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| Specification | Detail |
|---|---|
| Image |
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| Part | AJC-D7S |
| Voltage | 12v |
| Capacity | 7Ah |
| Type | Sealed Lead Acid (AGM) |
| Terminals | F2 |
| Length | 5.94 in / 150.9 mm |
| Width | 2.56 in / 65 mm |
| Height | 3.7 in / 94 mm |
| Weight | 4.5 lbs |
Considerations
Lithium Ion
Using Lithium Ion batteries is an option but would require modifying the charge circuit in the UPS. A lead acid battery will charge using a voltage of 14.4v unlike a 3S battery which would charge at a voltage of 12.6v.
Example:
3S7P
14Ah
Questions:
- Could we use a BMS with a DC-DC drop down converter to modify the DC going to the BMS to 12.6v?
Lithium Iron Phosphate
Using Lithium Iron Phosphate (LiFePO4) may be a better idea since it is a drop in replacement for Lead Acid. Charge Voltage for a 4S pack would be 14.4v (3.6v/cell).
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Spec
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Value
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- Standard Charging: 2.5A, 1.0C rate
- Maximum Charging: 10.0A, 4.0C rate
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- Charge and Discharge: -30°C to 55°C
- Storage: -40 oC to 60 oC
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Lithium Iron Phosphate Battery Replacement
I ordered this LiFePO4 battery off amazon which is the exact same size as the original.
Cost: $63 CA plus Taxes.
NASTIMA 12V 8Ah Rechargeable Lithium Iron Phosphate Battery,Built-in BMS, 4000+ Cycles LiFePO4 Battery Pack
https://www.amazon.ca/dp/B0B5WBHDDN?smid=A32QMQUDJWY3FO&ref_=chk_typ_imgToDp&th=1
Our battery has the following dimensions:
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3.7 in / 94 mm
150/26 = 5.7
94/26 = 3.6
We could fit about 15 batteries in the space of our current lead acid battery.
Conclusion
Will leave it for now. If I had some good LiFePO4 cells kicking around I may see how many I could fit. The ones I have are old and have a max capacity of about 1500 mAh.
References
| Reference | URL |
|---|---|
| DIY Replacement Battery 12V 18650 Li-ion For APC Back-UPS 650 | https://www.yousun.org/archives/101 |
| Replace battery | https://www.youtube.com/watch?v=_dydlRHFjrc |
| Details | https://www.yousun.org/archives/660 |
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