[Lam Lam2]

it drains battery fast (From 79% to 8% within 2 hours).

[howarmat]

no clue...you give no details at all

what phone first of all?

[anon(9742832)]

it drains battery fast (From 79% to 8% within 2 hours).

3 G and below the phone is working much harder to stay connected

[Tsepz_GP]

it drains battery fast (From 79% to 8% within 2 hours).

Whatever phone you are talking about must be incredibly faulty.

[Troy Tiscareno]

You might think that if a given area has SOME signal, that it would have 2G, 3G, and LTE signal equally - but that's absolutely NOT the case. You may have a distant cell tower with 3G on one frequency and a closer, lower-power tower with LTE on another frequency (for example). If that was the case, then using LTE would likely strain the battery a whole lot less, because the LTE signal is likely to be stronger, given that the LTE tower is closer. By turning off LTE and forcing the phone to a less-optimal connection, you may be forcing the phone to turn up the radio power significantly in order to maintain connection to that 3G tower - which naturally would run down your battery much more quickly.

It's also important to remember that cellular towers and frequencies are NOT fixed forever - in fact, carriers are constantly upgrading towers, re-farming frequencies, and doing their best to push users towards newer technologies (such as LTE) which can handle more bandwidth on a given frequency than the older technology could. So, just because 3G might have worked great in an area a year ago does not mean it will work great in that area today.

Obviously I have no idea where the OP lives, but it wouldn't be unusual at all for what I described to be the case. 3G has become a "back-up" connection and LTE is the primary connection today - and in a couple of years, 2G and 3G are going to be shut off completely and everything (phone calls and data) will all be on LTE. So, whatever you're trying to accomplish by forcing the phone to 3G is unlikely to be helping and very likely to be hurting your battery life - and that wouldn't be the fault of the phone.