# TLDR Review: TET Group 51 Lithium Car Battery

*Published: 2026-04-03 | Updated: 2026-04-03 | Source: https://shopsavvy.com/reviews-tldr/tet-group-51-lithium-car-battery*

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## Product: TET Group 51 Lithium Car Battery
**Brand:** T.E.T LITHIUM

## Pros
- Maintains consistent, reliable performance over time, even in low or sub-zero temperatures.
- Strong cranking power with 840CCA, easily starting vehicles including models like Lexus LS460 and 2015 Honda CRV.
- Lightweight and compact design makes installation especially easy, including tight spaces like under passenger seats.
- Bluetooth app control adds a useful feature to monitor and manage battery status remotely.
- Allows the ability to shut off power to the vehicle, which is great for those with infrequently driven cars.
- Responsive customer support knowledgeable about the battery management system.
- Comes with a solid 2-year warranty, providing peace of mind.
- Performs well as a drop-in replacement with no complicated setup needed.
- Long-lasting power with no major performance degradation noticed over at least six months.

## Cons
- Some users experienced unexplained sudden shutdowns and power loss during use.
- Occasional issues with charging, where the battery stays around 90% and doesn't fully complete the charge cycle.
- No clear way to diagnose problems or manually put the battery into pairing mode via the app.
- Durability over the very long term is still uncertain due to limited extended-use data.
- The battery may show a slightly used or worn appearance even when functioning well.

## Bottom Line

The TET Group 51 Lithium Car Battery offers solid performance packed in a lightweight, compact design that fits easily in many vehicles, backed by smart Bluetooth controls and helpful customer support. While some users have encountered quirky issues like sudden power loss and incomplete charging, these don’t appear widespread or critical for most applications. If you want a reliable, modern LiFePO4 starter battery with strong cold-cranking amps and a good warranty, this is a strong contender. However, if troubleshooting or advanced diagnostics are top priorities, you might want to keep an eye out for other models with more mature app support.

If you’re interested in exploring additional Lithium automotive batteries with Bluetooth features and proven durability, we can help you find comparable options to see what best fits your needs.

## Pros vs Cons at a Glance

| Pros | Cons |
|------|------|
| Maintains consistent, reliable performance over time, even in low or sub-zero temperatures. | Some users experienced unexplained sudden shutdowns and power loss during use. |
| Strong cranking power with 840CCA, easily starting vehicles including models like Lexus LS460 and 2015 Honda CRV. | Occasional issues with charging, where the battery stays around 90% and doesn't fully complete the charge cycle. |
| Lightweight and compact design makes installation especially easy, including tight spaces like under passenger seats. | No clear way to diagnose problems or manually put the battery into pairing mode via the app. |
| Bluetooth app control adds a useful feature to monitor and manage battery status remotely. | Durability over the very long term is still uncertain due to limited extended-use data. |
| Allows the ability to shut off power to the vehicle, which is great for those with infrequently driven cars. | The battery may show a slightly used or worn appearance even when functioning well. |
| Responsive customer support knowledgeable about the battery management system. |  |
| Comes with a solid 2-year warranty, providing peace of mind. |  |
| Performs well as a drop-in replacement with no complicated setup needed. |  |
| Long-lasting power with no major performance degradation noticed over at least six months. |  |

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*About this review: We pulled together findings from professional and user reviews, and cross-referenced them with ShopSavvy's pricing data from thousands of retailers to give you the short version.*