Propane Gas Water Heater running w/o electricity

[230gr]

Propane Gas Water Heater running w/o electricity

We are getting a Propane Gas Water Heater installed later this week and I have been looking at ways to run it in a grid down condition. It seems that all the new efficient gas water heater have electrical ignitor and a venting assist fan. I don't have the units specs  yet but I think the electrical requirements may be fairly minimal.

Has anyone else been considering this?     

[TWP]

If you haven't already purchased the heater, you might look into "tankless" gas water heaters, also called "demand" water heaters.  They can be much more efficient than keeping a 20-30 gallon tank at constant temperature, whether it gets used or not.

[230gr]

I have no real choice on the gas water heater as we are getting it through a state Energy & Fuel Assistance program. We could not afford it otherwise as the gas water heaters are incredibly expensive. They are even installing it for us so I absolutely can not complain.

I was planning on adding additional insulation the water heater, which, I understand, will hold the water hot for several days between burns. This should give us hot to warm water without firing up the woodstove in summer or building a wood fire outside. Hot water will be an expensive commodity TEOTWAWKI in terms of labor and resource expenditure. My hope is to run enough current from solar charges batteries to run the ingition and vent fan every few days.  Water will still have to be hand humped into the tank and the hot water carried up stairs by muscle power but still worth it.

[TWP]

230gr

I see no reason you cannot run a very small inverter off your battery bank.

This would run the spark igniter and fan (should be much less than 100 watts) and do it "on demand".  Look for a smart controller which senses the demand and turns on the inverter.

You could also manually turn on the inverter, say once a day or every couple of days, depending on how long your tank will hold heat, or immediately after you make a large draw on the hot water supply.

If you use a higher power inverter, you may run other appliances, but beware of overloads if the water heater triggers while you're also using another high power appliance.  Switching or simply unplugging the loads will solve this, even if it slightly more inconvenient.

You have lots of options right now, pre-EOTWAWKI,  while the equipment can be purchased off-the-shelf.

[230gr]

Yes, need to save up a bit but I have some ideas.

[pqtb]

Have you thought about installing a large water storage tank then install a small pressure tank/pump to provide house with pressurized water.  It would be easier to keep/fill a large water tank.

[230gr]

Are you thinking Grid down or now?

[TWP]

Are you thinking Grid down or now?

I'm not sure to whom you are addressing this question, so:

Do it now, as soon as you can afford it.

Design the power system to use both grid power and local power (solar panels, etc.).  That means DC pump motors which can run off battery banks.  Try to avoid using AC pumps because the efficiency of the inverter will cause your battery system to work much harder (shorten lifetime).

The large water tank with a smaller pressure tank (pqtb suggestion) is doable now.  You don't need a large pressure tank, 5 to 10 gallons is fine for household usage.  If you must run water to the garden, then look at a gravity feed tank (on a small tower) which doesn't need power to push the water through hosing.

You only need power when you pump water INTO the tank, preferably done during the time you normally don't use the battery system.  For instance at night, or when you're doing something else.

Try not to put heavy drain on the battery system during the charge cycle (when the sun is best on the panels).

Ok, information overload yet?

[230gr]

Hopefully, I have a designed the power system to be useful with both grid up power and solar panel power. I have a DC water pump that can run off battery banks but not much of a battery pack yet. If everyone shows up, we will have a multitude of vehicle car and truck batteries which, though not deep charge, should still work if we watch our discharge and charging.   

The AC water pump would take way too much out if the battery packs to be practical plus what you lose to the inverter.

We do have a 5 gallon pressure tank now and it is fine for household usage. 

The DC pump is low volume compared to the our normal AC pump so my idea was to fill 3 or 4  50 gal plastic drums set on the front deck with water when the sun shines then run water to the garden when needed by gravity feed water through hosing.

Because the battery bank and solar panels are small preferably and designed to run the water pump, and not much else, using it during the time we aren’t use the battery system for doing something else was not thought to be a problem. However, I have since assed a 12V rechargeable nebulizer, 12V BIPAP, a small 12V cooler (for insulin) and now the gas water heater.  I may need more solar panels

[TWP]

230gr  It sounds like you have the basics in place then.  You can add more water storage, more batteries and more solar panels as time and money permit.

Wish I was anywhere near as ready as you are...

[230gr]

Well, I have been working on this since the late 70s doing just what you said. Studying what would work grid down, saving what money I could, looking for the best price and making the buy. I was fortunate that I was working part time for a friend who removed old wood/coal furnaces and replaced them. Got my original wood furnace and two wood cook stoves from him as he was a prepper (not by that name of course) saved & refurbished for the local "prepper" community (close to 500 families at that time). Though most of them seemed to think TEOTWAWKI would be a gentle decline into the 1880s technology, was preparing for a revolution (you remember the 60s and early 70S?) then an all out nuclear war at the Soviets began to break up.     

[beorn]

Ive seen a propane electric heater that ran of a 9 volt battery but i would guess with a fan involved
it may need a little more than that but it sure sounds like it would not take much to make it work grid down.

[230gr]

We had two guys over today from Weatherization to check out the venting on on our shower and bathroom fan so they can come tomorrow to blow in extra insulation. 

While they where here the installed 110V outlet for the gas water heater. They said it would draw very little current mostly for the vent fan. I will know more when I study the manual and schematics.  May be I could replace the AC fan with a 12V DC fan.

[TWP]

Re the gas water heater, the electronics are probably designed to use 110v AC, so you still need an inverter to drive off battery it in a grid-down situation.

I'd go with the inverter so you don't lose the warranty on the water heater by making a hardware modification.  The power drain with inverter is very small, only runs the thermostat, gas igniter and fan.  And you can switch it on/off manually so you don't have a constant battery drain.

[230gr]

Electronics are designed to use 110v AC but  my understanding is that inverters do take a good bite from your battery current so it would be nice to avoid using on when possible  to drive off battery it in a grid-down situation.

There are so would not chance out fan now but would have a 12V DC replacement to put in SHTF. Have to know about the set up & components. Same for gas igniter and thermostat. Might be able to bypass thermostat and run on demand, just don’t know enough yet.

The Weatherization guys are here (hooking up a big suction fan to test for air leaks) and found that the company that we hired previously did not connect the bathroom fan to the out side vent so it was dumping humidity directly into the attic. Not a good thing.