I have an OVMS installed in my 2020 Nissan e-NV200 which has generally worked flawlessly for a couple of years, but for at least the last year or so I have been experiencing a recurring issue where the cellular connection drops shortly after starting a journey, from any location
The behaviour is very repeatable:
if I reboot the OVMS and leave the van parked, it can stay connected for days without issue, but once I start driving, the telemetry connection will often fail within a short time of setting off.
The OVMS itself remains alive, but the PPP/cellular connection drops and telemetry stops working until I reboot it again.
I am using:
SIM7600 modem
Hologram SIM
usually roaming on O2 UK
Some diagnostics I have run:
modem still appears registered on the network (+CGREG: 1,5)
CGATT remains attached
signal strength is generally good
PPP shows “Not connected”
CEER returns “Requested service option not subscribed”
This is making me wonder whether the issue may relate to:
LTE roaming handoff
Hologram/O2 interoperability
PPP reconnect handling
or possibly power dips affecting the modem during movement
Has anybody else seen similar behaviour, particularly with:
SIM7600
Hologram SIMs
UK roaming networks
or OVMS in Nissan Leafs/e-NV200s?
If so, did you identify a cause or a reliable fix?
Hardware: OVMS WIFI BLE BT cores=2 rev=ESP32/3; MODEM SIM7600
Firmware: 3.3.005-3-g4f3f7688/ota_0/main (build idf v3.3.4-851-gfa4f07fb3b Sep 7 2025 08:02:51)
Running partition: ota_0
Boot partition: ota_0
Factory image: 3.3.001-33-g58d01654
OTA_O image: 3.3.005-3-g4f3f7688
OTA_1 image: 3.3.005-2-g40245d7b
Server Available: 3.3.005-3-g4f3f7688 (no update required)
OTA build Sun Sep 7 08:08:09 CEST 2025
Thank you.