12 power supplies, batteries, options for cart.

[larry long]

For the Cart based folks here,

How do you distribute power?

Do you use a battery? or a 12 volt power supply?

Can you put a charger on your battery while using it?

I'm looking at PSC  Cart Power, and Remote Audio Hotbox. The PSC has built in 8 amp power supply although I'm not sure it would be enough to run a Cooper 106, Deva2, SD 702t, a Monitor and a Venue.

I'm also building pelican battery with a SLA 33aH batt, any recommendations for a charger?

thanks,

Larry Long

[David Terry]

For the Cart based folks here,

How do you distribute power?

Do you use a battery? or a 12 volt power supply?

Can you put a charger on your battery while using it?

Larry Long

Larry,

I have a rack space on the rear of the cart with 12 XLR-4Fs (one XLR4-M) that are paralleled.  The XLR's get power from standard 12V 32AH gel cell/Pelican.  The battery is resupplied by a 12V switching power supply.    This power supply keeps the battery topped off and if AC power gets pulled by accident, my system keeps going without a hitch.  Of course I can run for several hours just on a battery...

This worked fine until I added a Deva and DVD-RAM.  Got buzzy!  I presently use a separate battery for those, but plan to build an isolated power supply-distribution system to replace the paralled XLR 4 rack, using DC to DC converters.   

David Terry

[Jeff Wexler]

I have had the best success with cart power supplies I have built on much the same principles that David Terry outlines. In the simplest terms it consists of a sealed lead acid battery of whatever capacity you need or are willing to live with weight wise, and an AC powered Regulated DC power supply. NO CHARGERS involved in this supply --- I have never seen a cart power supply that works properly when employing any sort of CHARGING circuit --- they almost always create audible switching noise.

As David points out, when AC is available, the Regulated DC Power supply provides a nominal 13.8 vdc that "floats" across a fully charged battery. If you have sized the current rating of the power supply to match or exceed the current draw by the equipment, the equipment operates, the battery stays fully charged and in a sort of standby state. If the AC gets pulled the equipment continues to operate but drawing on the battery alone. When the AC is restored, the power supply replentishes the battery while also continuing to operate the equipment.

Lastly, the way in which this DC is distributed to the various pieces of equipment on the cart can be problematical. One solution for many of the problems (and possibly this is where David had buzzes) is to make the cabling that goes to each DC connection point as HOME RUNS. That is, NOT several 4-pin XLR-F connectors wired in parallel but rather each connector wired directly to the output of your cart powerv supply. This for some reason helps to solve problems that may develop amongst various devices being powered from a common power source. You may find that there are some devices because of the design of the individual power supplies used in the piece of equipment and how it behaves when connected to a common power source, that noises cannot be avoided. This was the case for me with a Lectrosonics T-1 IFB transmitter on the cart (an item I no longer own or use). If the T-1 was connected to external battery supply and anything else on my cart was connected to the same supply and then connection (audio) was made to the T-1, buzzing was unavoidable.

Regards,  Jeff Wexler

[larry long]

Can you recommend a particular power supply ? Also is your battery enclosed? Vented with a fan?

thank you gentlemen

[Darren]

I use a 32ah gell cell.  DC power from this is routed to a heavy duty marine rated bus bar, via a 12 guage cable, where it is is then distributed to all of the devices that require it, via 16 guage wire.  It is very important to use the appropriate guage of wire depending on what the current draw of your devices are and the length of the wires needed.  If the wire guage is too small, you will experience voltage drop.

I have an actual charger, rather than a DC power supply, built into my cart.  It is a Samlex 1215 "smart" charger with a 15 amp max output.  I have the charger plugged in whenever there is AC available, which these days is just about always.  I have not experienced any adverse audio artifacts as a result of using this charger rather than a DC PSU.

A recent addition is a Samlex 300 Watt Pure Sine Wave inverter to run my 01V96.  This is connected directly to the battery via a very short 12 guage wire.

[Simon Paine]

Remote Audio aparently has something coming out very soon.

Here is a little bit of info: http://www.trewaudio.com/meon.htm

Looks promising.

anyone see it in person yet ?

[Jeff Wexler]

I saw the RemoteAudio cart power box at NAB. It is solidly built, very well thought out (as are ALL of the products that come out of RemoteAudio) and would provide long lasting and very secure power for even the most current hungry sound carts. One of the most unique aspects of this unit is the use of Nickel-Metal Hydride batteries instead of the much more common sealed lead acid batteries. There are many benefits to using these batteries but COST is not one of them. The NMh batteries have a totaly different charge - discharge characteristic that Glen Trew feels provides distinct advantages in a cart power supply. They do require a unique charger which is built into the box and they are not pleased with a regulated power supply "float" across the battery (so there is a regulated DC supply but it is not connected to the battery). So, if I understood the description from Glen Trew, when AC is available it is the AC that is powering the DC poower supply which is powering the equipment, and then the AC is also powering the charger which is charging the (unused) battery. When the AC goes away, everything switches over to pure battery power (charger turns off) and the battery begins to discharge. All of this happens seamlessly, or so I was told, and with proper attention paid to the extensive diagnostic and status readouts, it will provide reliable all day powering of any sound cart.

The unit is going to be quite pricey, I think around $1800., and for me it is too complex and overkill for my needs. I'll stick with the cart power supplies I have built myself --- approx. $200. in parts and about a day to build.

Regards,  Jeff Wexler

[larry long]

Glen mentioned the Meon to me, looks cool. I heard the price was like  $1,500 from someone other than Glen.

Darren, I checked out some Samlex products, ty.

So Glens Hot box powered by a batt in a case on the cart with a http://www.tessco.com/products/displayProductInfo.do?sku=12892&eventPage=1 power supply atached to the batt? seem like the right setup? So this Power supply acts like a charger by keeping the batt topped off while actually just using the supplied regulated power, right? ( don't wanna blow up the stuff I just got lol )

Many thanks there are so many options it hurts my brain.

Larry Long

[Fernando]

I was using lead acid batteries before (small 7Ah to be more modular)

Now I'm using 65W Li-Ion NP1 and I'm very happy. I have 14 currently.

I run the Deva with 2 for a long day. 1 or 2 for the wireless video RX and monitor. 1 or 2 for the wireless and wireless feed to video/director.

The deva uses one internally and one externally with a NP1 box. The video has a single box and swap the battery manually, same for the wireless (although I'll get a double box for this)

I try to avoid distribution as much as I can. If I have to, I use a BDS or a small box I built with the cables going out of it instead using male and female connectors to keep it simple and much lighter.

This way I never have to plug my cart to AC, so one less cable and one less thing to worry when re-setting. In fact I only use one cable, the boom one, and I'm going to eliminate it very soon.

Li-Ions are also very light and using NP1 means you only carry the weight you need/want.

I can charge 8 65W NP1 in 5 hours using two 4x chargers from Proctor&Bray (UK). IDX has one that can charge 4 in 2 1/2 hours.

Fernando

[S Harber]

I use an Astron 14 amp dc power supply, they comme in a few sizes/thicknesses, that floats over 35aH battery in a pelican.(Take the air release valve off forever on this)

Very cost effective and works like a charm.

This is distributed to the back of the cart where it hits a few 4 pin xlrs on a rack panel.

Then there are run to the cooper, the cantar, monitors and an ifb.

There is also a run to the wireless section that fans out 8 ways rather than having individual runs. Venue is around the corner.

Scott Harber

[Jeff Wexler]

I don't know any way around the weight factor as long as we go on using sealed LEAD acid batteries. You just have to make the decision how much capacity do you need on the cart and how much weight are you willing to put up with. Those who are pursuing other battery technologies (nickel metal hydride, lithium ion, etc.) will save on weight but will have other factors to consider (cost, specialized charging schemes, etc.).

As far as powering the Cooper, my older 106+1 as many of you may know, really wanted to see at least 15 vdc, particularly for proper use of Phantom power on all inputs. When I was using the 106+1 it typically did not get the full 15 vdc it wanted but rather was usually getting the nominal 13.8 vdc that was powering everythig else. Now, everything on my cart, including the Cooper 208, is much more forgiving on the range of DC voltage it likes to see, typically 10 vdc up to 16 vdc range, so I do not have a problem with proper voltage going to any of the equipment I have on the cart.

At present, my main cart supply has only 20 ah battery capacity (this is the battery on its own) so I have limited run time for the whole cart if no AC is present, but I also have light weight. I have made a companion chassis box that sits on top of the main cart power supply and this has an additional 20 ah for a total of 40 ah when I think I will be in situations without AC. This add on need not be on the cart adding weight when it is not needed.

Regards,  Jeff Wexler

[larry long]

Rich,

Glen Trew makes a Juicer that steps up 12 volt to 24. I intend to use this on the 106 with his hotbox and the 13.8 power supply I just got.

S Harber,

Two things, So if I put two female 4pin xlrs in the pelican case both wired straight to the terminals, come out of my power supply via 4 pin, plug it into one of the battery ports and take the other out of the batt to my dist it should float the fully charged batt. Right?

Second, Do you fuse the batt internally?

Thanks,

Larry Long

[Jeff Wexler]

Second, Do you fuse the batt internally?

Thanks,

Larry Long

I fuse everything but not internally, externally accessible fuses or breakers. I fuse the DC output from the battery to the 4-pin connectors, I fuse the DC output of the regulated power supply that is feeding the battery, I fuse the AC input to the power supply. Actually, the last 2 cart power supplies I built I used fast acting circuit breakers, the push-pull switch type (like the ones on the Steadicam) so they act as switches also.

-  JW

[larry long]

Jeff,

Fuse the hot side with like 15 amp?

LL

[Jeff Wexler]

Jeff,

Fuse the hot side with like 15 amp?

LL

Yes, although use a 10 amp breaker (and anyone here who is far less electrically challenged than me, and that's probably almoist anyone else, should chime in here about fuse protection practices, amperage, etc.

-  JW

[larry long]

Jeff,

You have explained this to me but I'm kinda freaked by power.  I understand signal flow with audio, I just need things spelled out for me as far as power. I need to know which safeguards to put in place. I can't fry this new gear.

My new cart will be coming alive this week and I'll post pics of it as it is built.

Everybody, thanks for the help! I have more questions than answers. I'm not a newb but I'm going out on my own now. Been mixing for 11 years under someone elses umbrella.

Thanks all,

Larry

[S Harber]

So if I put two female 4pin xlrs in the pelican case both wired straight to the terminals, come out of my power supply via 4 pin, plug it into one of the battery ports and take the other out of the batt to my dist it should float the fully charged batt. Right?

Second, Do you fuse the batt internally?

Yes, one XLR for the DC input and the other to the output that goes to a DC distro, both XLRs are connected to the battery which allows the DC supply to float over the battery when plugged in. This does 2 things;

Keeps the battery charged while supplying DC down the chain.

Reverts back to the battery if the DC supply is unplugged for whatever reason.

The battery is fused on the + legs/pin4.

Scott Harber

[larry long]

Think I'm catching on fellas thank you.

Larry

[FSBELLA]

LL,

I think yr on the right track with the psc power max (6 individual outs with isolated filters per. also, it chargers yr pel.batts) & 2-12v pelican batts (excide charger) or wait a few weeks for the remote audio meon, that product looks to be winner.

later,

fsbella

[larry long]

Hey this should power the Macbook and my DVD-ram ya think? Coming off of the 13.8v supply with a 33 ah batt floating in there.

http://www.invertersrus.com/inv150ps.html

Frank it took me awhile to put your username with your real name, the "Grits" comment did it. You still at LSC?

LL

[Darren]

Hey this should power the Macbook and my DVD-ram ya think? Coming off of the 13.8v supply with a 33 ah batt floating in there.

http://www.invertersrus.com/inv150ps.html

Larry,  Just make certain that where ever you purchase your inverter has a generous return policy.

I recently tested quite a few sine wave inverters.  I found their published specs to be shark infested waters even with popular brands.  One 300 watt sine wave inverter I tested would trip it's internal breaker every time I would try to power it up with only an 80 watt load.  All of the other 300 watt sine wave inverters I tested worked perfectly with the very same load.  Try to determine what your load's surge (power on) requirements will be and make certain that the inverter that you use is capable of handling it.  Surge ratings very greatly on different manufacturer's inverters, even though they may all have the same continous power rating.

Also be aware that some inverters emit audible buzzes or hums and some have fairly loud fans that cycle on an off as required.  As well, some inverters can cause RFI problems.

As far as power requirements go, I am not entirely certain but I believe that the new macs require 80 watts (plus whatever their surge requirements are) so, together with your drive, 150 watts may be cutting it too close.  Other specs to pay attention to are efficiency (expressed as a percent) and no load current draw.

Best,

Darren

[larry long]

Darren,

Thanks for the advice, I just got a little 175w and I'm going to try it this week, 30 day return policy =).

Came across this in my never-ending power quest.

http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_200313775_200313775#productinfo

Something to keep on the truck maybe ?

thanks again,

LL

[Darren]

Came across this in my never-ending power quest.

http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_200313775_200313775#productinfo

Something to keep on the truck maybe ?

Larry,

I have this exact unit in my truck.  It serves two purposes for us.  It provides power to the truck on the rare occasion that the electrics dept have not been able to provide us with any (and we need to load the truck at night and want to turn the interior lights on, or when we need to do some quick soldering), and it is used for an aux battery for my sound cart on the even rarer occasion that we need to be able to operate for a significant portion of the day without power.  This device is a very worthy investment.  They can often be found on sale at reduced prices.

Best,

Darren

[Guest tourtelot]

I like these for inverters:  http://www.donrowe.com/inverters/puresine_300.html.  The only change I made to mine was to put in a Speakon 2-pole (I don't use 4-pin XLR for the main feeds; way to small a contact area) and a Pabst ball-bearing fan with a 100 ohm resister in-line to slow it way down to make it quiet(er).

D.

[Darren]

I like these for inverters:  http://www.donrowe.com/inverters/puresine_300.html.  The only change I made to mine was to put in a Speakon 2-pole (I don't use 4-pin XLR for the main feeds; way to small a contact area) and a Pabst ball-bearing fan with a 100 ohm resister in-line to slow it way down to make it quiet(er).

D.

Yes, that is my favourite inverter as well.  In fact, if you look at the photo of the rear of my cart, you will see this exact inverter mounted there.  It powers my 01V96 and one of my backup hard drives.  However this does prove what I was referring to about specs being shark infested waters.  The URL you have supplied gives a spec of >90% efficiency while Samlex's own site states that the efficiency is 85%.

http://www.samlexamerica.com/customer_support/pdf/sinewave.pdf

I'd love a source and part number for that fan if you have one.

Best,

Darren