Anyone ever run a Loudbox Mini thru an inverter/battery combo?

dannyg1 · #1 07-09-2015, 09:44 PM

I'm wondering if anyone has any experience running a Fishman Loudbox Mini through a small (350w in my case, pure sine) inverter and at moderate to quieter volume. If so, what AH rating bettery did you use and how long did you get before running out of power?

Fishman specs the amp as having a 145watt/2.5 amp max draw but that sounds very high to me. I'm expecting around 85 watts/ less than one amp in my application, figuring to be using only the first 5 watts of power max.

jonfields45 · #2 07-10-2015, 06:01 AM

This is the battery I use with my DBR10. Probably overkill for my usage and certainly for yours. It does a 3 set outdoors gig for 100 people or so with much to spare (which I judge by how quickly it recharges). AGM batteries are not deep discharge bullet proof, just a big improvement over a standard lead acid, so not driving it to zero is a good idea.

https://www.chromebattery.com/12v-26...connector.html

At 17 lbs. it is not too unreasonable to lug around.

Tomm Williams · #3 07-10-2015, 08:26 AM

Caution.............depending on the topology of the system, a MSW inverter could cause eventual damage to the unit. I toasted two Peavey IPR3000's the very moment I turned them on with exactly this set up. Use a PSW inverter instead.

Irish Pennant · #4 07-10-2015, 10:29 AM

There are plug in amp meters that cost less then $20.00 that you can use to plug in appliances in order to check their actual amperage use. I used one when I was setting up some solar panels and battery banks. It helped in determining which appliances where to be on what circuit.

evenkeel · #5 07-10-2015, 02:20 PM

I've used a battery and inverter to power a Fishman SA220. Also a Fender Passport 150. I also would on occasion run a Vocalist pedal thru the inverter, in addition to the PA's. Battery was a group 24 deep cycle marine battery. The inverter was a 400 Watt unit from Harbor Freight. Both are way more than is needed but I had them for other reasons. Worked fine thru several three to four hour outdoor gigs. I would also run a MP3 thru the PA during breaks.

I no longer go thru all this as I use a Roland street cube for those gigs where electricity is not available.

jonfields45 · #6 07-11-2015, 08:42 AM

Fishman tech support is easy to reach on the phone and you could call them to find out if a full sine wave inverter is required for the Loudbox Mini. I've used the cheaper modified sine wave type with multiple Mackie, QSC, and Yamaha powered speakers with no problems, but no harm in calling.

dannyg1 · #7 07-12-2015, 05:03 PM

Thank you all for some much needed information. I am going to be using a pure sine wave inverter so, no need to check on that. The group 24 marine batteries are typically 80-100ah, some though, are as little as 35ah (and weigh 25lbs). Which one was in use on that SA220?

Mackie has also come out with a new option called the Freeplay. 11lbs, 10 hr run life on a proprietary 7.4 volt lithium battery. Compression tweeters though, so probably not the greatest sound quality (More PA, less Schertler or Loudbox sound quality. Though some can sound pretty great, I doubt a $400, 11lb, 7.4 volt will sound great. I'll be trying the first one I can find though).

Anyone ever measure the power draw of a Loudbox mini at 11 oclock volume, flat EQ?

http://freeplay.mackie.com/

jonfields45 · #8 07-12-2015, 06:34 PM

Quote:

Originally Posted by dannyg1

Anyone ever measure the power draw of a Loudbox mini at 11 oclock volume, flat EQ?

No, but here's an educated guess. Assuming you don't drive it into distortion, and that you are not playing heavy metal music, then it will be putting out at most 60 watt peaks with a 10:1 peak to average ratio. Thus the average power will be 6 watts. I've hefted one of them and it strikes me that it is too heavy to be a modern switching power supply driving a class-D amp, so it is likely to be much less than 90% efficient and we can lowball that at 50%. That leaves you at a 12 watt current draw from the inverter which means as little as 3 Amp-Hours will do the job (three sets). Double or triple that for margin and to not take a cheaper AGM battery too far down the discharge cycle.

jonfields45 · #9 07-13-2015, 05:47 AM

Quote:

Originally Posted by jonfields45

No, but here's an educated guess. Assuming you don't drive it into distortion, and that you are not playing heavy metal music, then it will be putting out at most 60 watt peaks with a 10:1 peak to average ratio. Thus the average power will be 6 watts. I've hefted one of them and it strikes me that it is too heavy to be a modern switching power supply driving a class-D amp, so it is likely to be much less than 90% efficient and we can lowball that at 50%. That leaves you at a 12 watt current draw from the inverter which means as little as 3 Amp-Hours will do the job (three sets). Double or triple that for margin and to not take a cheaper AGM battery too far down the discharge cycle.

By the way, this is exactly how Roland rates what is likely a 5 watt sustained RMS power amp like the Cube Street EX as 50 watts (same for all those 1-2 KW powered PA speakers). A modern switching amp can reproduce huge peak to average waveforms that the older technologies could not. But any electric guitarist that puts the 50 watt Cube Street EX up against a Fender 40 watt Hot Rod Deluxe will know something is not adding up...

evenkeel · #10 07-13-2015, 07:45 AM

Quote:

Originally Posted by dannyg1

Thank you all for some much needed information. I am going to be using a pure sine wave inverter so, no need to check on that. The group 24 marine batteries are typically 80-100ah, some though, are as little as 35ah (and weigh 25lbs). Which one was in use on that SA220?

The big, heavy, ugly one. Weighs a bit over 50 lbs. 150 minutes at 23 amp draw is the factory (duracell) spec.

Bobby1note · #11 07-13-2015, 08:12 AM

Quote:

Originally Posted by dannyg1

I'm wondering if anyone has any experience running a Fishman Loudbox Mini through a small (350w in my case, pure sine) inverter and at moderate to quieter volume. If so, what AH rating bettery did you use and how long did you get before running out of power?

Fishman specs the amp as having a 145watt/2.5 amp max draw but that sounds very high to me. I'm expecting around 85 watts/ less than one amp in my application, figuring to be using only the first 5 watts of power max.

I'm powering a pair of Yorkville NX55P loudspeakers, plus an AER Compact 60/2 (as monitor), plus a Soundcraft EFX-8 and a few LED washlights, with a 1500w Xantrex MSW inverter, and a 115ah Deep-cycle battery. We've had zero issues, and we've run the system for up to 8 hours without shutting down for breaks. I've been using that set-up since 2008, but only on those rare occasions where no AC is available.

I've also got a smaller 300w Xantrex MSW inverter, which I use if I'm running only the Compact 60/2, an EFX-8 and a LED few wash-lights. I haven't bothered looking for a smaller battery for that set-up.

dannyg1 · #12 07-21-2015, 10:14 PM

I thought that you all might like to know what my results are with the combo of a Fishman Loudbox Mini, a Samlex SSW350 pure sine inverter and a UB1250 12v 5ah battery, used, so I'm not sure of it's 100% health, though it will run my Vox Mini5 Rhythm for 7 hours or more.

I'm running the system until the 11v alarm sounds constantly on the inverter (Not to actual shutdown) and with a freshly charged battery. I get 27.4 minutes of playing with guitar and vocals. Looks like I'm going to need 55ah of battery to power this properly for my sets (I say glumly).

jonfields45 · #13 07-22-2015, 06:17 AM

It might be the inverter efficiency (only specified at "peak" efficiency), though that is also a small battery (and the battery might be defective). You can get a cheap MSW inverter at Harbor Freight and return it if it does not work better for you. There is not a lot of love for that Samlex on Amazon. Needing double the A-H of what I use for a DBR10 at a fairly large venue (with capacity to spare) does not seem right.

dannyg1 · #14 07-22-2015, 12:05 PM

Jon, Thanks for the sympathetic message.

The Samlex converter is not the highest rated PSW inverter out there but, after watching an insane number of youtube videos by a true inverter geek, I learned that Samlex is held in high regard.

This particular model, giving a 10-14% harmonic distortion reading when loaded to 50%, isn't performing terribly when compared to its competition (By the youtube guy's commentary and bench results at least) and almost any MSW inverter will be delivering something very close to a square wave by 50% output.

My other option was to buy a Xantrex SW600, a much better toy, but almost dbl the price and twice the size + weight. The PowerBright APS300 (This Samlex's most direct competition) got a 'I don't recommend that you buy this' from the guy on youtube (who'd done a full battery of tests on it).

So, to better test this set-up I have here, I've ordered proper, heavy guage and short length cabling for both the inverter to battery connect and a 2 ft, 14 AGW power cable for the amp. I've also ordered a brand new 12v 18AH battery, just to start from a test point I can be sure is well settled. With some luck, I'll be able to do better than 10ah per hour.

On the subject, I see that my inverter is rated to work with battery voltages up to 15v. I wonder if adding the extra 3v will still trigger the alarm at the obligatory 11v? Might that make it so I get much more runtime?

evenkeel · #15 07-22-2015, 12:49 PM

Hope this works out for you. In the world of batteries a good rule of thumb is "weight and size matters". A'ka the bigger, the heavier, the better. You also want some extra capacity just for insurance. Plus, you do not want to run a deep cycle battery down to zero very often. That will kill a battery very quickly. Better to have the extra capacity, run the discharge to about 30-40% of capacity, have the extra insurance and not have to replace the batteries so often.

Another point to consider. Temperature will have a huge effect on run time. If you are outdoors, in the hot sun the battery will run down much faster than in a cool room at home. So, again having some extra capacity is a good insurance policy.