Power issue at an outdoor venue

[mikemo6string]

I use a looper for percussive effects, beats. I do hit the guitar top, but I don't pound on it. My mic technique is good.

It's fairly energetic music. I think the music is generally there to keep the spirits high, keep folks engaged and "spending their dough." I'm not there to put on a concert, if you know what I mean. Loud enough to keep it engaging, but also that folks can have a comfortable conversation nearby.

I keep my levels to suit the venue. Friday it was outside under a gazebo, pretty far from the crowd. I pushed the system pretty hard, especially the single QSC (we had A/C power at that one, and that Schertler was very hot... like hot to the touch). Saturday we were in the middle of a crowded market, with people sitting ten feet away. Much quieter (we used the Roland BA-330 there). I'm always aware and try to keep the music suited to the type of event.

[dannyg1]

I ask about your dynamics because a high-dynamic vocal performer will pull much more power through the system than most. Two of the electrical engineers on the forum posted their own estimates of real world amps pulling through their inverter systems and both are satisfied with remarkably small inverters driving rather large amplifier/speakers (jonfields45 used a 400w mod sine to drive a Yamaha Dbr10 and Mandobart, a Cotek 125w pure sine, of very high quality, to drive a Carbon AG300 amp. From memory so you'd do best to read their comments directly).

Without looking up power draws on your equipt, I think you'd do best to run from two smaller pure sine/battery systems, concentrating 1 to each amp and plugging the mixer and auxiliary stuff into one speakers inverter or the other, whichever is closer. The key thing you've said is that you had your Schertler running hot.

I would suppose that a 600w inverter would be best on each inverter system but I'm sure that a 300w would work fine at least most of the time. If you were to use only one inverter, I'd suggest you get a high quality 800-1000w and run with heavy cabling through two parallel connected 12v batteries (still run at 12v) to help keep your voltage stable under load.

Splitting the duty between two inverter systems will keep your costs down, simplify charging complexities, give more run time to weight efficiency. It also guarantees that you'll be able to easily run through an inverter/battery system brdakdown.

I think of Samlex as the defacto standard In the inverter market, like Martin is to guitars. They make three lines of pure sine, please avoid the cheapest 'SSX' line entirely. Their 'PST' and industrial quality 'SA' lines are where you ought to be looking.
There are many other brands that are rebadged Samlex 'SA' series inverters and they're where you'll be able to find your bargains, look carefully at the photos for likeness to the 'SA' equivalent, be sure they're pure or true sine and be sure they're 12v (industrial market inverters are much more common in 24-48v version than consumer models are).

Some brands to look for: Cotek, Go Power, Thor, Vanner. Some other companies make the very finest quality inverters - Victron and Exeltech.

Originally Posted by mikemo6string

I use a looper for percussive effects, beats. I do hit the guitar top, but I don't pound on it. My mic technique is good.

It's fairly energetic music. I think the music is generally there to keep the spirits high, keep folks engaged and "spending their dough." I'm not there to put on a concert, if you know what I mean. Loud enough to keep it engaging, but also that folks can have a comfortable conversation nearby.

I keep my levels to suit the venue. Friday it was outside under a gazebo, pretty far from the crowd. I pushed the system pretty hard, especially the single QSC (we had A/C power at that one, and that Schertler was very hot... like hot to the touch). Saturday we were in the middle of a crowded market, with people sitting ten feet away. Much quieter (we used the Roland BA-330 there). I'm always aware and try to keep the music suited to the type of event.

[mikemo6string]

I see that there is more information in back posts on this forum than I thought. I'll dig through it. Thanks for all the input.

For what it's worth, the Schertler gets quite hot often.

One thing I haven't mentioned is what type of battery I'm currently using. It's a Duralast Marine Battery, 24 MD-DL. 550 CCA, 85 amp hours, 685 CA. A couple of years old, and it gets very sporadic use.

And now I'll go figure out exactly what the current draw is on each piece of gear.

[dannyg1]

There is one last option: To build a car audio amplifier system that runs from 12v (these really like to see 14.4v because we that's what the alternator puts out while driving, so they run a bit less well at 12.8v and under, typiCal 12v standalone battery voltages), hooked to passive speakers and a mixer of some sort.

This could be a cost competitive option, depending upon which components you choose and will be the most efficient as well, possibly running up to 35% longer.

You may be able to run a USB powered audio interface into a Windows 10 tablet, running some sort of light audio editor and mix through that. I doubt that an Atom powered tablet could get through that load but, you might be able to.

[mikemo6string]

There is actually another option, I suppose, since I drive a Prius. Couldn't I hook up an inverter to the Prius battery, and effectively have a generator system that is already maintained?

As far as power draw goes, I'm easily confused.

My Schertler has this on the rear panel:
Power consumption 105 watts
120V - 60Hz
T3,15A - L250V

QSC K10
100-240V ~ 2.3-1.1A 50/60Hz

Mackie 1202
120 VAC 50/60Hz 25W
500mA/250V slo-blo

Strymon Ojai
each output reads 500mA 9V

Hmmm.

[dannyg1]

Your Schertler is telling you that it takes around 0.9a @ 120v to run uses a 'T3' shaped fuse that blows at 15a. Meaning that it'll pull around 3-5 amps from the power supply directly.

Your QSC K10 wants 2.3 amps available at 120v and your mixer wants around 0.4a @ 120v.

Your Strymon should have a power draw printed to its power input and thats what you need. Figure it's around the same as the mixer.

You're looking the pull around 4 amps max on the 120v side of the inverter. That's quite a lot.

Going here and calculating usage:

https://www.batterystuff.com/kb/tool...-inverter.html

Says that you need a 480w inverter and that your max pull will be around 45amps on the battery side. That means you need very short 6ag cabling or better on the battery side and a larger than 50ah battery to handle the load. Your battery should work but, as I said before, you'd really do better with two in parallel.

I'd say that a 600w inverter should be your minimum for the full system but probably will brownout during heavy load (which is most probably why your Schertler runs hot). An 800-1000w inverter will make sure you have power to cover dynamic peaks.

On the Prius - It may even have an inverter built in it (Teslas do) but can you consistently play next to your car?

Here's a link on Prius/inverter install and use:
https://www.peakprosperity.com/wsidb...s-backup-power

Originally Posted by mikemo6string

There is actually another option, I suppose, since I drive a Prius. Couldn't I hook up an inverter to the Prius battery, and effectively have a generator system that is already maintained?

As far as power draw goes, I'm easily confused.

My Schertler has this on the rear panel:
Power consumption 105 watts
120V - 60Hz
T3,15A - L250V

QSC K10
100-240V ~ 2.3-1.1A 50/60Hz

Mackie 1202
120 VAC 50/60Hz 25W
500mA/250V slo-blo

Strymon Ojai
each output reads 500mA 9V

Hmmm.

[mikemo6string]

This is certainly a wealth of information. Thank you. I hope some of this was helpful to other folks. It certainly was to me.

I spent a lot of today on the forum, reading the past threads that were recommended here. Then I spent the last couple hours getting some actual playing in. Cheers.

[dannyg1]

Glad to help.

[mikemo6string]

I'm now looking at inverters that I can hook up to both my marine battery and my 12v Prius battery.

I still can't decide which inverter/cabling to buy.

There is a company near me, ConVerdant Vehicles, that has a couple of 1K units left. 1000watt pure sine wave inverters, with cabling and digital metering, for $299. Then there is something like this on Amazon:

https://www.amazon.com/gp/product/B0...f_rd_i=desktop

That's a lot cheaper. In either case, I'd access the 12v in the rear of the Prius and, using alligator clips, run power from the battery. The inverter could also be used with the marine battery I have.

I had a bit of input already about quality inverters: Samlex, Cotek, Go Power, Thor, Vanner (thanks, Danny). There are also (relatively) cheap 1500watt pure sine inverters (3000w surge) for around $200. Any thoughts on this? Additionally, though it's not related to guitar, is providing some emergency power at home during outages. A higher power inverter could potentially keep my refrigerator and lights running during an outage.

[dannyg1]

Refrigerators have high inductance startup loads and you'd probably need a 2500-5000w inverter to get it running, which is far too large to use for your sound system efficiently (larger inverters run far less efficiently under small loads. That's why you should match your load pretty closely).

I'd suggest that you try to get a 600w Samlex SA style inverter and, if you really can't find one inexpensively, buy a 300w and see if that'll do it ( This is the electrical engineers solution and neither of them report any trouble with their systems). I'm a bit uncomfortable recommending this but they're the professionals when it comes to this stuff so I'll defer.

[dannyg1]

I just went surfing eBay to see what inverters were available for cheap and saw that all of the Vanner 600w inverters that were around $100 were from car installs and are designed to run with the alternator running. You can tell this by looking for the sticker that tells you the min and max voltage before the inverter will alarm and shut off. You're looking for 15v on the high end and 10-10.5v on them low end.

If you buy one that shuts down at 11v or 11.5v on the low end, these are the alternator runnig models, you'll be depriving yourself of about 40% of your otherwise available runtime and you'll also experience the trouble of the inverter shutting down prematurely under heavy load. On the positive side, your battery will last far longer, as in years of service, with one of these.

I thought that important enough to post the warning. I didn't find any great deals on a 600w BTW, but I didn't look really hard. I'm sure I could find one with some digging.

[dannyg1]

Hey Mike,

I found one of the more premium Taiwan made Samlex PST 300' for dirt cheap. This will certainly work for at least most of what you're looking to power:

http://www.ebay.com/itm/Samlex-PST-3...3D292163443556

[mikemo6string]

You rock, Danny. So if I were just looking to power a Fishman SA220, or SA330 (100 watts more), would I be okay with the 300W inverter? Most gigs I can get by with just the smaller system.

Are there any concerns when purchasing a used inverter (although this one is certainly cheap)?

[dannyg1]

Originally Posted by mikemo6string

You rock, Danny. So if I were just looking to power a Fishman SA220, or SA330 (100 watts more), would I be okay with the 300W inverter? Most gigs I can get by with just the smaller system.

Are there any concerns when purchasing a used inverter (although this one is certainly cheap)?

I would say, considering that this particular one is built in the same factory as the SA series, that it's a very high quality inverter with a low freq power supply. If any of them 300 watt'rs will handle it, this one will.

As for buying used, like anything else you take a chance. Seems to me that this one is inexpensive enough to buy and test.