Default Hangs constantly when battery is under 20%

After upgrading to 4.3, i moved on ZNXT ROM but when battery gets low phone starts to hangs alot and after pulling out the battery it works ok.
but after battery gets above 25% it doesnt hang then, whats the matter?
i tried to be on the stock 4.3, still same problem.

XM-C1904, ROOTED, right now on ZNXT rom
Sony Xperia M C1904 Rooted/Unlocked Bootloader
Unofficial AICP
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