From Newsgroup: sci.electronics.repair
On Mon, 1 Dec 2025 12:56:42 +0100, "Carlos E.R."
<
robin_listas@es.invalid> wrote:
On 2025-12-01 03:04, Paul wrote:
On Sun, 11/30/2025 7:42 PM, micky wrote:
The person in the story, may have a powerwall too.
The individual in the story, seems to be on a tear, with regard
to free energy and running his own "electric company". The installation
isn't big enough to be self-sufficient during the winter.
The powerwall charges off mains, instead of using the solar panels.
The powerwall comes with an interface for solar panels, a limited
number of chains of them. But doing an equivalent using used laptop
batteries is a lot cheaper.
But used batteries, besides holding little charge, can lose their charge >fast
You have to grade the batteries before re-use.
Then you deploy them in mixed/matched groups of AH ratings.
You could aim for about 80% of label capacity, for first
commissioning, at < 25% of the initial material cost (new).
Batteries are rarely retired due to their own age - more
frequently it's the device, connectors, software or dumb
user at fault.
Batteries with higher AH will do more work in the parallel
block, and age more quickly, but the mixed blocks will show
similar properties, on avarage. That is the aim.
Expense is in labour, which for DIY projects, is moot.
RL
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