3
$\begingroup$

I want to create a battery backup for my radios. Initially I'm thinking of using an Epic PWRgate and a LiFePo4 battery, so the battery is charged by the same power supply that's running the radios. The LiFePo4 batteries require a charge voltage of 14.4v. Radio gear all appears to require 13.8v±15% (11.7-15.8v), so no problem with raising the voltage there. My current power supply isn't adjustable though, and the few I've found that are have a big knob on the front which seems too easy to bump and end up damaging something.

Is there a better way to go about this? Or another precaution I can take to prevent an incorrect voltage from starting a fire?

Improve this question
$\endgroup$
3
  • 1
    $\begingroup$ Congratulations for carefully reading the manual. The block diagram shows a garden-variety "12V" supply connected to the PWRgate's "Power Supply" input, but the manual calls for the voltage you identified. I'll bet they get a lot of returns. $\endgroup$
    – Brian K1LI
    Commented Mar 17, 2021 at 15:59
  • 1
    $\begingroup$ Depending on how many A-h of backup power you need, you might also consider the Bioenno Power BPP-160. Its "all in one" design obviates the need for separate anything. $\endgroup$
    – Brian K1LI
    Commented Mar 17, 2021 at 16:01
  • $\begingroup$ That's an interesting option. Do you lose much by converting from DC->AC->DC ? $\endgroup$
    – Brad Mace
    Commented Mar 17, 2021 at 16:25

2 Answers 2

Reset to default
2
$\begingroup$

One thing that works, though it may be a bit silly: use the "Solar" input of the Epic PWRgate instead of the "Power" input.

The PWRgate's output voltage will come from the battery or from the "Power" input, whichever is higher. If you don't connect "Power", then it will always be coming from the battery. The "Solar" input is regulated down (by an MPPT DC-DC converter) to charge the battery. And the solar input will tolerate up to 30V. So if you take one of those power supplies with the knob on the front and turn it all the way up (generally that makes 16 or 17 volts) it will be fine, and your radio will still see a max of 14.4V or so. Even a 24V fixed supply would probably be alright.

The one caveat that I can think of for this: when using the "Power" input, the PWRgate can pass up to 40A safely. But the solar charge controller tops out at 10A. You can still draw more than that, but it will be the battery that supplies the rest of the current. This may or may not suit you, depending on your radios, your duty cycle, and how concerned you are about cycle life on the batteries.

Improve this answer
$\endgroup$
1
$\begingroup$

One option appears to be using a DC to DC converter designed for charging house batteries in RVs, which will automatically correct the incoming 13.8v to whatever the battery requires. There are some 20A models that are cheaper than a PWRgate.

120v AC -> Power supply -> 13.8v DC -> DC-to-DC converter -> LiFePo4 battery -> rigrunner -> radios

It's possible I'm still making this more complicated than necessary though.

Improve this answer
$\endgroup$

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .