20volt External Battery

[Nehem11e]

Obviously I am not going to wire it straight in, but I have multiple 20v batteries almost always charged. They also have plenty of capacity to power the Trusdx all weekend on a camping trip probably a week long camping/canoeing trip. They are also very lightweight and easy to pack. You probably know what I’m talking about. It’s my 20 V Dewalt power tool batteries.

What I’m curious about is what type of voltage regulator or step down I should use. The options I see are a linear or switching.

I like the linear option because it provides a nice clean Power supply.

I like the switching option because it’s more in line with the trusdx mission of high efficiency

I worry that the switching option will introduce noise or be problematic for the radio. Has anyone tried this already and if so, what did you do?

For a linear option I was thinking of home brew with a LM317 and some capacitors and resisters

For a switching option I was initially thinking something like this
https://www.amazon.com/LM2596-Converter ... 08NV3JCBC/

I am interested in the thoughts out there. And I will report back what I find.

Abe

[vk4tj]

The LM317 might be a little bit lightweight for a TRUSDX, being spec'd at 1.5 amps (if cooled with liquid nitrogen . The L200C is a bit better @ 2 amps. Anything higher is apt to be a counterfeit, so don't bother. If you don't mind some added complexity, a 317 + PNP wraparound is not a bad fit for your application. Of course, much of the bus gets regulated AGAIN inside the rig, so you could take that transistor and simply construct an "emitter follower" zener regulator instead, since the regulation requirements are not onerous.

[Nehem11e]

I looked up the zener regulator with an emitter follower. I like that. Just need to get a 14 volt zener diode I think I have the rest in my stock.

Thanks!

Abe