On Thu, 11 May 2017 04:03:29 -0700 (PDT), wrote:

If the OP uses 4 1.5V Lion in a parallel batt carrier wired
in series to a second same carrier the V is 3.0
3 in series is 4.5V

Correct ?

No. Most (not all) LiIon cells are a nominal 3.7V. Plug one of these
into something made for a 1.5v akaline battery and you will have a
smoking ruin. This is a very real problem. I have several
flashlights that use 14500 LiIon cells which are exactly the same size
as a AA battery. If I accidentally plug one of these into a AA
battery holder, it will probably destroy the device.

So in potential possibility repairing a failed proprietary
integral batt device is possible.

Nope. Plugging in the wrong battery does not make things go better or
fix them.

I have 2 devices, a Pioneer 2DIN receiver and a new Amprobe
510 multimeter asking connect to ground first. I had operated
under the auto batt standard of grounD last.

Is this a current sea change ?

No. It is also wrong. In a car, I'm told that you connect the ground
(negative) battery terminal last. That's because when you tighten the
positive battery terminal with an un-insulated wrench, and you
accidentally hit the grounded chassis or grounded battery frame, if
the ground (negative) terminal is disconnected, there will be no
spark, arc, smoke, or exploding battery. Of course, grounding the
ground lead with a wrench will not do anything dangerous.

With a voltmeter, you connect ground (negative) first, and then apply
voltage. Pretend you're measuring that output of a solar panel or
battery powered vehicle, where the voltages are rather high. If you
connect the positive lead first, the leakage inside the voltmeter will
deliver most of that voltage to the ground (negative) lead, which is
currently just dangling. Grab the dangling lead while trying to
connect it to ground, and you can get zapped by the high voltage.

AA multimeter ground first is a PITA with insulation penetration.
The 2DIN is deadly. Why is there not a safety relay turning off
power if no ground ?

If there were no ground, you would not have a place to stand.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558