Owning Solar Batteries 101

[@marktiller1383]

I've had a Tesla powerwall2 since August 2017and solar since 2016. All have worked perfectly since install. Today if I had unlimited amount of money to install whatever I wanted, I'd have sunpower panels, emphases iq8 micro inverters and at least 2 emphase batteries. Unlimited money 4

[@michaelhorton6881]

I like the series but really need to caveat that this is for Australian audiences, currently paying 35p per kWH and increasing in October, having 20kWh batteries allows me to buy off peak energy at 7.5p and use batteries during day when expensive. This delivers a very rapid ROI, faster as electricity continues to rise. Adding solar to the batteries later will enable me sell back to guide at 25p during peak periods.

[@sophtayl]

Finn, great informative series of Vids, mich appreciated. I'm looking into adding a BESS. Current config is 3ph 10kw solar (fronius inverter) nsw postcode 2572. Rural property on grid... I guess a couple of questions 1) I believe I am limited to AC coupled which defaults to needing a battery inverter. Is there any benefit in exploring a 3ph inverter for batteries ( such as red earth) or is it more economical to go with single phase on one leg and get it managed through some form of distribution ( assume an inverter or some other tech can handle this)? Our current average daily load is between 35 and 45kw ( pool + other bits in shed from time to time). I am considering a 10 to 15kwh bess, ( balancing cost vs size). Recent changes in nsw re FiT have killed my solar payback so need to consider options. Any thoughts?

[@houstonchorley2944]

Here a question. The BYD house battery is 13kw and around $11k A BYD atto 3 long range is 150kw at a cost of $47k Once you get V2L does that mean the Atto3 (Or just an EV in general) has more value than a house battery? Does that add up or is it a bit too simplified? Good job you guys

[@MrLexhoya]

I think (just my 2 cents) this is the reason: EV cars are likely to receive service and are made in higher volumes. This means that (home)battery systems, that often receive no service or don't come with a paid maintenance plan, are a one off sell to the manufacturer or installation company.

[@mixalis6168]

What is three systems you recommend, From budget, mid and top tier systems ??

[@QueenslandSolar]

Depends what you want them for?

[@esecallum]

The average car battery will have an Ah rating somewhere around 50Ah. The 50Ah means that it can push 12 volts out at a rate of 50 amperes in an hour. COST $60. NO NEED for these overpriced DANGEROUS FIRE CATCHING batteries. so get 10 for $600. connect in series to get 120 volts or a parallel combination and charge via solar cells and have inverter output desired voltage. total cost under 3000 including solar panels!!!

[@cvwagon]

@@esecallum Get educated mate. Car batteries cannot be discharged to their stated Ah rating, are not designed for bulk power storage, degrade over time, do not balance well under discharge load, are not sealed (safe) and the cost per watt over their lifetime exceeds properly costed lithium batteries. Times have moved on from ghetto style lead acid battery banks.

[@sophtayl]

I considered this a couple of years ago. Lead acid batteries are much cheaper, but also require a lot more maintenance ( Finn does mention this early in one of the trilogy). I guess, how many of us are good at keeping maintenance in check...

[@Nobody_Famous]

@@esecallum something to consider is 50% Depth of Discharge (D.O.D) for lead acid. Automotive batteries aren't the same as deep cycle lead acid used in off grid applications. 300 charge cycle life is a number commonly thrown around. Keep in mind Finn is talking about approved batteries for grid interaction in Australia 🇦🇺

[@esecallum]

The average car battery will have an Ah rating somewhere around 50Ah. The 50Ah means that it can push 12 volts out at a rate of 50 amperes in an hour. COST $60. NO NEED for these overpriced DANGEROUS FIRE CATCHING batteries. so get 10 for $600. connect in series to get 120 volts or a parallel combination and charge via solar cells and have inverter output desired voltage. total cost under 3000 including solar panels!!!

[@billbreaker1680]

The problem is, voltage in e-vehicles are higher than 12 volts. Even higher than the regular 51.2 volts used in hybrid solar inverters such as Deye, Luxpower, Growatt and others... If you'll check the voltages of Tesla or Nissan Leaf, it is around 400 volts and are contemplating on making 800 volt systems on their next models. Getting even a 400-volt system will mean that you connect greater number of batteries (sold in the market) in parallel then in series to achieve it. You will have a very heavy car design with no assurance of fitting it all.