| Table of Contents |
|---|
Lithium
...
Assumptions
18650 Battery Assumptions
...
Battery Spec 3S30P - 60Ah
...
Parallel Cells to Get Capacity
60Ah/2.0Ah
...
Dimensions (mm)
1 cell: 18mm x 65mm
(long pack)
=18*3 x 18*30 x 65
=54mm x 540 mm x 65mm
(3 rows on 30 cells)
=18*9 x 18*10 * 65
=162 x 180 x 65
4.25” x 10.6” x 2.6”
If battery stops being useful at 10.8 for some appliances (AC Inverter), then we would end up getting 50% the capacity of the 3S battery pack.
My solar battery charger supports the 3S configuration.
Pack Distribution
Using rePackr.com:
Pack Dimensions
...
Battery Spec 3S40P - 80Ah
...
Parallel Cells to Get Capacity
80Ah/2.0Ah
...
Battery Spec 4S20P - 40Ah
...
Parallel Cells to Get Capacity
40Ah/2.0Ah
...
Would need to step down the voltage to 12v which may introduce some losses but would allow us to use the full capacity of the batteries.
Test Results of Batteries
Spreadsheet: 88af-18650.xls
...
Phosphate (LiFePO4) Battery Pack
I have 96x2=192 cells
Assumptions
LiFePO4 26650 Battery Assumptions
| Specification | Value |
|---|---|
| Nominal Voltage | 3.2v |
| Max Voltage | 3.6v |
| Cutoff Voltage | 2.0v |
| Capacity | 2300mAh |
Battery Spec 4S24P - 48Ah (based on salvaged batteries)
| Specification | Value |
|---|---|
| Nominal Voltage (4 x 3.2v) | 12.8v |
| Max Voltage (4 x 3.6v) | 14.4v |
| Min Voltage (4 x 2.0v) | 8v |
| Cells in Series for Voltage | 4 |
Parallel Cells to Get Capacity 48Ah/2.0Ah | 24 |
| Total Cells Required | 96 |
Dimensions (W x L x H) 1 cell: 26mm x 65mm pack size: 26*4 x 26*24 x 65 | 104mm x 624mm x 65mm |
Salvaged Batteries
Picked up a couple of BAE UPS battery packs.
...
Could use 3 BMSs for this configuration or just one.
Someone else's solution
Battery Charger
Solar Charger
ALLPOWERS 20A Solar Charge Controller Solar Panel Battery Intelligent Regulator with USB Port Display 12V/24V
...
Max Input: 18V, 320W, 17A
Battery Examples
Tesla's Power Wall
| Capacity | Ah @12V | Cost |
|---|---|---|
| 7 Kwh | =7000/12 =583 Ah | $3,000 US |
| 10 Kwh | =10000/12 =833 Ah | $3,500 US |
Jehu's Power Wall
| Spec | Details |
|---|---|
| Capacity | 4.4Kwh |
| Ah @12V | 366 Ah |
| #cells | 600 |
| Cell | 18650 |
References
| Reference | URL |
|---|---|
| Buying Used Batteries | https://batteryhookup.com/ |
| A123 Spec | https://www.batteryspace.com/a123-lifepo4-26650-rechargeable-cell-3-3v-2500-mah-50a-rate-8-25wh-anr26650m1b---un38-3-passed-and-iec-listed.aspx |
| Battery Pack Calculator | http://repackr.com/ |
...