# [evdl] dc-dc converter



## EVDL List (Jul 27, 2007)

*Re: [EVDL] DC-DC CONVERTER*

black is common, 12V is most likely red, yellow should be output.... fuse
red and yellow and test.

Where'd you get it?



> Louis Pelletier <[email protected]>wrote:
> 
> > list; i need some help. i'm wireing my little EV and useing
> > a chineese 48 v to 12v convertor. ther is 3 wires, black,
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] DC-DC CONVERTER*

u say 12v is red, yellow is output???????????
which one is the imput????????
right now it's tied as to which way to wire it up.
i know i have a 50-50 chance of it burning it up.LOL
some one must know. i got this from the local
Raylight dealer and he don't know and they don't
have scehmatics for the scooters. a real fly
by night outfit. the raylight MT-A electric pedal assist
are in my opinion a POS.
Louis in central BC
----- Original Message ----- 
From: "Travis Gintz" <[email protected]>
.

> black is common, 12V is most likely red, yellow should be output.... fuse
> red and yellow and test.
> 
> Where'd you get it?
.

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## EVDL List (Jul 27, 2007)

*Re: [EVDL] DC-DC CONVERTER*

It is designed just as a converter, or also as a 12 volt battery charger?
If it's designed to run in parallel with a 12 volt auxiliary battery, you
could hook 12 volts up to an input, and see if anything is on the other
side. If you picked the 12 volt side, it will either be nothing, or 48
volts on the other side (if it's a bidirectional DC-DC converter -- unlikely
for these cheap ones). If you picked the 48 volt side, you might still get
nothing on the other side, but you might get some lower voltage output. And
you are unliked to blow it up this way. Unless it is not designed to work
in parallel with an auxiliarry battery, in which case, you are likely to
blow it up.

For the bidirectional DC-DC converters I've used, black is common, red is
usually the 12 volt positive, and yellow is the higher voltage positive.
But, I have no idea if this is the same or not. But, if I had to guess, I'd
guess that yellow is the input(48 volts), and red the output (12 volts).

Z



> Louis Pelletier <[email protected]>wrote:
> 
> > u say 12v is red, yellow is output???????????
> > which one is the imput????????
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] DC-DC CONVERTER*



> Louis Pelletier wrote:
> > u say 12v is red, yellow is output???????????
> > which one is the imput????????
> 
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] DC-DC CONVERTER*



> Willie McKemie wrote:
> > On Thu, Mar 26, 2009 at 07:11:26PM -0700, Louis Pelletier wrote:
> > > u say 12v is red, yellow is output???????????
> > > which one is the imput????????
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] DC-DC CONVERTER*

thanks Willie. i will try it tomorow. i got my batterys in today.
i hooked up the controller and motor and the throttle. i went
to put the fuse in a big spark. the fuse didn't blow, every thing was
off. so i unplug all the wires. no reading accross the fuse terminals.
that good. i plug the 2 wires to the controler and get 51.4 voltes
across the fuse terminals. i have not checked the amp draw yet.
i thought that there was not suposed to be any juice to the contrllor
untill i energise the small red wire to turn the controllor on.
i don't recall seeing any relay in these scooters. i'll tackle this in the 
mornnig
with a fresh mind.
Louis in central BC
----- Original Message ----- 
From: "Willie McKemie" <[email protected]>
.
>
> MY BAD!
>
> What my supplier ACTUALLY said was red - 36-42v, yellow - 12v, black -
> common.
> http://is.gd/pltG
. 

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## EVDL List (Jul 27, 2007)

*Re: [EVDL] DC-DC CONVERTER*

Louis,

What you saw sparking was the charging of the
input capacitors of the controller.
That is why most controllers are connected with a
"pre-charge" (resistor) to charge the capacitors 
more gently and avoid burning of the contacts when
you turn the controller on every day.
It is not required and you need a way to control it
but in a vehicle with a low voltage pack where you can
use the key switch to enable the controller with pack
voltage (36 or 48V *fused*) then you can use the
accessory position r the start position, whichever makes
first contact, to pre-charge via a resistor before you
fully engage the controller.
One of the cheapest pre-charge resistors is a 100W bulb,
you may have them lying around from converting your house 
to compact fluorescent lamps - that is how I got a stack
of those bulbs...

Regarding the DC/DC converter,
I suggest you take the advice that was given to try 12V
first on one side and then on the other side.
If you measure a (small) voltage on the other wire
when supplying 12V then you can increase the 12V to your
pack voltage and the other side should deliver 12V.

I guess you can't open the thing?
If you measure for a diode on input and output then
you should find a "fly-back" diode on the output:
if the current goes from ground (black) to output
then it flows through the fly-back diode and output
inductor in a typical buck converter. The input is
likely not having a diode, just input capacitor which
will show as a slowly climbing resistance if you measure
with your multimeter, but the output will also have a
capacitor with the same effect. So it is more likely that
you can find the output by switching your multimeter to
diode measurement and checking for the diode on the output.

Success,

Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [email protected]
Tel: +1 408 383 7626 magicJack: +1 408 844 3932
Tel: +91 (040)23117400 x203 XoIP: +31877841130

Please consider the environment before printing this e-mail.
-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Louis Pelletier
Sent: Saturday, March 28, 2009 8:07 AM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] DC-DC CONVERTER

thanks Willie. i will try it tomorow. i got my batterys in today.
i hooked up the controller and motor and the throttle. i went
to put the fuse in a big spark. the fuse didn't blow, every thing was
off. so i unplug all the wires. no reading accross the fuse terminals.
that good. i plug the 2 wires to the controler and get 51.4 voltes
across the fuse terminals. i have not checked the amp draw yet.
i thought that there was not suposed to be any juice to the contrllor
untill i energise the small red wire to turn the controllor on.
i don't recall seeing any relay in these scooters. i'll tackle this in
the 
mornnig
with a fresh mind.
Louis in central BC
----- Original Message ----- 
From: "Willie McKemie" <[email protected]>
.
>
> MY BAD!
>
> What my supplier ACTUALLY said was red - 36-42v, yellow - 12v, black -
> common.
> http://is.gd/pltG
. 

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## EVDL List (Jul 27, 2007)

*Re: [EVDL] DC-DC CONVERTER*

Willie,Cor, list, as for the dc-dc convertor ,
the red is the hi voltage imput, yellow is the 12 v
and black is common. i had a set back today,
that used motor i had is coging and not turning
very fast. however i had 2 more and i was able to make 
one out of 3. these are the motor gear box units.
the one that i plan on useing was a Raylight brand.
after looking in the motor housing and it looks
like a spegeti factory with 2 dozzen little wires every
where and inside the other 2 which were the velo-teg
brand, was much neater and simpler. as a mater of fact it looked 
like an industrial 3 phase motor. tomorrow i off to get
a truck battery isolation switch. so close to a first run.
thank for the help guys
Louis in central BC
----- Original Message ----- 
From: "Cor van de Water" <[email protected]>
.


> Louis,
> 
> What you saw sparking was the charging of the
> input capacitors of the controller.
> That is why most controllers are connected with a
>.>

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## EVDL List (Jul 27, 2007)

*Re: [EVDL] DC-DC CONVERTER*

i mistyped, red is input (48V).



> Louis Pelletier <[email protected]>wrote:
> 
> > u say 12v is red, yellow is output???????????
> > which one is the imput????????
> ...


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## EVDL List (Jul 27, 2007)

*[EVDL] DC-DC converter*

In my hunt for an "inexpensive" DC-DC converter I found these

http://www.astrodyne.com/smartcat/pdf/SD350.pdf

Specifically the SD350D...

I liked TWO (2) things...

PRICE $135
Input Range 72VDC to >144V

This is the 350W version, ([email protected]) which should be more than I need for my
GEO, but they have larger units.

PS...THEY ANSWER THEIR EMAIL. When I asked a question, I got an answer
back...Wow...what a concept.

Bob Sisson
1993 Geo Metro Convertible Project
Gaithersburg MD


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