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submitted 1 month ago by [email protected] to c/[email protected]
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[-] [email protected] 70 points 1 month ago

Time until full charge isnt really a relevant metric for utility storage, you want larger storage, which would increase full charge time. Rate of charge is what matters.

[-] [email protected] 28 points 1 month ago* (last edited 1 month ago)

210 Ah cells to 90% in 12 minutes.

Assuming I can math early on a Monday morning:

90% of 210 is 189

189 / 12 is 15.75

So they charge at 15.75 an Ah per minute. Not sure how that compares honestly.

[-] [email protected] 11 points 1 month ago

The C rating is generally what battery charging (and discharging) is measured in. C being the capacity of the pack. So if the pack is 10 Ah and it takes 10 hours to charge it's 1c, if it takes 1 hour to charge then it's 10c.

I found this high current battery pack that's rated for 30c. https://www.lipobattery.us/high-discharge-lithium-ion-battery-30c-2/

I don't feel like doing the math for this battery pack.

[-] [email protected] 3 points 1 month ago

The C rating is for discharging only.

[-] [email protected] 10 points 1 month ago

The C rating can absolutely still be used when talking about recharging, it's just usually less relevant.

[-] [email protected] 4 points 1 month ago

No. The C rating is a cell's maximum discharge rate without damaging the cell.

You absolutely can't charge that 30C battery at 30A

[-] [email protected] 8 points 1 month ago

Batteries have separate C ratings for charge and discharge.

[-] [email protected] 1 points 1 month ago

You are not completely right. 1 C means it can (theoretically) be charged in 1h. Regardless of the capacity.

10 C means it can be charged in 1/10th of an hour.

To get the maximum current, multiply the capacity by the C rating.

[-] [email protected] 1 points 1 month ago

So like 4-5c roughly if the 90-100% charge rate is similar to the 0-90%. Way lower than some of the lithium cells I've seen at 30+c

[-] [email protected] 15 points 1 month ago

They're brand new and the writer needs a number to look impressive.

[-] [email protected] 2 points 1 month ago

but that catched my attention for EVs.

[-] [email protected] 1 points 1 month ago

And last decades

[-] [email protected] 20 points 1 month ago* (last edited 1 month ago)

I'm curious what the temperature resiliency is for sodium-ion batteries. I had a power outage recently where I was relying on a lithium-ion battery. As the temperature in the house plunged, it because so inefficient that charging a single phone overnight drained a quarter of the battery.

[-] [email protected] 13 points 1 month ago* (last edited 1 month ago)
[-] [email protected] 8 points 1 month ago

It was slightly above freezing in the house, so definitely not operating at peak efficiency. From a brief search, it looks like sodium-ion does have a similar temperature sensitivity, though it may be to a different degree.

[-] [email protected] 4 points 1 month ago

If I'm not mistaken sodium ion is better with temperature and durability. The biggest problem is energy density, so they can't compete in any applications where size and weight matter. This leads to their 2nd biggest problem, which is that there's so much production infrastructure for lithium that no one wants to invest in new assemblies for other battery chemistries

[-] [email protected] 3 points 1 month ago

If I'm not mistaken, those portable power stations with AC inverters consume power even when not in use. You probably should use the DC output wherever possible.

[-] [email protected] 2 points 1 month ago

It has outputs through USB-A, USB-C, AC, and DC-vehicle (whatever it's called). I think the AC inverter was off, though I had been using it earlier. I was definitely charging fully through the USB-C output. Good point, though.

[-] [email protected] 3 points 1 month ago

They're meant to have a much wider temperature range than Li-ion, theoretically.

[-] [email protected] 2 points 1 month ago

What size? That sounds like a little 2000mah power bank.

[-] [email protected] 1 points 1 month ago

That's the thing, it wasn't. It's an Ecoflow Delta Power Station, We tested boiling 1.5 liters of water off it and it used 15% of the capacity. Meanwhile, charging the phone overnight drained 30%.

[-] [email protected] 4 points 1 month ago

That doesn't seem normal. Did you like use the phone all night otherwise it should charge up quickly and then not use any noticeable energy.

[-] [email protected] 3 points 1 month ago

You would think, but we went directly to bed with as many blankets and coats as we could find. Just plug it in and let it charge. The phone has a maximum power draw of maybe 20W when speed charging. Not exactly boiling water.

[-] [email protected] 2 points 1 month ago* (last edited 1 month ago)

I need to do some more formal testing, but I've found the discharge rate of my ecoflow to be baffling compared to my Jackery or a big Bluetti I have. My experience has been similar to yours.

Which has surprised me because in general I've only heard good things about them.

[-] [email protected] 2 points 1 month ago

Did you find it was connected to temperature or other drop offs in capacity?

[-] [email protected] 9 points 1 month ago

Wonder if there's a trade off with the faster charging, or if it's just a side effect of the grid power setup.

[-] [email protected] 5 points 1 month ago

How many decades do they last before needing replacement?

[-] [email protected] 10 points 1 month ago

They're meant to survive an order of magnitude more cycles than Li-ion. But I'm containing my enthusiasm until we see them lasting a long time in real life use.

[-] [email protected] 1 points 1 month ago

Lithium isn't used for grid batteries because weight doesn't matter. Grid batteries with lead acid last 3 decades. Does this one last longer?

[-] [email protected] 3 points 1 month ago

Lithium is used in grid storage:

And that's just what I could find in a couple of minutes.

[-] [email protected] 5 points 1 month ago

I have read encouraging numbers about charge cycles for sodium batteries, I'm quite curious too about real values.

this post was submitted on 13 May 2024
311 points (99.4% liked)

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