| Table of Contents |
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Assumptions
18650 Battery Assumptions
| Specification | Value |
|---|---|
| Nominal Voltage | 3.7v |
| Max Voltage | 4.2v |
| Cutoff Voltage | 3.0v |
| Capacity | 2500mAh |
Configuration Options
This section will look at the pros and cons of a 3S versus 4S configuration.
3S (9V-12.6V)
| Specification | Value |
|---|---|
| Nominal Voltage (3 x 3.7v) | 11.1v |
| Max Voltage (3 x 4.2v) | 12.6 |
| Min Voltage (3 x 3.0v) | 9v |
| Cells in Series for Voltage | 3 |
Pros:
- Can charge it from the car
- Works with most chargers (solar and car chargers)
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- Would not get full capacity when using with an inverter. The inverter would shut off at 10.5v.
4S (12V-16.8V)
| Specification | Value |
|---|---|
| Nominal Voltage (4 x 3.7v) | 14.8v |
| Max Voltage (4 x 4.2v) | 16.8v |
| Min Voltage (4 x 3.0v) | 12.0v |
| Cells in Series for Voltage | 4 |
Pros:
- Would be able to use the full capacity of the battery when converting to AC.
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- Would need to step down the voltage to 12v which may introduce some losses.
- Could not charge it off of the car
Configuration
Battery
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Spec 3S56P - (130 Ah)
| Specification | Value |
|---|---|
| Nominal Voltage (3 x 3.7v) | 11.1v |
| Max Voltage (3 x 4.2v) | 12.6 |
| Min Voltage (3 x 3.0v) | 9v |
| Cells in Series for Voltage | 3 |
Parallel Cells to Get Capacity |
80Ah/2.0Ah |
| 56 |
| Total Cells Required |
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
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Other Possible Packs
Battery Spec 3S40P - 80Ah
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Parallel Cells to Get Capacity
80Ah/2.0Ah
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Battery Spec 4S20P - 40Ah
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Parallel Cells to Get Capacity
40Ah/2.0Ah
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Battery Management System
3S 100A Li-ion Lithium 18650 BMS Battery Charger Protection Board with Balance
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| 168 |
| Specification | Details |
|---|---|
| Capacity | 112-128.8 Ah |
| Cell Capacity | 2.0-2.3 Ah |
| Cells | 3x56=168 cells |
The Plano 50 Cal Ammo Box can hold a total of 192 cells (about 150Ah).
Battery Management System
50A BMS
3Series 50A 11.1V/12V/12.6V BMS PCB Protection Board for 18650 Li-ion Battery Cell with Balance
| Features |
|---|
| Continuous Discharge Current: 50A Momentary Discharge Current: 150A Charge Voltage: 12.6V Charge Current: 50A Overcharge Detection Voltage: 4.28±0.025V Overcharge Protection Delay: 0.5S Overcharge Cancel Voltage: 4.08±0.1V Balance Detection Voltage: 4.20±0.025V Balance Cancel Voltage: 4.20±0.05V Balance Current: 60±5mA Over-discharge Detection Voltage: 2.8±0.1V Over-discharge Detection Delay: 0.1S Over-discharge Cancel Voltage: 3.0±0.1V Overcurrent Detection Voltage: 150mV Overcurrent Detection Delay: 9mS Overcurrent Protection Current: 200±10A Protection Cancel Condition: Disconnect Load Short Circuit Protection Condition: Outside Load Short Circuit Short Circuit Detection Delay: 250uS Protection Cancel Condition: Disconnect Load Main Circuit Conduction Internal Resistance: ≤25mΩ Working Current: ≤30uA Sleeping Current(Battery Over-discharge): ≤10uA Operating Temperature:﹣30℃~﹢80℃ Size: 75×51.5×15mm/2.95×2.02×0.59" |
100A BMS
3Series 50A 11.1V/12V/12.6V BMS PCB Protection Board for 18650 Li-ion Battery Cell with Balance
Test Results of Batteries
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Battery Hookup Modem Batteries
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We spot tested tens of thousands of these cells and they came out around full capacity overall. These are a great source of genuine LG 2200mah cells because the modem batteries are either never used at all or they were used as backup only with less than 3 cycles. Modem batteries only gets cycled hen a house loses power which is very rare in our region.
| Brand: | LG |
| Model: | LGDAS31865 (ICR18650S3) |
| Capacity: | 2200mAh Rated |
| Voltage: | 3.60V Nominal |
| Charging: | 4.20V Maximum 1075mA Standard 2150mA Maximum |
| Discharging: | 3.00V Cutoff 430mA Standard 3225mA Maximum |
| Description: | Blue Cell Wrapper White Insulator Ring 18650 Form Factor |
Almost every pack we opened had the light blue lg cells, some had dark blue lg cells with the same specs. Either way they are all name brand cells, the best ones out there
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Packaging
I bought Plano 50 Cal Ammo Box, Black
Interior dimensions: 11.25" x 5.5" x 7"
Build
Battery Capacities
https://docs.google.com/spreadsheets/d/1mlgodp0UQAi1QGu0aGxJdH-wnCkg5dZosCjmBs_kSDo/edit#gid=0
Rpackr Configuration:
Build Pictures
Revised Build Pictures
Added 100A BMS and additional wiring to support the load. Then added terminals and USB and 12V port.
Added a battery meter
References
| Reference | URL |
|---|---|
| Buying Used Batteries | https://batteryhookup.com/ |
| Battery Pack Calculator | http://repackr.com/ |