# [EVDL] Cheap DC/DC



## EVDL List (Jul 27, 2007)

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## EVDL List (Jul 27, 2007)

"...you want a not -so-expencive DC converter??? put a used altenator 
on it and be done with it.some will push out 135 amps you need more 
than that??? no one does. With the ICE gone,, 80 to 90 is what ALL 
newer cars/trucks will ever need, ABS requires 50 amps to be a working 
unit,

lights about 30 , heater fan on "HI" will use 35 amps , wipers about 
15 I dont like radios so theres no amps there...


1. An alternator is going to need a dual-shaft motor and a mount - if 
the main work is already done, many conversions only have one output 
to power the wheels - are you suggesting someone spend even more to 
get a motor with a second output shaft? Then there is the expense of 
mounting the alternator.

2. DC-DC takes no mechanical skill to mount or "drive", just wiring 
ability! You get few problems if you buy a good converter, but that is 
much more than "handymen" sometimes want to spend.

3. I don't know about you, but I need a radio and hopefully a CD and 
even a input for my iPod. Even if you listen to NPR instead of rock, 
most of us need something, and some need a lot of ear-splitting noise 
from it!

Think more
Talk less
Become wise


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## EVDL List (Jul 27, 2007)

I can see some real advantages to using an alternator - mainly, price, and
reliability.
On the other hand, it just wouldn't fit on some cars ( like my Echo, where a
tail-shafted motor wouldn't fit in the engine bay), and there is also the
extra weight and poor efficiency to consider.

And - it only works with a spinning motor, so your headlights would be a bit
dimmer at a stoplight ( unless you waste a LOT of energy to keep the motor
spinning)

Phil

On Wed, Apr 1, 2009 at 2:56 PM, Electric Blue auto convertions <


> [email protected]> wrote:
> 
> >
> >
> ...


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## EVDL List (Jul 27, 2007)

Maybe I'm missing something but I thought the point was that the alternator
charges the accessory battery (just as a DC-DC converters usually does). It
wouldn't be providing the power directly to the accessories. So as long as
the accessory battery is being kept up to charge, there would not be any
dimming of the lights. Or are people not using accessory batteries?

Peter Flipsen Jr
Pocatello, ID



> Phil Marino <[email protected]> wrote:
> 
> > I can see some real advantages to using an alternator - mainly, price, and
> > reliability.
> ...


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## EVDL List (Jul 27, 2007)

When the alternator is spinning (or the DC/DC running) the
aux battery sits at 14V typical.
With the battery left to its own devices, it sits at 12V
or lower, dependent on current (sag) so the lights,
wiper blades and fans are definitely going to be impacted
especially since power goes with the square of the voltage.

You can easily see the difference when you have a running vehicle
and you stop the engine and watch the difference in the accessories.

Regards,

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 SLPinfo.org
Sent: Thursday, April 02, 2009 1:33 AM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Cheap DC/DC

Maybe I'm missing something but I thought the point was that the
alternator
charges the accessory battery (just as a DC-DC converters usually does).
It
wouldn't be providing the power directly to the accessories. So as long
as
the accessory battery is being kept up to charge, there would not be any
dimming of the lights. Or are people not using accessory batteries?

Peter Flipsen Jr
Pocatello, ID



> Phil Marino <[email protected]> wrote:
> 
> > I can see some real advantages to using an alternator - mainly,
> price, and
> ...


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## EVDL List (Jul 27, 2007)

> SLPinfo.org <[email protected]> wrote:
> 
> > So as long as
> > the accessory battery is being kept up to charge, there would not be any
> ...


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## EVDL List (Jul 27, 2007)

Hi, Peter
If there were no accessory battery, you would have no lights (or
accessories) at all when the motor (and alternator) stopped spinning.
If you do have an accessory battery ( and the alternator is stopped) the
accessory battery voltage will droop - depending on the load.
If you have a small accessory battery, and the lights, heater, wipers, etc,
on, and drawing a lot of current, the accessory battery could easily droop
to 11 1/2 to 12 volts.

The car's lights and accessories are designed for (and normally supplied
with) about 14 volts. So, with a stopped alternator they would be somewhat
dimmer.


And, normally, the alternator ( or DC-DC) *does* supply power directly to
the accessories - as well as supplying some current as needed to keep the
battery at 14V. The accessory battery normally supplies no current to the
accessories, unless the alternator ( or DC-DC) cannot keep up with the load.

Phil



> SLPinfo.org <[email protected]> wrote:
> 
> > Maybe I'm missing something but I thought the point was that the alternator
> > charges the accessory battery (just as a DC-DC converters usually does).
> ...


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## EVDL List (Jul 27, 2007)

>
>


> SLPinfo.org <[email protected]> wrote:
> >
> >
> >> > So as long as
> ...


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## EVDL List (Jul 27, 2007)

> Jeff Shanab <[email protected]> wrote:
> 
> >
> > But I would like to point out a difference on the battery usage when you
> ...


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## EVDL List (Jul 27, 2007)

I've been driving with just a DC-DC converter for the last 7 months. I have
one of the Chinese HZW 300W devices. It is sufficient to run all my loads. I
havent had a problem with it yet, other than it does not have an inrush
current limiter built in. I had it wired across the pack to provide 12V all
the time. They are adjustable if you drill a small hole to get to the
adjustment screw. It's nice to have one designed to run on my 96V pack!

About a week ago I changed my setup to use a 14Ah 12V gel battery and only
turn on the converter when in 'run'. I changed to this because I noticed the
DC converter used more power from my main pack than I liked. Now that I have
switched I get about 2 miles more range. The only drawback is if the battery
dies for whatever reason. I have to open the hood and short the DC converter
on to get my car to do anything. It also resets my link-10.

But it hasnt died since I put in the 14Ah battery. 5Ah is not enough to keep
going all night apparently!

An alternator was not an option. For starters, I didnt have an alternator to
put in! And I just dont have room for it. I took out the A/C and PS also to
make room for batteries.

I drive 12.5 miles per day, 5 days per week. Charging in the evening at
home.
-Jon Glauser
http://jonglauser.blogspot.com
http://www.evalbum.com/555
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## EVDL List (Jul 27, 2007)

> Jon Glauser <[email protected]> wrote:
> 
> > About a week ago I changed my setup to use a 14Ah 12V gel battery and only
> > turn on the converter when in 'run'.
> ...


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## EVDL List (Jul 27, 2007)

Yes, when using a alternator and 12 volt accessory battery, it is best to 
use a deep cycle battery like a U.S. Battery EV-145 and a alternator design 
to charge a deep cycle battery.

This type of alternator can charge a battery at 13.5 to 15 volts. Normally 
I have my set at 14.8 volts for this type of battery and had no problem with 
it since I replace the standard alternator and battery back in 1985.

I have four IOTA's 45 parallel together, and only are use when I'am climbing 
steep hills while I switch off the alternator and/or disconnect the main 
motor pilot shaft from the accessory, so as to keep my motor ampere at or 
below 200 amps.

Fifty percent of my drive time is up-down hills like a roller coaster, so on 
the down hill run, the alternator is switch back on and the inverters are 
off which now show 0 motor and 0 battery amps while the accessory drives may 
be producing up to 100 amps DC which also provides a regenerative braking.

Before I made this change, it was dangerous to drive this EV down long steep 
icy hills which at one time I did not dare hit the brakes and the EV got up 
to 80 mph one time and was able to miss all the other cars.

Roland




----- Original Message ----- 
From: "Jeff Shanab" <[email protected]>
To: <[email protected]>
Sent: Thursday, April 02, 2009 7:04 AM
Subject: Re: [EVDL] Cheap DC/DC


> >
> > On Wed, Apr 1, 2009 at 2:02 PM, SLPinfo.org <[email protected]> 


> > > wrote:
> 
> > >
> > > The alternator is usually keeping the system around 13.5 to 14.5 volts
> ...


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## EVDL List (Jul 27, 2007)

I have 300w HWZ Series 120v to 12v that works like a champ! It list for
around $180. I also run this through a 55ah AGM 12v battery with a 2
amp-charger with inter-lock wiring. Unit keeps up with 300w Road Pro Heater
in winter and handles the lights for night driving in 30-40 mile trips...

David Oberlander
Dodson Services Electrical Contractors, Inc.
[email protected]
Ofc: 972-235-0881x103
Mbl: 469-867-0834
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of Jon Glauser
Sent: Thursday, April 02, 2009 10:23 AM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Cheap DC/DC

I've been driving with just a DC-DC converter for the last 7 months. I have
one of the Chinese HZW 300W devices. It is sufficient to run all my loads. I
havent had a problem with it yet, other than it does not have an inrush
current limiter built in. I had it wired across the pack to provide 12V all
the time. They are adjustable if you drill a small hole to get to the
adjustment screw. It's nice to have one designed to run on my 96V pack!

About a week ago I changed my setup to use a 14Ah 12V gel battery and only
turn on the converter when in 'run'. I changed to this because I noticed the
DC converter used more power from my main pack than I liked. Now that I have
switched I get about 2 miles more range. The only drawback is if the battery
dies for whatever reason. I have to open the hood and short the DC converter
on to get my car to do anything. It also resets my link-10.

But it hasnt died since I put in the 14Ah battery. 5Ah is not enough to keep
going all night apparently!

An alternator was not an option. For starters, I didnt have an alternator to
put in! And I just dont have room for it. I took out the A/C and PS also to
make room for batteries.

I drive 12.5 miles per day, 5 days per week. Charging in the evening at
home.
-Jon Glauser
http://jonglauser.blogspot.com
http://www.evalbum.com/555
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Usage guidelines: http://evdl.org/help/index.html#conv
Archives: http://evdl.org/archive/
Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev

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Usage guidelines: http://evdl.org/help/index.html#conv
Archives: http://evdl.org/archive/
Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev


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## EVDL List (Jul 27, 2007)

>
>


> Jeff Shanab <[email protected]> wrote:
> >
> >
> >> >
> ...


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## EVDL List (Jul 27, 2007)

*[EVDL] cheap DC/DC*

Has anyone used one of these DC/DC converters?
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3D110782182251&ssPageNam=
e=3DADME:X:RTQ:US:1123#ht_2045wt_1165

It strikes me as being very cheap. The seller says they are isolated out=
put. My system would have a small supplemental 12V battery.

Chris Darilek
'72 BMW 2002 EV in the works
Austin, TX
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## EVDL List (Jul 27, 2007)

*Re: [EVDL] cheap DC/DC*

I learned the hard way in winter to go with 60A, not 35.
Dimmed headlights, and slow wipers when applying the brakes is not cool.

Sent from my iPod



> Christopher Darilek <[email protected]> wrote:
> 
> > Has anyone used one of these DC/DC converters?
> > http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=110782182251&ssPageName=ADME:X:RTQ:US:1123#ht_2045wt_1165
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] cheap DC/DC*

Here's my 2-cents on DC-DC converters (after having an IOTA fail several
times).

http://www.corbinstreehouse.com/blog/2011/04/plug-bug-dc-dc-converters/

corbin



> Lee Hart <[email protected]> wrote:
> 
> > On 4/30/2012 8:56 AM, Christopher Darilek wrote:
> > > Has anyone used one of these DC/DC converters?
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] cheap DC/DC*

Bob is right, 30amps is not much power on the 12-14v aux. supply, his biger
battery is propably being recharged at times when he is stopped and parked.
I still say the GM internally regulated one wirw marine type alternator
belt driven from the back shaft of the main motor is when coupled to a AGM
aux. battery in typical automotive sizes is more reliable and way less
costley than the DC/DC converter and available rebuilt at any auto parts
store worldwide.
Regards,
*Dennis Lee Miles*
*++++++++++++++++++++++++++++++++++++++++*


> Bob Bath <[email protected]> wrote:
> 
> > I learned the hard way in winter to go with 60A, not 35.
> > Dimmed headlights, and slow wipers when applying the brakes is not cool.
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] cheap DC/DC*



> On 30 Apr 2012 at 6:56, Christopher Darilek wrote:
> 
> > It strikes me as being very cheap.
> 
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] cheap DC/DC*

The only lead in my conversion is in the house battery, and my 636 watt-rated dc/dc won't keep up with under 400W of loads when the lead starts sagging (turn on the headlights and the system hits 12.2V or less after a long float at 13.8V). I want something stiffer, with good backup capacity in case of dc-dc failure, and something that likes staying on a set float voltage without a lot of standby losses (unlike my flooded nicads).

Who's using a lithium house battery? DIY or commercial product? I was disappointed to see lead house batteries in both the Leaf and iMiEV...

Jay Donnaway
www.karmanneclectric.blogspot.com

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## EVDL List (Jul 27, 2007)

*Re: [EVDL] cheap DC/DC*

Hi Dennis,

I think, like most people, I want to get away from all that 'dodgy' belt driving stuff - it seems just <so> old fashioned!

But, as you say, in terms of bang for buck, you would be hard pressed to beat a belt driven alternator. I imagine it is even reasonably efficient as the belt & pulley system is at least 90% efficient - more if a toothed one were used. Also, it's all very easy to to wire in and the engineering involved in mounting it is simple, too. If you use the one that came with the donor vehicle then the cost would be minimal - $15 to $100, depending on whether or not you do your own metalwork.

Lastly, it puts out plenty of power... up to 80A I gather.

Have you investigated the relative efficiencies of the 2 alternatives at all?

The only 3 down sides I can see are 1/ the lack of efficiency when there is little electrical load ie the alternator still rotates when there is no load on it causing a pointless drag on the motor, 2/ the additional hassle involved in making up the alternator bracket rather than just bolting in a DC-DC converter and 3/ the need to 'service' the system - ie check the belt, pulleys and alternator for wear and correct tension.

I would also install a simple (cheap) battery conditioner to keep the Pb-A battery topped up when the vehicle was plugged into the mains. This will take care of any parasitic loads (radio, alarm etc) and stop the charging system having to spend any time or effort charging up the aux battery when you first start driving the vehicle. But this applies to both alternator and DC-DC converter options.

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



> Dennis Miles wrote:
> 
> > Bob is right, 30amps is not much power on the 12-14v aux. supply, his biger
> > battery is propably being recharged at times when he is stopped and parked.
> ...


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