The large potential of solar heat can be used as a Solar Water Heater (SWH). Conventional SWH has a disadvantage, namely the discrepancy of heat absorption time with its use time. To resolve this problem, Thermal Energy Storage (TES) tanks are used using the Latent Heat Storage (LHS) method. This method uses 10% paraffin and copper powder as Phase Change Material (PCM). Paraffin which has a high energy density mixed with copper to have high conductivity. The purpose of this study is to know the rate of heat absorption that occurs during the charging process with variations in flow of rate. This study used water as Heat Transfer Fluid (HTF) and PCM which consists of a mixture of paraffin and copper powder as a heat storage medium. The heater used in this study as heat simulator given by the sun. The hot water produced by the heater is moved by the pump into the TES tank. The thermocouples installed in the TES tank and connected to the data logger recorded temperature every 5 seconds. The charging process continues until the temperature of the TES outlet reaches a temperature of 70 C. The charging process will be repeated on 4 variations of flow rate, namely 600, 700, 800 and 900 mLPM. The results of this study indicate an increase in temperature during the charging process. The absorption rate obtained by Paraffin-Cu at latent conditions, shows that much more energy is received than the absorption rate in sensible conditions. The highest absorption value of Cu-paraffin was obtained 188.21 joules / s in latent conditions while 46.56 joules / s in sensible conditions. The results of the study stated that the greater the flow of rate, then the greater the rate of absorption and increase in temperature.