Energy storage 18650 up to 24kWh class Paragon, Powerwall

metalMANiu wrote:

The problem is that no one but the residents benefit.

The problem will be that it would take years to complete the formalities at the Polish Water Authority, then the project, water rights and environmental decision, land ownership, and finally the building permit. Taxes as for a hydroelectric power plant and all in all, with small capacities, it will be cheaper to buy such a volume from the DSO.

gulson wrote:

That is why it will be hard, because the whole of Europe is lagging behind, but I am optimistic 💪

.
Not all of it, just the countries that joined the eu in 2004 and after. The old 15 are fine unless you are talking about southern countries such as Greece, Spain and Portugal which have not progressed too much.

Added after 48 [minutes]:

@remzibi and if the cells heat up when charging you immediately dismiss it? I even when charging with tp4056 the sanyo heats up and all batteries with them I threw in the scrap.

@andrzejlisek As if you had energy storage that would last a year (xD), it would be enough to charge it with PV alone, in the sense that with the money for windmills and waterwheels you would also buy PV.

As for the project itself I'm impressed too, you can see a great deal of time spent, congratulations!
It's a bit inspiring, but the resulting device also carries no small risk. It could be minimised by moving the store away from the house, building it with non-flammable materials, maybe even dividing it a little into several smaller ones, monitoring it, plus some kind of automatic incident response system (disconnection / maybe fire extinguishers).
Probably counting some reasonable man-hours, the whole project would not make economic sense, but after all, you have to do something in your spare time, and the resulting construction is certainly pleasing to the eye.

All in all, I still have a question, maybe to the author or maybe someone else knows the answer, about the discharge of the (used?) cells themselves. Does it differ significantly from one cell to another, can it be measured somehow, should I be worried about it?

In my opinion, assembling batteries from different cells is a bad idea. The choice of Li-Ion technology should result in the energy storage being moved to an external container (preferably an isotherm). And a third point: I would consider LiFePO4 cells as less prone to fire and higher current capacity and longer life.

andrzejlisek wrote:

@remzibi .... Suppose you just take apart another battery from an electric scooter and find most of the cells usable, do you also do a voltage equalisation before attaching to the storage?

.

Yes, of course , before I weld another module of cells, they all have their voltages equalised, after about a month's storage it is usually between 4.13V-4.15V.
I plug the next string of 14 welded modules into the magazine when the magazine is fully charged and therefore also has 4.13V-4.14V per cell (which is meticulously taken care of by the balancer), then no current flows after plugging in and there is no need to fiddle with any equalising resistors. When the sun goes down in the evening, the new added cells already discharge normally with the rest of the storage and enter their normal cycle with the whole.

>>21297512
Heating a house with a heat pump means that 4000-5000 kWh are needed for the heat pump alone plus a house of 3000 kWh also you can multiply and add and it will never be enough.

Update, it's been over a month since the magazine completely paid for itself, so after a full financial 'blip', everything is now going to the upside.
As befits an experimental magazine - the experiment continues - and the mothballing continues

Next news, sometime in March I noticed that some of the cell sockets from one batch started to crack after a while, so within two weeks (fortunately these were weeks of no sunshine at all) the storage unit was rebuilt to mechanically prevent this kind of malfunction in the future. The cracked sockets were replaced. The sockets that have the print on them are OK and nothing happens to them, but the ones from the Chinese supplier that don't have such prints and numbers - they started to break, so I LOSE to the quality of some Chinese stuff.
Below are pics of how they break down and how I rebuilt the magazine (disassembling/disassembling it was one afternoon - I was surprised myself how quickly you can take something apart ) . This info would actually need to be added to the first post.

.

.


By the way, I throw in an example of a cell caught during a periodic thermal imaging inspection, a point of higher temperature by 3 degrees relative to the background, a cell that got a slight leak (after removing the tee shirt, I found a tiny electrolyte leak, a droplet). There was still a long way to go before such a cell was destroyed, maybe 3-6 months, but the thermal imaging had already caught the "dude" early enough - the cell was of course replaced immediately (without shutting down the storage), service-wise the design works.
Here the thought really comes to mind that if the factory packs were not sealed and people/users were able to check with thermal imaging, the number of different "accidents" could be significantly reduced.

partyzancik wrote:

@remzibi and if the cells heat up when charging do you just blow it off? I have had sanyo cells heat up even when charging with tp4056 and I have thrown all the batteries with them in the scrap

Yes, with a 700mA landing current, anything above 40 deg C drops out automatically, cells usually start to heat up when charged above 3.9V, charging of course I check with thermal imaging and not "finger" .
Example photo of a thermo cell which will be discarded in a moment

Thank you so much for updating the topic and sharing the link control. I can see that you are approaching this professionally, one can take example from you.