Building retirement home off grid

[Mike Rugy]

Organic Farmer
Thanks for sharing your set up.
We will be using a Walltherm wood stove along with two storage vessels.
Plan on using four hydronic solar panels which should get us by from May to September for our domestic hot water and heating needs.
When the panels don't generate enough heat we will have to light the Walltherm.
Wallterm uses a secondary burn chamber for gasification. This should work when we are at the house.
The water storage vessels have an option for two electric heating elements. Can install either 2x2kw or 2x4.5 kw electric heating element.
The micro hydro from what I understand will need a "dump load" once the batteries are topped off.
Thinking that this might be the place to put the excess power being generated in our absence ?
Cooking will be with a propane stove.
Just in case that I cannot get enough heat with the above setup while we are south.
Will rough in for a propane fired condensing boiler or a combi boiler.

[Mike90250]

Well, I think you may be better off just building an insulated battery pit or shed next to your house. Use an exterior wall if you need to get some heat into the battery bank. Add it's own hydronic system. Maybe a twin shed next to the generator pad ?

But putting batteries UNDER the floor, in a restricted access area, where you have to manhandle the cells from the crane to destination, is only going to make you pull your hair out in a couple years.

If you put the batteries in the same room with the electronics, you need a lot of venting to keep the vapors from corroding the electronics.

Just make sure the insulation won't absorb and trap the hydrogen !

it's real easy to make things safe under normal conditions.. It's when the diversion load for the hydro burns out, or it's SSR dies in a lightning storm, that over-charges the batteries and gets them boiling really good. Then you have problems.

[Sunking]

How so ? Please let me know what my concerns should be ?

NEC, CEC, and IBC codes require unrestricted space.

[SunEagle]

NEC, CEC, and IBC codes require unrestricted space.

Just like in a sub.

[Sunking]

Just like in a sub.

Not under the jurisdiction of NEC/CEC/IBC. Those guys show up and we load them in the torpedo tubes and eject them.

[SunEagle]

Not under the jurisdiction of NEC/CEC/IBC. Those guys show up and we load them in the torpedo tubes and eject them.

Those Navy guys play rough.

[organic farmer]

On boats I served on; directly over each battery, the deck plates above were remove-able. So when we were in-port, sections of deck-plate were removed. Temporary over-head trolleys were installed to hoist a suspect battery straight-up out from it's slot, and horizontally over to the nearest vertical hatch. From there a cable from crane out on the pier, was snaked down to grab the battery. Then it was slowly lifted, while men jostled it back and forth, around each obstruction.

[Alaska Man]

I would go with AGM's

I have AGM's and if they are off-gassing then that's a bad deal. You probably just killed your batteries you definitely shortened their lives. They only would do that if they were being severely overcharged. I'm off grid in Alaska so my batteries live inside with me next to the woodstove.

[paulcheung]

Nope - the H2 will collect at the highest point in the room - it will not be evenly distributed.

My battery room was a bathroom 5'x8' flat ceiling, it has a 2'x2' window and a 3'x7' door connected to another room 8'x8', the room has another window 3'x4' and another exit 3'x7' door which closed all the time except when the generator is running or when I attending the batteries, the windows are 3 feet from the ceilings, the windows are on the same side of the walls, there is a 6 inches block wall separate the two rooms and the doors are in one direction.

Should I be worry about H2 build up and explode? what can I do if it is possible the H2 might build up, can a fan to blow the air now and when be a good idea?

Thanks.

[Grizzly Brian]

Maybe you could build a little "battery room/box" in the crawlspace and tilt the "ceiling" toward the outside wall and vent just that small space?
It might also make it easier to insulate if needed. Good luck with your project. Keep at it.

Brian

[russ]

Should I be worry about H2 build up and explode? what can I do if it is possible the H2 might build up, can a fan to blow the air now and when be a good idea? Thanks.

Just a vent pipe in the ceiling and you could not possibly keep the hydrogen in the room.

[SunEagle]

Maybe you could build a little "battery room/box" in the crawlspace and tilt the "ceiling" toward the outside wall and vent just that small space?
It might also make it easier to insulate if needed. Good luck with your project. Keep at it.

Brian

I was thinking the same thing. Create a smaller enclosure with a high spot around the batteries and vent that area instead of venting the entire crawlspace. Hopefully the OP will find an easy and safe way to maintain his batteries.

[Mike Rugy]

NEC, CEC, and IBC codes require unrestricted space.

NEC = National Electrical Code ?
CEC = California Energy Code ?
IBC = International Building Code ?

Please let me know if these acronyms are correct.

Being in Canada the above do not apply but here in BC we use the BC Building code which is a clone of the NBC, National Building Code.
Also checked with the BC Safety Authority.
But you got me thinking and have contacted all authorities and here if what I received back.

1. Battery room/storage area if in a occupied dwelling must have a vent.
This can be done passively by bringing vent into room and then venting at highest spot on ceiling.
Another venting option is to have a small fan to expel or create a change of air for this space.
Room must have a door with a weather strip system and a self closer.

2. No Electrical panel shall be in a space where the height of the room is less than 6'-8". No panels in crawl space.
Charger, controller, monitoring equipment, batteries are ok in crawl space.

3. Recommend installing a Hydrogen Sensor with an audible siren where occupants can hear siren. But not required. Will do this.

The siting of our home is such that the "battery room" exterior wall is facing the water front.
By passively venting this area I will always get a breeze/wind from the "inflow" of winds during the day.
We have a concrete deck which cantilevers the whole front of the house so if I was to attempt to vent the Hydrogen gas
it would probably never make it out due to the pressure difference of the wind.
So I think it best to vent up through the roof of the home. Will install a little dc powered in line fan just to make sure it
is always drawing air out of the room.
Terminate 2" pipe up through the roof. Terminate with two 90s so no rain can get in should be ok or will it restrict
the Hydrogen from escaping ?

Thanks for all of the post and the input, the Navy ones are great.

[SunEagle]

NEC = National Electrical Code ?
CEC = California Energy Code ?
IBC = International Building Code ?

Please let me know if these acronyms are correct.

Being in Canada the above do not apply but here in BC we use the BC Building code which is a clone of the NBC, National Building Code.
Also checked with the BC Safety Authority.
But you got me thinking and have contacted all authorities and here if what I received back.

1. Battery room/storage area if in a occupied dwelling must have a vent.
This can be done passively by bringing vent into room and then venting at highest spot on ceiling.
Another venting option is to have a small fan to expel or create a change of air for this space.
Room must have a door with a weather strip system and a self closer.

2. No Electrical panel shall be in a space where the height of the room is less than 6'-8". No panels in crawl space.
Charger, controller, monitoring equipment, batteries are ok in crawl space.

3. Recommend installing a Hydrogen Sensor with an audible siren where occupants can hear siren. But not required. Will do this.

The siting of our home is such that the "battery room" exterior wall is facing the water front.
By passively venting this area I will always get a breeze/wind from the "inflow" of winds during the day.
We have a concrete deck which cantilevers the whole front of the house so if I was to attempt to vent the Hydrogen gas
it would probably never make it out due to the pressure difference of the wind.
So I think it best to vent up through the roof of the home. Will install a little dc powered in line fan just to make sure it
is always drawing air out of the room.
Terminate 2" pipe up through the roof. Terminate with two 90s so no rain can get in should be ok or will it restrict
the Hydrogen from escaping ?

Thanks for all of the post and the input, the Navy ones are great.

There is the CSA or Canadian Standards Association which follows the NEC (National Electric Code) pretty closely. Not sure if there are any additional requirements in those standards that you would have to follow.

[Mike90250]

This is the "standard" battery box vent fan http://zephyrvent.com/
BUT it needs a control signal, it only needs to run when the batteries are 3/4 full or more.
Relying on a power vent, I'd use 2, for redundancy.

Check the sensor lifetime on your hydrogen sensor. And the replacement cost, and any calibration requirements.
Co sensors are 4 years, O2 sensors are 6 months. Never used H.