Project needing guidance (I am a beginner and need help!)

[allardjf78]

Hi everyone,

if I am here today, it's because I have no experience with batteries and I really need your help so I don't hurt myself or die in a horrible way. I am currently working on a project that is truly awesome and will require me to use multiple LEDs on a costume so it has to be portable. So I tried going on the internet and find a solution but I found that to be difficult since I have to use about 32 x 5mm LEDs and no small amount of AA or D batteries are going to be sufficient. (By the way, 4 of them are UV LED)

I went to a LED store that ''helped me'' although I have a feeling the guy did not really put any care into getting me what I needed since he usually deals with 10K $ and more each transactions and mine was only 200$. So, to power this baby, he gave me a 12v18ah Lead-Calcium battery, telling me that this is what I needed to power that many LEDs for an extended amount of time without my power diminishing as time goes by and my battery slowly dies. He somehow made a calculation without really telling me the specs of the LEDs (which look like very regular 5mm LEDs...) He also specified that my LEDs should be wired in series of 4 at a time to protect them. I asked if I needed resistors but he told me no.

Now, I went online to get some safety tips just to make sure I am not doing something incredibly stupid and I stumbled on some very scary stuff about exploding batteries with severe acid burn, something about charging the battery creating a dangerous gaz and such. I know I have a charger that is meant to not over-charge my battery but for some reason, I am now terrified of what I have bought and I need the precious advice of knowledgeable people to ensure I do this right (if I still do it at all) and don't get myself killed or severely wounded.

My Concerns Are :

-Is me wearing a battery like this one, strapped to my back, dangerous?
-What are the chances of my battery blowing up or leaking?
-How do I prevent that?
-Since this battery is going to be strapped to me, could my movement make the battery leak acid on me?
-During the charge, I read that the battery could leak gaz and thusly, needs to be in an open space. Can I charge it underneath my kitchen's hut? Because I have no room outside my house since it's winter and I have no garage.
-(Confirm with me) Is the proper sequence for plugging my battery + first then - and the other way around for unplugging?

Also, here is a plan that I have made. If you find anything that makes no sense, know that I have very little knowledge and it is highly likely that there are things that could need changing and I will appreciate your every feedbacks.


Thank you very much

 

[MikeMl]

You lack understanding of how to hook up LEDs. Read this tutorial


The biggest hazard with that battery is that you get a hernia carrying it around, or that you drop it on your foot.

Your pictured battery is a "Sealed Lead Acid" (SLA), sometimes called "Absorbed Gas Mat" (AGM) type. These do not leak unless dropped and the case splits open. There are battery types that have a higher energy storage capacity per unit weight of the battery than SLA.

All of the hazards related to charging lead-acid batteries is a result of not using proper charging methods.
With the proper voltage-limited charger, you can charge it anywhere, even indoors. Any battery can explode if charged improperly.

 

[JimB]

-Is me wearing a battery like this one, strapped to my back, dangerous?

Carrying an acid containing battery strapped to your back is a bad idea.

-What are the chances of my battery blowing up or leaking?

Blowing up - very unlikely.
Leaking - if it is not a sealed battery, very likely.

-How do I prevent that?
-Since this battery is going to be strapped to me, could my movement make the battery leak acid on me?

Use a different battery technology, such as NiCd or NiMH.

-During the charge, I read that the battery could leak gaz and thusly, needs to be in an open space. Can I charge it underneath my kitchen's hut? Because I have no room outside my house since it's winter and I have no garage.

Use a NiCd or NiMH battery and there will be no problem.

-(Confirm with me) Is the proper sequence for plugging my battery + first then - and the other way around for unplugging?

Does not make the slightest difference.

Also, here is a plan that I have made. If you find anything that makes no sense, know that I have very little knowledge and it is highly likely that there are things that could need changing and I will appreciate your every feedbacks.

The connection of the LEDs is incorrect, you need a current limiting resistor in each chain of LEDs.
The connection from the battery to the switch is a recipe for disaster. (Think red hot molten copper wire and smoking insulation).

JimB

 

[ronv]

I think I would start by taking everything back and getting my $200 back. Then come back here with what you want to do - what colors, how long etc. and we can help. Or you can reverse the order as the how long may have forced you into a very large battery.

 

[allardjf78]

I think I would start by taking everything back and getting my $200 back. Then come back here with what you want to do - what colors, how long etc. and we can help. Or you can reverse the order as the how long may have forced you into a very large battery.

I will be using 4 x UV LED and 28 x blue LED.

Also, here is a picture of the ACTUAL battery I have.

The one in the diagram was simply a picture taken of a random 12v18ah battery on google image.

In the meanwhile, I will start reading on how to properly assemble LEDs

 

[allardjf78]

The connection from the battery to the switch is a recipe for disaster. (Think red hot molten copper wire and smoking insulation).

JimB

What do you suggest?

 

[House0Fwax]

What do you suggest?

The switch should go from the '+' of the battery to the LEDs. Do NOT get the '-' of the battery involved. In your diagram there is a chance of the switch 'shorting out' the battery, that would lead to red hot molten etc...

 

[MikeMl]

You seem to lack another critical piece of information. How long do you want to run the LEDs between recharges?

A typical 5mm LED requires about ~25mA. White LEDS have a forward drop of ~2.5V, so you could run series strings of 4 each (dont forget the current-limiting resistor). 32/4 is 8 strings, so the total current draw from the battery is 8x25mA = 200mA. The battery you pictured is 18Ah, means that it would run your LEDs for 18/0.2 = 90 hours, which seems excessive. I'm guessing you would be much happier with a battery that runs these for 4 to 8 hours between recharges, which would require a 1 to 2 Ah battery; much easier to carry.

 

[allardjf78]

The switch should go from the '+' of the battery to the LEDs. Do NOT get the '-' of the battery involved. In your diagram there is a chance of the switch 'shorting out' the battery, that would lead to red hot molten etc...

View attachment 69728

Thank you very much. I find it funny that this is how the company that sells the rocker switch tells me that this is how I should have installed it. But I find myself with no experience and that gives me little choice but to trust you lol. (hoping you are trusthworthy and won't get me burned lol)

 

[allardjf78]

You seem to lack another critical piece of information. How long do you want to run the LEDs between recharges?

A typical 5mm LED requires about ~25mA. White LEDS have a forward drop of ~2.5V, so you could run series strings of 4 each (dont forget the current-limiting resistor). 32/4 is 8 strings, so the total current draw from the battery is 8x25mA = 200mA. The battery you pictured is 18Ah, means that it would run your LEDs for 18/0.2 = 90 hours, which seems excessive. I'm guessing you would be much happier with a battery that runs these for 4 to 8 hours between recharges, which would require a 1 to 2 Ah battery; much easier to carry.

This is very difficult for me since I have near-to-zero experience in making this type of thing.

The seller asked me what I wanted. So I told him I needed 28 Blue LEDs and 4 UV LEDs powered up for a total of 6-8 hours.
I still have to figure out how many resistors of what type I need to put where on my diagram and if I have to change my battery. Some of you suggested NiCd or NiMH and I'll take a look on that.

Once again, I thank everyone of you trying to help me but this feels all very foggy to me since I seem to only understand 10% of what you are all telling me. What I need are not advices (although yes I do...) but answers because I have next-to-no clue to what I am doing. HouseOFwax has been very helpful in sending me a modified version of my diagram, showing me what I need to change.

I am visual. Telling me I need to calculate this and that is very hard for me since my knowledge is not even basic. I can solder this entire diagram once I'll know it's not going to be dangerous. And that is how knowledgeable I am.

 

[House0Fwax]

If you are using that ACTUAL switch, then it is possible (because it looks like an 'illuminated' type) that your original diagram is correct.
However, if you are using a different type then usually the centre connection will connect to one of the outer connections in one position, and the opposite connection in the other position. Your original diagram would have the LEDs connected in one position and the battery shorted in the other.

 

[MikeMl]

What are you trying to do? Is this just a visual display thing, or are you somehow trying to make something where a remote scanner looks at the location of the LEDs to measure their position?

 

[throbscottle]

It occurs to me that if this is a costume then the resistance of the wire might count for something as likely to be long thin wires. It would be good to have a diagram with actual wire gauge and length on it for each batch of LED's, to take into account for limiting resistor values. If we're going to provide answers might as well make sure the LED's are evenly lit!

 

[allardjf78]

Alright, I understand I have not given you enough precision on what I am actually trying to do.

I am working on a costume that will require LEDs to light up my back. Here are (for fun) some pictures of what I have so far :









Pretty much, I am making a cybernetic prop for a game that will look like a futuristic armor (not meant to receive hits)
The reason I need the LEDs is to highlight my ''spinal cord'' not yet completed. So yes, I need your expertise to make sure I do this right because so far, the results are nice and if done right, the spinal cord should be the master piece of the entire armor. I had the intention of attaching the battery to my lower back but I am open to all of your advice and if I should actually change that battery or keep it.
The battery has to be rechargeable, I need 28 blue LEDs and 4 UV LEDs. After talking to the ''expert'' that sold me my material, he told me this is what I needed. Now internet, I would like you to guide me into how I will complete this project in a safe manner.

 

[ronv]

Here is my 2 cents. I would use 10 AA batteries in a holder. You can Google 10 AA battery holder.
Then use 10 rechargable AA batteries for 12 volts @ 2.2 amp hours.
Hook up 10 parallel strings of 3 leds in series with a resistor like the picture and 1 more string with 2 leds.
Add the switch as shown. Make sure to observe the polarity of the battery and the leds.

 

[allardjf78]

Here is my 2 cents. I would use 10 AA batteries in a holder. You can Google 10 AA battery holder.
Then use 10 rechargable AA batteries for 12 volts @ 2.2 amp hours.
Hook up 10 parallel strings of 3 leds in series with a resistor like the picture and 1 more string with 2 leds.
Add the switch as shown. Make sure to observe the polarity of the battery and the leds.

I could make strings of two LEDs work. What I am wondering is your about the 10 AA batteries, together will produce 2.2 ah? And altogether, will this allow me to light up 32 LEDs for 6-8 hours?

 

[ronv]

It would be better if you can do 3 per string because you don't wase so much power in the resistors. If you do 2 each that is 16 strings of 0.02 amps each or 0.32 amps X 6 hours = 1.9 ah.
If you do 3 per string + one with 2 it is 10 strings @ 0.02 = .2 amps plus 1 string at .02 amps or almost 10 hours.

 

[eTech]

This is very difficult for me since I have near-to-zero experience in making this type of thing.

The seller asked me what I wanted. So I told him I needed 28 Blue LEDs and 4 UV LEDs powered up for a total of 6-8 hours.
I still have to figure out how many resistors of what type I need to put where on my diagram and if I have to change my battery. Some of you suggested NiCd or NiMH and I'll take a look on that.

Once again, I thank everyone of you trying to help me but this feels all very foggy to me since I seem to only understand 10% of what you are all telling me. What I need are not advices (although yes I do...) but answers because I have next-to-no clue to what I am doing. HouseOFwax has been very helpful in sending me a modified version of my diagram, showing me what I need to change.

I am visual. Telling me I need to calculate this and that is very hard for me since my knowledge is not even basic. I can solder this entire diagram once I'll know it's not going to be dangerous. And that is how knowledgeable I am.

Hi

Maybe you can fashion something using a combination of fiber optic and/or other luminous material?

If you could reduce the number of light sources, and instead, "pipe ithe light" where it needs to be seen on the costume, you could reduce power requirements, battery size, weight, etc...

My two cents....

eT...

 

[allardjf78]

Hi

Maybe you can fashion something using a combination of fiber optic and/or other luminous material?

If you could reduce the number of light sources, and instead, "pipe ithe light" where it needs to be seen on the costume, you could reduce power requirements, battery size, weight, etc...

My two cents....

eT...

I thought of that. What I need for the spine is a powerful light source (multiple LED) to highlight the back. I am already using EL Wire at other spots but even in low light, it will not be very noticeable. That is why, for this project, I will be using LEDs.

 

[eTech]

I thought of that. What I need for the spine is a powerful light source (multiple LED) to highlight the back. I am already using EL Wire at other spots but even in low light, it will not be very noticeable. That is why, for this project, I will be using LEDs.

Some of the costumes I've seen are very bright and the wearer isn't lugging around a huge battery pack.. ;-)

So...at what distance does it need to be seen?

Maybe you could imbed some small re-chargeable batteries in the spine itself?

eT