Notices

The standard configuration for openvpn keepalive is 10,60 which means: ping every 10s and restart the connection if there is no response within 60s

If googling for the keepalive settings there are some talks about battery draining with these "short" ping intervals but no suggestions for better settings. I can verify a significant higher battery drain with openvpn started.

Are there some experiences with longer keepalive intervals?

actually you want a much higher keepalive interval anyways, short network dropouts will have an avalance effect which causes it to reconnect way too often which costs more than just a few seconds lag. iirc I have a 120seconds ping timeout (and persistent tun devices/connections) which works much better than constant reconnecting.

Just for my understanding (I found out - my settings do 10,120 and persist_key and persist_tun): What causes the most draining? Pings (every 10s, 3g packets) or reconnect (3g and cpu for keying stuff but - hopefully? - less often)? Does it have any effects when opening a tunnel via 2g (e. g. for the ping intervals on lower bandwidths)