Recommended Posts

(edited)

Ive installed solar battery systems on homes that are completely offgrid. Its expensive initially as the lithium batteries are expensive, but the first 1 of the homes i did has been running perfectly for nearly 3 years now. Very rarely do they need to start back up generator - only when bad weather means thick clouds for many days in a row it happens.

Total cost of the 15.3kwh lithium battery was $10k.

5kw solar system including high quality 7.5kw continuous output inverter charger and solar inverter (AC coupled) $15k.

Installation $5k. Total system cost = $30k AUD.

Thats the price of going off grid never to have a power bill again. I expect the LIFePO4 batteries will last in excess of 10-15 years and they usually dont cycle very deep - in decent weather they are fully charged by 1030-11am each day.

@DanilKa -The offgrid storage batteries are nothing like the lithium batteries in your mobile phone. Completely different lithium chemistry. LiFePO4 cells are rated at 5000+ cycles @ 70% depth of discharge. In my off grid home - typical discharge per night is only 30%.

Hot water and cooking is done with Gas.

Edited by catch22
  • Great Response! 1

Share this post


Link to post
Share on other sites

4 hours ago, catch22 said:

Total system cost = $30k AUD.

Sweet as, mate. Only takes 15 years to pay back, assuming they have similar consumption to ours. And Tesla PowerWall using Li-polymer finger batteries with limited cycle life. 

You’ll be alright, as long as customers believe they are saving the world 

Share this post


Link to post
Share on other sites

2 hours ago, DanilKa said:

Sweet as, mate. Only takes 15 years to pay back, assuming they have similar consumption to ours. And Tesla PowerWall using Li-polymer finger batteries with limited cycle life. 

You’ll be alright, as long as customers believe they are saving the world 

In their case - No - it paid for itself in the first couple of years because their new house is on a 150acre block of land and needed a 500m power line through the rainforest to the nearest transformer to be connected to the grid. The cost of installing that power line was about $20k...  so these types of off grid installations makes sense financially - which is why only a few select cases like this are being done. Doing it now is also getting cheaper - that price was 3 years ago and everything now is alot cheaper, batteries, solar panels, inverters etc... and of course i could have done it cheaper if i chose cheaper quality equipment, however the customer chose good quality equipment which hopefully will last a along time. The cheap chinese garbage lasts just past the warranty and then its junk...

Tesla powerwall uses similar chemistry to LifePO4 - i think Tesla is using lithium ion nickel manganese cobalt or LiNMC. Its similar in characteristic but not identical to LiFEPO4- nice long life with many cycles and relatively safe.  These are still nothing like a mobile phone battery which are typically Lithium Polymer or LiPo types. Li po batteries are much more dangerous, have considerably higher energy density - hence good for small devices and portability and light weight etc but have much worse lifespan and prone to catching fire or explosion. Hence - we dont use LiPo batteries in EV cars as they are too dangerous and wouldnt last more than a year or 2 before needing replacement. Shame tho as they they would make an excellent high performance EV battery due to their light weight and high energy density - some people have used them to make drag cars and drag bikes - VERY fast!

 

  • Upvote 2

Share this post


Link to post
Share on other sites

16 hours ago, catch22 said:

Ive installed solar battery systems on homes that are completely offgrid. Its expensive initially as the lithium batteries are expensive, but the first 1 of the homes i did has been running perfectly for nearly 3 years now. Very rarely do they need to start back up generator - only when bad weather means thick clouds for many days in a row it happens.

Total cost of the 15.3kwh lithium battery was $10k.

5kw solar system including high quality 7.5kw continuous output inverter charger and solar inverter (AC coupled) $15k.

Installation $5k. Total system cost = $30k AUD.

Thats the price of going off grid never to have a power bill again. I expect the LIFePO4 batteries will last in excess of 10-15 years and they usually dont cycle very deep - in decent weather they are fully charged by 1030-11am each day.

@DanilKa -The offgrid storage batteries are nothing like the lithium batteries in your mobile phone. Completely different lithium chemistry. LiFePO4 cells are rated at 5000+ cycles @ 70% depth of discharge. In my off grid home - typical discharge per night is only 30%.

Hot water and cooking is done with Gas.

When I used to live in Perth a friend of mine (Had a 5.5KW system facing NW and NE) put in an ASHP hot water cyclinder which effectively stored the electricity as hot water. 

He had a Gas stove but also had a portable electric hob he used in the day time so they only really used the gas for evening meals. 

Share this post


Link to post
Share on other sites

(edited)

9 hours ago, catch22 said:

In their case - No - it paid for itself in the first couple of years because their new house is on a 150acre block of land and needed a 500m power line through the rainforest to the nearest transformer to be connected to the grid. The cost of installing that power line was about $20k...  so these types of off grid installations makes sense financially - which is why only a few select cases like this are being done. Doing it now is also getting cheaper - that price was 3 years ago and everything now is alot cheaper, batteries, solar panels, inverters etc... and of course i could have done it cheaper if i chose cheaper quality equipment, however the customer chose good quality equipment which hopefully will last a along time. The cheap chinese garbage lasts just past the warranty and then its junk...

Tesla powerwall uses similar chemistry to LifePO4 - i think Tesla is using lithium ion nickel manganese cobalt or LiNMC. Its similar in characteristic but not identical to LiFEPO4- nice long life with many cycles and relatively safe.  These are still nothing like a mobile phone battery which are typically Lithium Polymer or LiPo types. Li po batteries are much more dangerous, have considerably higher energy density - hence good for small devices and portability and light weight etc but have much worse lifespan and prone to catching fire or explosion. Hence - we dont use LiPo batteries in EV cars as they are too dangerous and wouldnt last more than a year or 2 before needing replacement. Shame tho as they they would make an excellent high performance EV battery due to their light weight and high energy density - some people have used them to make drag cars and drag bikes - VERY fast!

 

Thanks. Indeed, if you are remote and off-grid, Solar+Storage could be more cost-effective than diesel generation. My example for for cities.

On Tesla 2170 finger batteries: https://www.teslarati.com/inside-tesla-model-3-2170-lithium-ion-battery/

It puzzles me why they choose to use ~AA bettery type for cars, instead of making it to shape its easier to fit and cool (or heat, as recent Canada/US experience shows).

True, cost of equipment came down big time. I've opted to use "cheap chinese garbage" - 6.6KW Jinko 260W Tier 1 panels and Zeverlution 5000 5KW inverter. Cost me $3399 AUD with split installation on two roofs. I guess it is President Trump's tariffs on solar panels I have to thank for that. We have severe shading and I didn't want to invest in anything with more than 3-4 years payback.

Breakthrough in battery technology/cost will change electricity generation and light transportation lanndscape and I'm watching this space.

Back to blackout issue - it shits me that I cannot use my panels in a broad day light if there is outage. If there is a long power loss, I'm thinking to disconnect it from the grid and supply 230/50Hz from small generator or UPS to start the inverter. Balancing load to avoid frying your mini-grid would be a challenge, I guess. Am I crazy thinking this way?

Edited by DanilKa

Share this post


Link to post
Share on other sites

(edited)

@DanilKa - It all depends on what your inverter is capable of. If you can control the inverter and change it to zero export mode - then you can trick it into thinking the grid is still there by using a change over switch to the generator. Kind of defeats the purpose of it tho having to start and then run a generator in the first place tho!

The reason some inverters are required to be like this (no output if no grid)  is that if the power goes out - the energy utility want the solar inverters to stop feeding the grid as they no longer have control over what voltages are on the lines or in what areas. If they shut it down - they want to shut everything down for safety reasons - whether it be a major fault that needs to be repaired by linesmen or at the switch yard etc... Some of the better quality inverters are capable of "islanding" which is what you want it to do. However not all utility companys allow them, nor are all inverters capable of doing it. You need to ask your utility company if they allow any inverters that they have approved on their network which can do "islanding" mode. These particular inverters immediately disconnect from the grid when they detect the grid voltage is gone which satifies the utility company requirement. However they can continue to supply your home in islanding mode until the grid comes back online, and when they detect it they can re synchronize and reconnect to the grid once again. Your at the mercy of your energy provider in terms of where you live and what they will allow on their network...

Edited by catch22
  • Great Response! 1

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
You are posting as a guest. If you have an account, please sign in.
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.