60mil a day and you are killing batteries 3 times a day. I'd look at upping my nic level a bump, if you are 1.5mg go to 3mg, if you are 3mg go to 6mg. If you are having to suck on that mod like a pacifier you are not getting enough nic to keep your body chemistry in balance. JMO, instead of looking at better charge length, you are like above to low on nic if you are vaping nic juice, or your power is just way to high. Vaping is about juggling variables like nic, clouds, etc.
I've seen LiPo's that are 10k mah plus, but downside they do not have the CDR for our needs, highest mah high drain battery is the LG HG2. Maybe look at an iStick100watt, dual battery in parallel so it would have double the mah, 2x HG2 in it for instance would be 6000mah.