Anyone ever put a stack of Lithium Polymer cells inside there portable  o-scope? - Page 1
Forum section: electronics / general

author: pullin-gs
author_rank: Regular Contributor
timestamp: April 13, 2012, 01:30:29 pm
content: 1st Post!Share your experience putting a LIPO battery w/charge circuit in your oscilloscope (Rigor, ATTEN, etc.).Is grounding requirement a showstopper?Having a portable scope which needs no power cord has advantages.Most (all?) field work I do is troubleshooting telecommunications circuit waveform problems.Would my traces be crap even if I clipped the scope to frame-ground?What kind of "scope-time" do you get before batteries are depleted (%80 capacity...take it down further and the cells are toast)?What is your charge circuit?Internal?Integrated using scope's PS?External?Respectfully,Paul Blakeslee

author: ejeffrey
author_rank: Super Contributor
timestamp: April 13, 2012, 01:56:02 pm
content: Your traces will be fine. The main problem with battery powering a scope that is designed to be earthed is safety. If you connect the ground clip to a live wire, the whole scope becomes live, including the bnc shields on any unused channels, and any IO connectors.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: April 13, 2012, 03:00:46 pm
content: Quote from: ejeffrey on April 13, 2012, 01:56:02 pmSome battery scopes (e.g. Owon) tend to have plastic outer shells on the BNCs.

author: Unknown
author_rank: Unknown
timestamp: April 13, 2012, 06:45:12 pm
content: Many battery powered scopes have insulated BNC connectors. This is the only safe way to go, in my opinion, since there is no way to ensure that the reference lead is at a safe potential. Manuals for some bench scopes with battery state that the scope should be connected to ground with a separate grounding wire when used with potentials above ~30 V RMS or so. Insulated BNC connectors are much more fragile, especially when mated with standard BNC hardware, so they're rarely used for grounded bench scopes.Apart from this, I don't see any signal integrity issues, since the inductance of the long wire to the grounding rod is way too high to be of any use at typical oscilloscope frequencies. Keep in mind that even a 6" ground lead causes ringing with fast edges.

author: pullin-gs
author_rank: Regular Contributor
timestamp: April 14, 2012, 12:35:13 pm
content: Thanks all.....sounds like a neat mod (adding lithium battery to scope).I'll have to give it a go once I get another scope....my 20-lb analog scope would require a 20 pound battery, so that will never happen!:D

author: G7PSK
author_rank: Super Contributor
timestamp: April 14, 2012, 03:33:24 pm
content: I have an old telequipment valve scope that is made to take some form of rechargeable battery internally, I don't have the battery but the compartment and terminals are there. The case is metal so what the safety factor is when run on batteries or external dc power source which it also has I cannot imagine. The only reason I keep the unit is it would not be worth selling it and if I have something I want to have a look at which has high voltage or spikes on the voltage I can have look without worrying about blowing the thing up, valve circuits seem to be immune from high voltage spikes and even if I did blow this unit up I would not cry about it.

author: T4P
author_rank: Super Contributor
timestamp: April 14, 2012, 04:13:41 pm
content: Quote from: G7PSK on April 14, 2012, 03:33:24 pmOf course they do , they run at a few hundred-thousand volts !