"Larry Jaques" wrote in message
...
On Sat, 21 Oct 2017 19:52:17 -0400, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message
. ..
On Sat, 21 Oct 2017 13:05:38 -0400, "Jim Wilkins"
wrote:


So far I'm impressed with this:
https://www.amazon.com/uniquegoods-S.../dp/B01N3YSE6S

Yeah, that's probably good for 7A. Teensy!


AFAICT it performs as advertised. My variac + arc welder transformer
power supply goes to 57VDC or 70ADC but not both at once, and not
over
30A for very long. I'm fairly sure I used it to test the DPS5015 at
15A to at least 35V but I can't find the data. It's a difficult
measurement because my power resistors have to be reconfigured
several
times as the voltage rises and they get very hot, 500-600F.

At least it's not C. Sounds like a pretty nifty supply. Was that a
little fan on the backside of the power transistor mount plate?
Still,
they don't look up to 7.5A each, so I'm surprised. Cute little
guy.

Yes it's a fan. I made an open backed aluminum box to house it. I
didn't check output noise and ripple because they don't matter for my
high current applications and I grabbed a 13.8V 19A supply cheap
during Radio Shack's clearance sale. The DPS5015 is somewhat unstable
in constant current mode.

Ripple from the unregulated welder transformer supply is surprisingly
low, about 1V p-p at 20A, thanks to its high self inductance and the
nearly 0.1 Farad output cap. Its output regulation is poor, Zout is
around 1 - 2 Ohms, which means the current stays nearly constant as
battery voltage rises. That's good during the bulk charging phase but
dangerous once the charge nears completion, so I have to limit the
maximum battery voltage by charging through a 20A solar panel
controller or the DPS5015.

The 20A controller is a WindyNation P20L. Amazon offered it for $19.99
until I bought one, then the price jumped to $30.

-jsw