would this be a good battery (samsung 8s) to pair with sbms0?

[A. J. Tarnas]

here's a battery pack that looks promising to me:

https://batteryhookup.com/products/samsung-8s-lithium-ion-29-6v-60ah-1-776kwh-module

seems like one of the cells could be detached and the pack would behave as a 7s 24v bank. or two packs could be arranged into 13s 48v (it's not explicitly stated but perhaps the nominal cell voltage is 3.7v).

think it will play well with electrodacus?

i would use 2, 4, or 6 60-cell panels and a dssr20 for each pair. i live off-grid in the mojave desert near joshua tree -- full sun most days of the year. my primary loads are 500-1000w of cooling (intermittent load -- on maybe 20-40 min per 60min) in summer during daylight, and waterheating in winter during daylight.

[Dacian Todea]

Yes it looks like those cells can be reconfigured as 7s or 7s2p or 7s4p just parallel groups of cells tho you may need to build some cell bus bars to do that.

I guess they where 68Ah cells originally so they where heavily used for a few years.

You will need to consider that the 60Ah was likely measured when fully charged to 4.2V (spec is 4.15V but I do not think they tested to that) and then SBMS0 default settings so battery lasts longer is 4V max that means about 70% of the capacity at 4.2V thus about 40Ah usable on those cells.

When you consider all that is about 1.2kWh usable storage capacity for $250 so around $200/kWh thus more expensive than the typical LiFePO4 CATL cells people usually buy. The 280Ah/3.2V cells for a bit over $100 from China.

[Bernd]

i placed an order in china beginning of january for 32x 280Ah EVE cells and paid 3457$ incl. tax, customs and shipping door2door. This is 108$ per cell. Looking at 8x 150Ah cells is maybe a good option as well if Tarnas wants to stay below 500$ for the battery.

Code hier eingeben...

[A. J. Tarnas]

thanks for the response. i'm too afraid to buy cells from china. i'm not sure how to get over that fear. shipping times that could extend into months, unknown seller reputability and battery quality, and i've never bought anything through alibaba -- possible customs issues? i need a walkthrough. til then i'm stuck with bigbattery and battery hookup til someone buys CALB-type cells, warehouses them stateside, and resells them at a small profit (rather than a huge profit, as is currently happening).

i just went out on a limb and bought the currently-listed battery hookup a123 7s "24v" packs.

https://batteryhookup.com/products/25-6v-78ah-1-99kwh-lithium-ion-a123-module-7s?variant=36899899211938

https://www.youtube.com/watch?v=jlRdVWedZ8A

[Dacian Todea]

Alex,

Is not a good thing to go on a limb :)

The batteries you linked to on batteryhookup website and the Youtube video are very different.

The 7s3p 78Ah on batteryhookup is made with 26Ah NMC cells while the 7s3p 58Ah battery in the video is made with 19.5Ah LiFePO4 cells same one's I have in my house pack just mine are 8s much more appropriate for 24V devices.

Batteryhookup and other similar companies get garbage (things that will normally need to be recycled as they are the end of life) and try to give them a second life by reeling them to the general public.

Of course you can use one of those packs but not more than one with the SBMS0.

Not sure what the current capacity is as 78Ah was nominal (this battery is produced since 5 or 6 years ago) but say it still have 70Ah at 4.15V then usable if you charge only to 4V default to SBMS0 should be around 50Ah

The spec for those cells is below

Length227mm

Operating Temperature Range-30ºC to +55ºC

Width161mm

Storage Temperature Range-40ºC to +60ºC

Depth7.5mm

HumidityCheck

Weight550g

AltitudeN/A

Operating Limits

Approvals

Nominal Voltage3.7V

TransportUN 38.3

Max Charge Voltage4.15V***

EUCARLevel ≤ 3

Minimum Cell Voltage2.8V***

Max 10 Sec Discharge Current355A

Continuous Discharge Current155A

Cycle Life>1000**

Specific Power2500 W/Kg

Specific Energy180 Wh/Kg

Warranty provided if proof can be submitted that the cell has been used in accordance with the manufacturers guidance at all times.

** Based on optimal operating conditions.

*** Typical values stated, temperature and load effect the values

[A. J. Tarnas]

Awesome! Thanks for researching all that and seeing the situation
clearly. I'll make the best of it. I intended to try adding an SBMS0 to
just one pack, as a standalone 1.5kwh bank. (I see you are estimating that

the packs might only be good for ~1.2kwh each.)

Do you know a reliable seller of the new grade-A CATL cells that you
recommended as being close to $100/kwh earlier?