Quick verdict
Five small LED display boards that connect to a lithium pack's balance lead or main terminals and show the voltage and charge state of 2 to 8 cells in series, from 5 to 30 volts, for lithium-ion, LiPo and LiFePO4 packs. They are hobby-grade modules for people who build or repair packs, check e-bike and robot mower batteries or test cells before storage. The module draws under 10 mA while connected, so disconnect it after reading. Instructions are thin and the first power-up defaults need setting.
Strengths
- Reads per-cell and total voltage on 2S to 8S packs
- Works with Li-ion, LiPo and LiFePO4 chemistries
- Five modules for the price of one branded meter
- Tiny and light for a tool bag or bench
- Fast 500 ms refresh
Weaknesses
- Needs access to the pack terminals or balance lead; tool packs are sealed
- Draws current while connected; do not leave it on a pack
- Instructions are sparse and the setup is fiddly
The overall YardToolLab Score is out of 100. Section scores are out of 10.
Knowing What a Pack Is Doing Inside
A lithium pack that will not take a charge or runs down fast usually has one cell out of step with the rest, and the only way to see it is to read each cell. These LED modules do that on any pack from 2 to 8 cells in series, lithium-ion, LiPo or LiFePO4, across the balance lead or the main terminals. Five come in the pack for the price of one branded checker.
This review is based on the listing specifications and on how hobby battery checker modules are used generally. We have not used these modules ourselves and the brand is a generic importer.
What It Reads
Connect to a balance lead and the module cycles through each cell’s voltage and the total, with an indicator of charge state. Connect across the main terminals and it reads the total only. A pack whose cells read 3.3, 3.3, 3.3 and 2.9 has a weak cell, and that is the diagnosis a multimeter on the terminals cannot make.
Where It Applies
Robot mower batteries, e-bike and scooter packs, LiFePO4 batteries for carts and solar, and the hobby packs for drones and RC cars all expose balance leads or terminals. Sealed cordless tool packs do not; across their terminals the module gives total voltage, which still tells you whether a pack is too flat to store.
Setup
The module needs the cell count and chemistry set at first power-up, and the instructions are a few lines. Expect to press buttons and watch which lights change until it makes sense. Once set, readings are immediate.
Current Draw
Under 10 mA sounds like nothing and it drains a small pack over a few weeks. Read, note, disconnect. Never leave a module on a stored pack.
Who Should Buy It
- Anyone who builds or repairs lithium packs.
- Owners of e-bikes, robot mowers and LiFePO4 batteries with balance leads.
- Hobbyists checking LiPo packs before and after flights.
Common Owner Complaints
Confusing setup and packs drained by a module left on. Patience; disconnect.
Technique Tips
Write the cell count and chemistry setting on a label stuck to each module so the setup is done once per pack type. Read packs at rest, half an hour after use or charge, since a pack straight off the charger reads high and one straight off a tool reads low. Keep one module with the robot mower or e-bike and one on the bench.
What the Numbers Mean
For lithium-ion, a cell at 4.2 volts is full, 3.7 is about half and 3.0 is empty; store at 3.7 to 3.8. For LiFePO4, 3.6 is full, 3.3 is the long flat middle and 2.8 is empty. A cell more than a tenth of a volt from its neighbours after a charge is the weak one.
Alternatives to Consider
A branded LiPo checker with a readable screen and a buzzer. A multimeter for total voltage only. The pack maker’s app for smart batteries with Bluetooth.
Verdict
For reading cells on packs that expose them, five of these modules cost less than one proper checker and do the job once set up. Learn the buttons, read quickly and take it off.
Full specifications
5-Pack 2S to 8S DC 5 to 30V Lithium Battery Charge LED Display Tester for Li-ion, LiPo and LiFePO4 Packs FAQs
The number of cells in series. A 12V LiFePO4 is 4S, a 7.4V LiPo is 2S, an 18V tool pack is 5S. The module reads any from 2 to 8.
Only across its main terminals for total voltage. Per-cell readings need the balance lead, which sealed tool packs do not expose. For e-bike, robot mower and hobby packs with balance leads, it reads each cell.
It draws a few milliamps all the time it is connected, which flattens a pack over weeks. Read and remove.
To about a tenth of a volt, which is enough to spot a weak cell or a pack that is too low to store.
