Hi Sam,
Thank you for checking out Backendless. We have our own socket server implementation used for real-time database and Overview - Backendless SDK for JavaScript API Documentation, however, you’d need to use our SDK (any of them) in order to send/receive events/messages. My understanding you would not have the freedom to inject our SDK into the chargers. A possible solution would be to stage a separate (your own) server that can accept messages from the chargers and then proxy them into Backendless for further processing.
Regards,
Mark