basically you'll have to run your battery at a slightly higher voltage to compensate for the higher resistance to get the same vapor...but even though you are using a higher voltage setting you should be using less amps from the battery so it should run the same or a little longer....
It's really hard to explain ohm's law in a quick simple way...but if you had a battery that only put out...let's say...3.7 volts like a regular ego battery and the little battery inside of it could only push a maximum power level of 2.5 amps than the lowest resistance you could use is 1.5 ohms. Battery power is measured in mah...or MilliAmp Hours... there is 1000 ma, in one amp.....so if you have a 1300 mah battery it can push 1.3 amps for a one hour timespan before the battery is completely discharged. So if you have a 1.5 ohm coil pushing it's max 2.5 amps you can run your e-cig for about 27 minutes continuously or take about 320 drain the battery in an ideal world...we don't use the battery to it's completely discharged state because it would give a terrible vape so it's more like 250-300 depending on your vaping style
All of our vaping batteries we use whether they are ego style or 18650 mod batteries are a rechargable Lithium battery of some kind whether they are regular "low drain" ICR or "high drain" IMR batteries we use in mods for sub ohming. The difference between the two is how fast you can discharge the battery or "how quickly you can pull any number of amps" from them. ICR batteries with their chemistry usually have very high storage capacity for their size but have to be drained slowly or at a lower amp rate. IMR batteries with their chemistry have much less storage but can be drained much faster or at a higher amp rate. The speed at which they can be drained is their "C" rating. You multiply their C rating by their rated storage capacity to get their discharge rate. Most ego and ICR batteries have a C rating of 2 to 4....so if you have a 1300 mah (or 1.3 amp hour) ego battery like yours and it's C rating is 2...then 2x1.3 is 2.6 amps.... the microchip in the ego battery limits it to 2.5 for safety so you don't overdischarge your battery.
The ICR ones are typically used in ego batteries are tiny batteries and to get the 1300 mah storage capacity they have low amp limits. When the batteries are fully charged they actually have a voltage of 4.2 and when they are fully discharged they are somewhere around 3 volts...they're called "3.7" volt batteries because that's the average in the middle...but actually to power our vaping gear we don't really discharge them below 3.3-3.5 because they'd be too weak below that to give off any sort of good vapor. Now I know this is long but to answer your question of what difference the resistance makes it takes some explaining and it's good to have a basic idea of battery knowledge for every vapor regardless of what kind of battery they use so I am going to try and make an analogy to explain it simple because Ohm's law sucks to explain in simple words. I have a hard time wrapping my head around it so please don't misunderstand me.
Think of the battery as a river. Now the battery has voltage.... the voltage is how much water pressure the river has and the amps it is pushing is how fast/strong the current is and the ohms/resistance is a boat....the watts is the amount of movement of the boat in the current as a result of the combination of these two factors. This is very crude but it will serve the analogy.
When the battery is fully charged It's like a river just past a waterfall or rapids or an open dam where there is high pressure and the current can easily carry your boat on the current...as you move away from the source of that pressure (the voltage drops in a battery as you discharge it over time,) the pressure in the water decreases but the current is still carrying the boat...finally you get to a point down the stream so far away from where you started there is no longer enough pressure in the current to push the boat and the battery stops (the battery is dead) and your boat sits there doing nothing.
If two boats are in the same river,( on a unregulated 3.7 volt battery) and one is heavy (higher resistance) and one is lighter (lower resistance) then this is what will happen....
The heavier the boat (more resistance) will take longer from the pressure (voltage) to get the boat moving (heat the coil) and the current will pull on it less (draw less amps) as it moves along at a lower given speed (less watts produced) and take more time to get to the place in the river where the current can't move the boat (drain the battery dead)
The lighter the boat (less resistance) will take much less time from the water pressure (voltage) to get the boat moving (heat the coil) and the current will pull much more (draw more amps) moving the boat much faster than the heavy boat (more watts produced) and get to the place where the current can't move the boat any more much faster. (drain the battery dead)
That's the difference between a 1.5 ohm coil (the lighter boat) and a 1.8 ohm (the heavier boat) coil and the effect it has on a battery.
But because you have a adjustable voltage battery the drain the coil has on the battery is a little different. It's like using a motor on a boat to control it's speed in conjunction with the current instead of just floating down stream.
Instead of the resistance of the coil directly effecting battery drain and wattage you have chip in your battery that adjusts the voltage output allowing you to "change the water pressure of the river" so to speak to suit your taste. As a result your battery life depends on how much power the chip inside your eGo needs to put out the desired amount of voltage you have it set to. When you turn the voltage setting higher than the actual voltage the battery like the highest power setting has chip has to drain a little extra power out of the battery boost the output to the level you want it at making your battery drain faster....if you turn your voltage setting down lower than the voltage level of the battery like the lowest setting is it only uses a little power and your battery will last longer. When you change the resistance of the coil you change the curve of your chips power consumption rate.
In all honesty...you will have to use I higher voltage setting to get the same vapor you're used to getting from a 1.5 ohm coil out of a 1.8 ohm coil...but even though you're using a higher power setting it shouldn't make much of any difference on your battery life because of the lower amp/higher voltage ratio.
I know this was long, I hope it makes sense and it's not all Greek sounding. It's hard to explain in a short and simple manor but I wanted to give you the best answer I could. Happy vaping and welcome to "The Underground"
