---
product_id: 318372905
title: "QWORK® Battery Capacity Tester, Battery Monitor, Voltage Range 8V-80V and 0-100A Sampler base, with 6.5ft / 2m Custom Cable, for Auto Car Motor Boat Caravan RV"
brand: "qwork"
price: "379.11 DT"
currency: TND
in_stock: true
reviews_count: 13
category: "Qwork"
url: https://www.desertcart.tn/products/318372905-qwork-battery-capacity-tester-battery-monitor-voltage-range-8v-80v
store_origin: TN
region: Tunisia
---

# 0-100A high precision current detection Auto data storage & memory function 8V-80V voltage range QWORK® Battery Capacity Tester, Battery Monitor, Voltage Range 8V-80V and 0-100A Sampler base, with 6.5ft / 2m Custom Cable, for Auto Car Motor Boat Caravan RV

**Brand:** qwork
**Price:** 379.11 DT
**Availability:** ✅ In Stock

## Summary

> 🔌 Stay powered, stay ahead — never get caught off-guard with QWORK® Battery Capacity Tester!

## Quick Answers

- **What is this?** QWORK® Battery Capacity Tester, Battery Monitor, Voltage Range 8V-80V and 0-100A Sampler base, with 6.5ft / 2m Custom Cable, for Auto Car Motor Boat Caravan RV by qwork
- **How much does it cost?** 379.11 DT with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.tn](https://www.desertcart.tn/products/318372905-qwork-battery-capacity-tester-battery-monitor-voltage-range-8v-80v)

## Best For

- qwork enthusiasts

## Why This Product

- Trusted qwork brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Precision Power Insight:** Monitor your battery’s voltage, current, and capacity with pinpoint accuracy for smarter energy management.
- • **Universal Compatibility:** Seamlessly supports lithium, lead-acid, NiMH, and lithium iron phosphate batteries from 8V to 80V, perfect for cars, RVs, boats, and e-bikes.
- • **Comprehensive LCD Display:** Large backlit screen delivers real-time, multi-metric battery data—voltage, current, consumed power, and capacity—at a glance.
- • **Effortless Data Retention:** Automatically saves your last test data even after shutdown, so you never lose track of your battery’s health.
- • **Extended Reach Installation:** Includes a 6.5ft (2m) custom cable for flexible, hassle-free setup in any vehicle or portable equipment.

## Overview

The QWORK® Battery Capacity Tester is a high-precision voltmeter and ammeter designed for professional-grade battery monitoring across a wide voltage range (8V-80V) and current up to 100A. Featuring a large backlit LCD, it provides real-time data on voltage, current, consumed power, and battery capacity, with automatic data storage for convenience. Compatible with multiple battery chemistries and ideal for automotive, marine, RV, and portable applications, it ensures you maintain optimal battery health and avoid unexpected power failures.

## Description

Product Description QWORK Battery Monitor Voltmeter Ammeter with 6.5 ft Custom Cable Install First, open a round holes of 54.5mm on the panel of the equipment. Then install the coulometer from the front of the panel. Finally tighten the bracket on the back. Product Overviews This is a kind of high precision current type battery capacity tester(also known as coulometer)，which can test the voltage，current and capacity of battery to help users know the state of battery in time. It have memory function. It is suitable for mobile and portable equipments、e-bike、balance cars、cleaning machines、instruments、ups and so on. It is suitable for lithium batteries, lithium iron phosphate batteries, lead-acid batteries and nickel-metal hydride batteries which working voltage is from 8V to 100V. Connect First, series connect the sampler to the negative circuit of your battery. B- of sampler connects to B- of battery. P- of sampler connects to P- of output or C- of charge. Then take a wire of 0.3-0.75 mm².One end of the wire connects to positive of battery，another end connects to B+ of sampler (any one is ok). Finally connect sampler to battery monitor by the shielded wire. After confirm and power on, it will be work normally. Using steps 1. Connect and check the current Power on after complete the connection as shown, the screen should display capacity percentage. If the screen has no response, please check the connection. Then charge or discharge the battery, and check whether the display current is equal to the actual current. If the deviation is large please check the connection. 2.Capacity reset On first use, the percentage and capacity are not the actual value, you should reset the capacity: discharge the battery totally and hold the“V”key for 3 seconds to set the capacity zero or charge the battery fully and hold the “ %”key for 3 seconds to set the capacity full. And it doesn't need to do this again later, except replace the battery. 3.Check and reset the actual capacity If you find the display capacity don't match the actual capacity，please check and reset the actual capacity：discharge the battery totally and hold the“V ”key for 3s to set the capacity zero，then set the capacity value as large as possible. Then charge the battery fully，and the display capacity is the actual capacity. Finally set the display capacity as preset capacity (Please refer to use and setting). Use and setting Attention When charging or discharging，the coulometer must be at work. Otherwise the capacity will not be accurate. When the charge or discharge current is less than backlight off current, coulometer enter a low power state and backlight off. And it can memory the capacity. Because of high sensitivity，when the coulometer is in standby mode (battery has no input or output current)，if it is interfered by electromagnetic radiation (open or close inductive loads，such as the motor) nearly，the backlight will shortly open. When the current changes frequently the date acquisition may produce error，and it will affect the accuracy. The tester cannot be exposed in the sun for a long time or in the environment with large amounts of ultraviolet radiation when using or storing，particular in winter (＜-20℃) and summer (>60℃) otherwise it will shorten the life of LCD. Other description 2. Connect the load，when the discharge current is higher than backlight on current, the backlight on (if backlight blinking，the RS+ and RS- are inversely), and display discharge indicator ,indicate battery is discharging. (Picture 1) Break the load, and connect the charger. When the charge current is higher than backlight on current, backlight blinking (if backlight on，the RS+ and RS- are inversely), and display charge indicator ,indicate battery is charging. (Picture 2)

Review: Good monitor. Well made - This is working fine on my 24v lithium system. I am using it to monitor two 12v 110 amp lithium batteries in series (24v)i have been using it tor a few months now with no problems
Review: I bolted it directly to the battery. 4m cable ! - Great 4m cable !!! The 350A model is taller than the 100A model Be careful not to bend it! *My tips* (Not expert) Mainly for motorhomes: Note. To set backlight always off: Hold down both arrow buttons together for 3 or 4 seconds. To later temporarily illuminate, press the “A” button, briefly. To set backlight always on: as above. (It will flash on and off during charging.) but when the resultant current (explained later) flow is below 100mA, the backlight always automatically turns itself off. Note: The level of current shown on the “A” screen depends on two factors: 1. The current now going into the battery which perhaps depends on the solar charger and the Sun and the 240 V charger. 2. The current flowing out to devices which opposes 1. to give the resultant current. (The meter will detect tiny currents drawn by such things as the standby current for the solar controller and Bluetooth devices.) Note: The Current Screen has two displays: “A” and “Ah”. Pressing the A button swaps between them as shown on the screen. “A” shows the current now flowing. Note: Perhaps you can use the following method to set up the meter without discharging your battery to zero Volts. * Set the meter to remember your battery's claimed capacity (Ah)* 1. Wake the backlight if needed by pressing the A button. 2. Show the “A” screen on the meter if needed (Current Mode) by pressing the A button again. 3. Show the.”Ah” screen on the meter by pressing the A button again. (Setting Mode) This shows what the meter thinks your batteries claimed capacity is. 4. Correct this figure if needed by holding down the A button for 3 seconds to enter the blinking setting mode then pressing the arrow buttons to match the “Ah” written on the battery. 5. Press the A button again to save and exit back to the “A” screen. *Set the meter to show when your battery is full (100% capacity)* 1. Charge the battery to full. 2. Wake the backlight if needed by pressing the A button. 3. Press the % button to show the present presumed capacity. 4. Hold down the % button for 3 seconds to correct to “100%”. Done!

## Features

- Battery Condition - High precision Current detection. You can read the battery bank like a fuel gauge, and also clear note the battery status.
- LCD displays - Large backlit LCD displays multiple battery information (voltage, current, consumed power and battery capacity)
- Data storage - designed to automatically store the last testing data when the system shuts off Voltage Capacity - voltage range 8V-80V and current range 0-100A
- Wide Application - It is suitable for mobile and portable equipment, balance cars, cleaning machines,e-bike, instruments, RV, Boat, Caravan etc.
- 100% Satisfied Service - Sincerely hope our products could give you a good experience and some help. Within a month you purchase this product, you can enjoy a worry-free return service. And any questions feel free to contact us, we will try our best to help you.

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B08HWFPGL5 |
| Best Sellers Rank | 115,235 in Automotive ( See Top 100 in Automotive ) 130 in Car Battery Testers |
| Brand | QWORK |
| Colour | Black |
| Compatible Devices | Devices with battery banks (8V-80V, 0-100A) |
| Country Of Origin | China |
| Customer Reviews | 4.3 out of 5 stars 339 Reviews |
| Item Weight | 250 Grams |
| Item weight | 250 Grams |
| Manufacturer | QWORK |
| Manufacturer Part Number | WD3941 |
| Maximum Operating Voltage | 80 Volts |
| Measurement Type | Voltmeter |
| Min. Operating voltage | 8 Volts |
| Minimum Operating Voltage | 8 Volts |
| Model Number | WD3941 |
| Power Source | Corded Electric |
| Power source | Corded Electric |
| Specification Met | Specifications Met |
| Style | Voltage |
| Style Name | Voltage |
| UPC | 792332966894 |
| Unit Count | 1.0 count |

## Product Details

- **Brand:** QWORK
- **Colour:** Black
- **Item weight:** 250 Grams
- **Power source:** Corded Electric
- **Style:** Voltage

## Images

![QWORK® Battery Capacity Tester, Battery Monitor, Voltage Range 8V-80V and 0-100A Sampler base, with 6.5ft / 2m Custom Cable, for Auto Car Motor Boat Caravan RV - Image 1](https://m.media-amazon.com/images/I/71drQVfQnsL.jpg)
![QWORK® Battery Capacity Tester, Battery Monitor, Voltage Range 8V-80V and 0-100A Sampler base, with 6.5ft / 2m Custom Cable, for Auto Car Motor Boat Caravan RV - Image 2](https://m.media-amazon.com/images/I/61JJnrYQnbL.jpg)
![QWORK® Battery Capacity Tester, Battery Monitor, Voltage Range 8V-80V and 0-100A Sampler base, with 6.5ft / 2m Custom Cable, for Auto Car Motor Boat Caravan RV - Image 3](https://m.media-amazon.com/images/I/61vvdVoaG1L.jpg)
![QWORK® Battery Capacity Tester, Battery Monitor, Voltage Range 8V-80V and 0-100A Sampler base, with 6.5ft / 2m Custom Cable, for Auto Car Motor Boat Caravan RV - Image 4](https://m.media-amazon.com/images/I/71a5ThB13pL.jpg)
![QWORK® Battery Capacity Tester, Battery Monitor, Voltage Range 8V-80V and 0-100A Sampler base, with 6.5ft / 2m Custom Cable, for Auto Car Motor Boat Caravan RV - Image 5](https://m.media-amazon.com/images/I/81DpcoCDptL.jpg)

## Questions & Answers

**Q: Can the flashing screen be turned off when charging?**
A: Long press the left and right keys at the same time.

**Q: Unit appears to go to sleep mode, meaning there is no display at all with voltage applied. button press turns on the device then works ok. Fix for it?**
A: When the battery is neither charging or discharging the screen turns off. When not connected to the grid, which is the usual case with me, generally the screen will go dark around sunset or sunrise when the demands from my RV equal the power produced by my solar panels. When connected to the grid and my battery disconnected from the RV, the screen will be dark half the time. It lights up when my Morningstar charger decides my battery needs a modest "topping off."  It should be noted that the screen goes dark even when the charger is in float mode, the current being so modest as to be almost undectable.

**Q: Does it display 1/10, 1/100 or 1/1000 of a volt?**
A: 1/100.

**Q: how long has anyone extended their display cable**
A: I added 15ft to my original 13ft cable using CAT5 cable - just cut the existing cable in half and soldered the CAT5 in the middle. The original cable has a shield wire that connects to one of the pins; my CAT5 cable didn't have a shield but I combined the four white wires in the CAT5 and used that combined wire to connect to the shield wire. That left 4 wires in the CAT5 to connect to the remaining 4 wires of the original cable. The result worked fine.

## Customer Reviews

### ⭐⭐⭐⭐⭐ Good monitor. Well made
*by W***G on 25 June 2026*

This is working fine on my 24v lithium system. I am using it to monitor two 12v 110 amp lithium batteries in series (24v)i have been using it tor a few months now with no problems

### ⭐⭐⭐⭐⭐ I bolted it directly to the battery. 4m cable !
*by P***0 on 7 March 2025*

Great 4m cable !!! The 350A model is taller than the 100A model Be careful not to bend it! *My tips* (Not expert) Mainly for motorhomes: Note. To set backlight always off: Hold down both arrow buttons together for 3 or 4 seconds. To later temporarily illuminate, press the “A” button, briefly. To set backlight always on: as above. (It will flash on and off during charging.) but when the resultant current (explained later) flow is below 100mA, the backlight always automatically turns itself off. Note: The level of current shown on the “A” screen depends on two factors: 1. The current now going into the battery which perhaps depends on the solar charger and the Sun and the 240 V charger. 2. The current flowing out to devices which opposes 1. to give the resultant current. (The meter will detect tiny currents drawn by such things as the standby current for the solar controller and Bluetooth devices.) Note: The Current Screen has two displays: “A” and “Ah”. Pressing the A button swaps between them as shown on the screen. “A” shows the current now flowing. Note: Perhaps you can use the following method to set up the meter without discharging your battery to zero Volts. * Set the meter to remember your battery's claimed capacity (Ah)* 1. Wake the backlight if needed by pressing the A button. 2. Show the “A” screen on the meter if needed (Current Mode) by pressing the A button again. 3. Show the.”Ah” screen on the meter by pressing the A button again. (Setting Mode) This shows what the meter thinks your batteries claimed capacity is. 4. Correct this figure if needed by holding down the A button for 3 seconds to enter the blinking setting mode then pressing the arrow buttons to match the “Ah” written on the battery. 5. Press the A button again to save and exit back to the “A” screen. *Set the meter to show when your battery is full (100% capacity)* 1. Charge the battery to full. 2. Wake the backlight if needed by pressing the A button. 3. Press the % button to show the present presumed capacity. 4. Hold down the % button for 3 seconds to correct to “100%”. Done!

### ⭐⭐⭐⭐ Tiny instructions! Otherwise ok.
*by K***R on 15 July 2025*

The monitor works OK when combined with a shunt. My only gripe is with the instructions which are difficult to read as the font is TINY! Also the symbols both on the monitor switches and in the instructions are almost too small to decipher.

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*Product available on Desertcart Tunisia*
*Store origin: TN*
*Last updated: 2026-07-26*