Default follow up feedback of a 5000mah battery for i9020

My phone with a bulk mpj 5000mah external battery can go two days without a charge and the thought of topping off midday wouldn't even occur to me. I have this Google Nexus S 4G i9020 and think its stock battery is a problem since this year. I barely last it through a day of average use on one charge, read a thread about this company here so I pick up this as replacement.