best brands of inverters? best bank for the buck?

[Ampster]

Would point out 260ah x 52V = 13kWhr

Ha, I wish I could get 94kWh out of 7 cells. It took me 48 LF280s to get 42kWhs.

 

[OffGridInTheCity]

Ha, I wish I could get 94kWh out of 7 cells. It took me 48 LF280s to get 42kWhs.

Just for the record - Its 7 separate 260ah@48v batteries (14s100p each). Total of 7 x 260ah@48v = 1820ah@48v. I use 52v (instead of 48v) because 52 is the average operational voltage

 

[Daddy Tanuki]

Ha, I wish I could get 94kWh out of 7 cells. It took me 48 LF280s to get 42kWhs.

I think he meant that he has 7 packs at 260 amp/hour per pack at 52 volts.

 

[OffGridInTheCity]

I think he meant that he has 7 packs at 260 amp/hour per pack at 52 volts.

Yea - here's a pic to clear things up

 

[Daddy Tanuki]

Yea - here's a pic to clear things up
View attachment 94465

I remember you talking about your packs in the past. you are way more DIy in that regards then I am, I stuck with the plastic cased CALB cells myself.

 

[Ampster]

Just for the record - Its 7 separate 260ah@48v batteries. Total of 7 x 260ah@48v = 1820ah@48v.

Thanks for the clarification. Does that mean you have 7 BMS's?

 

[OffGridInTheCity]

Thanks for the clarification. Does that mean you have 7 BMS's?

I use Batrium Watchmon (central BMS) with 98 longmons (14s * 7) to monitor the overall battery bank and throw the ABB SACE shunt-trip if any pack gets out of wack - e.g. low/hi volts and low/hi temps in my case.

 

[PeSCaLo]

I use Batrium Watchmon (central BMS) with 98 longmons (14s * 7) to monitor the overall battery bank and throw the ABB SACE shunt-trip if any pack gets out of wack - e.g. low/hi volts and low/hi temps in my case.
View attachment 94474

Amazing, I wonder if its still profitable to do this vs Prismatic. you think your cost was <$0.18/ watt?

 

[Britguy]

I remember you talking about your packs in the past. you are way more DIy in that regards then I am, I stuck with the plastic cased CALB cells myself.

Me too!
I paid just under $1000 ($940) for 18x 200AH second hand CALB +BMS, which give me about 6kWhr of storage.
(2 spares so I could chuck the worst performers). No idea how long they will last.

940/6000 = 15.5c/Watt

 

[OffGridInTheCity]

Amazing, I wonder if its still profitable to do this vs Prismatic. you think your cost was <$0.18/ watt?

I've kept good records over last 4 years... The cost is running ~$196/kwh for 90%+ original spec second hand 18650 cells all purchased from BatteryHookup, Battery Clearing House, Jag35, Power2Spare, (and a few from eBay till I learned my lesson). This includes everything (tools, cell holders, hundreds of feet of various wire, solder, electrical tape, voltmeters, iCharger X8, Batrium/longmons, zip-ties, shelves/galvanized metal for fire reduction, fire extinguisher, shunt-trip, US Tax Rebates... everything except free-labor on my part)

$196/kwh / 1000 = $0.196/wh. So let's say $0.20/wh

 

[PeSCaLo]

Wow , Amazing

I've kept good records over last 4 years... The cost is running ~$196/kwh for 90%+ original spec second hand 18650 cells all purchased from BatteryHookup, Battery Clearing House, Jag35, Power2Spare, (and a few from eBay till I learned my lesson). This includes everything (tools, cell holders, hundreds of feet of various wire, solder, electrical tape, voltmeters, iCharger X8, Batrium/longmons, zip-ties, shelves/galvanized metal for fire reduction, fire extinguisher, shunt-trip, US Tax Rebates... everything except free-labor on my part)

$196/kwh / 1000 = $0.196/wh. So let's say $0.20/wh

Now Im getting LFP cylindrical @$0.12/wh from china including shipping for que raw cells. I calculated $0.16/wh with everything including busbar holders, barley and fiberglass wrap.
Case & Man hr bring it up to $0.18 / wh


But after seeing your post, BCH has $0.3 / cell 18650. that could change the equation. maybe bringing the cost down to $0.12 wh w/ everything.

The only thing holding me back is the Fire risk. even with metal case & fiberglass wrap.

 

[OffGridInTheCity]

Wow , Amazing



Now Im getting LFP cylindrical @$0.12/wh from china including shipping for que raw cells. I calculated $0.16/wh with everything including busbar holders, barley and fiberglass wrap.
Case & Man hr bring it up to $0.18 / wh


But after seeing your post, BCH has $0.3 / cell 18650. that could change the equation. maybe bringing the cost down to $0.12 wh w/ everything.

It's hard to say exactly - but I agree, I paid (on average with all the discards) more like $1.00-$1.20/cell so $0.30/cell would make a significant difference. The labor to process 12,000 cells (so far) is A LOT but I'm retired/bored so it wasn't a big deal for me. I can see why LifePo4 bricks are popular!!

Cell acquisition is the hardest part. I've found it's best if a 'battery' (~14s100p in my case) is all the same cell type. To get 1,400 good cells I have to more but it's difficult to estimate the keep/discard ratio and then the source is gone if you guess wrong and you don't have enough to do the battery. Then you have to wait....

The only thing holding me back is the Fire risk. even with metal case & fiberglass wrap.

After 4 years of operation - with 10,000 cells in operation and following thousands of posts - fire is not a worry for me because....
- the cells are BMS'ed with visibility into failing packs so they can be taken offline before serious failure - e.g. its not a 10minute 'thing' but rather multiple days / weeks warning.
- operated in good ambient + cells never get warm (are ambient temp).
- lightly stressed (charge/discharge per cell) - average <100ma/cell with a 400ma/cell max before the master breaker trips - e.g. well within test parameters and the specifications of the cells.
- operating in the middle range (3.5v to 4.0v) for lithium-ion - low stress.

Of course there is some risk, less that taking a drive perhaps, LifePo4 has some risk, lead acid has some risk, but very few things in life are risk free. For me, I believe I'm operating at reduced/acceptable risk thru test/oversizing/low-stress/monitoring/proper-wiring. This is something you have to decide for yourself - I make no claims, just sharing what I'm doing!

Fire Protection: I have corrugated metal (roofing) over top of the battery bank to block flame from hitting the ceiling, cinder block walls on 3 sides, concrete floor, smoke detector right overhead, and a fire extinguisher - but the 4th side is open to the room.

 

[Daddy Tanuki]

It's hard to say exactly - but I agree, I paid (on average with all the discards) more like $1.00-$1.20/cell so $0.30/cell would make a significant difference. The labor to process 12,000 cells (so far) is A LOT but I'm retired/bored so it wasn't a big deal for me. I can see why LifePo4 bricks are popular!!

Cell acquisition is the hardest part. I've found it's best if a 'battery' (~14s100p in my case) is all the same cell type. To get 1,400 good cells I have to more but it's difficult to estimate the keep/discard ratio and then the source is gone if you guess wrong and you don't have enough to do the battery. Then you have to wait....


After 4 years of operation - with 10,000 cells in operation and following thousands of posts - fire is not a worry for me because....
- the cells are BMS'ed with visibility into failing packs so they can be taken offline before serious failure - e.g. its not a 10minute 'thing' but rather multiple days / weeks warning.
- operated in good ambient + cells never get warm (are ambient temp).
- lightly stressed (charge/discharge per cell) - average <100ma/cell with a 400ma/cell max before the master breaker trips - e.g. well within test parameters and the specifications of the cells.
- operating in the middle range (3.5v to 4.0v) for lithium-ion - low stress.

Of course there is some risk, less that taking a drive perhaps, LifePo4 has some risk, lead acid has some risk, but very few things in life are risk free. For me, I believe I'm operating at reduced/acceptable risk thru test/oversizing/low-stress/monitoring/proper-wiring. This is something you have to decide for yourself - I make no claims, just sharing what I'm doing!

Fire Protection: I have corrugated metal (roofing) over top of the battery bank to block flame from hitting the ceiling, cinder block walls on 3 sides, concrete floor, smoke detector right overhead, and a fire extinguisher - but the 4th side is open to the room.

hyou can only take so many precautions until you are like NASA... afraid to move lest you lose your your retirement...

 

[PeSCaLo]

It's hard to say exactly - but I agree, I paid (on average with all the discards) more like $1.00-$1.20/cell so $0.30/cell would make a significant difference. The labor to process 12,000 cells (so far) is A LOT but I'm retired/bored so it wasn't a big deal for me. I can see why LifePo4 bricks are popular!!

Cell acquisition is the hardest part. I've found it's best if a 'battery' (~14s100p in my case) is all the same cell type. To get 1,400 good cells I have to more but it's difficult to estimate the keep/discard ratio and then the source is gone if you guess wrong and you don't have enough to do the battery. Then you have to wait....


After 4 years of operation - with 10,000 cells in operation and following thousands of posts - fire is not a worry for me because....
- the cells are BMS'ed with visibility into failing packs so they can be taken offline before serious failure - e.g. its not a 10minute 'thing' but rather multiple days / weeks warning.
- operated in good ambient + cells never get warm (are ambient temp).
- lightly stressed (charge/discharge per cell) - average <100ma/cell with a 400ma/cell max before the master breaker trips - e.g. well within test parameters and the specifications of the cells.
- operating in the middle range (3.5v to 4.0v) for lithium-ion - low stress.

Of course there is some risk, less that taking a drive perhaps, LifePo4 has some risk, lead acid has some risk, but very few things in life are risk free. For me, I believe I'm operating at reduced/acceptable risk thru test/oversizing/low-stress/monitoring/proper-wiring. This is something you have to decide for yourself - I make no claims, just sharing what I'm doing!

Fire Protection: I have corrugated metal (roofing) over top of the battery bank to block flame from hitting the ceiling, cinder block walls on 3 sides, concrete floor, smoke detector right overhead, and a fire extinguisher - but the 4th side is open to the room.

Very interesting. Will go into detail on your setup over the weekend and get you my analisis.