How many times I can charge my 5000mah mobile from 12 volt 7ah battery?

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Charging a 5000mAh mobile phone from a 12V 7Ah battery depends on the efficiency of the charger used. A DC-DC converter is recommended to step down the voltage for the phone's USB input. The phone's battery capacity is approximately 18Wh, while the external battery holds about 85Wh. Assuming no energy losses, the external battery could theoretically charge the phone about 4.5 times, but real-world losses will reduce this number. Therefore, users can expect to achieve around 2-3 full charges from the 12V battery.
Biycchu
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Please help me. How many times I can charge my 5000mah mobile from 12 volt 7ah battery. I will use dc mobile charger.
 
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Welcome to the PF. :smile:

It depends on the charger. The most efficient ones will use a DC-DC converter to convert the 12V input to the 5V output for your phone's USB charger input port. Still, your phone has a 5Ah capacity at 5V, and your external battery has 7Ah capacity at 12V? If so, you will only get 2-3 recharges out of that external battery, most likely. What model is your phone, and which external battery are you wanting to use?
 
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It also depends on the phone. I had a spare battery for a Samsung Galaxy S5. It was rated at 5.6 AH
 
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my mobile is asus zenfone max pro m2. I will buy 7ah smf battery from amazon.
 
5Ahr phone bat is probably Li-ion single cell, therefore 3.7V. So your phone needs about 18Whrs (5Ahrx3.7V) to charge from 0% charge to 100% charge.

A 12V 7Ahr battery contains about 85Whrs of energy so assuming no losses you could completely charge your phone about 4.5 times from that battery. Now there will be some losses in both batteries and in the charger itself which will reduce the number of full charges.
 
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