is it possible to get 20 volt , 2 a from 2 power bank by connecting 4 usb port (each 5 v ,2.0a) .

if can what should i use to prevent damage , short circuit , and catastrophic .

i making a device whare you can use 2 power bank to get 20 volt to charge your laptop .
i have 2 powerbank which have 40 watt(combine 80 watt) , so i can charge my laptop up to 2 times.
is it possible to connect 4 usb 5v , 2 to get 20 , 2a volt or 4 x usb 5v 2a to get 1a current (parallel circuit and buck)

  • 3
    \$\begingroup\$ No, not possible if you consider you want 40 watts via some converter that has a maximum feed power of 40 watts. You might get 35 watts. \$\endgroup\$ – Andy aka Jun 8 '19 at 11:43
  • \$\begingroup\$ 'A' for ampere, 'V' for volt and 'W' for watt if you need it. All SI units named after a person have their symbols capitalised and are lowercase when spelled out. Capitals matter including those at the start of sentences. \$\endgroup\$ – Transistor Jun 8 '19 at 12:18
  • \$\begingroup\$ If you want people to treat your questions seriously you - MUST use Capital letters at the start of sentences. | you should start new ideas or questions on new lines or with a new paragraph. Note: This is not MY ideas - it is what is needed in practice to get good input from most people. || Your sentences need to convey clear thoughts. While it is possible to get a general idea of what you are asking some of your sentences do not make sense. \$\endgroup\$ – Russell McMahon Jun 8 '19 at 13:03
  • \$\begingroup\$ This is just a bad idea from start to finish. Buy a product that solves the ultimate need designed by someone who knows what they are doing, or accept that this is a problem without a simple solution. Save attempts to learn about electronics for projects that do not have the kinds of issues that high capacity battery and power boost systems do. \$\endgroup\$ – Chris Stratton Jun 8 '19 at 16:15

Is it possible to get 20 volt, 2A from 2 power bank by connecting 4 x USB ports, each rated at 5V, 2A

Is it possible to connect 4 x USB 5v, 2A to get 20V at 2A or 4 x (USB 5V at 2A) to get 1A current (parallel circuit and buck)

You can

  • Use completely separate power banks connected in series in series to get higher voltages.
    eg 4 x (USB 5V, 2A) powerbanks may be connected in series to get 20V at 2A.

  • Usually (!) connect multple 5V ports on the same power bank to get the sum of the current ratings, but only at the same voltage.
    eg a powerbank with 4 x 5V at 2A ports can (usually) have the 4 ports connected in parallel to give 5V at 8A.
    Note that it is technically possible that this will NOT work in some cases , but it usually will.

You cannot connect multiple ports on a single power bank to obtain increased voltage. This is because on power banks with multiple "USB" 5V output ports the negative grounded sides of all the ports are connected together. The ports MAY be separate outputs internally but commonly will simply be parallel connections to the same switching converter.
Either way, you cannot connect them together to get more voltage.


Boost Converter:

You CAN use a boost converter to increase the avai;lable voltage from one or more power banks, with some loss on power avai;able due to inefficincies in the converter.
For example you might use any of the following powerbanks
- 5V with 1 x 4A output
- 5V with 2 x 2A outputs
- 2 x (5V at 2A)

to provide a 5V at 4A input to a boost converter.
The 5V x 4A = 20 Watts input power would probably provide around 16 Watts +/- 2 Watts using typical boost converters.

In addition the 2 x (5V at 2A) powerbanks could be used in series to make a 10V x 2A supply to power a boost converter. This would possibly be slightly more efficient than a converter running on 5V input.

| improve this answer | |
  • \$\begingroup\$ Could use some cunning quad boost converter. Still less power than he wants, but would work. \$\endgroup\$ – Gregory Kornblum Jun 8 '19 at 13:15
  • \$\begingroup\$ @GregoryKornblum Yes. I've added a boost converter section. \$\endgroup\$ – Russell McMahon Jun 8 '19 at 13:23
  • \$\begingroup\$ This is a relatively problematic answer, because it seems to falsely imply that the goal is realizable; practically speaking, this project is not plausible, especially by the person asking the question. \$\endgroup\$ – Chris Stratton Jun 8 '19 at 16:06
  • \$\begingroup\$ @ChrisStratton I'd be (genuinely) interested in knowing why you consider the project implausible in practice. I have not tried connecting "powerbanks" in series. I should do so and report back. | 4 x (5V at 2A) "powerbanks" have (IMHO) a fair chance of providing a 20V x 2A supply. It is conceivable that this is not so for stability reasons, but I'd have a reasonable expectation of it working. | Using a boost converter from a 5V eg 4A powerbank to provide a 20V supply is entirely feasible, with power output and available total energy being issues. | ... \$\endgroup\$ – Russell McMahon Jun 9 '19 at 4:27
  • \$\begingroup\$ @ChrisStratton .. He says " .... i have 2 powerbank which have 40 watt(combine 80 watt ..." -> Assuming he is talking about 5V units that's a claim to have 2 x 5V at 8A units. If so a 5V x 16A or 10V x 8A source would be a good starting point. || THis unit CLAIMS 8.5V Vinmin, 15A Iinmax, 10-60 Vout, $US9.98 || ... YMMV :-) ... \$\endgroup\$ – Russell McMahon Jun 9 '19 at 4:39

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