UltraCap™ LPS-1 Operation and Pre-purchase thread

[mansr]

6 hours ago, Cyrus said:

I'd like to use my extra LPS-1 to power my router (5V ~ 3A), however I need a new DC cable to do so. Specifically a micro usb male connector for the router side. 

Where are you getting that current figure? Micro USB connectors are generally not rated for that much. It might help if you named the model of your router.

 

[mansr]

12 hours ago, Superdad said:

Sorry, but while you can run our UltraCap supplies in series for higher voltages--or in series and center-tapped to make a nice bi-polar (+/-) supply--paralleling for higher current does not work, as small mismatch between units results in most all the load landing on one or the other.  It takes my hand-picking pairs of boards that deliver--at a given current--output voltage within 10mV or less of each other, and then using at least 24-inches of equal length output cables to add some resistance.  I have done it a couple of times, but it is not a service we offer.

Wouldn't adding a small series resistor to each supply make it work reasonably well?

[mansr]

5 minutes ago, Superdad said:

Yes, but for general users (not expecting people to solder resistors in-line) just using equal length DC cables will take care of that part.  Still would have to match the two boards’s output voltages very closely.

Depending on the load, a series resistor as large as 1 Ω might be tolerable. Then a voltage mismatch of, say, 100 mV shouldn't be a problem.

[mansr]

44 minutes ago, Superdad said:

Gee, that would be terrible.  Would not want to put a huge 1 ohm resistor in series with our nice ultra-low-output impedance LPS!  To go from a few mOhms to 1 ohm--that would be a waste.  ?

Depends on the load. If there is a downstream regulator, and there usually is, it won't hurt a bit. Even a decent-size capacitor will often be enough.