LED bulbs, Batteries & Charging

[geeyou]

Hi folks!

This year will be my first burn and unfortunately I am a bit of a noob when it comes to electronics, and so I was hoping I could borrow some of your wisdom

My team and I will be building a small pavilion and in order to light the piece at night I have proposed 20 x 12W LED light bulbs (12V) at various locations which will be powered by deep cycle batteries.
Assuming these are lit up for 8 hours a night, doing simple calculations I've worked out that a night would require 160Ah.
12W @ 12V = 1Ah
20 x 1Ah x 8 hours = 160Ah

Therefore I've decided to go for 2 x 90Ah Deep Cycled batteries in series to obtain 12V 180Ah.
http://www.batterystuff.com/batteries/u ... 45826.html

These batteries will be recharged everyday during the day, and I've gone for a 12V 20A charger which will likely take 10 hours to charge the batteries (not sure if more would be a good idea, as I've been told it may just end up being "surface charged").
http://www.batterystuff.com/battery-cha ... -1120.html

I hope I am on track so far but this is where I'm a bit lost as I'm not quite sure how to work out what generator is best suitable for this setup...
If the generator charges the batteries at 20A at 12V for 10 hours (2400W), I should look for a generator that can output 2400W + power?

[Jackass]

Go big, put two of these in series.

[Captain Goddammit]

There are several miscalculations here.
The 20 amp charger at 12 volts is only 240 watts.
The charger will be plugged into a 120 volt AC generator. It would only be 2 amps at 120 volts. The system isn't perfectly efficient, but it'll be a tiny load on the generator.
The "20 amp" charger probably will not be charging the batteries at a full 20 amp rate. That rating is a theoretical max. Usually the rate will be much less.
The batteries will only charge at (or near) 20 amps when they are dead. The rate will decrease as they charge up.
And about batteries... you can't really use all the supposed capacity. You don't want to discharge them more than roughly 50%. And even if you did go further, your lights would be very dim.
You need about twice the rated amp-hour battery capacity as your load draws.

So... I believe you need twice the batteries, and either a much larger charger or several smaller ones.

[geeyou]

Thanks guys, much clearer now.

You don't want to discharge them more than roughly 50%

Hmm interesting, I actually thought Deep Cycle batteries were designed to be drained deep, but I keep getting mixed information about whether this is true or not.

Didn't notice the 12V output from the generator is limited to 6-8 amps output neither.
So assuming the charge rate is constant (impractical indeed, but just need to confirm the methodology re calculations!):
Using a 12V 20A battery charger with a 120VAC / 240VAC power supply to charge 12V batteries (~160Ah used) will take roughly 10 hours to recharge and yield about 240W while it charges?

[Captain Goddammit]

Theoretically according to math that leaves out a lot of other factors, yes.
But in practice, no.
The functional difference between deep cycle batteries and starting batteries is deep cycles are designed to provide lower amounts of current continuously for a longer time, and starting batteries are designed to provide large bursts of current for a shorter time.

[skippy3k]

Deep cycle batteries have thicker lead plates, which lends themselves to be better able to withstand extended discharge and charging cycles. So theoretically they can be drained more often than "regular" batteries without damage. But it's still hard on them.

[SnowBlind]

I actually thought Deep Cycle batteries were designed to be drained deep, but I keep getting mixed information about whether this is true or not.

Deep Cycle batteries can certainly go much lower than a regular car battery. Car batteries are designed to give a fairly high current for a couple of seconds, and then be recharged more or less right away. If they are discharged to low, especially if left low for longer periods, they will get damaged.

Deep Cycles are more resilient and handle lower discharges better, but only to a degree. If they get discharged all the way, or left discharged for long periods, they will take damage as well. The 50% number is usually consider the safe limit for deep cycles.

[geeyou]

Thanks for the explanation guys

Just as an update I have now decided to run the 160Ah setup off a 250Ah AGM Deep Cycle battery (either Universal or Scorpion), which will be charged during the day using a Samlex 12V 50A charger and should take approximately 4 hours to charge to full!

The charger will be running off the 230V output of a Yamaha EF2000is generator (I believe the Yamahas and Hondas are very playa friendly...) and although the setup only uses about 600W, we'll be using the generator for other things at the same time (charging other batteries).

[digital]

TThe charger will be running off the 230V output of a Yamaha EF2000is generator (I believe the Yamahas and Hondas are very playa friendly...) and although the setup only uses about 600W, we'll be using the generator for other things at the same time (charging other batteries).

I absolutely love my Yamaha 2000is. To me, it is the perfect single person playa generator.

[Token]

Pardon my crazy thinking here ...

240W of LED lighting! Do you really need the equivalent light of 20 x 100W incandescent bulbs? It will be crazy bright in the Playa night. Maybe you have a 5000 square foot pavilion or some such.

You are willing to spend big bucks on heavy deep cycle batteries and industrial chargers to store KW's of juice that can alternatively be directly run from a lowly Honda EU1000 with power to spare which you will need anyway to charge the unnecessary batteries?

Even if you really want all that lighting, why not just run everything from the generator and invest some money on an external gas tank so you can just run all day and night.

[Captain Goddammit]

Ok wait a minute here. The Yamaha ef2000is DOES NOT have a 230vac output.
The Samlex will work though because it can operate on 120vac.
I still think you will be a little short on battery capacity but it'll probably work well enough.
Physical testing ahead of time would be VERY prudent.

I do think you're a little crazy to spend that much money on chargers and batteries when, as was mentioned, you could just run on the generator directly.
You're gonna run it just as much or more using your inefficient, more expensive and unnecessarily complicated system.

By the way, 240 watts of LED lighting isn't that much, I have more than that on my MV!

[geeyou]

It will be crazy bright in the Playa night.

Haha, you might be right. I've always been quite pessimistic about how bright the lights will be, even my renders have probably been quite unrealistic.
http://i.imgur.com/uMmVJTZ.jpg

Even if you really want all that lighting, why not just run everything from the generator and invest some money on an external gas tank so you can just run all day and night.

as was mentioned, you could just run on the generator directly.

Hmm I had not considered this option before. The reason for this was because we actually have three pavilions we're building at different sites, all of which run off batteries and we were hoping to share a single generator which will sit at the camp to charge all the batteries (hence 2000W). Since these quiet generators are more reliable but cost more, it feels like a cheaper option to split the cost three ways rather than getting three separate smaller generators.

But if I were to run directly from the generator, all I would need is to do is wire the bulbs together, get an inverter and run off the 120vac?

[Token]

Ah, the plot thickens!

Consider the following:

10 x 3/5W LED, like the Luxeon or Cree. One of the 700 - 1000 mA drive jobbies.
1 x 100W Solar Panel
1 x 10A Charge Controller
1 x 105Ah Battery

Repeat at each pavilion.
Low maintenance.

That's a lot of work for your first year. The whole slaving over battery charging every day, lugging stuff every few hours. Epic Fail. Just don't even consider it. After the second day you will say fuckitall and burn the pavilions, LED lights and all.

[Captain Goddammit]

That's a lot of work for your first year. The whole slaving over battery charging every day, lugging stuff every few hours. Epic Fail. Just don't even consider it. After the second day you will say fuckitall and burn the pavilions, LED lights and all.

That is exactly the reality of it. Way too much tedious time consuming work and expense.
If you go simple and just run on generator at at least one of your pavilions, why then bother with the expense and hassle of stepping down to 12 volts? Just use 120 volt lights. And if you're on a generator, you can just use the cheapest light bulbs and be fine.
You're putting up three pavilions in three different locations? As in, too far apart for running cords between them?

[geeyou]

lol these alternatives sound better already, more fun less work! Sold

Although I have never worked with a solar panel before, I presume the driver is used to regulate amperage into the LED lights from the 12V battery to make it more efficient, then the 10A Charge Controller will deal with charging the 105Ah battery via the 100W solar panel during daytime?

You're putting up three pavilions in three different locations? As in, too far apart for running cords between them?

Yup, we had submitted several proposals for grant and three of them got it so they're kinda treated as three separate things - just that we're all sharing a single camp together. Running straight from generator does sound more and more appealing as it actually works out cheaper if we just get a second hand Yamaha, hooking to external tank isn't expensive neither.
My only worry is that if the generator is at the artwork it might ruin the mood a bit hearing the generator in the background? I'm not sure how quiet the playa gets during night time...but then these generators are built to be quiet so maybe it won't be so bad.
Mathematic wise, I presume with a 1000W generator I'll be able to run 20 x 50W bulbs - and anything above this will be an overload..

[tink2011]

Just some advice here from a long-time burner and mutant vehicle owner. Go with the generators at every site. They will last longer than the batteries and be little to no work. Since you are virgin burner, you are imagining running all over the place dragging batteries and regulating generator use and then running batteries back to the pavilions as "worth it to show your art"...I'm here to tell you that will NEVER happen on the playa. You are going to get all turned around at 7:30 and F (or is it 8:15 and D?), amazed by everything you see and find yourself sipping a bar concoction while watching clowns jump on trampolines or men throwing rubber darts at naked women and you will completely forget your pavilions. It will suddenly be dusk and you'll realize that you completely spaced out charging a set of batteries and you're now screwed! That's when you will be one million times happy that your camp invested in the extra generators. No muss, no fuss (and will last years longer than the battery set-up). HAVE FUN!

[Captain Goddammit]

As a pretty long time burner I'll wholeheartedly agree with everything tink2011 said.
One small extra bit of info: the playa altitude is almost a mile high, the air is thinner and motors make less power. As a result, generator output on the playa is a little less than normal.
Figure 15 or 20%.

[geeyou]

Thanks guys! Yea I think we're pretty much going to run it straight from the generator.

Just need to figure out how to trench the cable now (placing the generator some distance away from the art) and source some IP67 120v spotlights
Then I can just wire all the lights together into a single plug (parallel), grab an external fuel tank...and done hopefully!

[geeyou]

Hmm actually I've been trying to source IP67 spotlights all morning and they all seem to be LEDs, the cheap ones at least...
Initially I thought LEDs were only 12V but then a few of them actually say they have an input voltage of 110-277V, I guess these fittings have a built-in transformer / miniaturized circuitry to convert AC to DC?

I have also just tried screwing a 12W LED bulb into a standard bulb holder and plugging it into the socket...and that worked so I guess that's the same principle

[geeyou]

lol sorry to spam, I wish i could edit my previous posts
Did some more research and I believe this is to do with GU10 / MR16 fitting, where the former doesn't require any additional transformers.

I'm hoping then that I can get several lights like this that I can just wire together and plug into the generator!

[GreyCoyote]

Actually Capt, there are 240v variants of both the Honda eu2000 and the Yamaha EF2400, and it appears he is coming from offshore, so its possible he is bringing one.

OP: check your voltage. It matters!

[geeyou]

Quick amperage question...

If I take 20 x 120VAC 10W LED Lights (such as these) and connected them in parallel and power them straight from the generator, the total current in the circuit would be rougly 83mA x 20 = 1.6Amps.

If I then take the same lights that run on 12V DC (such as these) and connected them in parallel and power them via 12V batteries, the total current is suddenly 0.83A x 20 = 16.6Amps, which is more than an 18 gauge wire can handle (commonly used in lamps I've been told...), so I'd have to replace all the wires in the fittings with something stronger? Have I overlooked something?

[Popeye]

Yes, #12 wire for a 20A load #14 for 15A. Always a good idea to go up one wire size for long runs, say over 100 feet, to minimize voltage drop.

Edit to add: wire size is determined by ampacity which is the cross sectional area of the wire and the material it is made of and somewhat by insulation type not by the power (VxA). Use 12 and you should be ok.

[geeyou]

Aha, thanks Ulisse! Better stick to 110V stuff then haha.

As it stands, I think my easiest option (also laziest and probably cheapest ) is to go for 20 of these AC spotlight fittings, wire them in parallel using a junction box / terminal blocks, hide everything inside the pavilion and just have a single outlet cable coming out (and trenched) connecting to the generator 30ft away with a baffle box.

The power output is only about 200W so a Yamaha / Honda is probably overkill...has anyone used a Kipor before? This is a lot cheaper and the sound level in the spec seems decent.
http://www.amazon.com/Kipor-770W-Digita ... ator+1000w

[Captain Goddammit]

That's a tough call... yes, the Kipor will work and people report them being pretty decent.
It boils down to what else you'll do with it after the art display this year. In the long run, the Honda (or Yamaha) is pretty cheap. I ran my last pair of Honda EU2000s for 12 years, and sold them for $1400! And they still worked great, in sure they have another 12 years in them. And when you need parts, you can get anything for a Honda easily. Long term, the Honda is probably the cheapest, considering how many years it will work and how much resale value it has.

If you're just buying the generator to use this year on that art project and don't care about future use, I'd say buy the Kipor.

[geeyou]

Sorry guys, need to pick your brains again
Just wanted to check this is the right way of setting up parallel lighting using terminal blocks, before I blow everything up!



1. If I group all the Live / Neutral / Earth wires into a single terminal for each respectively, will the current still split evenly? (i.e. Red circled area is currently 2 sets of wires sharing 1 terminal)
2. The wire that comes with the light I can't really change...but if current is shared evenly then all I need to make sure is that the wire on the other side of the terminal is able to carry at least 1.6A?

Appreciate your help!

[digital]

I don't see any resistors in your circuit. Are they part of the LEDs?

LEDs are typically pretty sensitive so you might consider resisting the flow of electrons as not to damage the diodes.

[geeyou]

Ah I'm not sure actually...these are LED spotlights (had to use Fritzing for the diagrams! ) and I thought normally you'd only need resistors for those tiny LEDs with the 2pin legs?

[digital]

I thought normally you'd only need resistors for those tiny LEDs with the 2pin legs?

Or three pins. Or four.

In your diagram above I just see raw LEDs. If they are some kind of assembled unit then they might have the necessary circuit inside -- just be sure before hitting the playa.

That said, still not a bad idea to add resistors. Just in case.

[Popeye]

Sorry guys, need to pick your brains again
Just wanted to check this is the right way of setting up parallel lighting using terminal blocks, before I blow everything up!



1. If I group all the Live / Neutral / Earth wires into a single terminal for each respectively, will the current still split evenly? (i.e. Red circled area is currently 2 sets of wires sharing 1 terminal)
2. The wire that comes with the light I can't really change...but if current is shared evenly then all I need to make sure is that the wire on the other side of the terminal is able to carry at least 1.6A?

Appreciate your help!

If you are using the 120VAC 10W fixtures you listed above I would be very surprised if they need additional resistors. These light fixtures look like they have a 12" or 18" cord coming off them. This cord will carry 10 Watts divided by 120V = .0833A.
The wire coming from your generator and feeding 20 fixtures will need to carry 20 x .0833 = 1.6A.
If you go back to your original idea of 12VDC fixtures the amperage draw will be 10 times that for the same power. Reduce voltage increase amps porportionally and power stays the same. Somewhere areound here the Captain has a page that explains this very well.