The RTK Express will not turn on!
I received the RTK Express Kit (GPS-18380) yesterday, charged the RTK Express with the charger included and was able to try the RTK for a few minutes and then turned if off. Now (the next day) it will not turn on! When I plug the charger into the RTK Express, the battery LED comes on (red) for a moment and then goes out. I can’t tell if the battery is charged or is dead, but the RTK Express does not turn on!
I have verified that the charger has power.
I have pushed the “POWER” button, held it down for 1 second and held it down for 3 seconds. I have done the same with the “SETUP” button. I have repeated this with both buttons.
Sounds like it’s a faulty RTK express. Very disappointing. Hope sparkfun team will come up to you with a good solution.
Its been two weeks and Spark Fun has not responded to the forum entry, email or phone calls. I am very disappointed with their Customer Service.
Handled separately via email (for those wondering it was a defective unit, we replaced it with an upgraded version/kit)
3 Mar 2022
The replacement was received on 1 Mar, it seems to have the same issue. After charging the device I was able to power it on for and use it. The device powered on and off several times. The next day, it was hard for it to power on again. But after it was powered on, the device seemed to work fine and power off and on again normally. Later that evening, the device would not power on again. Today, 3 Mar, the device will not power on. To be clear, the display on the device does not light up and show the initial screen.
The charging circuit seems to be working properly. With the device fully charged (charging LED off) and plugged into a USB port, the charging LED comes on as soon as the power button is depressed. The charging LED goes off within 3 seconds. This behavior is repeatable if I wait about 30 seconds between power button presses. However, when the power button with only a few seconds between presses, the charging LED does not always come on.
Yesterday, I had the RTK Express plugged in all day to a USB port. The battery indicator was showing the battery was fully charged. After I was done using the device, I unplugged it from the USB port. A couple of hours later when I tried to power on the device again,the device would not power on. Initially it was not plugged in. I tried plugging in the RTK Express to the power adapter and it still would not power on. After trying and failing to power the device on for over 15 minutes, I gave up.
This morning, 3 Mar, the RTK Express again would not turn on. Again I plugged it into the charger and it failed to power on again. However after begin plugged in for over an hour, the RTK Express did power on and display the power on screen:
SparkFun
RTK
Express
V1.9
The system was left in “Base” mode when it was powered off and returned to that mode when powered on. The battery indicator shows that the battery is fully charged.
In my years of writing firmware and device drivers, I would interpret these systems as follows:
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Power down has not properly turned off the system and is draining a full battery within a couple of hours.
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The charging LED goes out before the battery is fully charged (power button/LED behavior).
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After being unplugged for a while, the RTK Express needs over an hour to charge prior to power on.
This is quite interesting. I’ve been having strange battery issues with my RTK surveyor kit as well. One of the units can sit there, plugged in with power applied to both USB ports and not charge, no charging led. But it will power on.
Then if I leave it powered on and watch the serial print out battery status messages. All sorts of interesting things will happen. 0 % battery, 255% battery ( integer underflow?) Discharging down to 0v even though it is a lithium battery? And then suddenly starting at 3.6 again. I have opened it up a couple times to look at the battery and it looks healthy. I’m running it as a base station so I’m not sure it even matters. Considering unplugging the battery for safety.
Lee, we are working with your returned unit and running tests. Thanks for letting us know what is going on here in this topic.
Mandrewoid, Fill out a return form and we can get the the part for testing and repair: https://www.sparkfun.com/returns
Similar problem, RMA form completed.
I used every few months the unit had been working normally. Now it lights up for about 3 seconds, the com port is also up for about the same. The display was mostly not showing anything and when trying to isolate just before it stopped booting I captured this log:
load:0x40080400,len:3648
entry 0x400805f8 0x36 - MAX17048 Fuel Gauge
0x3d - SSD1306 (64x48) OLED Driver
0x42 - u-blox ZED-F9P GNSS Receiver
Error: I2C Bus Not Responding
Display started LittleFS Started
SparkFun RTK Express Plus v4.4
Profile ‘Profile1’ loaded
Fuel gauge configuration complete
Batt (100%): Voltage: 4.20V Charging: 58.86%/hr Green
Module failed config block 0
GNSS configuration complete
System time set to: Monday, May 04 2026 16:26:09
Rover config fail
Rover config failed
Batt (100%): Voltage: 4.20V Charging: 58.86%/hr Green
It sounds like a known issue; continue with the RMA process
It has a 1-year warranty, how long ago did you purchase the unit?
I’ve heard back with an RMA, thanks. The unit was purchased 7 months ago from Sparkfun.