I want to hook up some lights and my alarm system on my bike and maybe even try some heated gloves etc. I'm running 66.6v lipo batteries. How do you guys running voltages greater than 48v power your lights and gadgets which require 12v inputs? Ebikes.ca has dc to dc converters up to 48v, but nothing higher. I've found others that will go up to 72v but they are over $100 which is more than I want to spend. I could just get a separate small 12v battery to run my gadgets in that case but would prefer to run everything off my main battery if I can find an inexpensive way to do it.
dc to dc converter for running 12v gadgets?
- Thread starter electr0n
- Start date
dutchlincoln
100 W
- Joined
- Sep 27, 2011
- Messages
- 135
There have been several reports of people using the switched type of power adapters for mains voltages. They should be the ones capable of accepting a wide input range without having to physically switch over, for instance 100-240 volts.
I've tried it myself, and it works indeed!
I took a 100-240v switched adapter at 48 volts, and it had a steady output of 12 volts.
As they handle up to 240V, 72V shouldn't be a problem.
Good luck.
I've tried it myself, and it works indeed!
I took a 100-240v switched adapter at 48 volts, and it had a steady output of 12 volts.
As they handle up to 240V, 72V shouldn't be a problem.
Good luck.
ohzee
100 kW
yea I can get my hands on some also let me know. Mostly lcd/laptop power supplies work.
The one's that switch between 110/240 seem to be the one's that work.
The one's that switch between 110/240 seem to be the one's that work.
Evoforce
10 kW
Thunderstruck Motors, LLC has them for $40ish dollars including the shipping for the 72v ones that I have. 707-827-7973. Enjoy!
ebent
10 kW
Bought mine from thunderstruck. Works fine. I added a power buss. So I run the 12v to the buss and wire all 12v stuff to the buss. It powers a head light, tail light, motorcycle stereo and a cigarette lighter for charging my phone. If you have an ample size battery it makes sense to avoid various battery packs.
Thanks for the leads. I have access to laptop power supplies. Although I'm a little confused. The input side of those laptop power supplies are expecting a/c from the mains outlet between 100v and 240v and will convert this to dc output somewhere around 18v and 3 to 4 amps, at least the ones I have access to. They are from current model laptops. Are you saying these power supplies will still work off my 66v battery rather than plugging into the a/c?
BLUESTREAK
1 kW
- Joined
- May 10, 2009
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- 472
I bought 6 from THUNDERSTRUCKMOTORS.COM, (3) 60volt and (3) 72volt and thay have never missed a lick. 8) 8) 8)
dutchlincoln
100 W
- Joined
- Sep 27, 2011
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- 135
electr0n said:
Yep, they (most likely) will
Check out this thread:
http://endless-sphere.com/forums/viewtopic.php?f=16&t=2264
http://endless-sphere.com/forums/viewtopic.php?f=16&t=2264
Evoforce
10 kW
Hi fecter! Neither one of those links in that thread are working.
tgtomm
1 µW
- Joined
- Dec 1, 2011
- Messages
- 2
Go onto ebay and search for lm2596hv. This should bring up some cheap but decent quality buck converters with a wide input range and adjustable output from china. They are also very high efficiency.
I was going to build a converter from one of these chips before discovering the ready made circuits on ebay. I bought one of these fully potted and use it to run my magicshine light. I would recommend getting one with a heatsink so that you can suck more amps from it
edit: sorry just re-read the spec and it only goes up to 60v, thought it was higher. Still this might be useful for someone else so will leave it up
edit2: switch mode power supplies:
For some background info, the reason some switch mode wall-wart or laptop power supplies work on dc is that the first thing they do (after fuses) is rectify the ac to dc. this circuit is just some diodes and doesn't care about what form its input power is in. It then passes this through a smoothing capacitor to obtain a steady voltage before passing through a buck converter to get useful voltages out the other end.
Some potential issues are:
1. the buck converter has a minimum voltage higher than your battery voltage. this is likely if its a multi stage converter often found in some high power pc supplies or the supply has multiple output voltages.
2. the supply first reduces the AC input voltage using a step down transformer. This is easy to spot though as it would require a fixed input voltage and is fairly uncommon in everyday ac/dc adaptors
3. you are supplying a lower voltage so to get the same output power you will draw a higher current and this could possibly trigger some kind of protection circuit. Most adapters specify a maximum input current - try not to exceed this
I was going to build a converter from one of these chips before discovering the ready made circuits on ebay. I bought one of these fully potted and use it to run my magicshine light. I would recommend getting one with a heatsink so that you can suck more amps from it
edit: sorry just re-read the spec and it only goes up to 60v, thought it was higher. Still this might be useful for someone else so will leave it up
edit2: switch mode power supplies:
For some background info, the reason some switch mode wall-wart or laptop power supplies work on dc is that the first thing they do (after fuses) is rectify the ac to dc. this circuit is just some diodes and doesn't care about what form its input power is in. It then passes this through a smoothing capacitor to obtain a steady voltage before passing through a buck converter to get useful voltages out the other end.
Some potential issues are:
1. the buck converter has a minimum voltage higher than your battery voltage. this is likely if its a multi stage converter often found in some high power pc supplies or the supply has multiple output voltages.
2. the supply first reduces the AC input voltage using a step down transformer. This is easy to spot though as it would require a fixed input voltage and is fairly uncommon in everyday ac/dc adaptors
3. you are supplying a lower voltage so to get the same output power you will draw a higher current and this could possibly trigger some kind of protection circuit. Most adapters specify a maximum input current - try not to exceed this
stripedtuna
100 W
Awesome.....
thanks tgtomm.. that unit is perfect for what i need.
Much appreciated,
Tuna..
thanks tgtomm.. that unit is perfect for what i need.
Much appreciated,
Tuna..
Evoforce said:
Sorry, things like that tend to go out of date.
Allelectroncis is still around: http://www.allelectronics.com/make-a-store/category/480/Power-Supplies/1.html
mst3kpimp said:
Yes, it will. It's best to have a switch for it. I run mine off the same line that feeds the controller so it comes on when I turn on the key.
I haven't measured how much drain there is on standby with any of these. That would be an interesting test.
ebent
10 kW
With my system turned on, red rear led flasher from grin on, Amp for motorcycle stereo on, my draw is 0.10amps. The draw modestly increases as the volume goes up with the music . Stay with led's for light, very low draw. Using the main pack for accessories has never been a problem. It is more effecient to own a little more AH than to constantly change aa's or aaa's. And the aa's will quit at the most inconvenient time.
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