CMB16D Portable power and a Secondary question

[thebaronn]

Hello!

For the last few years I have been using the DC boards with lantern batteries and the ELLs for a mobile lighting effect for halloween.

Here is the typical setup. 2 Lantern Batteries for the 12V power. Then 1 lantern battery for a 6V power supply on the 2nd bank which is where I ran the lights from (4.5V battery operated LEDs from Creative Displays and Novelty Lights). I was sporting 3 lantern batteries, ugh.

Then the last year, some one mentioned that I could use the 2 lantern batteries for the board and just draw 6V from one of the two (that battery would just discharge faster) and that worked. But again, 2 lantern batteries, ugh.

Funny thing is I used the same lantern batteries 2 years in a row!!!

1st question: This year I am interested in doing something different. I am looking for a lighter setup and a rechargeable option. I am not an electrical person at all. I purchase my stuff put together because there is a far greater chance that I can get it working! What kind of power supply would I need to run 12V to power the DC board and ELL? And really it only need to work for 4-5 hours. (halloween is usually four 10 minute shows accross a 2 hour period).

2nd question: All these years I have been using 6V lantern batteries to power 4.5V Battery LEDs (20ct LEDs strings). Usually 10-15 sets of lights run off of one lantern battery. Now, I know that when I hook just 1 strand to the Lantern battery, it gets fried pretty quickly. But they "seem" to be okay when I have that many. (i have lost random strings occasionally) This year I would also like a rechargeable option for these lights. Would I look for a 6V option or should I tone it down? I am open to all options right now. And does anyone know how much power these consume? On the websites, they usually say: will run for for about a day off of 3 AA batteries! (I mean, I have no clue anyway and then they give me this arbitrary number???)

Thank you in advance!

Eric

I was looking at this: http://www.ebay.com/itm/Portable-All-In-One-12V-9V-5V-Li-ion-Rechargeable-Battery-Pack-For-CCTV-Camera-/150855675210?pt=US_Rechargeable_Batteries&hash=item231fb2ed4a

But I really have no idea how to figure out if it will power both the 12V and 5V sides at the same time, and how long will it power the lights and the board? But, the size is beautiful!

Edited August 26, 2012 by thebaronn

[edvas69]

I have always used these batteries for 12vdc RGB strip for our road diversions to light up signs, at 7.2 amp/hour one 5 metres strip will last a few hours. So depending on what lights or what load will determine how long you will get. But at least these are rechargable and i would just recharge them every night.

You can also get these batteries in a 6VDC option and by connecting these batteries together you increase your amp/hour rating, but here is a rechargable 12amp/hour 6 volt battery that would work well

To find a 4.5 to 5vdc rechargable battery will take a bit more research as they are not very common at all.

These will definetly give you a lot more longevity than using latern batteries and cost you a lot less in the long run because they are rechargable

[thebaronn]

I have always used these batteriesfor 12vdc RGB strip for our road diversions to light up signs, at 7.2 amp/hour one 5 metres strip will last a few hours. So depending on what lights or what load will determine how long you will get. But at least these are rechargable and i would just recharge them every night.

You can also get these batteries in a 6VDC option and by connecting these batteries together you increase your amp/hour rating, but here is a rechargable 12amp/hour 6 volt batterythat would work well

To find a 4.5 to 5vdc rechargable battery will take a bit more research as they are not very common at all.

These will definetly give you a lot more longevity than using latern batteries and cost you a lot less in the long run because they are rechargable

Thank you, maybe a lightweight option isn't a reasonable notion.

[Max-Paul]

Hi Eric,

Ok, well lets look at the problem of burning out the LED string(s). Ok, normally the string is supposed to be powered by 4.5 volts. So putting them across 6 volts, you are increasing the voltage across each LED I think about .75 volts at least. Here is what I would suggest to keep it simple. First most 5mm size LEDs draw .02 amps each. Now blue, green and white LED need about 3.3 to 3.5 volts. And red, orange and yellow need about 2.2 volts. So group 1 (b,g,&w) will put all 20 in parallel. So, 20 X .02 = .4 amps. And group 2 (r,o, & y) can be wired with pairs in series (10) and 10 pairs in parallel. So 10 X .02 = .2 amps. So in worse case of 15 sets of White would have a current draw of 6 amps if all where turned on at the same time.

My suggestion is a pair of sealed lead acid batteries. As in the past you wire both batteries in series to get your 12 volts to run the controller. But off of the middle positive post you wire two diodes that have a forward current rating of 10A. wire these in series and you will have a 1.2volt drop across them. They will need a heat sink depending on how much current you actually draw. Now the positive leads from the LED string go to the diodes. And the negative leads will go to the proper negative terminals of the controller.

Without actually having the strings to examine. I am just guessing what is what current wise. But without any doubt in my mind the voltage needs and the example of how to tone down the voltage. Now with the two diodes dropping the voltage by 1.2 volts, we are now only .3 volts high. This is forgivable compared to the 1.5 volts.

[thebaronn]

Hi Eric,

Ok, well lets look at the problem of burning out the LED string(s). Ok, normally the string is supposed to be powered by 4.5 volts. So putting them across 6 volts, you are increasing the voltage across each LED I think about .75 volts at least. Here is what I would suggest to keep it simple. First most 5mm size LEDs draw .02 amps each. Now blue, green and white LED need about 3.3 to 3.5 volts. And red, orange and yellow need about 2.2 volts. So group 1 (b,g,&w) will put all 20 in parallel. So, 20 X .02 = .4 amps. And group 2 (r,o, & y) can be wired with pairs in series (10) and 10 pairs in parallel. So 10 X .02 = .2 amps. So in worse case of 15 sets of White would have a current draw of 6 amps if all where turned on at the same time.

My suggestion is a pair of sealed lead acid batteries. As in the past you wire both batteries in series to get your 12 volts to run the controller. But off of the middle positive post you wire two diodes that have a forward current rating of 10A. wire these in series and you will have a 1.2volt drop across them. They will need a heat sink depending on how much current you actually draw. Now the positive leads from the LED string go to the diodes. And the negative leads will go to the proper negative terminals of the controller.

Without actually having the strings to examine. I am just guessing what is what current wise. But without any doubt in my mind the voltage needs and the example of how to tone down the voltage. Now with the two diodes dropping the voltage by 1.2 volts, we are now only .3 volts high. This is forgivable compared to the 1.5 volts.

I thought there was something I could add to the line to drop the voltage, thank you. I read online that it is safe to overvolt LEDs by 25%? But I guess it really doesn't matter because I do not know the specifics of these LEDs.

I do have an electrical question, why does everything seem "ok" when I have all of the lights on (as compared to when I just have 1 strand hooked to a 6V that burns out instantly)?

I'm am trying to get the specs on the battery LEDs, nothing yet.

Thank you

Eric

Edited August 27, 2012 by thebaronn

[edvas69]

I do have an electrical question, why does everything seem "ok" when I have all of the lights on (as compared to when I just have 1 strand hooked to a 6V that burns out instantly)?

One word: Voltage drop,

So using ohms law you can see the relationship between load and voltage

Volts = Current (amps) / resistance (ohms)

or we can use

Volts = power(watts) / current (amps)

So the more power and current requirements the lower the voltage that will be supplied to the lights depending on the guage of wire that you are using to connect your strings

The other thing as well is the load you are putting on the battery may be higher than the battery can deliver and thus the voltage drops at full load.

So when all your lights are on the voltage that the lights actually see would be lower than what is seen if only the one string was used.

Edited August 27, 2012 by edvas69

[thebaronn]

One word: Voltage drop,

So using ohms law you can see the relationship between load and voltage

Volts = Current (amps) / resistance (ohms)

or we can use

Volts = power(watts) / current (amps)

So the more power and current requirements the lower the voltage that will be supplied to the lights depending on the guage of wire that you are using to connect your strings

The other thing as well is the load you are putting on the battery may be higher than the battery can deliver and thus the voltage drops at full load.

So when all your lights are on the voltage that the lights actually see would be lower than what is seen if only the one string was used.

That is not good. So Maybe I need to stay with the 6 volts. Decisions, decisions......

Thank you for the good info,

Eric

[Steven]

A lantern battery is usually made of alkaline cells, which have a higher internal resistance than other voltage sources. A higher internal resistance means that the voltage will drop as more current is being used. The voltage on your battery probably drops lower than 5 volts when all your lights are turned on.

To get small size and weight there is one answer: Lithium-Ion. These batteries are very common as they are currently used in every mobile phone and laptop. 12-volt versions are available for hand-held power tools, and can be purchased at any Lowe's or Home Depot. I have the Milwaukee M12 power screwdriver, drill, and impact tool that I use every day and would recommend for your power tool use. If I was to build a wearable LOR display like you do, I would "borrow" one of the M12 batteries.

Use 5 volts for your LEDs. That's probably close enough to 4.5 volts to avoid burning them out. To get 5 volts from your 12V battery, use a DC-DC converter. Here's one that will take 9-36V input and product a regulated 5-volt output. It says "high efficiency", so the small battery should last.

An M12 battery and the DC-DC converter will weigh much less than a single lantern battery, and you can probably get both for about $50. The lithium ion battery will last for thousands of charge cycles, and you don't need to "cycle" it like a NiCd.

[thebaronn]

A lantern battery is usually made of alkaline cells, which have a higher internal resistance than other voltage sources. A higher internal resistance means that the voltage will drop as more current is being used. The voltage on your battery probably drops lower than 5 volts when all your lights are turned on.

To get small size and weight there is one answer: Lithium-Ion. These batteries are very common as they are currently used in every mobile phone and laptop. 12-volt versions are available for hand-held power tools, and can be purchased at any Lowe's or Home Depot. I have the Milwaukee M12 power screwdriver, drill, and impact tool that I use every day and would recommend for your power tool use. If I was to build a wearable LOR display like you do, I would "borrow" one of the M12 batteries.

Use 5 volts for your LEDs. That's probably close enough to 4.5 volts to avoid burning them out. To get 5 volts from your 12V battery, use a DC-DC converter. Here's one that will take 9-36V input and product a regulated 5-volt output. It says "high efficiency", so the small battery should last.

An M12 battery and the DC-DC converter will weigh much less than a single lantern battery, and you can probably get both for about $50. The lithium ion battery will last for thousands of charge cycles, and you don't need to "cycle" it like a NiCd.

If I still lived close to you, I would take you out to dinner!

Thank you

[Steven]

If I still lived close to you, I would take you out to dinner!

Thank you

You're welcome! Now, at least you can "Like" my post.

[thebaronn]

Here is the finished setup for one of the props. Thank you again!