inverter modification to run cheap CFL's from 24V-72V batts

[monster]

i wish i knew more about this but is it even remotely possible to mod a mains 12v car inverter to run from our batteries? if you guys can mod a switch mode sullpy http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=4125 then why not an inverter. it would be nice to run 240V stuff from our bikes especially cheap CFL's that are available every where.

 

[amberwolf]

Take a look at this thread:
http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=14193

You don't need an inverter to run at least some CFLs (most of the ones I've tested so far, all of which are *really* cheap ones), as long as your pack voltage is around a third of the mains voltage or higher. Less, once it's kickstarted. As long as the CFL has an electronic ballast (most do), they'll run on DC as well as AC.

If you need an extra boost, some laptop power supplies (maybe a lot of them) will run on 24V and up. Most of them output 19VDC, and many are isolated outputs, so they can be wired in series with the pack that powers them, to effectively boost the output of the pack for a CFL or other high-voltage/low-current device.


EDIT (ADDED): Hmm...actually you replied in that thread, so you must need something more than what is there. Sorry!

As for the inverter modifications, you probably could input more than 12V to it, but I don't know how *much* more, without modifying the input stage.

One option is to carry a small 12V battery just for the inverter to run the lights. It could be SLA or it could be Lithium (4 or 5 cells should do).

 

[monster]

can you post a link to a cheap CFL that you know will work on 48V lifepo4? preferably an ebay item.

all the LED options i've looked at are 10x the price of the MR16's that i have at the moment. bike lights break all the time, especially if they are a DIY job so it's got to be cheap. it would be nice to have 5x more efficient lighting though.

 

[torker]

I would think cfl would be a lot more fragile than even an mr16. You can pick up a 3 watt led flashlight for 20 bucks or so and it would be really robust. I've got an Eveready proffesional I think they call it and it has about a 2 inch diam. reflector. That thing will light up trees 100+ feet away like a spotlight. Not to debunk your idea but cfl seem pretty flimsy.

 

[monster]

my MR16's have always broken at the pins. i think it was because of my DIY pvc pipe housings that i used them in. i've had less breakages now that i solder on to the pins direct. cheaper is always better. i have 50w of halogen light at the moment. if i were to replace it i wouldn't want to go dimmer so i would need about 10w of LED that would be 60 bucks. the same light power could be had for just 5 bucks with CFL's. it's no contest.

on ebay right now...
halogen 100 lm/£
LED 10 lm/£
CFL ?

 

[torker]

Yea as long as you have a way to focus them/ a good reflector and a way to stabilize them against breakage. Have you already come up with a mounting system?

 

[monster]

these strip lights look ok. florescent is the best ebay key word to use, not cfl. under £10 and they have a housing, reflector etc. might make a good light.


http://cgi.ebay.co.uk/12v-Fluoresce...ervan_Caravan_Accessories?hash=item1c0efe403e

 

[torker]

We are talking bike lights? I guess I don't understand how you plan to focus the light like a spot "aka" mr16 with built in reflector. That under counter light is made to spread out the light in a large area. Plus the "tombstones" The plastic clips that hold the lamp at either end were not made for shock. The lamps would have to be glued in to stay put. Do you have a picture of your mr16 setup? Also I may have a link to some led floods that I use for landscape lighting. They are 10 dollars each but may still not be bright enough. Actually this is still a better option. I know it is 15 dollars but I think in the long run you'd be happier. These suckers are bright.http://www.allelectronics.com/make-a-store/item/FL-606/HIGH-BRIGHTNESS-3W-LED-FLASHLIGHT/1.html

And it would be easy to mount and compact. Don't let the 3 watts fool you. I bet a couple of these would compare to 50 watts of mr16 halogen at 1/10 the current draw.

 

[amberwolf]

Focusing light from CFLs is difficult. I am still trying to work out a way to do it right, and I suspect it will take a largish parabolic reflector (like a dome lamp for reptiles) along with a fresnel lens (like on the flat surface of the old overhead projectors) mounted on the open end of the reflector.

I have the lens, but I don't have a reflector yet to test the idea out.


BTW, if anyone needs some little power supplies for 5V items on a bike, I have a feeling that these:
http://www.sparkfun.com/commerce/product_info.php?products_id=9621
will probably work on low-to-medium voltage DC input to get that 5V output too. They look exactly like a couple of Samsung phone chargers I've tested to work on my 36V pack, except for the custom connector.