On Sat, 08 Apr 2017 11:59:09 -0700, edhuntress2 wrote:

On Saturday, April 8, 2017 at 2:00:06 PM UTC-4, Jim Wilkins wrote:
"Tim Wescott" wrote in message
...
On Fri, 07 Apr 2017 08:51:21 -0700, edhuntress2 wrote:

Yo Jim -- and anyone else who may be interested.
.............

Should be able to do the signal processing digitally, so the hard
part will be making a user interface that allows the pro users to get
the most out of it while making it easy enough for the ordinary guy
so it doesn't just get thrown through the wall.

--
Tim Wescott

I can't claim that I'm good at it but I have a lot of experience
designing user interfaces and writing the instruction manuals.

I'm experimenting with a homebrew grid / solar powered battery charger
that can be set to run unattended or used manually to diagnose and
restore neglected Lithium, NiCad and Lead-acid batteries. Earlier this
week it recovered solder-tabbed Li-ion 18650s from "dead" cell phone
boosters, this morning it brought back a fully discharged DeWalt NiCad
pack enough for the automatic charger to accept it, and now it's
working on an AGM that went bad in storage. The once useless battery
delivers 60A.

It's a simple circuit, the hard part is knowing how to use it, and I
don't have all the answers yet.

Maybe the reason they aren't on the market already is that they can as
easily destroy a battery as save it.
-jsw

Speaking of Li-ion, Metabo claims that their new 36 V cordless tool
battery pack can deliver 2,500 Watts, as used in their new 9-in.
angle-head grinder.

Maybe my arithmetic is off, but that says roughly 70 A to me. The
battery pack looks like it's just a standard 10-cell pack. I've read
that the low-end internal resistance for advanced Li-ion cells is around
0.5 Ohms.

My calculation says the battery pack is dissipating 350 Watts or so at
full load, which sounds unreasonable. This is a normal-size 36 V battery
pack.

What do you think?

That's a bit over 11C, which is well within the limits that model
airplane battery packs are run these days. Every day packs come out that
can handle more current for the capacity -- it's probably tools like that
which are driving it.

--
Tim Wescott
Control systems, embedded software and circuit design
I'm looking for work! See my website if you're interested
http://www.wescottdesign.com