Anyone got a Tesla Powerwall?

[allthegearandnoidea]

Hi All



Tesla or similar battery setup. Currently looking to buy a rural proprty and most have no access to power. Keen to hear anyone's experiences doing similar and setting up solar/battery system for a normal full size house running everything from fridge to heating, aircon tv computer etc.

Cheers

[TassieTiger]

I’ve set up at least 6 remote cabins, 10 radio sites, various off grid components, etc etc with solar / inverted power.
Unless the Tesla power walls have come down in price, you can get more storage and longer life from a normal lead acid set up - but will need the room to store batteries. You will also have less drop off in power storage - is Tesla are reported as losing 30% capacity after 2-4 years.

Two big ticket items in a nominal house kill solar/ battery power - electric heating and fridges - so put some thought into how best you might manage.
That being said - I am currently running a 300 litre fridge/freezer on solar at home, but after 7 days of questionable sunlight hours, batteries are depleted (1200 amp hour bank).
From memory - a first Tesla power wall has just under 900amp hours available.

[poid]

The powerwalls really shouldn't be losing 30% capacity over a few years, suggests there is something really wrong with how they are charging etc! Powerwalls also need grid power dont they, they cant be used off grid?

First thing, with off-grid power don't think in terms of 'normal house'. The way you use power and do certain things needs to be different. For example, air con can draw a hell of a lot of power so a house should be designed to minimise the cooling you need. Location, materials, aspect etc are all very important. Oversize your solar panels and use power hungry appliances during the day, rather than at night, to reduce the battery capacity you need. You want to find energy efficient appliances, as the difference between an efficient fridge and an energy hog can be huge.

You'd want to use fireplaces for heating out in the bush. You can cook on gas using LPG bottles, similarly you can use either solar hot water or instant gas running off LPG.

Lithium batteries have come down in price a lot recently, and panels are always getting cheaper. At the moment I have a small off-grid system at my farm to runs lights, a pump and 12v fridge but may expand that to a proper system to power other appliances.

[TassieTiger]

Tesla guarantee 70% storage capability over 10 years, using their nominated max charge rates and depletion calculations (which I should say couldn’t really be met in many southern states in winter) but with a round trip power value of 90% in the first year (so 10kws in equals 9kw out), even using their own numbers sees a dramatic drop off in real world useable power...

A 250ah sun extender lead acid 12 battery costs about $900 with 20 year design life. 68kgs each.
A 2v 200ah cell can be bought new for about $450 - need 6 of them to make 12v, so 1200 amh for $2700 with 20 years but these are 30kgs each x 6 = 180kgs...

[Sergeant Hartman]

Tesla need grid.

Mate best is to talk to an electrician that does off grid. There are other types of batteries that are cheaper and better

[Blr243]

When I was hunting the cape roughly 20 years ago, at night I would sometimes help wind the handle on an old Deisel banger generator so In the house we could cook, use lights, and put some juice into the fridges ...one year when I returned they had solar panels (roughly 3 m by 5 m ) and batteries and power that was 24/7 and it was free, silent and so much better so now years later things would be vastly improved from that and I expect you will have a very reliable system available......next to the old Deisel banger generator there was a set of cattle yards and usually a dead cow that the boars would visit every night , so of course after dinner I would grab my bow and visit the boars ....an 1/8 th of a moon, barefoot , moving incredibly slowly , shooting at 10 m or less with no bushes only the cover of darkness , it was very tricky , only once did I get treed with a boar clicking away underneath . Am I getting “off topic” again ?

[allthegearandnoidea]

Oh dear....looks like I need to read up on this stuff - can'ty really understand it all. Lucky were in lockdown. My dream is to buy a 100 approx acre property with pasture land or state forest buffer where I can shoot centrefire without the neighbours complaining. Also maybe a bit of spotlighting bunnies too. I'd like to know that we could build a house and have a reliable power source.

[poid]

Tesla guarantee 70% storage capability over 10 years, using their nominated max charge rates and depletion calculations (which I should say couldn’t really be met in many southern states in winter) but with a round trip power value of 90% in the first year (so 10kws in equals 9kw out), even using their own numbers sees a dramatic drop off in real world useable power...

A 250ah sun extender lead acid 12 battery costs about $900 with 20 year design life. 68kgs each.
A 2v 200ah cell can be bought new for about $450 - need 6 of them to make 12v, so 1200 amh for $2700 with 20 years but these are 30kgs each x 6 = 180kgs...

Most will guarantee 80%, then again I wouldnt expect a Tesla product to be built to the long run. Would much rather use an LG lithium than a Tesla.

6 of the 2v cells would give you 200ah@12v

[TassieTiger]

Correct - I’ve got my series screwed with my parallel, voltage increase 6x2 = 12 but keeps amh.

My local cabin is 1000w of panels, via renogy solar reg, on 2 x 12v sunextenders that are 250ah each - to operate 8 CCTV cameras 24 hours a day to a NVR, 3G external modem to a 5m yagi antenna. That is a reasonably power hungry set up...
I’m operating everything off a 2000w inverter.
When I stay at the cabin, along with the cams - those batts will also run 2 x 80w LED flood lights outside and 2 x 10w LED internal lights all night, a radio, few device chargers and still be well over 11.5v come morning, if they were fully charged the day previous. I cannot run an elec jug, micro heater, mini fridge, etc - the inverter over loads and I don’t want to deplete batts.

Another friends cabin in central highlands runs a small fridge, sat Tv, CCTV, etc off a similar setup but with 4 of the same batteries. He gets extreme cold and weather and that too impacts losses.
The biggest issue in Tassie for solar and I assume similar for Vic is the pathetic usable solar hours per day May to Sept where some charts will average only 2 useable hours per day...on good days. There are some weeks in the middle of Tas where we will not see the sun for 5-7 days at a time...and it’s these bad times that need careful considerations with system design, with many ppl opting for a back up generator with bat charger.

[Sergeant Hartman]

Yep its sad when you has e a 15kw system, during summer it generates 120kw per day and in many days during winter it might only make 20-30kw

[TassieTiger]

Yep its sad when you has e a 15kw system, during summer it generates 120kw per day and in many days during winter it might only make 20-30kw

I had been toying with a wind turbine for winter months as that’s a bit of a constant - however a few months back, I heli’d into a mountain to check on a site and found a work wind turbine smashed into a hundred parts. They are industrial and cost work about $7k each.
Closer inspection and reviewing on site cameras showed that a wedge tail eagle had shst on one of the blades a few days before a 100kmh wind. This put the turbine blades out of balance and...we all know what a washing machine does when out of balance...I shouldn’t have laughed because it cost work a lot of money but geez...you think you’ve got everything sorted.

Some other tech/alternate options out there being developed - if you have a river/creek with constant flow, some great little water driven turbines are available. Think a person in Vic was close to sorting cold start problems with a fresh air spinner - seen on every shed in the country...