Building a big 280AH 24V Battery - Whats the best supplier for cells right now?, also, sanity check for my numbers.

[Supervstech]

That's good to keep in mind, thanks for that.

Wait, so those 280aH bad boys, at 24v, are rated at over 7kwh?!

And configured 48v they are over 14.3Kwh!... math is fun ain’t it?

 

[Steve_S]

Is that an electric on demand hot water heater or gas fed with an electric panel only?

My Cookstove (Unique Offgrid), On-Demand Hot Water and On-Demand (Radiant Heating) are all Propane.
There is simply no sense in having a Hot Water Tank, it's like leaving your car idling in the driveway 7/24 just because you "might" go for a drive. Water Tanks have to heat the water every hour just to keep it at the set temp, whether you use it or not.

 

[heirloom hamlet]

My Cookstove (Unique Offgrid), On-Demand Hot Water and On-Demand (Radiant Heating) are all Propane.
There is simply no sense in having a Hot Water Tank, it's like leaving your car idling in the driveway 7/24 just because you "might" go for a drive. Water Tanks have to heat the water every hour just to keep it at the set temp, whether you use it or not.

Completely agree.
We are trying to build a bit of a mini-cabin eco-village, that people can come to stay at, for both an awesome experience to learn something about the world and themselves AND to observe how off-grid living looks and feels in real life...rather than just watching videos of other people doing it in their own life. I felt like there was a lot of that, but few places to dip your toe in the water, so to speak.
I'm close on grounds prep, cabin designs, composting toilets and solar arrays. Now on to rainwater harvesting...need to find just the right soft start pump and on-demand water heater. I want each to contain it's own independent system. Which do you use?

 

[heirloom hamlet]

yep!

Qty	Ah	AVG Volts	Cell Wh	Total Wh		Cell cost	~shipping	$ total		$/Wh	$/kWh
XUBA
16​	90​	3.2​	288​	4608​		$28.50​	$171.00​	$627.00​		$0.14​	$136.07​
8​	105​	3.2​	336​	2688​		$35.19​	$171.00​	$452.52​		$0.17​	$168.35​
4​	120​	3.2​	384​	1536​		$36.80​	$171.00​	$318.20​		$0.21​	$207.16​
4​	152​	3.2​	486.4​	1945.6​		$70.00​	$171.00​	$451.00​		$0.23​	$231.81​
4​	280​	3.2​	896​	3584​		$82.67​	$252.40​	$583.08​		$0.16​	$162.69​
8​	280​	3.2​	896​	7168​				$1,076.50​		$0.15​	$150.18​

Do we know what the C Rating is of these 280aH cells?

 

[heirloom hamlet]

And configured 48v they are over 14.3Kwh!... math is fun ain’t it?

What is the C Rating on those things?

 

[newbostonconst]

My Cookstove (Unique Offgrid), On-Demand Hot Water and On-Demand (Radiant Heating) are all Propane.
There is simply no sense in having a Hot Water Tank, it's like leaving your car idling in the driveway 7/24 just because you "might" go for a drive. Water Tanks have to heat the water every hour just to keep it at the set temp, whether you use it or not.

Unless you are in a heating dominated climate, then it really worth the cost. The heat wasted just goes to heat your house so no big loss.

 

[HomeTownHockeyFan]

Do we know what the C Rating is of these 280aH cells?

According to their documentation, it is 1C for both charge and discharge.

 

[Steve_S]

Unless you are in a heating dominated climate, then it really worth the cost. The heat wasted just goes to heat your house so no big loss.

I use separate On-Demand for Hot Water because my Radiant Heating has Propylene Clycol in it, I AM in Canada and it isn't wise to run radiant slab heating with water. Yes, there are ways to both Heating & Hot Water through one On-Demand system. Being a Geezer with creaky bones & joints, I MUST SAY, there is no substitute for a nice warm radiant heating system. I even have the slab in the Pumphouse /Powerhouse plumbed for it, in advance of Solar Radiant Heating. Water Tank "wasting heat" to the house is still extremely WASTEFUL of Power and most special is Solar Generated and quite ridiculous.