Looking for help getting/making a battery powered 5v power supply

[Chaadster]

Guys and Gals,

I'm looking for some really rudimentary info here, as I have zero-to-low electronics knowledge.

I'm working on a project to outfit my bicycle trailer with rope LED lights around the frame for safety. For style, I'd like some that "chase" or otherwise flash and change colors.

I found what I'm looking for from an online retailer (superbrightleds.com), but the kit presents a couple of problems for which I need a little help solving.

Strangely, the LEDS run on 5v power and the RGB controller (which gives the cool, programmable effects) runs on 12v, making for an awkward (I think) portable, battery powered supply scenario.

Assuming two power supplies are in fact needed, there's no problem with the controller power supply, as the retailer has an 8 cell, AA battery powered supply that plugs right in. They don't seem to have a similar solution for the LED strip, however.

It would seem possible to get what I need, but I just can't find one, in particular because the lights appear to draw 2440mA max, which is beyond the supplies I've been able to find.

So, my questions are:

1. is such a battery pack possible?

2. Is one available?

3. If not, could I fab one simply (remembering my rudimentary knowledge and skills)?

The only requirements for this project are that the power supplies be quite portable; I don't want to lug around a car battery! I could certainly use rechargeable lithiums or a non-standard battery, so long as they're not wickedly pricey or huge.

Here's the kit I'm thinking to use, for reference: https://www.superbrightleds.com/cgi...&category=BARS&Page2Disp=/specs/RGB_DC-83.htm

Any help and insights are appreciated!

 

[srizbf]

I
.....It would seem possible to get what I need, but I just can't find one, in particular because the lights appear to draw 2440mA max, which is beyond the supplies I've been able to find....

since the LEDs requires 2.4A @5v , if you want a battery pack , you can have one , but the time of use will be very short.
and the battery may be even heavy.

instead if you can find a bicycle dynamo of that rating (with appropriate regulator included), i think you can do it with minimum weight.

 

[Chaadster]

Srizbf,

Thanks for that; it's what I was thinking regarding run time being short.

The specs for the LEDs only indicate max current draw of 2.44A, so perhaps a flashing mode would draw less than all on constant, my thinking here being that it may be possible to see 3 hours of run time off a fairly small battery (5000mA capacity?). That would be an acceptable trade off for the portability.

I like the idea of a generator, but then I'd have fluctuating brightness based on speed, and none when stationary. I'd rather throw a 5lb battery in a trailer and be done with it.

Do you think a run time calculator like this is useful in calculating my requirements?: **broken link removed**

 

[Chaadster]

Well, through my internet ramblings I did find a more appropriate kit, mainly in that it is a fully 12v system, but also because it is tidier and costs less. Wow, when does that ever happen!

In any case, I won't be pursuing this project any further, so don't bother posting for my sake. For the good of the internet? Okay...but for my benefit, don't bother!

Thanks anyway, and I hope I'll be back around for bigger and badder projects in the future!

 

[Charles Bronson]

You asked for rudimentary info, so I hope this helps...

You could use a 12V 7Ah rechargable lead acid battery, the type used in emergency lighting and alarm boxes. They are easy and cheap enough to come across.

For the 5Volt part, you could buy an off the shelf DC to DC convertor such as https://www.powerstream.com/dc6.htm. I have no affiliation with that site and have never purchased from them, link included just to show what you may be looking for.

You can wire directly to the 12V battery for the controller, use a suitable inline fuse.

Use the DC convertor connected to the 12V battery, again with a suitable fuse. And on the 5V side of the DC convertor to power your leds, Again put an inline fuse on your leds. Never hurts to be cautious.

That I believe is the simpilest solution. The leds should draw less current on flashing mode. If they are only on half the time they should only use half the current over time.

With the above setup, you should be able to squeeze it into a small enough enclosure under the saddle or attached to the cross bar. You may even be able to design the enclosure and make it a feature of the bike!

The above setup should last a few hours. If you need a longer operating time you could put a second battery in parallel. If you have a different 12V source you can use that, the setup would still be the same.

The DC to Dc convertor is switched mode, this is more efficient then trying to knock up a linear convertor for yourself.

I hope this helps.




Edit* While I was typing the above, I see the original poster found what he was looking for. Just like me to be late to the party Next time!

 

[tpetar]

Cheapest solution is to get small lead acid battery 12V 7Ah or 9Ah. You can use even two in parallel to get higher capacity.
You have possibility to install small solar cells for charging of batteries.

My opinion is that is better to make leds for higher voltage and lower draining current form batteries, with this you will get more leds with smaller current, and of course longer working time.

 

[Chaadster]

You asked for rudimentary info, so I hope this helps...

You could use a 12V 7Ah rechargable lead acid battery, the type used in emergency lighting and alarm boxes. They are easy and cheap enough to come across.

For the 5Volt part, you could buy an off the shelf DC to DC convertor such as https://www.powerstream.com/dc6.htm. I have no affiliation with that site and have never purchased from them, link included just to show what you may be looking for.

You can wire directly to the 12V battery for the controller, use a suitable inline fuse.

Use the DC convertor connected to the 12V battery, again with a suitable fuse. And on the 5V side of the DC convertor to power your leds, Again put an inline fuse on your leds. Never hurts to be cautious.

That I believe is the simpilest solution. The leds should draw less current on flashing mode. If they are only on half the time they should only use half the current over time.

With the above setup, you should be able to squeeze it into a small enough enclosure under the saddle or attached to the cross bar. You may even be able to design the enclosure and make it a feature of the bike!

The above setup should last a few hours. If you need a longer operating time you could put a second battery in parallel. If you have a different 12V source you can use that, the setup would still be the same.

The DC to Dc convertor is switched mode, this is more efficient then trying to knock up a linear convertor for yourself.

I hope this helps.




Edit* While I was typing the above, I see the original poster found what he was looking for. Just like me to be late to the party Next time!

Charles,

No, I'm glad you posted, because that was exactly what I was looking for!

I'm not sure the setup I'm going with will even work, so I'm delighted to have this to fall back on. Thank you!

By the way, the voltage converter you linked to shows outputs at 4.5v and 6v; do you suppose either will power up the LEDs, with the brightness intensity going up with the higher voltage? It's probably impossible to know without more info on the LEDs, but it would be unlikely going up from the listed 5v to 6v would damage the LEDs, would you say?

---------- Post added at 20:13 ---------- Previous post was at 20:10 ----------

Cheapest solution is to get small lead acid battery 12V 7Ah or 9Ah. You can use even two in parallel to get higher capacity.
You have possibility to install small solar cells for charging of batteries.

My opinion is that is better to make leds for higher voltage and lower draining current form batteries, with this you will get more leds with smaller current, and of course longer working time.

How would I step down current to LEDs, and would that make them less bright?

 

[tpetar]

How would I step down current to LEDs, and would that make them less bright?

Put 6 red led with 25mA in serie with 1R resistor, this will be one chain. Just as example, you can have just on trailer rear 4 x 6 LED 25mA = 24 LEDs and total draining current 100mA. You can even add turning lights with yellow leds.
If you whant to step down current in led this will cause less bright in them for sure, but I dont see why you whant to do this ?