One suggestion would be a Kgo - I think they are 3.7v (not 3.4 like Ego) can anyone confirm that? I think people get a kit with 1100mah batteries?
Or look at mods - get something sturdy. simple mechanical, and the batteries are standard industrial batteries, protected lithium Ion or preferred would be AW IMR (a bit less charge but hold the voltage up better). Keep spare batteries around. They only cost about $5 per battery. Something with as much charge as your largest Joye batteries will likely be larger than your Ego though.
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Re cartomizers - they have nothing to do with T and do not use an atomizer. You batteries are Ego batteries with 510 threading. You can use any 510 or Ego cartomizer 1.7 to 3 ohms (1.7 is the hotter end of that range). Some will only go as long as 2 ohms on mass produced encased big batteries like Ego and will only go lower on mods. Some will go down to 1.5 ohms on Ego etc but those do occasionally kill mass-produced big encased batteries. The most popular cartomizers for Ego and all 450mah+ 510-threaded devices are Boge 510 2 ohm.
I get Boge cartos at Liberty-Flights.com, LiteCigUSA.net, NiteliteVapor.us. Goodprophets, Crystal Clear Vaping
And note - Liberty-Flights.com states their warranties on all parts. Go check their size and see if your battery was under warranty.