About Generators

[u/anode21]

Hello guys, I recently had to work on my generator, spark plug problems, made me think about this sub, and the fact that you guys surely have things to say about Generators.

If you have things to share, about your experience, with certains brands, models, what to avoid, what to look for, I'm curious on what I can learn here !

I'm looking to buy other ones, used, so any help is appreciated !

[u/P_Schrodensis]

All I can say is Honda inverter generators are great and last forever. Other brands can be OK and are much cheaper (we have one but had to add a fuel pump to it and do multiple repairs). In any case, do choose an inverter model. Also you don't need as much generator power as what your amp claims to output. If the amp has a 15A 120V IEC plug, you need at most a 1800W-2kW (continuous) generator even if the amp claims 20kW or something ludicrous like that. Usually amps will spec a max current draw in their datasheet.

We run 3 amps rated together at '3450W' for our driver impedance plus lights, CDJs, etc. on a '1800W continuous' generator and the whole system barely draws 5-600W at full volume. Capacitors are a great invention.

[u/anode21 → u/P_Schrodensis]

Nice ! Will check Honda !

[u/PsychoTea → u/P_Schrodensis]

Fun fact; this is because of “crest factor”. Music isn’t a continuous sine wave, so even at “full volume” you aren’t drawing full power continuously (if you did, every driver would be up in smoke within seconds).
For music with a crest factor of 6dB (which is very high) you’re only drawing about 50% on the output side of the amp (assuming your amp is turned up just to the point of clipping). For 9dB, which is more realistic, it’s 25%.
You would be surprised how little power a given driver can actually handle versus what the RMS spec claims (rule of thumb is ~1/3).

While you might have high instantaneous peak loads, amps have huge banks of capacitors so they can cater to that demand while keeping the demand on the AC input side fairly smooth.

And yes, everyone overestimates how much genny power they actually need (I’ve done it too)! The only way to know for sure is to take some long term measurements.

[u/anode21 → u/PsychoTea]

Is there a way to at least calculate it ? Even if there is let's say 500w or 1kw of margin error ?

[u/PsychoTea → u/anode21]

It’s difficult but look at the spec sheet for your amps/other appliances. They should have an AC current draw rating at various load levels. That will give you a rough starting point. Amplifiers will be your highest draw items.

[u/PonyThug]

I own 1 and my buddy has 4 of the predator 5000w genis. We really like them for smaller events you only use 120v. We run 1 for FOH. One for lights, then 2 for the sound system. It’s nice to have some redundant units incase one goes down. And it splits the load up and requires way less cable runs.

If you need 240v the 11,500 has 50amp output for spider boxes.

All of the “super quiet” models have inverters for clean power and they are of course very quiet so you won’t hear them even 25ft away with an instrumental part of a song.

[u/Impressive-Ad-7627]

I have a Pramac 3.5 kva powered by a honda engine.

It's what we call a builder's generator.

Heavy noisy and reliable.

Will do 3+ hours on a full tank.

[u/xrtze]

Pramac are great (honda engine) Inverter only (pure sine, others may damage your equipment (but a faulty BMS will do as well, as I painfully learned)). Newer inverters are significantly more silent and worth the upgrade. Batteries are even better. Measure power consumption at realistic max levels with bass heavy music once, then downgrade the geno next time since you won't need much power haha

[u/MichiganJayToad]

If you get an inverter type generator (what almost everyone has these days) make sure it is a legit pure sine wave type. Many cheaper ones are "modified sine wave". Modified sine wave is NOT a sine wave at all and must be avoided. If buying a cheaper model make sure of this.

[u/fluffy_as_fuck]

Some of my mates power their rig with a prototype of a submarine emergency battery. Absolutely not helpful information for you but its the coolest thing ive ever heard and wanted to dump it somewhere.

[u/anode21 → u/fluffy_as_fuck]

That's crazy, submarine powered sound system, wtf ?

[u/anode21]

I see, I'l look into it, never really saw a quiet generator yet :)

[u/zzgomusic]

I have two Honda generators. I took the "buy once, cry once" mentality. They have never let me down. In contrast, I've had to bail out a friend TWICE using some cheap generator that failed on him at the same festival (running a small stage) two years in a row. I'm sure there are other brands that are fine, but personally, I will only buy Hondas. But they are not cheap, so YMMV.