Since Wazapp seems to use quite a bit of battery when it's just idling on 3G connection, I did some investigations using Energy Profiler. In particular, I found that every 3 minutes, i.e. during each ping, there's a pretty significant increase in current draw of about 200 mA lasting for over 15 seconds. If this is amortized over long time it adds about 17 mA to the average current consumption, which is more than twice the consumption on my device when Wazapp is not active. There were other spikes probably related to Wazapp as well, but those exactly 3 minutes apart were clearly identifiable.

In contrast, when having a single MfE account on push there were no significant current spikes at all during the test interval and the current consumption stayed constant at about 7 mA, in other words there is clearly some room for improvement.

So, may I suggest that the pinging interval be made adjustable to account for 3G networks of different reliability, or better yet make it adaptive if it's possible to determine if each ping was necessary or not. Also, might be better to use the system heartbeat timer for the pings instead of just a QTimer so that the pings could get aligned with other system background activity, although I suspect that on most devices there are no other processes polling the network nearly as often as every 3 minutes.

Edit. I'll add that on Wifi there are no ping-related spikes visible.