I'm new here and I hope this is the right place to ask!

I have assembled a 6P 18650 battery pack out using Samsung 25R cells, soldered altogether with Nickel strips, effectively giving me 3.7V 15Ah.

I want to increase the voltage, so I hooked it up to a "XL6009 boost converter" module and also on a "250W 10A boost converter" module, both of which would not allow me to go anywhere near or above 5V!

This has lead me scratching my head and pulling hair out, as I do not understand why this is happening. Both lower and higher end modules are not able to "do the job", leaving me very confused. I was wondering if anyone might know why this is the case? And what would I have to do if I want to step-up to 7-10V??

Thanks and I look forward hearing back!

Do you think it's simply because the input voltage is too low??

  • \$\begingroup\$ What sort of load are you testing this with? \$\endgroup\$
    – NPE
    Oct 21, 2018 at 0:19
  • \$\begingroup\$ This is a complicated kind of troubleshooting. At a first glance, the setup that you described should work. But if it isnt't working, the classical reasons: 1) you connected the wires the wrong way; 2) the step-up modules are defective; 3) the batteries are dead, or empty. There's not much more to be said, because you gave few information about the subject. You should start troubleshooting testing every piece of the setup separately. \$\endgroup\$
    – mguima
    Oct 21, 2018 at 0:39
  • 2
    \$\begingroup\$ Reading XL6009 datasheet tells me that the minimun input voltage is 5 V. \$\endgroup\$
    – Long Pham
    Oct 21, 2018 at 7:08
  • \$\begingroup\$ NPE - I've tested it with my LED setup in parallel, and with a multimeter measuring directly on the output of the moldules for voltage. \$\endgroup\$
    – Omar Al
    Oct 21, 2018 at 13:56
  • \$\begingroup\$ mguima - 1) Wires are definitely not connected the wrong way. 2) Modules are not defective, I've tested/used them for other things within this project and they do work, I mean two faulty boost converters obtained at different times, I must be very unlucky then :( 3) Batteries were charged before assembly, and still gives me a reading of 4.2V. \$\endgroup\$
    – Omar Al
    Oct 21, 2018 at 13:56

1 Answer 1


I would have to assume that you are using some sort of XL6009-based converter module that has all the required passives. I have no information about the other module you are using.

A quick look at the XL6009 data sheet shows that the minimum operating voltage is 5V. Although there would be a bit of design wiggle room, there is no expectation that it would operate below that.

There are other options that might work with your application.

  • \$\begingroup\$ Edgar Brown - Thanks for that! The other module is this: amazon.co.uk/DC-DC-Boost-Converter-Step-up-Constant/dp/… I don't know exactly what chips it uses (yet) but I hope this helps! I've checked the "other option" module you've linked, and I might give it a go but it's max current is only 1.4A. I'm not entirely sure of its inner workings but I was hoping to operate the circuit on 4A at 12V. Do you think this is possible with this perhaps?? \$\endgroup\$
    – Omar Al
    Oct 26, 2018 at 22:04
  • \$\begingroup\$ @Omar That module specifies on its Amazon page that the Input voltage has to be in the 8.5-48V range. A quick search found this one, based off an LM2587, (banggood.com/…) \$\endgroup\$ Oct 26, 2018 at 22:14
  • \$\begingroup\$ Yes, however as previously mentioned, i was able to take a (NP-F) battery at 7.4V and be able to increase the voltage. Your search was a pretty good shout! My only concern is how will I be able to adjust the current more specifically to my needs? I.e. 4A? \$\endgroup\$
    – Omar Al
    Oct 28, 2018 at 0:53
  • \$\begingroup\$ You don't have to "adjust" the current (unless you are talking about adding current limiting, which some DC-DC modulators allow). Your actual load will determine how much current is drawn from a constant-voltage supply. \$\endgroup\$ Oct 28, 2018 at 0:57
  • \$\begingroup\$ Yes! That is what I meant, Current Limiting. the 250W module does allow current limiting (it has two potentiometers) but the XL6009 moldule and the one you suggested only allows for adjusting voltage. Is there no way to limit the current specifically to a certain amp value?? In my OP I stated I've assembled a 6P 18650 battery pack out using Samsung 25R cells, soldered altogether with Nickel strips, which I believe it'll give me 3.7V 15Ah. Correct me if I am wrong. \$\endgroup\$
    – Omar Al
    Oct 28, 2018 at 21:39

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