top secret project..some assistance needed

[thejudges69]

I'm working on a Top secret project for my son and I can't elaborate to much just in case someone I know sees this.

Anyways, I need to use a battery to power some small LED lights totaling about 20 lights. Anyways, I think I came up with a solution....a power wheels battery.... Now the question...can you mount them horizontally? are they a dry type battery?

 

[thejudges69]

Also, has anyone ever seen a way to charge a battery off of a rotating wheel? Like something that lays against the wheel and charges while your moving?

 

[ishiboo]

I'm working on a Top secret project for my son and I can't elaborate to much just in case someone I know sees this.

Anyways, I need to use a battery to power some small LED lights totaling about 20 lights. Anyways, I think I came up with a solution....a power wheels battery.... Now the question...can you mount them horizontally? are they a dry type battery?

Most are wet cells.

Also, has anyone ever seen a way to charge a battery off of a rotating wheel? Like something that lays against the wheel and charges while your moving?

They make generators for bicycles that work off a friction contact with the back tire... You could feed that to a voltage regulator.

Given movement you can generate power off anything, of course, but that sounds like what you're looking for versus a magneto or alternator

 

[thejudges69]

The charger part isn't super important, I will be able to recharge at the end of the day, I was concerned the lights may dim after a long day but, they don't really draw that much.

Are the batteries sealed? I want it horizontal so its tucked up under and hidden.

 

[SunnyBeach]

20 LED lights is not much. Depending on how you configure things, regular (AA, C, D, or 9v) batteries could work.

 

[ishiboo]

The charger part isn't super important, I will be able to recharge at the end of the day, I was concerned the lights may dim after a long day but, they don't really draw that much.

Are the batteries sealed? I want it horizontal so its tucked up under and hidden.

I doubt it.

Get a small AGM battery.

 

[thejudges69]

I should say 20 lights total LEDs will prolly be more like 30-40 actual diodes, whatever I use has to be small and rechargeable also these lights will be on for several hours a day, up to possibly 8-10 hours.

 

[SunnyBeach]

You may have something more elaborate/specific in mind but there are kits with LED lights and battery packs that may work.

This is one from Amazon (among the 100s of others there).

 

[zkling]

Don't forget to put proper size resistors on the LEDs.
Depends on the wheels power batter. The small ones I've seen are completely sealed.

 

[thejudges69]

more like this,

I think tomorrow I'm going to run to interstate batteries with the main structure after some looking I have an idea.

 

[thejudges69]

Don't forget to put proper size resistors on the LEDs.
Depends on the wheels power batter. The small ones I've seen are completely sealed.

I want a 12v battery and 12V lights so there is no issues, everything should light right up and be fine.

 

[rsanter]

Use an alarm system back up battery
They are dry cell batteries and can be put in whatever orientation.
You can also put 2 of the 6 volt lantern batteries in series to get 12 volts

Bob

 

[HOTFR8]

more like this,

I think tomorrow I'm going to run to interstate batteries with the main structure after some looking I have an idea.

You should be able to get a battery you can mount side on but it will be expensive. I have seen a few used in Hot Rods.

Hawker Pacific and Braille batteries are two brand names that come to mind.
GOOGLE them and see if that helps you.

Keen to see what you are doing.

I sell those lights so I have some idea what you may be doing.

 

[racingtadpole]

You want an AGM (absorbed glass mat) battery to lay on its side. Its still a Lead Acid gel cell battery, but the electrolyte is trapped in a fibreglass mat type structure so it can be mounted in pretty much any position.

 

[snyder]

Don't overlook a battery from a cordless drill. Easy to get, mounts anyhow, and you probably already have one.

 

[koditten]

Rob the battery out of a jump pack. most are sealed agm batteries.

 

[Grazz256]

For 20 of those LEDs you need about 1 amp hour per hour of operation. So if you want 8 hours of run time you'll need a motorcycle or similar battery.

For those that care thats 0.05 amp per light (via google for similar lights) * 20 lights = 1 amp of load.

Cheers

 

[454ragtop]

A lot of portable generators with electric start have a small 12 volt battery which is laid on its side, probably just what you're looking for.
HTH, Jim

 

[Kevin54]

usually some good stuff in here for hobbyest http://www.micromark.com/

 

[signcrafter]

The smaller power wheels batteries I've seen are sealed.

 

[6brzina]

How about a small solar charger mounted somewhere if possible?

 

[zkling]

I want a 12v battery and 12V lights so there is no issues, everything should light right up and be fine.

Still, it is a wise idea to put resistors in the circuit, especially if it is intended to be used on a long term basis and depended upon. They help to regulate the current and thus heat and extend battery life. If you wanted to get fancy you could even put a pot in place to act as a dimmer.

 

[thejudges69]

I think I'm going to scratch the charger idea. I think that its going to be to much. Right now we are trying to redesign the steering mechanism to include a bearing and a nicer setup. I think that I can fit the battery under the rear structure and built a small box to support it and keep it hidden. Wiring will be a cinch and it will charge off it 110v which is the best setup for what the intended use is.

 

[benjamintmiller]

If these LEDs are meant for 12V, they will have resistors built in. LEDs have 1.7 - 3.3 volts of voltage drop across them (depending on color). This means that when supplied with 12 volts, 10.3 volts could essentially be dropping across the wires leading to the LED. This will be hundreds or thousands of amps for a fraction of a second, then the LED will burn out.

Using LEDs like this does waste a great deal of current. Consider this: 6 1.7V LEDs wired in series will use 10.2V, leaving a much smaller voltage drop of 1.8V for the resistor.

Let's figure 20mA as a sample current we want to run through the LEDs:
Running one of them plus a resistor on 12V:
10.3V * 20mA = 206mW of wasted current

Running six of them plus a resistor on 12V -- each of these will be as bright as the previous example
1.8V * 20mA = 36mW wasted current for 6 bulbs = 6mW wasted current for one bulb

In the above example, using single 12V LEDs wastes about 35 times more power than using six of them in series.

 

[Strouty]

When in series, do they act like christmas lights? Where if one burns out, they all go? Another idea, would be to go with some "D" batteries to make 3 volts and just not use resistors. You could wire up multiple batteries to keep the 3 volts, but have a bunch of capacity. If he used a 6 volt battery, would that reduce the draw due to less use of resistance? Or would it be the same since there would be half the voltage?

 

[benjamintmiller]

When in series, do they act like christmas lights? Where if one burns out, they all go?

Yes, but LEDs will last over 50,000 hours before burning out if not overdriven.

Another idea, would be to go with some "D" batteries to make 3 volts and just not use resistors.

This is not a good idea. You should always limit the current through LEDs, either with resistors or with some sort of current regulator. It is true that you can drive them without a resistor as long as the voltage provided is less than the typical voltage drop across them, but if the voltage fluctuates and you end up supplying more voltage than the voltage drop, they will burn out.

If he used a 6 volt battery, would that reduce the draw due to less use of resistance? Or would it be the same since there would be half the voltage?

If he used a 6 volt battery to drive a single 1.7V LED, there would be less wasted power across the resistor vs doing the same with a 12 volt battery.

 

[Bubbles]

I use to use a battery out of A ups to power the gps on my snowmobile. That was mounted on an angle almost sideways with no trouble. It's the same kind of battery.


That spent a lot of time upside down too

 

[Spam16v]

go get a battery for an emergency sign, they're cheap sealed agm's usually.

http://www.amazon.com/s/ref=nb_sb_n...+battery+12v&rh=i:aps,k:exit+sign+battery+12v

search Exit Sign battery 12v, cake.

 

[HOTFR8]

I hope we will see the end result when it is no longer top secret.

 

[03protege]

http://www.batterymart.com/c-sealed-lead-acid-batteries.html
http://www.remybattery.com/Sealed-Lead-Acid-Batteries-C42.aspx



Get a SLA designed for a battery backup system.

I've made many purchases from the above websites and they are g2g in my book.

 

[Joe69]

Napa sells batteries that are intended for electric brake breakaway switches, that are sealed.

Joe

 

[dogdog]

not sure how much you wanted to spend.

you can always google "led driver" for all your led circuits needs.

as far as battery.
you can get some Sub C NIMH or NICAD batteries (the same ones that is in your tool packs) with the weld tabs to build your battery packs of the voltage and capacity you needed. only catch is that they have to be matched. means of the same capacity, otherwise you could burn one or 2 cells. Ebay sells them cheap now with higher capacity also. 16x 1.2V sub C with 6000mah for about $25. at least you get to mount them almost anywhere you wanted.

and get an appropriate nicad / nimh charger for the battery packs you needed.

usually a lot of RC model places have them as well.

 

[EOC_Jason]

Go to your local sporting goods store... You can get a 12V, 8 or 9Ah battery for like $20... They are AGM with just spade connectors so you can mount them whatever direction you like. They will be by the deer feeders.