Many merchants and cashiers have experienced this frustration: a sudden power outage during peak checkout hours, leaving transactions unrecorded; delivery drivers losing order data while replacing POS machine batteries; machines malfunctioning during outdoor checkouts due to extreme cold or heat... In reality, a simple supercapacitor can solve these POS power challenges. The following 15 easy-to-understand Q&A guide explains the selection and use of Yongming supercapacitors, making them easy to understand for both store operators and product selection.

## 1. Q: Why do POS machines need supercapacitors as backup power?

A: The most crucial aspect of POS machines is that transactions must not be interrupted or lost. If the power goes out while a card is being swiped, or the machine shuts down while the battery is being replaced, the transaction could be lost, complicating subsequent reconciliation and issuing receipts to customers. The role of a supercapacitor is to provide instantaneous power during these power outages: during the tens of seconds it takes to replace a battery or during a sudden power outage, it can power the POS machine, allowing it to successfully complete transactions and save records without losing data due to a restart.

## 2. Q: What are the advantages of supercapacitors over ordinary batteries (such as the lithium batteries in mobile phones)?

A: Compared to ordinary batteries, supercapacitors hit the pain points of POS terminals, offering significant advantages:
- **Longer life**: Ordinary batteries degrade after only a few thousand uses, while supercapacitors can withstand over 500,000 cycles. Based on 100 transactions per day, this translates to 13 years, roughly the same lifespan as the POS terminal, eliminating the need for frequent replacement.
- **More powerful power**: During peak hours, POS terminals consume significant power due to continuous card swiping and receipt generation. Supercapacitors can deliver a burst of power without the "stuck" nature of batteries.
- **Quick charging**: Ordinary batteries take 1-2 hours to fully charge, while supercapacitors can be plugged in and used in minutes. Delivery drivers can rest at the convenience store while the terminal is fully operational for the next round of deliveries and payments.
- **Hot and cold-resistant**: From -40°C outdoors in Northeast China to 70°C in southern kitchens, they operate reliably, unlike batteries that freeze in cold weather or quickly lose power in hot weather.
- **No Maintenance**: No issues with battery bulging or leakage; just install it and forget about it, saving the time and expense of repairs.

## 3. Q: In which POS machine scenarios are supercapacitors most effective?

A: Not all POS machines require them, but in these three scenarios, you'll immediately notice the difference:
- **Mobile POS (for takeout, outdoor markets)**: If a delivery driver's POS machine battery dies, they can be replaced without shutting down the machine. The supercapacitor provides power between removing the old battery and inserting the new one, preserving order data and eliminating the need to re-login to the system.
- **Fixed POS (for supermarkets and convenience stores): Most useful during power outages and voltage fluctuations. For example, if the voltage suddenly drops during peak hours, the POS machine won't "stop working after each card is swiped," allowing users to wait in line for cashiers without interruption.
- **High-frequency POS machines (gas stations, large supermarkets): Consecutively swiping dozens of cards and printing a large number of receipts can cause the machine to "suddenly drain power." Supercapacitors can replenish power in real time, providing greater stability than relying solely on batteries and reducing issues like "card swiping failures" and "receipts breaking mid-print."

## 4. Q: How do you use a supercapacitor and the POS machine's main battery (e.g., a lithium battery) together?

A: The most common method is to connect them in parallel (technically called "parallel"), which simply means "dividing the work":
- The main battery is responsible for "daily power": For example, when the POS machine is in standby mode or scanning a QR code to check bills, these "non-power-consuming" situations are all powered by the main battery.
- The supercapacitor acts as an "emergency backup": When the main battery is running low, the voltage drops, or it's removed for battery replacement, it immediately replenishes the battery, preventing the POS machine from experiencing voltage drops and providing the "high power needed during power-consuming situations"—the machine won't go black or freeze during this entire process, and the user won't notice anything.

## 5. Q: What should I pay attention to when charging a supercapacitor to avoid damaging it?

A: The key is to "charge steadily and not exceed the safe voltage." Don't charge it like you're charging a mobile phone battery!
Supercapacitors are sensitive to "overvoltage": For example, they can only withstand a maximum of 2.7V; charging to 3V could damage them. It's recommended to use a "small chip" specifically designed for charging supercapacitors. This chip does three things:
- Prevents voltage from exceeding the upper limit: strictly controls the charging voltage within a safe range;
- Controls the charging speed: prevents excessive current from damaging the capacitors;
- Provides visibility into the charging status: lets you know whether the capacitors are fully charged, eliminating the need to wait.

## 6. Q: What precautions should be taken when connecting multiple supercapacitors together (for example, connecting two in series)?

A: The key is to ensure that each capacitor shares the same voltage, otherwise some will be damaged.

Even capacitors from the same batch can have varying charge storage capacities and resistance to current flow. If connected in series, some capacitors will bear more voltage, making them more susceptible to damage over time. There are two solutions:
- A simple "passive method": Connect a small resistor next to each capacitor to allow the higher-voltage capacitor to "discharge," maintaining a consistent voltage;
- A more efficient "active method": Use a dedicated circuit to "shift" the charge from the higher-voltage capacitor to the lower-voltage capacitor. This is suitable for applications requiring high stability (such as bank cash registers).

## 7. Q: What key indicators should I consider when choosing a supercapacitor?

A: Don't get too complicated; just focus on these six "practical parameters":

- Capacity: This determines how long the capacitor can last in the event of a power outage. For example, cash registers consume the most energy, so you need to choose one that can last long enough to complete a transaction.

- Maximum voltage: This must match the POS terminal's power supply voltage, neither too high nor too low.

- Resistance to current flow: The lower the resistance, the faster the power supply during power-consuming periods, making card swiping and receipt printing more stable.

- Maximum current: This must be greater than the current required by the POS terminal during its most power-consuming periods, otherwise it will not be able to supply power.

- Operating temperature range: For outdoor use, choose one between -40°C and 70°C; for indoor use, choose one between -20°C and 60°C.

- Size: POS terminals have limited space (especially small handheld devices), so you need to choose a size that can fit inside.

## 8. Q: How can I test the performance of a supercapacitor and whether it will cause a power outage and lost orders?

A: Don't just look at the specifications; test it in actual use. Focus on these three scenarios:
- Simulating a sudden power outage: Deliberately cut off the power while swiping a card or printing a receipt to see if the POS machine can complete the transaction, store the record, and then shut down safely using the capacitor;
- Frequent battery replacement: Remove and reinsert the main battery several times to see if the machine restarts and if data is lost;
- Hot and cold environment testing: Place the machine in an extremely cold (e.g., -20°C) or extremely hot (e.g., +60°C) location and test its backup performance during a power outage to see if it is sensitive to both cold and heat.

## 9. Q: How long do supercapacitors last? Does it match the warranty period of the POS machine?

A: The lifespan of a supercapacitor depends primarily on how many times it can be used and whether its charge storage capacity decreases.
Yongming's supercapacitors can be reused over 500,000 times. Assuming a POS machine processes 100 transactions per day, this means they can last over 13 years. While most POS machines only have a warranty period of 3-5 years, the lifespan of these capacitors far exceeds that. You don't have to worry about the capacitor failing first; you can truly "install and forget about replacing."

## 10. Q: Can supercapacitors fail? What if they do? How can they be prevented?

A: Supercapacitors don't fail suddenly. They typically fail gradually: for example, their charge storage capacity decreases or the resistance to current flow increases.

For applications requiring high checkout stability (such as gas stations and banks), multiple supercapacitors can be connected in parallel. This reduces current resistance and provides a more stable power supply. Furthermore, even if one fails, the others will continue to function, preventing the POS machine from suddenly losing backup power.

## 11. Q: Are supercapacitors safe? Will they catch fire or explode like lithium batteries?

A: Absolutely not! Supercapacitors store charge by physically adsorbing charge, much like a sponge absorbs water, rather than by chemical reactions like lithium batteries. Therefore, they don't generate high temperatures or catch fire or explode.

Yongming's supercapacitors also feature multiple protections: automatic voltage relief when the voltage is too high, and automatic current limiting when the current is too high. This eliminates safety issues even in extreme conditions (such as being exposed to high temperatures or being hit).

## 12. Q: Will extreme heat affect the lifespan of supercapacitors? How can this be avoided?

A: High temperatures significantly impact the lifespan of supercapacitors—for every 10°C increase in temperature, their lifespan can be shortened by 30%-50%. For example, a supercapacitor that lasts 10 years at room temperature (25°C) might only last 7 years at a kitchen counter (35°C), and only 5 years at 45°C outdoors. The solution to avoid this is simple: When installing a supercapacitor, avoid placing it near heat-generating components in the POS machine (such as the machine's "brain" chip or charging module). For desktop POS machines, try to place them in a well-ventilated area, not in a stuffy cabinet.

## 13. Q: Does using a supercapacitor make the POS machine more expensive?

A: On the surface, adding a supercapacitor will cost a little more in parts (e.g., 10-15 yuan more per machine), but from a "total cost from purchase to use" perspective, it actually saves money:
- Saves on design costs: No need for a leak-proof battery casing or complex battery protection circuitry;
- Saves on maintenance costs: Supercapacitors require less frequent replacement, while regular batteries need replacement every 1-2 years. For 100 machines over 5 years, this can save tens of thousands of yuan in battery replacement costs;
- Saves on after-sales service costs: No customer complaints due to lost transactions due to power outages, and no need to hire someone to fix "data loss" issues. These hidden costs are far greater than the cost of parts.

## 14. Q: Do supercapacitors need to be replaced regularly?

A: No! If you choose the right model, its lifespan can be synchronized with that of the POS terminal—if the terminal lasts 10 years, the capacitor will also last 10 years. You don't need to replace the capacitor until the terminal is scrapped. For merchants, this means "buy a POS terminal and you don't have to worry about capacitors," saving them the trouble of frequent maintenance.

## 15. Q: As supercapacitor technology develops in the future, what benefits will it bring to POS terminals?

A: Future supercapacitors will "store more power and be smaller," which is great news for POS machines:
- Machines can be made thinner and smaller: For example, current handheld POS machines use capacitors that take up a lot of space. As capacitors become smaller, machines can be made as thin and light as mobile phones, making them easier for delivery drivers and street vendors to carry.
- Longer-lasting power outages: Capacitors of the same size will be able to store more power, allowing transactions to be completed after a power outage while also facilitating a longer power cycle, such as waiting for a power call or battery replacement.
- More comprehensive functionality: For example, after a POS machine loses power, the capacitors can still connect to a 4G network, transmitting transaction data to the cloud in real time, making it completely immune to both network and power outages.