Run time, battery and USB-C charging on a laser level
Why one run-time figure says nothing
A laser with four planes switches on four optical modules. Each one draws power. A run-time figure therefore depends entirely on what was switched on when it was measured — and brands do not all measure in the same configuration. Comparing two figures therefore means comparing two configurations.
That is the form to look for: a run time per configuration. A page that gives one number alone does not say under what conditions it was obtained. On our 16-line, reckon on six hours of run time, with the 4,000 mAh lithium battery.
How do you read a capacity in mAh?
The milliamp-hour measures an amount of charge, not an amount of energy. To compare two batteries you need the same voltage: 5,000 mAh at 3.7 V and 5,000 mAh at 7.4 V do not store the same energy. A capacity on its own therefore cannot be compared.
| What is stated | What it tells you | What it does not |
|---|---|---|
| Capacity in mAh | The charge stored | The energy, without the voltage |
| Voltage in V | The level of the chemistry | Nothing on its own |
| Run time in hours | The real result | In what configuration |
Run time in hours, with the configuration stated, remains the most useful figure. The 12-line and the 16-line state the same 4,000 mAh lithium battery, and the same run time of about 6 h.
What USB-C charging changes
Three things, all practical: no proprietary charger left to lose, since the phone cable does the job; a power bank gets you through a site with no socket; and on most models charging happens during use, which a dedicated mains unit does not always allow.
- No proprietary charger left to lose. The phone lead charges the instrument.
- A power bank is enough on a site with no socket.
- Charging happens while you work on most models, which a dedicated mains unit does not always allow.
The other side: charging over USB is slower than a dedicated fast charger. Over one day on site that is manageable; over several days running, a second battery stays more comfortable.
Does cold change anything?
Yes, and it is the most underrated factor. Lithium chemistry loses usable capacity at low temperature: an instrument stated to work from -10 °C to 50 °C works well at -5 °C, but its real run time there is markedly below the one measured in the workshop.
Both our 360° models state use from -10 °C to 50 °C. A range for use and a range for storage are two different things, and they are not the same.
How do you stretch the run time on site?
Four habits, from the most effective down: switch off the planes you do not need, which almost doubles the run time going from four to one; use the remote rather than switching the instrument back on; do not leave it in the cold between jobs; and charge before the day, not during it.
- Switch off the planes you are not using. By far the most effective: going from four to one almost doubles the run time.
- Use the remote control rather than switching the instrument on again at every move.
- Do not leave the instrument in the cold between jobs: a night in the van costs capacity.
- Charge before the day, not during: a battery at room temperature charges better than a frozen one.
And pulse mode?
It modulates the beam so a detector can pick it up. It draws no noticeably more, but it weakens the visible line: you read the detector, not the line. Remember to switch it off when you come back indoors. Indoors, the visible line is worth more than the signal.
The rest of the criteria are in how to choose a line laser.
- Run time depends on how many planes are lit: look for the breakdown, not one bare number.
- mAh only compare at equal voltage.
- USB-C does away with the proprietary charger, at the cost of a slower charge.
- Cold cuts the real run time, even inside the stated range for use.