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  #31  
Old 05-27-2016, 08:25 AM
Mandobart Mandobart is offline
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Originally Posted by dannyg1 View Post
Buy a charger that pushes at least 15 amps. Larger batteries take too long to charge otherwise. Many people can get by with overnight charging routines but I quickly learned that it's too time intensive and you'll end up wanting your charging done asap.

I use a 25amp charger and it's still not fast enough..
I've never used lithium ion batteries like Danny has, but if you are using a typical sealed lead acid batteries I strongly advise against such high charge rates for several reasons:
1. Battery charge and disharge produces hydrogen. The faster the rate you charge, the higher gassing from the battery. In a very small, poorly ventilated space this can be explosive (I remember the battery well fire on a submarine back in the 80's. Scary). More likely for most of us is the pressure from the H2 builds faster than it can relieve in an SLA which can swell or crack the case.
2. High charge and discharge rate produces lots more heat. Excessive thermal cycles on a battery shortens the life by distorting/cracking the plates.
3. A high charge rate results in a shallow charge. As you charge a battery the terminal and plate to plate potential rises, which resists further charge flow. You get a better charge, capable of supplying the battery's full rating with a slow charge.

I charge all my batteries at 2 A or less. If I absolutely needed the ability to run my inverter for 5 hours and immediately be ready for another 5, I would get another battery and have it charged up and standing by. Both batteries would live a longer life.
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  #32  
Old 05-27-2016, 10:35 AM
dannyg1 dannyg1 is offline
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Mandobart - I believe that 1c charge rates are not considered ultrafast or stressful, that's correct by most of what I've read. 1C on a 35ah battery is charging at 35 amps.

The major warnings in terms of high charge voltages that I've studied say that excess heat and gassing happen when you're pushing voltage without ramping down , as an older auto shop charger would've done as compared to the modern muliti-stage charger I'm using.

It is a good idea to slow charge the battery every 10-20 charge cycles as you'd said, though the explanations offered were a touch more nebulous than your description.

Finally, charging a 35ah battery at 2amps is a 36-48 hour charge cycle. That's pretty serious waiting on the side of caution. Most high cycle use machines I can find that use 15ah or better batteries charge at 10amps minimum and many at 20amps or better, lead acid or lithium, medical carts as a prime example.

Safety is a concern in hospital working environments.

I'd like to hear more exactly what charge rates you consider safe because by almost everything I've read 1C or less is fine, except that is, here and by you.
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  #33  
Old 05-27-2016, 10:50 AM
dannyg1 dannyg1 is offline
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Here's a link that I'll use as citation:

http://www.powerstream.com/SLA-fast-charge.htm
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  #34  
Old 05-27-2016, 11:36 AM
Mandobart Mandobart is offline
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Interesting link Danny. I don't work in battery design and production; I'm in the use and maintenance end. The info in your link is the first time I've read that type of advice. It is possible that those in the battery/charger production and sales side could have different goals and motives than those in the use and maintenance side. This link is much more in line with the way I was trained in the USN and what we practice at the power plant. Granted that in my professional life I'm talking about multi cell industrial lead acid batteries in the 125 - 250 VDC range. Also, my professional experience is with relatively old technology, using batteries and chargers designed and built decades ago. The newer technology may very well have changed some of the old rules.

That said, I've always treated my vehicle and storage batteries like the ones at work, and I've had several last over 10 years. I think its unlikely that a high charge rate will be unsafe (unless the charger has some serious malfunction) but my training and experience is that consistently charging a battery at a 1 to 3 hour rate will shorten its performance and life. And I personally have no need to do so. My 2 A charger will restore a dead 35 A-hr battery in 17.5 hours. But my battery is never dead - I discharge it half way at most, meaning I need to restore 17.5 A-hr or less, which will take 9 hours (or less).
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  #35  
Old 05-27-2016, 12:27 PM
Bobby1note Bobby1note is offline
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I've run battery-powered rigs for roughly 9 years now, from compact/ultra-portable 1-man set-ups, to much more capable and elaborate set-ups, complete with twin 12" powered speakers, monitor(s), 12-ch mixer, and LED stage lighting. Basically, I'm using a single 12v/115ah deep-cycle battery(paid $89. at Costco in 2007), and I have a pair of Xantrex MSW 12vDC-120vAC inverters; one is rated at 300w, and the other is 1500w. The battery is relatively heavy, so I use a rolling/folding luggage-cart to move it around. I've never (repeat; never) had a lick of problems or issues with this set-up; no noise; no hiss, no issues period.

The small inverter easily handles my Compact 60, or any other amp that I have, for 8 hours and more. I don't have to compromise and use some of the cheap-sounding battery-powered amps that I generally see being sold for this type of application.

With the larger 1500w inverter, I've run a pair of Yorkville NX55P powered speakers for mains, as well as one NX55P as a floor-monitor, plus a 12ch Soundcraft EFX-8 console, and a few LED wash-lights, for 8 hours, with no sign that the rig was "running out of juice".

I bought both inverters on half-price sales at Canadian Tire, in 2007-8, and those ended up costing me $28. and $76.
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  #36  
Old 05-27-2016, 12:51 PM
dannyg1 dannyg1 is offline
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Mandobart, it's good to see that you tend towards John Fetter as the internet source for go9d battery info as well. Here's the page on ultra fast charging.


http://batteryuniversity.com/learn/a..._fast_chargers

According to this 1C is considered a fast charge and not ultrafast. I've had mostly good results using my 25amp charger and have never had an AGM seem warm to the touch after charging, including my 6ah 12v. I will ask John to specifically recommend charge amp and volt regimen and limits for various AGM batts and see what he says.

It should be noted though that in the comments sections of many of the pages Mr Getter is severely critical of modern AGM batteries and says that we'll all be lucky if they last a year at reasonable capacity.
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  #37  
Old 05-27-2016, 12:59 PM
dannyg1 dannyg1 is offline
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Bobby1note, it's experience like yours that keeps me from being too reticent about recommending modified sine inverters (and which leads me to believe boxes like the Duracell 600 can be fine low to moderate use solutions).

The advantages of pure sine are dramatic on the efficiency side though , which means less battery weight for the same run time and couple that with lower power supply stress, those things lead me to recommend pure sine to people using the systems more than every once in a while.

I'm big on the sound quality issues as well .Only the most expensive OEM solutions can compete with moderately priced amps run through an inverter set. There's no comparison.
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  #38  
Old 05-27-2016, 01:26 PM
Fret-O'File Fret-O'File is offline
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Quote:
Originally Posted by dannyg1 View Post
Bobby1note, it's experience like yours that keeps me from being too reticent about recommending modified sine inverters (and which leads me to believe boxes like the Duracell 600 can be fine low to moderate use solutions).

The advantages of pure sine are dramatic on the efficiency side though , which means less battery weight for the same run time and couple that with lower power supply stress, those things lead me to recommend pure sine to people using the systems more than every once in a while.

I'm big on the sound quality issues as well .Only the most expensive OEM solutions can compete with moderately priced amps run through an inverter set. There's no comparison.
If the Duracell 1300 (don't see the 600 available) is fine and not much to worry about as far as being modified instead of pure, it sure makes it a no-brainer and a very easy setup to lug around. Having the battery, inverter and charger all in one would be so convenient.
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  #39  
Old 05-27-2016, 01:36 PM
dannyg1 dannyg1 is offline
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Kurt, the Schumacher box at Wal-Mart is very inexpensive for all that it does (there's a charge circuit in there too) and has a 22ah battery in it for $130.

Other than that these boxes are ugly as sin, they're probably a good place for most people to start. I'd ask Schertler if they have any caveats about your using a modified sine inverter, just to be completely assured.
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  #40  
Old 05-27-2016, 01:46 PM
Fret-O'File Fret-O'File is offline
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Quote:
Originally Posted by dannyg1 View Post
Kurt, the Schumacher box at Wal-Mart is very inexpensive for all that it does (there's a charge circuit in there too) and has a 22ah battery in it for $130.

Other than that these boxes are ugly as sin, they're probably a good place for most people to start. I'd ask Schertler if they have any caveats about your using a modified sine inverter, just to be completely assured.
That's a good idea Danny. I had questions about a couple of other things and they responded quickly. I shoot em an email and let you know what they say.

How do you like the Jam 100? If I remember correctly you did pick one up.

I've been really digging the sound of it as well as the Schertler MAG6 & S-Mic. I'm thinking about adding a JJB SBT for a third source and one that can be EQ'd separately just to see what I get, maybe overkill but they are cheap enough to check it out.
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  #41  
Old 05-27-2016, 01:47 PM
zhunter zhunter is offline
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When I tried powering my Unico with a 400W MSW inverter, the noise was unbearable.

hunter
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  #42  
Old 05-27-2016, 01:51 PM
Fret-O'File Fret-O'File is offline
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Originally Posted by zhunter View Post
When I tried powering my Unico with a 400W MSW inverter, the noise was unbearable.

hunter
Really? Did you end up picking up a Pure SW inverter?
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  #43  
Old 05-27-2016, 02:01 PM
dannyg1 dannyg1 is offline
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I think the Jam 100 is a fantastic sounding and looking, amp . I have a real problem with the front end though and it's made me move on to other options.

Specifically the eq's and reverb are too subtle and don't seem to offer enough control to be useful on the street, where dramatic cuts and heavy reverb sounds can be required. In keeping it to use for club gigs and stages, because it's so incredibly neutral and powerful sounding. For my current everyday use, I'm moving to either the Genz Benz Compak 300 or the Fishman Loudbox 100. I may just end up back where I suspected I needed to be, but before I could afford it, at the Loudbox Artist.
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  #44  
Old 05-27-2016, 02:10 PM
Fret-O'File Fret-O'File is offline
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Quote:
Originally Posted by dannyg1 View Post
I think the Jam 100 is a fantastic sounding and looking, amp . I have a real problem with the front end though and it's made me move on to other options.

Specifically the eq's and reverb are too subtle and don't seem to offer enough control to be useful on the street, where dramatic cuts and heavy reverb sounds can be required. In keeping it to use for club gigs and stages, because it's so incredibly neutral and powerful sounding. For my current everyday use, I'm moving to either the Genz Benz Compak 300 or the Fishman Loudbox 100. I may just end up back where I suspected I needed to be, but before I could afford it, at the Loudbox Artist.
I noticed the reverb being a bit on the weak side but it's plenty for indoor use. I hadn't thought about the requirement for out on the street. The EQ seemed adequate but a sweepable mid sure would have been nice. Adding a decent preamp to give some more EQ options is easy enough.
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  #45  
Old 05-27-2016, 02:20 PM
dannyg1 dannyg1 is offline
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I keep looking at the prospect of using a seperate front end and other than the TC helicon play acoustic or the Zoom r24, I don't see any affordable options around. The ones that are available seem to offer good amounts of control but everything is buried in touch screens and nested menus.

Something like the Grace Felix with a reverb section and at a cost of sub $400 doesn't seem to exist. The box I keep coming back to is the Qsc touxhmix 8. Costs more than any of my amps though and runs at 19v (if I remember correctly). Maybe a tonedextet with a vocal channel and reverbs will come out in the future.
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