GoldenMotor.com Forum
Non-GoldenMotor related topics and Items For Sale/Wanted => Everything Else => Topic started by: Leslie on April 01, 2012, 05:44:27 PM
-
Do You need a switching regulator that converts the high volts and low current >into< low volts and high current?
GM forum memeber Monkey Magic put me onto these.
http://www.ebay.com.au/itm/DC-to-DC-Converter-VKA60MS03-1-48V-3-3V-12A-out-Nice-/370102917617?pt=LH_DefaultDomain_0&hash=item562bda59f1
(http://i.ebayimg.com/24/!B81leZw!mk~$(KGrHqV,!iUEzNtpPi(JBM4FtBcCGg~~0_12.JPG)
They are idiot proof and totally isolated from input to output they has a safety mechanism that kicks in if you muck up the fine adjustment. They wont output over 3.7v +trim @ adj <<< I think.
Can take up to 72v input, they are tiny in size too. I got mine to output 3.5v and is perfect for leds. With a 48v system and heat sink glue this to a good hunk of aluminium you can easily output 10 amps @ 3.5v.
It draws about .100ma from my pack to power a 1amp lighting system. Leaving this on over night or the next wont kill your pack. I could run my lights for 150 hours with this regulator.
However, with a linear regulator, you have to provide the current the light draws. And @ 1A the linear reg will flatten flat in 12 hours.
Imagine a 35 watt led light system on your bike. ;D a 35 watt led ststem would draw approx one amp from a 48v pack.
This light system I ran off this converter was 16 watts.
(http://i29.photobucket.com/albums/c251/soulelectronique/Lightsystem.jpg)
The big light in the middle fell sacrafice to kids touching little fingers, they picked the lens off. But still the two 3 watt torches is plenty enough. Almost as good as car lights.
-
Equasion to adjust trim.
(http://i29.photobucket.com/albums/c251/soulelectronique/Radj.jpg)
The formua is wrong notation. RKohm=
^%= desired percentage of change output.
(VO(100+^%) (100+2^%)
RKohm=( --------------- Minus --------------)
1.225 ^%
Anyone game?
I think I NAILED IT.
From 3.3 to 3.5v.
3.3(100+106)
------------------ = 5.27
1.225*106%
Minus
100+(2x106)=312
----------------------- =2.943
106
=2.327k
A 2.327k resistor.
I cant read the resistors Im loosing my sight. I just grabed some 4k to 1k resistors and just kept trying until I got what I liked.
If you get it wrong, the converter shuts down. Just disconnect and reconnect to reset.