XTAR MC2 2-Slot Battery Charger – 1A Constant Current USB Charger for 18650, 21700, 26650 & More (Supports Protected 21700)
Description
Overview
The XTAR MC2 is a compact, two-slot USB charger for cylindrical lithium-ion cells, covering everything from small 10440s up to 26650s and protected 21700 cells. It charges both slots at a full 1A simultaneously — no current-splitting penalty for using both bays at once — and uses a 3-stage charging process (trickle, constant current, constant voltage) to bring cells to a full, stable charge without overcharging them.
It's built for people who want a genuinely portable charger that doesn't force a trade-off between size and charge speed: small enough to carry in a bag, fast enough for regular use.
Full Specs
| Parameter | Value |
|---|---|
| Model | MC2 |
| Input | Type-C, 5V⎓2A |
| Charging Current | 1A per slot (both slots simultaneously — 1A x1 or 1A x2, not shared) |
| Charging Method | 3-stage: trickle charge → constant current → constant voltage |
| End-of-Charge Voltage | 4.2V ±0.05V |
| End-of-Charge Current | <130mA cutoff |
| Operating Temperature | 0°C to 40°C |
| Dimensions | L103mm x W53mm x H30mm |
| Weight | 54g |
| Compatible Chemistry | 3.6V/3.7V lithium-ion (Li-ion/IMR/INR/ICR) |
| Compatible Cell Sizes | 10440, 14500, 14650, 16340, 17335, 17500, 17670, 18350, 18490, 18500, 18650, 18700, 20700, 21700, 22650, 25500, 26650 |
| Protected Cell Support | Yes — supports protected 21700 cells |
| Special Feature | "0V" activation technology for recovering some over-discharged cells |
| Status Indicators | Green = standby or fully charged; Red = actively charging; Off/unlit = reverse polarity or abnormal insertion |
| Safety Protections | Reverse polarity protection, short-circuit protection, automatic charge cutoff |
How the Charging Process Actually Works
The MC2 doesn't just dump current into a cell and stop — it moves through three distinct stages:
- Trickle charge — a small preliminary current tops off and, where applicable, helps activate a deeply discharged cell before ramping up.
- Constant current — the charger increases and holds a steady current while the cell's voltage climbs; this is where most of the capacity gets restored, and it's the fastest-charging phase.
- Constant voltage — as the cell approaches full charge, the charger holds voltage steady and gradually reduces current, topping off the last portion of capacity without pushing the cell past a safe voltage.
This is standard, sound practice for lithium-ion charging — it's what protects cell longevity better than a charger that just charges at a flat current until it hits a voltage cutoff and stops abruptly.
What Makes This Charger Worth Considering
- Real 1A per slot, no splitting — plenty of basic dual-slot chargers cut each slot's current in half when both bays are occupied. The MC2 doesn't do that: each slot gets a full 1A regardless of whether the other is in use, so a typical 18650 charges in a few hours rather than most of a day.
- 0V activation — most basic chargers simply refuse to recognize a cell that's been discharged too far below its normal cutoff voltage. The MC2's activation function can attempt a slow, controlled recovery charge on some of these cells rather than treating them as dead on arrival. It won't save every over-discharged cell — some genuinely are beyond recovery — but it gives borderline cells a real chance.
- Broad size compatibility — from small 10440s (common in flashlights and ) up through 26650s, plus protected 21700 cells, this one charger covers most of the cylindrical lithium-ion formats you're likely to own.
- Simple status reporting — the LED colors are unambiguous: green means it's either standing by or done, red means it's actively working, and no light at all is the charger telling you something's inserted wrong before it does anything else.
What to Keep in Mind
- This charges bare cells only in the sense that it doesn't manage discharge-side protection. The MC2 handles charging safely (voltage/current cutoffs, reverse polarity, short circuit), but if you're using unprotected cells in a device, that device still needs its own low-voltage cutoff — the charger's protections don't extend to how the cell is used afterward.
- Operating temperature matters. Charging outside the 0-40°C range isn't something this charger is rated to handle safely — keep it somewhere reasonable, not in direct sun or a hot car.
- Two different cell sizes at once is fine. Because the slots operate independently with automatic detection, you can charge, say, one 18650 and one 21700 side by side without an issue.
Frequently Asked Questions
Q: How long does it take to fully charge a typical 18650?
A: At a full 1A, a 2,500-3,000mAh 18650 typically reaches full charge in roughly 3-4 hours, accounting for the tapering constant-voltage stage near the end. Larger cells (21700, 26650) will take proportionally longer given their higher capacity.
Q:Does charging two cells at once slow either one down?
A: No. Each slot delivers its own full 1A independently — you're not splitting a shared current budget between the two bays.
Q: Can this charge protected cells?
A: Yes, it supports protected 21700 cells. For other protected cell sizes, check the cell's own spec sheet — protection circuits vary and some add length that may not fit every charger's slot depth.
Q: What does it mean if a slot's LED doesn't light up at all?
A: That typically indicates a reverse-polarity insertion or another abnormal condition the charger has detected. Remove the cell, check its orientation, and reinsert.
Q: Is the "0V activation" feature safe to rely on regularly?
A: It's meant as a recovery option for occasional over-discharge situations, not a substitute for storing and using cells properly in the first place. A cell that repeatedly needs 0V activation is showing signs of wear or misuse and is worth watching more closely — or replacing.
Shipping and Returns
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Free Shipping: Enjoy free shipping on all orders over $65. For orders under $65, the shipping cost is $8.99.
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Delivery Time: Once shipped, orders typically arrive within 7–15 business days.
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Easy Returns: We want you to be completely satisfied. If you're not, you can return your product within 30 days of receiving your order. Please ensure the items are unused and in their original condition. For return instructions, please contact our support team.
Payment & Security
Payment methods
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
Security
Refund Policy
OneAndes Return & Refund Policy
At OneAndes, we are committed to providing high-quality cylindrical lithium-ion batteries for your drones, vacuums, garden tools, and other power needs. If you are not completely satisfied with your purchase, we are here to help. Please read our full return policy below before initiating a return.
1. Return Window
You have 30 calendar days from the date you received your item(s) to request a return. Any return request submitted after 30 days will not be eligible for a refund or exchange.
2. Eligibility Conditions
To qualify for a return, all items must meet the following conditions:
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Condition: Items must be unused, undamaged, and in the same condition that you received them.
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Packaging: Items must be returned in their original packaging with all accessories, manuals, and protective covers intact.
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Proof of Purchase: A valid receipt, order confirmation email, or proof of purchase must accompany all returns.
Non-Returnable Items:
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Batteries that have been installed, used, or show any signs of wear.
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Items marked as “Final Sale” or “Clearance” at the time of purchase.
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Customized or special-order products.
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Gift cards.
If a returned item fails to meet these conditions, we reserve the right to deny the return or charge a restocking fee.
3. How to Initiate a Return
Follow these steps to return your product:
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Contact Us: Email our support team at support@oneandes.com with your order number and the reason for return. We aim to respond to all return requests within 24 hours on business days.
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Receive RMA: We will provide you with a Return Merchandise Authorization (RMA) number and return instructions. Do not ship any item without an RMA number.
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Pack Securely: Place the item in its original packaging, include all accessories, and clearly write the RMA number on the outside of the box.
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Ship to Our US Warehouse: Ship the package to the following address:
OneAndes Returns
10320 6th St
Rancho Cucamonga, CA 91730
USA*Important: Lithium-ion batteries are classified as hazardous materials (Class 9). Please follow the shipping guidelines provided in Section 4 below. We recommend using a trackable shipping service and purchasing shipping insurance, as we cannot guarantee receipt of your returned item.*
4. Return Shipping Costs
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Defective or Incorrect Items: If the item you received is defective, damaged in transit, or different from what you ordered, OneAndes will cover the return shipping cost. In this case, we will provide you with a prepaid return shipping label.
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Buyer’s Remorse / Non-Defective Returns: If you are returning an item for any other reason (e.g., no longer needed, ordered the wrong model), you are responsible for the return shipping costs. You must prepay the return shipping cost using a trackable carrier that accepts lithium batteries. We do not provide prepaid return labels for non-defective returns.
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Lithium Battery Shipping Regulations: By law, all returns must be shipped in compliance with applicable dangerous goods regulations. We will provide guidance on proper packaging and labeling. Failure to comply may result in carrier refusal, seizure, or additional fees. We are not responsible for returned items lost or rejected by the carrier due to improper shipping.
5. Refunds
Once we receive and inspect your return at our Rancho Cucamonga, CA facility, we will notify you via email of the approval or rejection of your refund.
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Approved Refunds: If approved, your refund will be processed to your original method of payment within 5 to 10 business days. Please note that depending on your bank or credit card issuer, it may take additional time for the credit to appear on your statement.
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Partial Refunds: In certain situations, only partial refunds may be granted:
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Items not in original condition, missing parts, or damaged for reasons not due to our error.
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Items returned more than 30 days after delivery (reviewed on a case-by-case basis).
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Non-Refundable Fees: Original shipping charges are non-refundable unless the return is due to our error (defective product or incorrect shipment).
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Restocking Fee: We do not charge a restocking fee for defect-free returns, but we may deduct the return shipping cost, which will be deducted from your refund.
6. Exchanges
We replace items only if they are defective or damaged upon arrival. If you need to exchange a defective item for the same product, please contact us at support@oneandes.com. Exchanges are subject to product availability.
If you ordered the wrong battery size or model, please follow the standard return process above and place a new order for the correct item.
7. Damaged or Missing Items
If your package arrives visibly damaged, please take photos of the package before opening and contact us immediately. We will work with the shipping carrier to file a claim and arrange for a replacement or refund. Damaged or missing item claims must be reported within 7 calendar days of delivery. For immediate assistance, you may also call us at (213) 316-8849.
8. Order Cancellation
You may cancel your order without penalty if it has not yet been shipped. To cancel, email us at support@oneandes.com as soon as possible. If the order has already been processed or shipped, you will need to follow the standard return process upon receipt.
9. Warranty
All OneAndes batteries are backed by a 12-month limited warranty against defects in materials and workmanship. This warranty does not cover damage caused by misuse, improper charging, unauthorized modifications, normal wear and tear, or use outside of manufacturer specifications. For warranty claims, please contact our support team.
10. Contact Us
If you have any questions about our Return & Refund Policy, please reach out:
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Email: support@oneandes.com
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Phone: (213) 316-8849 (Mon-Fri, 9 AM – 5 PM Pacific Time)
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Mailing Address: 10320 6th St, Rancho Cucamonga, CA 91730, USA
We aim to respond to all inquiries within 24 hours during business days. Please include your order number for faster assistance.