Electronics, Lighting, & Gadgets - Help with DIY lights

I'm thinking about making my own light. I just got the Cygo lite Night rover and it wasn't as bright as I expected. I wanted to make one with 2 bulbs, a spot and flood, and probably 20 watts each. I've looked at the battery stuff at batteryspace and all-battery and have some questions. Maybe it is because I want 2 bulbs but it seems as expensive as buying the light all made. I was thinking I'd need 2 14.4v 4200 mah which are $60 each and 1 charger which is $30. That's $150 right there. I found the Cygolite Dual cross 300 for $150. So, if I went with just one bulb instead, would I be better off with a flood or a spot? I want to see the road but want something wider than just a spot. I'm riding on dark roads and want to see, not just be seen. What battery would I need if I got a 35watt bulb?

If you want to make a DIY light with two lamps (one spot, one flood), think about using the driving lights offered by JCWhitney (http://www.jcwhitney.com/autoparts/Product/tf-Browse/s-10101/Pr-p_Product.CATENTRY_ID:2003730/p-2003730/N-111+10201+600010204/c-10101). You can swap out the 12V 55W MR16s for a 20W spot and flood MR16 lamps available at local hardware stores for around $7 each (or cheaper online). For $20 plus shipping and $14 for two lamps, it's a relatively inexpensive. Then add a 12V battery of your choice depending on how much runtime you want. I'm using a 7AHr sealed lead acid battery and smart charger (http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=2909) from batteryspace. I think you will prefer spots to floods because they put more light where you need it on the road. If you use two spots, it gives you a wider spread than a single spot, but narrower than a flood.

If you want to make a DIY light with two lamps (one spot, one flood), think about using the driving lights offered by JCWhitney (http://www.jcwhitney.com/autoparts/Product/tf-Browse/s-10101/Pr-p_Product.CATENTRY_ID:2003730/p-2003730/N-111+10201+600010204/c-10101). You can swap out the 12V 55W MR16s for a 20W spot and flood MR16 lamps available at local hardware stores for around $7 each (or cheaper online). For $20 plus shipping and $14 for two lamps, it's a relatively inexpensive. Then add a 12 battery of your choice depending on how much runtime you want. I'm using a 7AHr sealed lead acid battery and smart charger (http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=2909) from batteryspace. I think you will prefer spots to floods because they put more light where you need it on the road. If you use two spots, it gives you a wider spread than a single spot, but narrower than a flood.

Here's where I'm confused. If I'm using 2 12v bulbs, don't I need 2 batteries? I need at least 1 hr of runtime but by next spring I might need 2 hrs. I've never worked with batteries so I don't know anything about them, just what I've been reading on here. Tomorrow I'm going to look for a 10w flood to switch out the 6w I've got now. Then I'll have 2 10w and see how that works.

No, you don't need two batteries. You can run both lights in parallel from the same battery. To determine what size of battery to get, use the formula Watts/voltage=Current For example: 20watts/12volts = 1.7 Amps. A 1.7 AmpHour battery will power your lights for one hour. A 3.4 AmpHour battery will power your lights for two hours. However, battery life will decrease as it gets colder and as the battery ages so your mileage may vary. I would suggest getting a battery that has at least 1.5 times the capacity that you think you need, that way you don't run the battery down completely on your longest ride.

You can use switches to turn on one or the other light or both lights.

So, if I want to run 2 20 watt bulbs for 2 hours I'd have to get a 10amp battery? All-battery has one but doesn't say how much it weighs, battery space has one but it's 3.6 lbs. That seems pretty heavy. The other option would be to go with a 10w and 15w instead. If I'm calculating right, I could use a 4.2 battery and get 2 hours. Batteryspace has one with a smart charger for $66 and only 1.3 lbs. It comes prewired with coaxial cable but I don't know if I'd be able to hook that up to the lights.

I took the Cygolite out in the street in front of the house last night once it was really dark. It seemed brighter than it did in the morning. Maybe it got washed out from the sky lightening yesterday morning and would be better when it's darker. I've got to stop by Home Depot and see if I can get a replacement 10w bulb to switch out the 6w and see what that does but the 6 is the flood. I might be better off replacing the 10w spot with a 15w spot and try that first.

I just had another thought on this. The Cygolite is a 6 volt battery and 6 volt bulbs. Can I get a 12v battery and 12v bulbs and still use the same casing for the bulbs so I don't have to do any wiring? Would there be a way to get the same kind of connector from the battery to the lights?

Two 20Watt, 12-volt bulbs running in parallel will draw 3.33 Amps. To run both for two hours will require at least a 6.66 AmpHour battery. The 7AmpHour 12-volt battery that I use weighs eight pounds.

Yep, If you go with 25Watts then you need a minimum of 4.2AmpHour battery.

Looking at bulbs.com http://www.bulbs.com/, it looks like both 6 volt and 12 volt lamps are available as MR-11 and MR-8 bases. So, yes, if you have a 6 volt MR-11 or MR-8 housing, then you can technically put a 12 volt lamp in it. However, the plastic housing may not be able to handle the heat produced by a larger wattage lamp (e.g., you want to put a 10W 12V in a housing made for a 6W 6V lamp). My old 6 volt Cygolite instructions say not to have the light on while stationary for more than five minutes due to excessive heat buildup. There are a number of DIYers who have experienced melted plastic housings that couldn't take the heat of the halogen bulb. They do get quite hot. My housings are metal and were designed to handle 55 Watt lamps. Even though I use 20 Watt lamps, the housings are too hot to touch.

You can probably find the right connectors at Radio Shack or online at other electrical/electronic stores. If you want to reuse the power cable from an existing 6V battery, cut the wires off from the battery and put connectors on it that match your 12V battery.

Ok. That helps. Would it be safer to just get the 6 volt 10w and 15w and use the same battery?

Yes, that would be the safer choice. Experiment with it, monitor the heat buildup with the higher wattage bulbs and see what happens. If it melts, then it was a grand experiment and time to try something else. If it doesn't melt, then we have a winner! That's part of the fun of DIY, it's the process as much as the product.

Have fun.