pilot, non sealed combustion water heater like an old Bosch or Paloma that story would change.  I would be a bit concerned with battery off gassing unless I had a sealed battery box and positive vent, like a Zepher fan.

Tony

wellbuilt

Thanks for the replies mike and tony . 

  I have kind of a cheesy direct vent unit  is sparker fired and draws air from the room . 
 My battery’s are in the garage and draws air from 4 4” pipes in the side of the battery box and is vented out side with a van run off my charge controller .
In Winter time I draw warm air from the house to add some heat to the battery’s .
 I probably should of bought a better water heater but this one has no fan and no electric and it’s sitting here so i geuss I’ll hook it up . 

Thanks for the reply John 

icarus

Just as a side note...unless you have real issues with capacity, there is little or no reason to warm the batteries from conditioned space.  In fact batteries like to be coo to cold.  While capacity is diminished with a cold battery, it’s longevity is enhanced.  If the batteries are in the garage, it is likely that they are substantially above freezing.  Even if they are below freezing, they are not going to get hurt.  

A fully charged FLA battery won’t freeze until -40.  Even a 50% charged battery will not freeze until below 0f.  

As for the water heater, as long as it is not risking the off gas of the batteries there should be no issue.  Assuming you vent the heater out doors, you can always rig up a air intake for it, drawing outside air, but beware, if you draw outside air from very cold outside, freezing the water heater is a possibility.  

There is a formula for how big a room needs to be for you not to have to draw outside air to fire a gas burning appliance, but in the case of a small demand water heater (< 50k btu/hour) almost any room save a small closet shouldn’t present a problem.

Tony

wellbuilt

Thanks  for the reply tony , there is no shortage of cold here , so  it’s better to run the battery down % wise then to keep them a little warmer and get more capacity hmmmm learn something new every day here, I use about 12 to 15 % of my power over night .
if I dropped to 20% over night I guess that would be alright . 

 In the winter my panels are covered with snow for weeks and I charge off generator most of the time . 

 I think cold battery’s will leave me running the generator every 2 day instead of 3 days , I’m sure my garage is -0 for weeks on end .
 How much capacity do I louse at say 20o  John 

Estragon

At 20°F, my guess is ~20%.  Mine are currently about 1/2 way there now (vs 25°C/77°F), and apparent capacity is down a bit over 10%.  They'll likely get down to near 0°F over the winter, and capacity will be down by about 1/3 or a bit more.

wellbuilt

I guess I’ll give it a try and see how it works for me.
 I have a2” intake pipe run to the hall way inside and can change back and forth from garage intake  to house intake. 

 Battery’s are 57o now while charging , I had a few 70 o battery’s reading over the summer but mostly 65/67o as a night reading . 

  Thanks for the reply estragon  at this time I’m only there on weekends so I don’t think running my power vent for 5/6 hours a day will get the battery’s all toasty but no to look at it .    John 

icarus

Is it not possible to clear the panels in the winter?  A long handled snow rake or brush?  Opening up just a corner of the panels will allow them to warm enough to melt most snow.  Tony

wellbuilt

Any thing is possible , I have 5 strings of 3 panels and the top 2 strings on the right side will get the snow blown off by the wind but when the snow slides down it piled up on my garage roof and there can be 5’ of snow in the Vally . 
  It just snows here allmost every day and for days on end  so the panels seam to have  snow on them all the time . 
 Last winter the system was off from before Christmas’s to the second week in February when the sun started to pop out a bit . 
 I have a area on the others side of the house to ground mount 12 15 more panels  for winter at a steeper angel . 
 I’m not sure if extra panels will really help much on a winter day I see 70 watts per string around 3/400 watts on The charge controller it helps with the day time loads and help keep the battery’s power up but it’s easy to just run the Honda .

 

icarus

Yea, it becomes a daily job.  I eschewed standing seam steal, simply because i frequently need to climb the roof.  I designed the house with a low backside, and 6/12 pitch so it is an easy climb.  Mid winter there is 4’ of snow on the north side.  The south side is 12/12 so I climb to the ridge from the back, and push the south snow off the PV.  My theory is, every wh helps.  Tony

wellbuilt

 If I was up there full time I could work some thing out, but most of the time the snow is to frozen to push off .
  It just seams like come thanks giving the sun is just gone till February  I get good sun at day break and by 10 am the sun is gone and it’s snowing .

icarus

Where is “up there”?  I have several panels mounted on the wall, vertically so that they shed snow while I am away, so that the batteries are assured a float charge all winter whether I am there or not.  

Tony

wellbuilt

I get to full charge and turn my system off when not there, I’m all ways @ full charge when I come back. 

  If I go up and plow every other weekend I can stay ahead of the snow on the road .

  Some years I get snowed out for 8 weeks but I can snow shoe in if I have to . 

 I’m in the Catskills 60miles west of Kingston ny . In Andes , 
 the funny thing is I did not see the mile markers on the road 6 feet high before I bought the land . 

icarus

Since you are not using it daily, cleaning the panels and or charging from a genny is not a real big deal.  T