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submitted 6 months ago by schizoidman@lemmy.ml to c/technology@lemmy.ml
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[-] blazera@lemmy.world 70 points 6 months 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.

[-] 0110010001100010@lemmy.world 28 points 6 months ago* (last edited 6 months 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.

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.

The C rating is for discharging only.

[-] BlameThePeacock@lemmy.ca 10 points 6 months ago

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

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

[-] cmnybo@discuss.tchncs.de 8 points 6 months ago

Batteries have separate C ratings for charge and discharge.

[-] B0rax@feddit.de 1 points 6 months 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.

[-] Cort@lemmy.world 1 points 6 months 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

[-] ChicoSuave@lemmy.world 15 points 6 months ago

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

[-] umbrella@lemmy.ml 2 points 6 months ago

but that catched my attention for EVs.

[-] delirious_owl@discuss.online 1 points 6 months ago

And last decades

[-] pingveno@lemmy.ml 20 points 6 months ago* (last edited 6 months 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.

[-] johnyma22@lemmy.ml 13 points 6 months ago* (last edited 6 months ago)
[-] pingveno@lemmy.ml 8 points 6 months 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.

[-] Dippy@beehaw.org 4 points 6 months 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

[-] zik@lemmy.world 3 points 6 months ago

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

[-] schizoidman@lemmy.ml 2 points 6 months 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.

[-] pingveno@lemmy.ml 2 points 6 months 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.

[-] LowtierComputer@lemmy.world 2 points 6 months ago

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

[-] pingveno@lemmy.ml 1 points 6 months 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%.

[-] Valmond@lemmy.world 4 points 6 months 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.

[-] pingveno@lemmy.ml 3 points 6 months 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.

[-] ripcord@lemmy.world 2 points 6 months ago* (last edited 6 months 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.

[-] pingveno@lemmy.ml 2 points 6 months ago

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

[-] the_third@feddit.de 2 points 6 months ago

I've got some 20-ish kWh LiFePo in the basement. The internal temperature barely reacts to a forgotten window in a cold winter night. The whole thing is just many kilograms of thermal mass. Are you sure the battery temp was your problem?

[-] hglman@lemmy.ml 2 points 6 months ago

Battery temp is certainly a problem. Hard to compare between y'all's stories what the issues are.

[-] mipadaitu@lemmy.world 9 points 6 months 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.

[-] delirious_owl@discuss.online 5 points 6 months ago

How many decades do they last before needing replacement?

[-] zik@lemmy.world 10 points 6 months 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.

[-] delirious_owl@discuss.online 1 points 6 months 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?

[-] zik@lemmy.world 3 points 6 months ago

Lithium is used in grid storage:

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

[-] the_third@feddit.de 1 points 6 months ago

Lead acid is pretty inefficient though, something like 80% iirc.

[-] delirious_owl@discuss.online -2 points 6 months ago

Again, that doesn't matter since the battery doesn't move. This is a grid battery

[-] the_third@feddit.de 5 points 6 months ago

Of course it's relevant. My LiFePos reach about 92% efficiency. Losing 12% of energy in the storage process or not losing them is a big difference.

[-] Allero@lemmy.today 1 points 6 months ago

The question is then whether it's cheaper to buy LiFePos instead of lead acid or to install more solar panels.

[-] the_third@feddit.de 2 points 6 months ago

Yep. But also you need to run lead acid in a smaller charge window so you need more of them and when running out of space more panels might not be feasible - many variables in the whole thing, I don't think there's a universal answer, one can't really get around setting up a small spreadsheet.

[-] Allero@lemmy.today 1 points 6 months ago

Agreed - it's not that there are no space constraints at all.

[-] capital@lemmy.world 1 points 6 months ago

You’re thinking of density. Efficiency certainly matters.

[-] Valmond@lemmy.world 5 points 6 months 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
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