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The best solar storage batteries


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Interesting results out of Oz, not sure if Sony, Samsung is available in SA and how the prices compare with e.g. Pylontech

Would imagine that in terms of price vs. performance Pylontech must be the clear winner out of the below bunch, pity we do not have something similar for the batteries available in SA.

Top performers

Models that demonstrated superior performance:

  • The Sony and Pylontech battery packs have so far demonstrated superior capacity retention; that is, their claimed capacity didn't significantly diminish over time.
  • The Sony, Samsung, Tesla Powerwall, BYD and Pylontech have shown high reliability.
  • The Samsung and BYD have shown consistently high efficiency. This is a measure of how much of the energy put into the battery is actually stored and able to be extracted for use again. Most of the batteries have efficiencies around 85% but these two achieved about 95% efficiency.

Added the price per kWh that i could find in brackets below

BYD B-Box < R8400 / kWh (not sure if the price is incl. VAT)

This battery has run without problems, and demonstrated high efficiency, though its capacity fade appears to be accelerating over time.

Pylontech US2000B < R5100 / kWh (not sure if the price incl. VAT)

This battery has had no problems in the test, and so far is showing very good capacity retention.

Samsung AIO10.8 - Available in SA?

This battery has proved very reliable and has had no operational issues. It's showing excellent efficiency so far. The battery is now sold under the brand name Hansol (a Samsung partner).


Sony Fortelion - Available in SA?

This battery has had no problems in the test, and so far is showing excellent reliability and capacity retention. Unfortunately, it appears to no longer be available in Australia.

Tesla Powerwall

This sample of the first-generation Tesla Powerwall has proved challenging to control for testing purposes, as it is not compatible with the SMA inverters used in the test lab. A Solar Edge inverter was used instead. While ITP is able to control the Powerwall to some extent, their only option was to have the Powerwall charge and discharge at its maximum rate, which is not ideal and may be accelerating its capacity fade. Nevertheless, so far this Powerwall has performed reliably and in line with its claims, with no operational problems. This model is superseded by the Powerwall 2.

Tesla Powerwall 2 < R10600 / kWh

Similar challenges were encountered as with the original Powerwall above. Also, a fault occurred with the first sample delivered to ITP; this was replaced by Tesla. The new sample has been on test since November 2018. There's not enough data to comment on its performance to date.


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Thanks for the link, from the last report from the link:

The only two battery packs that made it through unscathed during phase 1 and are still going strong are:

  • Samsung
  • Sony
  • GNB PbA

The only two battery packs that made it unscathed through phase 2 are:

  • GNB Li-ion
  • Pylontech

These large price tag batteries available also in SA, alas, did not manage to go all the way through phase two, which is worrying:

  • BYD LV - Suspected internal BMS failure of one battery module. BYD states all modules faulty due to cell imbalance
  • Tesla PW2 - Battery not cycling as it cannot be externally controlled, but could have been a dud and was replaced, the replacement is still going strong.

These once does not seem to like the higher temperatures, maybe best for the coast then:

  • Alpha ESS - Battery pack cycling affected by over temperature, Alpha removes its batteries


The survivors from phase 1:



The survivors from phase 2



The Round Trip efficiency for the contestants



Hysterical laughter when you realised your overpriced, premium battery did not survive its phase and was outperformed by a battery that now cost 50% less!:



Edited by WeNotGood
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