Tesla batteries

[Riverlander]

Hi. Please remember I know nothing about anything electrical but I have been looking up on the net about domestic house batteries and found they rate them in kWh. The Tesla at 14 kWh. Small van batteries are at ah. I know 400ah is a reasonable van set up but how does that compare to 14kWh or is it a completely different language.
Cheers John

[BruceS]

Play around with this John.
http://everydaycalculation.com/ah-kilowatt-hour.php
kWh is used more when it's 240V domestic power from the grid I think.

[T1 Terry]

http://everydaycalculation.com/kwh-ah.php is the same calculator the other way around. For a 12v nom. battery that would be 1167Ah providing all of the 14kWh could be used. Lithium ferrous or LiFeP04 can deliver all 100%, I think the chemistry cells Tesla use is limited to 80% or less so that comes back to 11200Wh or 933Ah at 12v if LiFeP04 cells were used, but double that if lead acid batteries were used to get a decent battery life.
Clear as mud eh What price is the 14kWh Tesla unit?

T1 Terry

[Riverlander]

Total cost inc. setup is about $10,000, But they cannot supply them in Aust. yet.
Had a chat to Zen and they were talking $15,000 for the battery I would need and they are preparing a full quote for solar and battery so will know the type and size in a few days.

[justgarbage]

To Riverlander

Hi John if you hop over to the Whirlpool Green Tech Forums your will find a ver long thread pertaining to the pro's and con's of Telsa batteries. Link below.
https://forums.whirlpool.net.au/forum-r ... ?t=2583260

We looked at it and the math does not quite add up. But household battery will no doubt become the norm for future generations.

[T1 Terry]

We will be doing a few house jobs when we get back from WA, possibly one really big job but more on that if it comes off. we did an off grid house in Bodalla NSW a few yrs back and he was so confident with the lithium compared to the lead acid set up he had before he decided to add an air con system.... a 7 kW split system with ceiling mounted cassette The batteries had no problems but the wiring was only ever set up for lights and a 1500w inverter, the 2 x 3kW inverters required to power the air con meant everything had to be upgraded including the dodgy wiring previous "solar professionals" had installed. Last report was the system was working so well now they use the air con reverse cycle instead of lighting the wood fire on all but the below zero nights which only occur a few days a yr.

T1 Terry

[Riverlander]

Zen actually said that the batteries at this stage are not financially viable if you were already on 240v power so one quote is the complete setup and another solar only/battery ready. Not jumping into anything quickly and yet to talk to the local installers and of course Terry.
Also as I am coming up to pension age I will have to do the maths as anything spent on the home is not included in the assets.
Cheers John

[justgarbage]

We will be doing a few house jobs when we get back from WA, possibly one really big job but more on that if it comes off. we did an off grid house in Bodalla NSW a few yrs back and he was so confident with the lithium compared to the lead acid set up he had before he decided to add an air con system.... a 7 kW split system with ceiling mounted cassette The batteries had no problems but the wiring was only ever set up for lights and a 1500w inverter, the 2 x 3kW inverters required to power the air con meant everything had to be upgraded including the dodgy wiring previous "solar professionals" had installed. Last report was the system was working so well now they use the air con reverse cycle instead of lighting the wood fire on all but the below zero nights which only occur a few days a yr.

T1 Terry

Terry you are obviously in the trade, might I enquire what the total battery capacity was for that residence?

We have 2Kw Solar installed about five years ago. Fortunately being retired we use maybe 50% of the array capacity when we are home during the day. I do wince at the 6c per kw that we get for KW's exported. Should I take another look at battery storage. I am not going to be around long term but Maryanne will. I would be interested in your thoughts.
John

[native pepper]

Zen actually said that the batteries at this stage are not financially viable if you were already on 240v power so one quote is the complete setup and another solar only/battery ready. Not jumping into anything quickly and yet to talk to the local installers and of course Terry.
Also as I am coming up to pension age I will have to do the maths as anything spent on the home is not included in the assets.
Cheers John

I constantly here this claim that going off grid is uneconomic using lifepo4, when that's not the case for everyone I know off grid and myself included. Of course if you're going to pay someone a fortune to supply and fit what is a simple job, except for the inverter to power box connection then it will be expensive.

It's different for RV installations, where you may need to do a lot of 240v/12v wiring, but converting a 240v grid home to off grid 240v is only a matter of connecting your inverter to the house system and that's it. The purchase of cells, charge control and inverters, should be done by you so you know exactly what you are getting and know all about it.

My house runs on 240v, 700amp lifepo4 cells through 3 x 12v inverters, one for each house circuit, some say over kill, but been off grid since 1976 and understand you need backups so if something breaks, you still have power. My neighbour has the same size pack, but uses a 3000-6000w x 12v inverter. Both our systems cost around $5000 fully operational, along with a few others, we bought a heap and had our controllers made for us, rather than use lead acid controllers with relays etc. Been down the path close to 9 years ago and also been down the BMS path, both are prone to failures. Now we use dedicated lifepo4 controllers and active cell equalisers, been doing this for close to 4 years and everything is still working just fine. My neighbour, has already gone through one big inverter and is using his backup one, but now has 3 smaller inverters and is going to change his system as soon as the big one stuffs it, which could be many years down the track.

[Newcastle George]

My house runs on 240v, 700amp lifepo4 cells through 3 x 12v inverters,

I assume you mean 700 amp hour.

George