# [EVDL] dc/dc converter hookup



## EVDL List (Jul 27, 2007)

A good solution for a dependable DC/DC converter is using a couple of SS 1/2
brick DC converters rated at 100w each and leave them on all the time. They
can be adjusted from 12v to 15.5v output. Using all LED lights, haligen
headlights will keep you in a trouble free area using little power unlike
most people using DC converters that seem to fail at a alarming high rate
that will bring your ride to a halt.

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## EVDL List (Jul 27, 2007)

> Bob Bath wrote:
> > Mine requires precharge, so that end is always on. But the output is not. It's kept the aux. batt. well charged for almost 7 years and 22k miles.
> 
> That's a good idea; I haven't heard of doing it that way before. Then
> ...


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## EVDL List (Jul 27, 2007)

Hello Ben,

I been running a bank of IOTA's 45 since 2000 with no problems. It is 
always disconnected with a contactor while the ignition switch is off. I use 
a Busman 10 amp fustron rated at 250 volts on the input side and its 
protected with a 30 amp fustron on the output side of each converter.

I have it set for 14.5 volts at no load, but it will pull down to less than 
14 volts when loaded. I do not turn on this unit with the load on. I have 
separate switches to turn on the devices separately, not every thing turns 
on at once.

This unit is only a power supply and if I have it set at 14.5 volts, it will 
overcharge the battery if the battery is the only thing connected to the 
converter. Setting it at 13.5 volts, the voltage will drop below 13 volts 
and the 12 volt battery which is a 135 AH deep cycle battery will not be 
charge fully.

So I install a Schumacher on board 12 volt Smart Charger that I can turn on 
with a switch that is connected to a 20 amp circuit breaker which is 
connected to the main AC input power receptacle. The charger will quickly 
charge the battery which has drop to about 90% SOC and than go into a 
maintain charge.

I since install a alternator that is design to charge a deep cycle battery, 
and only use the DC-DC converter as a backup. This large alternator is also 
a safety thing, which allows the EV to slow down on some very steep icy 
hills which I can load up to over 100 amps.

Roland


----- Original Message ----- 
From: "Ben Jarrett" <[email protected]>
To: "Electric Discussion List" <[email protected]>
Sent: Saturday, November 12, 2011 8:06 AM
Subject: [EVDL] dc/dc converter hookup





I've been trying to decide how I want to hook up my dc/dc converter to my 
pack. Whether it should
be "always on" or if I need a relay (or contactor) on the high voltage side. 
I'm also worried about inrush current.

I was thinking to help handle inrush current, I would need some sort of an 
inductor in series with the dc/dc
converter. I was wondering if just making a coil loop with the supply wire 
with about 10 turns wold
help at all.

I'm going to start looking through schematics on how other folks have hooked 
up theres, but thought
I'd ping the list to get lessons learned from other folks. Please let me 
know if yours is only enabled
during running and charging or it you just leave it always connected to dc.

thanks,
-ben
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## EVDL List (Jul 27, 2007)

I have hooked up my Elcon DC-DC two different ways. First, hooking it up so
it was switched by the main contactor. This worked OK, but because of my
precharge resistor, the converter kept cycling on & off and slowly draining
the pack.

I now have a DC SSR switching the converter with the ignition. I also have
inrush limiter to protect the converter. It is a large power resister that
has about 10 ohms resistance when cold and well under 1 ohm when hot. This
reduces startup current. It must be rated for the current the converter
draws. This has worked well for 8 months.

I don`t want to leave my DC-DC on all the time because I`m not sure its duty
cycle is rated to run 100% of the time.

Mike

> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On
> Behalf Of Ben Jarrett
> Sent: Saturday, November 12, 2011 8:07 AM
> To: Electric Discussion List
> Subject: [EVDL] dc/dc converter hookup
> =

> =

> =

> =

> I've been trying to decide how I want to hook up my dc/dc converter to my
> pack. Whether it should be "always on" or if I need a relay (or
contactor) on
> the high voltage side. I'm also worried about inrush current.
> =

> I was thinking to help handle inrush current, I would need some sort of an
> inductor in series with the dc/dc converter. I was wondering if just
making a
> coil loop with the supply wire with about 10 turns wold help at all.
> =

> I'm going to start looking through schematics on how other folks have
> hooked up theres, but thought I'd ping the list to get lessons learned
from
> other folks. Please let me know if yours is only enabled during running
and
> charging or it you just leave it always connected to dc.
> =

> thanks,
> -ben
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## EVDL List (Jul 27, 2007)

> Willie McKemie wrote:
> > A very large fraction of conversion troubles are associated with
> > dead 12v batteries. In my experience.
> 
> ...


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## EVDL List (Jul 27, 2007)

> Lee Hart wrote:
> > Willie McKemie wrote:
> > > A very large fraction of conversion troubles are associated with
> > > dead 12v batteries. In my experience.
> ...


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## EVDL List (Jul 27, 2007)

On 11/16/2011 08:13 AM, Willie McKemie wrote:
>


> Lee Hart wrote:
> >> Willie McKemie wrote:
> 
> >
> ...


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## EVDL List (Jul 27, 2007)

> On 16 Nov 2011 at 8:40, Jay Summet wrote:
> 
> > You could just leave a small DC charger ... always connected.
> 
> ...


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## EVDL List (Jul 27, 2007)

Why not approach it from the other way and use a 'wall wart' to keep 
the 12VDC system 'live' when you car is plugged into the mains and 
apart from powering your router all the time when plugged in (don't 
know how useful that would be), could also be keeping your abused 12V 
battery (or rather, its replacement) fully charged?

Regards, Martin Winlow
Herts, UK
http://www.evalbum.com/2092
www.winlow.co.uk




> Willie McKemie wrote:
> 
> > On Sun, Nov 13, 2011 at 12:58:38PM -0600, Lee Hart wrote:
> >> Willie McKemie wrote:
> ...


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## EVDL List (Jul 27, 2007)

You can use a battery maintainer by it self, or in combination with a Smart 
charger. I am using a maintainer on a ICE that been on a sports car since 
1973 with only 57 miles on. Start it up once a year with the same battery 
that was in it back then.

I am using a Smart charger that is install on board the EV. I got it from 
Wal Mart that is turn on with a 20 amp circuit breaker. It's a Shumaker type 
that can charge 6 or 12 volt standard, deep cycle, gel and AGM batteries. 
The ampere selection is 2, 15, and 40 amps. It has a voltage indicator and 
a State of Charge indicator.

The maintainer voltage from this unit is about 12.34 volts.

I have a transfer switch on the output leads of this charger, where I can 
select the on board 12 volt accessory battery or to 2-wire 50 amp Power 
Anderson receptacle which is the same type on the side of this charger for 
plugging in the battery leads. This extra tap off is use to balance charge 
the 6-volt batteries which I may do every three months after I do a normal 
balance charge with the main battery pack charger.

A 12 volt accessory deep cycle battery was install in 2000 using this type 
of Smart Charger, and I finally had to replace it last year. Like to 
squeeze every bit out of it before it is replace.

Roland




----- Original Message ----- 
From: "Martin WINLOW" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Wednesday, November 16, 2011 9:29 AM
Subject: Re: [EVDL] dc/dc converter hookup


> Why not approach it from the other way and use a 'wall wart' to keep
> the 12VDC system 'live' when you car is plugged into the mains and
> apart from powering your router all the time when plugged in (don't
> know how useful that would be), could also be keeping your abused 12V
> battery (or rather, its replacement) fully charged?
>
> Regards, Martin Winlow
> Herts, UK
> http://www.evalbum.com/2092
> www.winlow.co.uk
>
>
>


> Willie McKemie wrote:
> >
> > > On Sun, Nov 13, 2011 at 12:58:38PM -0600, Lee Hart wrote:
> > >> Willie McKemie wrote:
> ...


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## EVDL List (Jul 27, 2007)

>>> You could just leave a small DC charger ... always connected.

>> I did that with a Todd DCC and regretted it.



> Jay Summet wrote:
> > That is why a "smart" battery charger is a much better choice than a
> > pure DC/DC for continuous charging of your 12v accessory battery. You'll
> > want to pick one that reliably drops current/voltage once the battery is
> ...


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## EVDL List (Jul 27, 2007)

My EV had a separate charger like that at first. My problem was that it
died silently and I didn`t notice. The car died on the road when the 12V
battery died. That was the one time the car has left me walking. I
installed my DC-DC soon after. If you go for an external charger, make sure
you have some way to tell if it's working (or not).

Mike

> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On
> Behalf Of Martin WINLOW
> Sent: Wednesday, November 16, 2011 9:30 AM
> To: Electric Vehicle Discussion List
> Subject: Re: [EVDL] dc/dc converter hookup
> 
> Why not approach it from the other way and use a 'wall wart' to keep the
> 12VDC system 'live' when you car is plugged into the mains and apart from
> powering your router all the time when plugged in (don't know how useful
> that would be), could also be keeping your abused 12V battery (or rather,
its
> replacement) fully charged?
> 
> Regards, Martin Winlow
> Herts, UK
> http://www.evalbum.com/2092
> www.winlow.co.uk
> 
> 
>


> Willie McKemie wrote:
> >
> > > On Sun, Nov 13, 2011 at 12:58:38PM -0600, Lee Hart wrote:
> > >> Willie McKemie wrote:
> ...


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## EVDL List (Jul 27, 2007)

> Lee Hart wrote:
> 
> >>>> You could just leave a small DC charger ... always connected.
> >
> ...


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