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Multiple (battery/inverter) power sources in a small audio system - ground ?'s

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MattLeonard:
I often power small sound systems (speakers-on-stick size) with a LiFeP04 batteries/inverter setup - great for off-grid events. Usually, this is a 3kw inverter (so reliably a single 20a circuit). But for some slightly larger events - I'd like to use a 2nd inverter/battery setup that I could use - basically creating a 2nd circuit option.  Ideally - this could mean one inverter per side of PA, or PA on one circuit and monitors/backline on the 2nd.

-What are some considerations/best practices I should be thinking about if using (2) fully independent power sources?

-I know on traditional gennies a bonding kit is the norm - and while I could bond the chassis of multiple inverters together, I don't have the ability to sync phase. What are the real-world implications here?

-Could I physically isolate parts of the system that are on different power sources? i.e. - using wireless transmitter/receivers so that no physical path (copper or human) is possible between components?

I'd much rather than multiple 3kw inverters for modularity/redundancy than a single 6kw unit if possible. Thanks for any advice!





Grounding between them?

Stephen Swaffer:
I would bond the chassis together.  Basically, code calls for anything that "could be energized" to be bonded to a common ground to avoid "potential" (as in voltage) differences.

Why would syncing phase matter?  Does any of your equipment NOT convert the AC to DC before using it?



Riley Casey:
Speaking of Lithium battery power inverters what kind of run time are you getting with what kind of audio system? I'e been looking at these for small powered mixer & speaker on stick voice systems.

https://www.amazon.com/gp/product/B07SM5HBK1/ref=ox_sc_act_image_1?smid=AZF6YB7UVA7OU&psc=1

Steve-White:
I'm thinking about putting together an inverter setup for garden/gazebo weddings instead of the inverter genny.  It's pretty quiet and at 100' away with a large cart tipped on it's side is inaudible.  But, a battery inverter would be faster setup and tear down and that's the name of the game.

Thinking something with quick change out battery packs in case of a problem or long run time is needed.

That Jackery 518WH looks pretty good.  Packaged up, probably want two of them - better solution anyway than a single rig with spare battery packs.  Should have plenty of grunt to run a wedding ceremony size PA for 45 minutes or so, much of which is idle time on the system.

For the OP, heed what Stephen posted about bonding.  Absolutely positively bond multiple portable power sources together well.  That's a huge safety precaution.

MattLeonard:

--- Quote from: Steve-White on August 06, 2021, 09:59:02 PM ---I'm thinking about putting together an inverter setup for garden/gazebo weddings instead of the inverter genny.  It's pretty quiet and at 100' away with a large cart tipped on it's side is inaudible.  But, a battery inverter would be faster setup and tear down and that's the name of the game.

Thinking something with quick change out battery packs in case of a problem or long run time is needed.

That Jackery 518WH looks pretty good.  Packaged up, probably want two of them - better solution anyway than a single rig with spare battery packs.  Should have plenty of grunt to run a wedding ceremony size PA for 45 minutes or so, much of which is idle time on the system.

For the OP, heed what Stephen posted about bonding.  Absolutely positively bond multiple portable power sources together well.  That's a huge safety precaution.

--- End quote ---

 I think the small Jackery-size units are very limiting to what you can run - be cautious of the consumer-level inverter units that may not really be able to output the wattage the claim, at least not reliably, or handle transients in dynamic music.  And that won't deliver their full stated capacity either. Plan for a solid buffer on all specs. It really depends on the program material and volume - most Class D amplifier/powered speakers are very, very efficient and sip power.

The smallest inverter I use is a 1500w unit, and I've comfortably run 3 QSC k10.2's on that - at full (but not clipping/limiting) volume. I have done 4 (not at full volume) but have also had the inverter going into protect on some peaks. I ran a pair of Yamaha DXS subs and DZR tops (with a small mixer and pair of Sennheiser wireless) last night on my 3,000 water inverter - full volume, and it didn't blink.


If you want consumer form factor and ease - look at Bluetti or Delta Pro - both are releasing new units right now that are nextg-gen in terms of features, weight, energy density etc.  And they have expandable battery options - which is clutch
.

For more power at lower cost - DIIYsomething if you have basic electrical comfort. I have a pair of milkcrates that each hold ~2500wh of lithium-ion batteries. With an Anderson SB175 quick-connect cable - I can connect that to any of my inverters (mounted on plywood that sits nicely on top of the crate) and its module and light.  A more "pro looking" option would be to build  into a Pelican or similar)

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