Quick answer
The VIVI Electric Bike Battery for C26UL E-Bike (AMAK Series, 2024 and later models) is a proprietary replacement lithium-ion power pack featuring a 48V 7.8Ah capacity (374.4Wh) designed specifically to fit the frame and electrical architecture of newer 500W C26UL commuter e-bikes [3]. It is best suited for original owners whose current battery has degraded, lost capacity, or failed outside of warranty.
Because battery packs are heavily model-dependent—requiring exact matching of physical dimensions (approx. 15.4 x 4.3 x 3.0 inches), cradle integration, security lock alignment, and discharge terminal pin layouts (such as the 4-pin KT-D05 connector utilized on the 2024 AMAK series versus older 2-pin variations)—substituting generic alternatives is rarely feasible without custom electrical work [3]. However, buyers should note strict non-return policies on hazardous lithium components and anticipate extended shipping windows from regional warehouses [3].
VIVI Electric Bike Battery For C26UL Ebike - AMAK Series (2024 and later models) / 48V 7.8Ah
VIVI Electric Bike Battery For M026TGBUL Ebike - AMAK Series (2024 and later models) / 48V 7.8Ah
VIVI Electric Bike Battery For FM20UL Ebike - AMAK Series (2024 and later models) / 48V 7.8AhComparison of Replacement Battery Options
| Feature / Specification | VIVI C26UL Replacement (AMAK Series) [3] | Generic Universal Frame Batteries | Rebuilt / Recelled Original Packs |
|---|---|---|---|
| Voltage & Capacity | 48V 7.8Ah (374.4Wh) [3] | Varies (Typically 36V/48V, various Ah) | Dependent on original enclosure |
| Connector Type | 4 Pins (KT-D05) matched to C26UL [3] | Mixed (Requires splicing or adapters) | Original factory plug retained |
| Frame Fitment | Drop-in fit for C26UL AMAK cradle [3] | Universal mounting plate (rarely aligns) | Exact drop-in fit |
| Return Policy | Final sale / Non-returnable [3] | Varies by third-party marketplace | Varies by independent cell service |
| Safety Integration | Built-in BMS (up to 20A max discharge) [3] | Variable quality BMS protection | Retains original BMS circuitry |
Buyer Scenarios: Who Should (and Shouldn't) Buy It
Scenario 1: The Commuter Facing Range Drop
A daily commuter using a 2024 VIVI C26UL e-bike notices that after two seasons of regular use, the practical riding range has dropped by half, making round-trip transit unreliable. For this rider, purchasing the exact-match 48V 7.8Ah AMAK replacement restores factory range, sliding directly into the existing frame lock and mating securely with the 4-pin terminal base without wire modifications [3].
Scenario 2: The Owner of an Older Pre-2024 C26 Model
An owner of an older 2023 VIVI C26 model (utilizing a 2-pin ALX-072 setup) [3] spots the C26UL AMAK battery online and assumes it works universally across all "C26" iterations. This buyer should not purchase this specific variant. Due to shifting internal electronics, physical dimensions, and pin configurations between production years, cross-buying leads to incompatible terminals and a strict non-returnable financial loss [3].
When NOT to buy:
- You own a different brand or frame style: Never assume lithium packs are interchangeable across different e-bike brands, even if the voltage matches.
- You haven't verified your pin configuration: If your current battery uses a 2-pin connector (common on pre-2024 builds) rather than the 4-pin KT-D05 layout specified for the AMAK C26UL, this unit will not connect [3].
- You require an immediate fix: Shipping hazardous materials like lithium-ion batteries often involves ground-only transit restrictions, resulting in extended delivery windows [3].
Ownership Costs and Trade-Offs
- Upfront Expense: Purchasing a specialized OEM-style replacement battery requires a notable out-of-pocket investment relative to the total value of an entry-level commuter e-bike.
- The "No Return" Financial Risk: Because e-commerce channels enforce strict hazardous material transport restrictions, battery sales are generally final. Ordering the incorrect revision means absorbing total financial loss with no refund or exchange option [3].
- Lifespan and Cycle Management: The 7.8Ah capacity (374.4Wh) [3] is optimized for lightweight daily commuting rather than ultra-long distance touring. Maximizing its lifespan requires disciplined maintenance—storing the pack at 40% to 70% charge during extended periods of inactivity and topping it off every two months to prevent irreversible deep-discharge degradation [3].
Compatibility Checks
Before completing a purchase, verify these physical and electrical parameters against your existing hardware:
- Model Year & Series Code: Confirm your bicycle frame corresponds to the 2024 and later AMAK series designation (such as model identifier AMAK00016 for the C26UL) [3].
- Discharge Terminal Match: Inspect the base port. The C26UL AMAK variant relies on a 4-pin (KT-D05) configuration, distinct from older 2-pin (ALX-072) versions [3].
- Physical Dimensions: Ensure the compartment accommodates the 15.4 x 4.3 x 3.0-inch housing structure [3].
- Charger Specifications: Verify your charger matches the required output specs (Max Charge Voltage: 54.6V, 2A–3A current ceiling) to avoid overvoltage stress [3].
Pre-Purchase Checklist
- Verified the exact bike model number printed on the frame or manual.
- Inspected the battery base connector pins to confirm a 4-pin layout matches the listing [3].
- Accepted that battery purchases are final sale with zero return eligibility [3].
- Confirmed availability of a compatible 54.6V charger [3].
- Reviewed local storage and charging safety guidelines (avoiding confined hot spaces or unattended overnight charging) [3].
Frequently Asked Questions
Can I use a higher-capacity battery for longer range?
You can only use a higher capacity pack if it is specifically engineered by the manufacturer to match the exact voltage, physical cradle dimensions, and communication protocols of your specific e-bike model. Unauthorized third-party capacity upgrades can damage the controller or fail to mount securely.
How long does it take to charge the 48V 7.8Ah battery?
Using the standard 54.6V 2A charger, a complete charge cycle from a depleted state typically takes approximately 5 to 6 hours [3]. Never exceed recommended charging thresholds or leave packs charging unattended [3].
What causes a battery to become permanently damaged during storage?
Leaving a lithium-ion battery in a fully depleted state for extended intervals causes deep self-discharge, dropping cell voltage below safe operational limits. This inflicts irreversible chemical damage that falls outside standard manufacturer warranties [3].
Is it safe to charge the battery outdoors or in a shed?
Batteries should be charged in dry, temperature-controlled indoor environments (between 0°C and 45°C) away from direct sunlight, heavy moisture, and combustible materials [3]. Avoid charging in confined hot spaces like unventilated sheds or vehicles [3].
What should I do if my battery smells or deforms during use?
Immediately disconnect the battery from both the e-bike and the charger, move it away from flammable objects to a non-combustible surface, and discontinue use permanently [3].
Research Limitations
This guide is based on manufacturer catalog specifications and public merchant disclosures available as of late 2026. Specifications, pin arrangements, and availability are subject to change by component suppliers without notice. Buyers should independently cross-reference their exact serial numbers and hardware ports with customer support prior to ordering.