Building a Solar Portable Charger, with large capacity. Need help to not damage the the circuit

Thread Starter

Omgil877

Joined Oct 7, 2018
7
Hi, I am trying to build a solar portable charger for two phones and my aim is to charge the phones with 4 rechargeable batteries with each being 3.7 volts and 4,000 mAh for a total of 16,000 mAh. I am new to electronics so I don't know exactly how things have to be done. I want to use a -Dual USB 5V 1A 2.1A Mobile Power Bank 18650 Battery Charger PCB Module Board- and two -5V 250mA Monocrystalline 1.25W Mini Solar Panel Photovoltaic Panel- but the only question that I have is if I used the solar panels to charge the 16,000 mAh power bank and then I connect it to PCB module Board just like that would I damage the circuit? I think I have to use a resistor of 2,000 mAh for the PCB module board but I don't if that's all I have to do to not set my room on fire.

1) PCB Module Board: https://www.banggood.com/Dual-USB-5V-1A-2_1A-Mobile-Power-Bank-18650-Battery-Charger-PCB-Module-Board-p-1031593.html?p=VS162312352724201707&utm_campaign=12352724_987900&utm_content=1061

2) Solar Panels: https://www.banggood.com/5V-250MA-1_25W-Mini-Solar-Panel-Photovoltaic-Panel-p-987900.html?p=VS162312352724201707&utm_campaign=12352724_987900&utm_content=1061

3) bateries: https://www.banggood.com/2PCS-MECO-3_7v-4000mAh-Protected-Rechargeable-18650-Li-ion-Battery-p-992718.html?rmmds=warehouse-bottom-recommendations
 

Dodgydave

Joined Jun 22, 2012
8,389
All you need is to connect your batteries to B+/-,, and the solar panel would be connected to the micro usb input, but a 250mA panel would take longer to charge.

No resistors needed .
 

Thread Starter

Omgil877

Joined Oct 7, 2018
7
All you need is to connect your batteries to B+/-,, and the solar panel would be connected to the micro usb input, but a 250mA panel would take longer to charge.

No resistors needed .
Thanks for replying! what solar panels would you recommend to charge the batteries in 5 hours or less? if you plug something, like a phone, to the micro usb what would happen? would the phone charge the batteries? Do I need to have a solar panel controller?
sorry I am asking so many questions, I barely know about electronics
 

Dodgydave

Joined Jun 22, 2012
8,389
The micro usb is only for charging by solar or mains, no the mobile won't give out a charge, you have to use the bigger usb sockets,. The charger is limited to 2Amp input, so as not to damage the Lithium-ion batteries.

You're better getting a solar capable of 2aamps, cost permitting.
 

Thread Starter

Omgil877

Joined Oct 7, 2018
7
The micro usb is only for charging by solar or mains, no the mobile won't give out a charge, you have to use the bigger usb sockets,. The charger is limited to 2Amp input, so as not to damage the Lithium-ion batteries.

You're better getting a solar capable of 2aamps, cost permitting.
one last question...... this is the best solar panel I could find for the price

-solar panel [Voltage: 6V 520mAh, Power: 4.5W] (https://www.banggood.com/3Pcs-6V-4_5W-520mAh-Monocrystalline-Mini-Epoxy-Solar-Panel-Photovoltaic-Panel-p-1352806.html?rmmds=search)

it says it's a 4.5 watt solar panel, I did some math and I found that if I want to use 2 batteries the total wattage to charge them will be 59.2watts (8Ah x 7.4 volts = 59.2 watts) thus it would mean that if I use this solar panel it will take about 13 hours to charge them (59.2watts/4.5watts=13.16). And if use 3 of the same solar panels it would mean that I could charge the batteries in about 4 hours (59.2watts/ [4.5watts x 3] =4.4).

Are my assumptions correct? I just want to make sure before I spend too much money
 
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