# [EVDL] DC/DC with flexible pack voltage?



## EVDL List (Jul 27, 2007)

For my conversion, I'm planning on a Z1K-HV and PFC-20. This gives me 
some real options on batteries in the future.

The Z1K-HV gives 72-300V range
The PFC-20 gives 12-360V range

(These are both nominal voltages, right?)

So this combo can handle quite a range of pack voltages. I can have 10 
or 12 or 16 12V lead-acids (25 if I add more wheels to carry the 
weight). Or I can use 93 of the 3.2V50Ah headway packs that are being 
talked about, or some other lithium tech when it becomes affordable 
(maybe my 2nd or 3rd pack). Or something in the middle. And I can use 
these parts on my next EV once the current frame rusts to its grave. 
(This is all speculation. There is a 100% chance my first pack will be 
lead.) Even for the lead pack, having some breathing room will be 
nice. If I find my range to be 2-3 miles shorter than I'd like, I could 
squeeze in "just one more" battery (early enough in the pack's life 
cycle to make that not a terrible idea, hopefully), without blowing any 
voltage limits.

Thing is, I can't find a DC/DC converter that's equally flexible.

The Iota units at evsource are 108-170V or 208-320V. I assume because 
they're just switching power supplies meant for 120 or 240VAC usage. 
The ones EVA sells don't seem to go above 144V. I know this is probably 
the cheapest electrical component, so maybe I shouldn't worry about it 
and buy another one when I change pack voltages in the future. I also 
don't know if these are nominal voltages or absolute limits. If they're 
absolute limits, then a 168V lead acid pack would not be an option with 
the lower voltage Iota unit. The Brusa units look good, but the cost 
more than the Zilla. Ouch. Running without a DC converter is an 
option, but not a good one. A converter that outputs 14V for 10-14V 
input might be a compromise to using the accessory battery on its own, 
and keep the lights up bright. (Costs about $150) But now I'm just 
rambling.

Is anyone else thinking about what they have to do to switch battery 
technology in the future, or are you just expecting to configure future 
packs for the same voltage as your lead packs?

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

[No message]


----------



## EVDL List (Jul 27, 2007)

> Mark Eidson wrote:
> > I had a problem with my DC-DC dropping out when the pack dropped
> > during high current loads......I eventually had to add a separate 12V
> > battery for the Zilla and associated controls. me
> ...


----------



## EVDL List (Jul 27, 2007)

[No message]


----------



## EVDL List (Jul 27, 2007)

Is that what Otmar suggested, or did you even bring it up with him? 
(That's the first thing I would do.)

This seems crazy. If the zilla is powered by an accessory battery fed 
by the DC-DC, it shouldn't matter if the DC-DC cuts off. The result 
would be exactly what you have now, unless the DC-DC is lame and 
actually sucks current from your accessory battery when it undervolts.



> Mark Eidson wrote:
> > I tried having the batery tied to the DC-DC but I would still get drop
> > outs with the main contactor disconnecting and the Zilla reporting
> > errors under heavy acceleration. I once had to restore the default
> ...


----------



## EVDL List (Jul 27, 2007)

[No message]


----------



## EVDL List (Jul 27, 2007)

> I can't find a DC/DC converter that's equally flexible.

IOTA units (power supply) don't work very well below 110VDC input. When 
loaded, their output voltage drops with decreasing input voltage, but they 
handle the "brownout" very well. Roland uses them in series/parallel in 
his El Camino.

Ditto for the Zivan NG1-DCDC. It holds up better at low input voltage, but 
output voltage still sags.

The Belktronix DC/DC works from 84V to 200V. It will do 250V if you keep a 
1A or higher load on it. The manual requires precharging BOTH the input 
and output before connecting them, so you may need to use a precharge 
circuit if you regularly disconnect the input OR the output. I think a few 
listers are using them.

If you have an even number of batteries you could connect a DC/DC to each 
half of the pack. A 192V pack would feed two 96V DC/DC units. If their 
output voltage drops slightly with load (most do), they should draw 
similar amounts of current from each pack half.

You could also use the 10-14V input, 14V output converter with a modified 
version of Lee's battery balancer. Divide the traction pack up into 10-14V 
groups and take turns feeding the DC/DC with each group to avoid 
unbalancing the pack.

As a last resort, use another PFC-20/30/50 to keep your 12V battery 
charged. They run 60-250VAC, and SHOULD work with 84-336VDC (check w/ 
Manzanita to be sure). Not cheap, but rock solid (if a bit noisy with the 
dual fans).

-Adrian

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

[No message]


----------



## EVDL List (Jul 27, 2007)

what is the efficency of dual DC/DC converters?


----- Original Message ----- 
From: "Adrian DeLeon" <[email protected]>
To: <[email protected]>
Sent: Wednesday, January 09, 2008 8:37 PM
Subject: Re: [EVDL] DC/DC with flexible pack voltage?


>> I can't find a DC/DC converter that's equally flexible.
>
> IOTA units (power supply) don't work very well below 110VDC input. When
> loaded, their output voltage drops with decreasing input voltage, but they
> handle the "brownout" very well. Roland uses them in series/parallel in
> his El Camino.
>
> Ditto for the Zivan NG1-DCDC. It holds up better at low input voltage, but
> output voltage still sags.
>
> The Belktronix DC/DC works from 84V to 200V. It will do 250V if you keep a
> 1A or higher load on it. The manual requires precharging BOTH the input
> and output before connecting them, so you may need to use a precharge
> circuit if you regularly disconnect the input OR the output. I think a few
> listers are using them.
>
> If you have an even number of batteries you could connect a DC/DC to each
> half of the pack. A 192V pack would feed two 96V DC/DC units. If their
> output voltage drops slightly with load (most do), they should draw
> similar amounts of current from each pack half.
>
> You could also use the 10-14V input, 14V output converter with a modified
> version of Lee's battery balancer. Divide the traction pack up into 10-14V
> groups and take turns feeding the DC/DC with each group to avoid
> unbalancing the pack.
>
> As a last resort, use another PFC-20/30/50 to keep your 12V battery
> charged. They run 60-250VAC, and SHOULD work with 84-336VDC (check w/
> Manzanita to be sure). Not cheap, but rock solid (if a bit noisy with the
> dual fans).
>
> -Adrian
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev 

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

> Adrian DeLeon wrote:
> >
> > If you have an even number of batteries you could connect a DC/DC to each
> > half of the pack. A 192V pack would feed two 96V DC/DC units. If their
> ...


----------



## EVDL List (Jul 27, 2007)

This certainly seems to be a weak spot in EV components. Therefore, I 
am developing a DC/DC converter that has an input range of 70 to 500 
volts with an output of 14.7 volts from 0 to 140 amps. This is a Hot 
Juice Electric project and the progress can be monitored at: 
http://www.hotjuiceelectric.com/development.html

I bring this up for feedback.

At this time, a working prototype is in testing. All good so far except 
for one problem. There is approximately $1,200 in parts alone. I am 
afraid that adding labor and enough profit to maintain sustainability 
would push the price out of most peoples range.

The project is now being refined to maintain the current specifications 
and reliability while reducing the cost. The progress is encouraging, 
but I think it would help if I could get some feedback.

So, I present this question to the list: What would be a reasonable 
price for a DC/DC converter (I call it Chassis Power Module) that would 
maintain 14.7 volts output from 0 to 140 amps with an input range of 70 
to 500 volts?
Check out the website for additional information.

Keep the Juice flowing!

Ken





-----Original Message-----
From: Chuck Homic <[email protected]>
To: Electric Vehicle Discussion List <[email protected]>
Sent: Wed, 9 Jan 2008 10:55 am
Subject: [EVDL] DC/DC with flexible pack voltage?



For my conversion, I'm planning on a Z1K-HV and PFC-20. This gives me
some real options on batteries in the future.

The Z1K-HV gives 72-300V range
The PFC-20 gives 12-360V range

(These are both nominal voltages, right?)

So this combo can handle quite a range of pack voltages. I can have 10
or 12 or 16 12V lead-acids (25 if I add more wheels to carry the
weight). Or I can use 93 of the 3.2V50Ah headway packs that are being
talked about, or some other lithium tech when it becomes affordable
(maybe my 2nd or 3rd pack). Or something in the middle. And I can use
these parts on my next EV once the current frame rusts to its grave.
(This is all speculation. There is a 100% chance my first pack will be
lead.) Even for the lead pack, having some breathing room will be
nice. If I find my range to be 2-3 miles shorter than I'd like, I could
squeeze in "just one more" battery (early enough in the pack's life
cycle to make that not a terrible idea, hopefully), without blowing any
voltage limits.

Thing is, I can't find a DC/DC converter that's equally flexible.

The Iota units at evsource are 108-170V or 208-320V. I assume because
they're just switching power supplies meant for 120 or 240VAC usage.
The ones EVA sells don't seem to go above 144V. I know this is probably
the cheapest electrical component, so maybe I shouldn't worry about it
and buy another one when I change pack voltages in the future. I also
don't know if these are nominal voltages or absolute limits. If they're
absolute limits, then a 168V lead acid pack would not be an option with
the lower voltage Iota unit. The Brusa units look good, but the cost
more than the Zilla. Ouch. Running without a DC converter is an
option, but not a good one. A converter that outputs 14V for 10-14V
input might be a compromise to using the accessory battery on its own,
and keep the lights up bright. (Costs about $150) But now I'm just
rambling.

Is anyone else thinking about what they have to do to switch battery
technology in the future, or are you just expecting to configure future
packs for the same voltage as your lead packs?

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


________________________________________________________________________
More new features than ever. Check out the new AOL Mail ! - 
http://webmail.aol.com

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

> Adrian DeLeon wrote:
> >> If you have an even number of batteries you could connect a DC/DC
> >> to each half of the pack. A 192V pack would feed two 96V DC/DC
> >> units. If their output voltage drops slightly with load (most do),
> ...


----------



## EVDL List (Jul 27, 2007)

> Lee Hart wrote:
> > No; almost any DC/DC (or even AC/DC power supply being used as a DC/DC)
> > will work. The key is that they need to have an adjustable output
> > voltage, so you can set them to each provide half the load current.
> ...


----------



## EVDL List (Jul 27, 2007)

140 amps is nice, but that is a LOT of headroom. Could you offer a smaller 
model for less?

Personally, half that would be fine. The biggest load in my EV is the 
blower fan @ 28a. I have never seen any combination of accessories pull 
more than 68a peak.

-Phil
----- Original Message ----- 
From: <[email protected]>
To: <[email protected]>
Sent: Thursday, January 10, 2008 8:20 AM
Subject: Re: [EVDL] DC/DC with flexible pack voltage?


> This certainly seems to be a weak spot in EV components. Therefore, I
> am developing a DC/DC converter that has an input range of 70 to 500
> volts with an output of 14.7 volts from 0 to 140 amps. This is a Hot
> Juice Electric project and the progress can be monitored at:
> http://www.hotjuiceelectric.com/development.html
>
> I bring this up for feedback.
>
> At this time, a working prototype is in testing. All good so far except
> for one problem. There is approximately $1,200 in parts alone. I am
> afraid that adding labor and enough profit to maintain sustainability
> would push the price out of most peoples range.
>
> The project is now being refined to maintain the current specifications
> and reliability while reducing the cost. The progress is encouraging,
> but I think it would help if I could get some feedback.
>
> So, I present this question to the list: What would be a reasonable
> price for a DC/DC converter (I call it Chassis Power Module) that would
> maintain 14.7 volts output from 0 to 140 amps with an input range of 70
> to 500 volts?
> Check out the website for additional information.
>
> Keep the Juice flowing!
>
> Ken
>
>
>
>
>
> -----Original Message-----
> From: Chuck Homic <[email protected]>
> To: Electric Vehicle Discussion List <[email protected]>
> Sent: Wed, 9 Jan 2008 10:55 am
> Subject: [EVDL] DC/DC with flexible pack voltage?
>
>
>
> For my conversion, I'm planning on a Z1K-HV and PFC-20. This gives me
> some real options on batteries in the future.
>
> The Z1K-HV gives 72-300V range
> The PFC-20 gives 12-360V range
>
> (These are both nominal voltages, right?)
>
> So this combo can handle quite a range of pack voltages. I can have 10
> or 12 or 16 12V lead-acids (25 if I add more wheels to carry the
> weight). Or I can use 93 of the 3.2V50Ah headway packs that are being
> talked about, or some other lithium tech when it becomes affordable
> (maybe my 2nd or 3rd pack). Or something in the middle. And I can use
> these parts on my next EV once the current frame rusts to its grave.
> (This is all speculation. There is a 100% chance my first pack will be
> lead.) Even for the lead pack, having some breathing room will be
> nice. If I find my range to be 2-3 miles shorter than I'd like, I could
> squeeze in "just one more" battery (early enough in the pack's life
> cycle to make that not a terrible idea, hopefully), without blowing any
> voltage limits.
>
> Thing is, I can't find a DC/DC converter that's equally flexible.
>
> The Iota units at evsource are 108-170V or 208-320V. I assume because
> they're just switching power supplies meant for 120 or 240VAC usage.
> The ones EVA sells don't seem to go above 144V. I know this is probably
> the cheapest electrical component, so maybe I shouldn't worry about it
> and buy another one when I change pack voltages in the future. I also
> don't know if these are nominal voltages or absolute limits. If they're
> absolute limits, then a 168V lead acid pack would not be an option with
> the lower voltage Iota unit. The Brusa units look good, but the cost
> more than the Zilla. Ouch. Running without a DC converter is an
> option, but not a good one. A converter that outputs 14V for 10-14V
> input might be a compromise to using the accessory battery on its own,
> and keep the lights up bright. (Costs about $150) But now I'm just
> rambling.
>
> Is anyone else thinking about what they have to do to switch battery
> technology in the future, or are you just expecting to configure future
> packs for the same voltage as your lead packs?
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>
>
> ________________________________________________________________________
> More new features than ever. Check out the new AOL Mail ! -
> http://webmail.aol.com
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
> 

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

Who the heck needs 140 amps? Are you planning on powering a 5th wheel too?

I'm just asking. Seems to me that cutting the power in 1/2 would still be
more than adequate and would reduce costs quite a bit.
Heck, I think most people would be happy with 55 amps... well anyone
without a Wayland Sound System (tm)

> This certainly seems to be a weak spot in EV components. Therefore, I
> am developing a DC/DC converter that has an input range of 70 to 500
> volts with an output of 14.7 volts from 0 to 140 amps. This is a Hot
> Juice Electric project and the progress can be monitored at:
> http://www.hotjuiceelectric.com/development.html
>
> I bring this up for feedback.
>
> At this time, a working prototype is in testing. All good so far except
> for one problem. There is approximately $1,200 in parts alone. I am
> afraid that adding labor and enough profit to maintain sustainability
> would push the price out of most peoples range.
>
> The project is now being refined to maintain the current specifications
> and reliability while reducing the cost. The progress is encouraging,
> but I think it would help if I could get some feedback.
>
> So, I present this question to the list: What would be a reasonable
> price for a DC/DC converter (I call it Chassis Power Module) that would
> maintain 14.7 volts output from 0 to 140 amps with an input range of 70
> to 500 volts?
> Check out the website for additional information.
>
> Keep the Juice flowing!
>
> Ken
>
>
>
>
>
> -----Original Message-----
> From: Chuck Homic <[email protected]>
> To: Electric Vehicle Discussion List <[email protected]>
> Sent: Wed, 9 Jan 2008 10:55 am
> Subject: [EVDL] DC/DC with flexible pack voltage?
>
>
>
> For my conversion, I'm planning on a Z1K-HV and PFC-20. This gives me
> some real options on batteries in the future.
>
> The Z1K-HV gives 72-300V range
> The PFC-20 gives 12-360V range
>
> (These are both nominal voltages, right?)
>
> So this combo can handle quite a range of pack voltages. I can have 10
> or 12 or 16 12V lead-acids (25 if I add more wheels to carry the
> weight). Or I can use 93 of the 3.2V50Ah headway packs that are being
> talked about, or some other lithium tech when it becomes affordable
> (maybe my 2nd or 3rd pack). Or something in the middle. And I can use
> these parts on my next EV once the current frame rusts to its grave.
> (This is all speculation. There is a 100% chance my first pack will be
> lead.) Even for the lead pack, having some breathing room will be
> nice. If I find my range to be 2-3 miles shorter than I'd like, I could
> squeeze in "just one more" battery (early enough in the pack's life
> cycle to make that not a terrible idea, hopefully), without blowing any
> voltage limits.
>
> Thing is, I can't find a DC/DC converter that's equally flexible.
>
> The Iota units at evsource are 108-170V or 208-320V. I assume because
> they're just switching power supplies meant for 120 or 240VAC usage.
> The ones EVA sells don't seem to go above 144V. I know this is probably
> the cheapest electrical component, so maybe I shouldn't worry about it
> and buy another one when I change pack voltages in the future. I also
> don't know if these are nominal voltages or absolute limits. If they're
> absolute limits, then a 168V lead acid pack would not be an option with
> the lower voltage Iota unit. The Brusa units look good, but the cost
> more than the Zilla. Ouch. Running without a DC converter is an
> option, but not a good one. A converter that outputs 14V for 10-14V
> input might be a compromise to using the accessory battery on its own,
> and keep the lights up bright. (Costs about $150) But now I'm just
> rambling.
>
> Is anyone else thinking about what they have to do to switch battery
> technology in the future, or are you just expecting to configure future
> packs for the same voltage as your lead packs?
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>
>
> ________________________________________________________________________
> More new features than ever. Check out the new AOL Mail ! -
> http://webmail.aol.com
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>


-- 
If you send email to me, or the EVDL, that has > 4 lines of legalistic
junk at the end; then you are specifically authorizing me to do whatever I
wish with the message. By posting the message you agree that your long
legalistic signature is void.

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

[No message]


----------



## EVDL List (Jul 27, 2007)

Could this system be reversed to put voltage back into you drive pack one 
set of 12vdc batts. at a time from an alternator off the shaft of your 
motor, say if you were pulling the ev somewhere or even using a pusher 
trailer, or is there a more effecient way of doing this?


----- Original Message ----- 
From: "Lee Hart" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Thursday, January 10, 2008 11:34 AM
Subject: Re: [EVDL] DC/DC with flexible pack voltage?




> > Adrian DeLeon wrote:
> >>> If you have an even number of batteries you could connect a DC/DC
> >>> to each half of the pack. A 192V pack would feed two 96V DC/DC
> >>> units. If their output voltage drops slightly with load (most do),
> ...


----------



## EVDL List (Jul 27, 2007)

> Josh Creel wrote:
> > Could this system be reversed to put voltage back into you drive pack one
> > set of 12vdc batts. at a time from an alternator off the shaft of your
> > motor, say if you were pulling the ev somewhere or even using a pusher
> ...


----------



## EVDL List (Jul 27, 2007)

The expense is in the input range. The current capability adds some 
expense, but is dwarfed by the cost of tracking that large of input 
voltage range. I chose 140 amps because many OEM cars come with 90 to 
140 amp alternators. My personal conversion project, a Pontiac Fiero 
has a 140 amp alternator, so I want to maintain that capability and 
reliability.
Many EVs use an aux battery to fill in for generally poor DC/DC convert 
reliability. I would like to provide a system with enough headroom, 
both on the input side as well as the output side to be at least OEM 
automotive standard reliable.
Certainly, a DC/DC converter could be designed with less current 
capability, but the cost reduction would not be linear.

So, ignoring the output current, what do you think would be a workable 
price for a 70 to 500 volt input, OEM automotive reliability DC/DC 
converter would be?

Ken




-----Original Message-----
From: (-Phil-) <[email protected]>
To: Electric Vehicle Discussion List <[email protected]>
Sent: Thu, 10 Jan 2008 10:53 am
Subject: Re: [EVDL] DC/DC with flexible pack voltage?



140 amps is nice, but that is a LOT of headroom. Could you offer a 
smaller
model for less?

Personally, half that would be fine. The biggest load in my EV is the
blower fan @ 28a. I have never seen any combination of accessories pull
more than 68a peak.

-Phil
----- Original Message -----
From: <[email protected]>
To: <[email protected]>
Sent: Thursday, January 10, 2008 8:20 AM
Subject: Re: [EVDL] DC/DC with flexible pack voltage?


> This certainly seems to be a weak spot in EV components. Therefore, I
> am developing a DC/DC converter that has an input range of 70 to 500
> volts with an output of 14.7 volts from 0 to 140 amps. This is a Hot
> Juice Electric project and the progress can be monitored at:
> http://www.hotjuiceelectric.com/development.html
>
> I bring this up for feedback.
>
> At this time, a working prototype is in testing. All good so far 
except
> for one problem. There is approximately $1,200 in parts alone. I am
> afraid that adding labor and enough profit to maintain sustainability
> would push the price out of most peoples range.
>
> The project is now being refined to maintain the current 
specifications
> and reliability while reducing the cost. The progress is encouraging,
> but I think it would help if I could get some feedback.
>
> So, I present this question to the list: What would be a reasonable
> price for a DC/DC converter (I call it Chassis Power Module) that 
would
> maintain 14.7 volts output from 0 to 140 amps with an input range of 
70
> to 500 volts?
> Check out the website for additional information.
>
> Keep the Juice flowing!
>
> Ken
>
>
>
>
>
> -----Original Message-----
> From: Chuck Homic <[email protected]>
> To: Electric Vehicle Discussion List <[email protected]>
> Sent: Wed, 9 Jan 2008 10:55 am
> Subject: [EVDL] DC/DC with flexible pack voltage?
>
>
>
> For my conversion, I'm planning on a Z1K-HV and PFC-20. This gives me
> some real options on batteries in the future.
>
> The Z1K-HV gives 72-300V range
> The PFC-20 gives 12-360V range
>
> (These are both nominal voltages, right?)
>
> So this combo can handle quite a range of pack voltages. I can have 10
> or 12 or 16 12V lead-acids (25 if I add more wheels to carry the
> weight). Or I can use 93 of the 3.2V50Ah headway packs that are being
> talked about, or some other lithium tech when it becomes affordable
> (maybe my 2nd or 3rd pack). Or something in the middle. And I can use
> these parts on my next EV once the current frame rusts to its grave.
> (This is all speculation. There is a 100% chance my first pack will be
> lead.) Even for the lead pack, having some breathing room will be
> nice. If I find my range to be 2-3 miles shorter than I'd like, I 
could
> squeeze in "just one more" battery (early enough in the pack's life
> cycle to make that not a terrible idea, hopefully), without blowing 
any
> voltage limits.
>
> Thing is, I can't find a DC/DC converter that's equally flexible.
>
> The Iota units at evsource are 108-170V or 208-320V. I assume because
> they're just switching power supplies meant for 120 or 240VAC usage.
> The ones EVA sells don't seem to go above 144V. I know this is 
probably
> the cheapest electrical component, so maybe I shouldn't worry about it
> and buy another one when I change pack voltages in the future. I also
> don't know if these are nominal voltages or absolute limits. If 
they're
> absolute limits, then a 168V lead acid pack would not be an option 
with
> the lower voltage Iota unit. The Brusa units look good, but the cost
> more than the Zilla. Ouch. Running without a DC converter is an
> option, but not a good one. A converter that outputs 14V for 10-14V
> input might be a compromise to using the accessory battery on its own,
> and keep the lights up bright. (Costs about $150) But now I'm just
> rambling.
>
> Is anyone else thinking about what they have to do to switch battery
> technology in the future, or are you just expecting to configure 
future
> packs for the same voltage as your lead packs?
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>
>
> 
________________________________________________________________________
> More new features than ever. Check out the new AOL Mail ! -
> http://webmail.aol.com
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


________________________________________________________________________
More new features than ever. Check out the new AOL Mail ! - 
http://webmail.aol.com

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

Actually I was thinking of a single DC/DC powered by each traction battery 
in turn. Switch input batteries every few seconds to share the load. It 
would have wiring similar to your battery balancer. Your interpretation of 
my idea is also interesting as it balances the traction pack, but only on 
discharge.

> Adrian DeLeon suggested a related method; you could have N small DC/DC
> converters, one per battery. They all have 12-14vdc outputs, which are
> all connected together (thru a diode and fuse, as mentioned above) to
> your 12v accessory battery. If you arrange it right, these converters
> load their respective batteries according to their state of charge; so
> the highest-voltage battery delivers the most current. This would give
> you a DC/DC converter and a battery balancing system.


_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

> what is the efficency of dual DC/DC converters?

It should be the same as using a single DC/DC rated at twice the current.

2x 80% efficient DC/DC at 20A output = 40A output, 80% efficiency
1x 80% efficient DC/DC at 40A output = 40A output, 80% efficiency

The real danger is pack imbalance from unequal current draws. Some DC/DCs 
are designed to current share to within a few %. Some can be adjusted for 
nearly equal current draw. Others aren't.

But even a +/-10% difference in output current isn't too bad... One DC/DC 
at 22A vs 18A for the other is about 5.06A and 4.14A from each half of a 
120V pack, or 0.92AHr imbalance for every hour of use AT 40A OUTPUT. At 
20A out, it would be 0.46 AHr per hour. If your batteries/BMS can handle 
this then it's a non-issue.

I haven't tried parallel DC/DC converters because I have a 114V, 19 
battery system. With 54V and 60V inputs and mismatched 20A converters, 
worst case is 1.5AHr per hour imbalance when heavily loaded. More than I 
was willing to risk with no BMS.

-Adrian



_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

> I am developing a DC/DC converter that has an input range of 70 to 500
> volts with an output of 14.7 volts from 0 to 140 amps.
> I bring this up for feedback.

I agree on the overkill part...

500W to 700W would be plenty, especially if used with an SLI battery for 
higher peak loads (power steering).

What may work better is a combination DC/DC and "smart charger". It 
provides 14V when your EV is running, and performs a complete charge of 
the SLI battery when your EV is off (but only if needed). Optional would 
be a periodic "maintenance" charge for an EV that won't be in use for a 
while.

No capacity killing "float" charge for an always on DC/DC, and no chronic 
undercharging for a DC/DC that switches on only during EV use. Bonus 
points if it doesn't drain the traction pack in under a month 

-Adrian



_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

The Fierro is a bit of an odd duck because it drives the power steering
pump off the 12V supply.

I'm not an expert, but I'm not aware of any other car that comes stock
with 140 amp alternators.

My F-250 diesel Super Duty pickup with tow package comes stock with a 110
amp alternator and it has dual batteries (for cranking over the diesel.)

Having lots of current is nice, and a wide input range is nice, but most
folks who build EV are looking for "cheap". I think that is your primary
market.

If it was me, I'd start by offering a few different models with smaller
input ranges, i.e. 100-190V @ 70 Amps would satisfy the majority of your
market. Maybe have a second model that handles 135-220V, etc.

Save the does everything model for when you get a customer that demands it
and is willing to pay the premium price.

Heck you've been on the list long enough to know that many folks think
that $2,000 is too much to pay for a controller, let alone a dc-dc.

> The expense is in the input range. The current capability adds some
> expense, but is dwarfed by the cost of tracking that large of input
> voltage range. I chose 140 amps because many OEM cars come with 90 to
> 140 amp alternators. My personal conversion project, a Pontiac Fiero
> has a 140 amp alternator, so I want to maintain that capability and
> reliability.
> Many EVs use an aux battery to fill in for generally poor DC/DC convert
> reliability. I would like to provide a system with enough headroom,
> both on the input side as well as the output side to be at least OEM
> automotive standard reliable.
> Certainly, a DC/DC converter could be designed with less current
> capability, but the cost reduction would not be linear.
>
> So, ignoring the output current, what do you think would be a workable
> price for a 70 to 500 volt input, OEM automotive reliability DC/DC
> converter would be?
>
> Ken
>
>
>
>
> -----Original Message-----
> From: (-Phil-) <[email protected]>
> To: Electric Vehicle Discussion List <[email protected]>
> Sent: Thu, 10 Jan 2008 10:53 am
> Subject: Re: [EVDL] DC/DC with flexible pack voltage?
>
>
>
> 140 amps is nice, but that is a LOT of headroom. Could you offer a
> smaller
> model for less?
>
> Personally, half that would be fine. The biggest load in my EV is the
> blower fan @ 28a. I have never seen any combination of accessories pull
> more than 68a peak.
>
> -Phil
> ----- Original Message -----
> From: <[email protected]>
> To: <[email protected]>
> Sent: Thursday, January 10, 2008 8:20 AM
> Subject: Re: [EVDL] DC/DC with flexible pack voltage?
>
>
>> This certainly seems to be a weak spot in EV components. Therefore, I
>> am developing a DC/DC converter that has an input range of 70 to 500
>> volts with an output of 14.7 volts from 0 to 140 amps. This is a Hot
>> Juice Electric project and the progress can be monitored at:
>> http://www.hotjuiceelectric.com/development.html
>>
>> I bring this up for feedback.
>>
>> At this time, a working prototype is in testing. All good so far
> except
>> for one problem. There is approximately $1,200 in parts alone. I am
>> afraid that adding labor and enough profit to maintain sustainability
>> would push the price out of most peoples range.
>>
>> The project is now being refined to maintain the current
> specifications
>> and reliability while reducing the cost. The progress is encouraging,
>> but I think it would help if I could get some feedback.
>>
>> So, I present this question to the list: What would be a reasonable
>> price for a DC/DC converter (I call it Chassis Power Module) that
> would
>> maintain 14.7 volts output from 0 to 140 amps with an input range of
> 70
>> to 500 volts?
>> Check out the website for additional information.
>>
>> Keep the Juice flowing!
>>
>> Ken
>>
>>
>>
>>
>>
>> -----Original Message-----
>> From: Chuck Homic <[email protected]>
>> To: Electric Vehicle Discussion List <[email protected]>
>> Sent: Wed, 9 Jan 2008 10:55 am
>> Subject: [EVDL] DC/DC with flexible pack voltage?
>>
>>
>>
>> For my conversion, I'm planning on a Z1K-HV and PFC-20. This gives me
>> some real options on batteries in the future.
>>
>> The Z1K-HV gives 72-300V range
>> The PFC-20 gives 12-360V range
>>
>> (These are both nominal voltages, right?)
>>
>> So this combo can handle quite a range of pack voltages. I can have 10
>> or 12 or 16 12V lead-acids (25 if I add more wheels to carry the
>> weight). Or I can use 93 of the 3.2V50Ah headway packs that are being
>> talked about, or some other lithium tech when it becomes affordable
>> (maybe my 2nd or 3rd pack). Or something in the middle. And I can use
>> these parts on my next EV once the current frame rusts to its grave.
>> (This is all speculation. There is a 100% chance my first pack will be
>> lead.) Even for the lead pack, having some breathing room will be
>> nice. If I find my range to be 2-3 miles shorter than I'd like, I
> could
>> squeeze in "just one more" battery (early enough in the pack's life
>> cycle to make that not a terrible idea, hopefully), without blowing
> any
>> voltage limits.
>>
>> Thing is, I can't find a DC/DC converter that's equally flexible.
>>
>> The Iota units at evsource are 108-170V or 208-320V. I assume because
>> they're just switching power supplies meant for 120 or 240VAC usage.
>> The ones EVA sells don't seem to go above 144V. I know this is
> probably
>> the cheapest electrical component, so maybe I shouldn't worry about it
>> and buy another one when I change pack voltages in the future. I also
>> don't know if these are nominal voltages or absolute limits. If
> they're
>> absolute limits, then a 168V lead acid pack would not be an option
> with
>> the lower voltage Iota unit. The Brusa units look good, but the cost
>> more than the Zilla. Ouch. Running without a DC converter is an
>> option, but not a good one. A converter that outputs 14V for 10-14V
>> input might be a compromise to using the accessory battery on its own,
>> and keep the lights up bright. (Costs about $150) But now I'm just
>> rambling.
>>
>> Is anyone else thinking about what they have to do to switch battery
>> technology in the future, or are you just expecting to configure
> future
>> packs for the same voltage as your lead packs?
>>
>> _______________________________________________
>> For subscription options, see
>> http://lists.sjsu.edu/mailman/listinfo/ev
>>
>>
>>
> ________________________________________________________________________
>> More new features than ever. Check out the new AOL Mail ! -
>> http://webmail.aol.com
>>
>> _______________________________________________
>> For subscription options, see
>> http://lists.sjsu.edu/mailman/listinfo/ev
>>
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>
>
> ________________________________________________________________________
> More new features than ever. Check out the new AOL Mail ! -
> http://webmail.aol.com
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>


-- 
If you send email to me, or the EVDL, that has > 4 lines of legalistic
junk at the end; then you are specifically authorizing me to do whatever I
wish with the message. By posting the message you agree that your long
legalistic signature is void.

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

FYI,

No Power steering in a Fiero unless it's been added by someone. The
140A alt was intended for that purpose but GM never put any PS units
in sell-able cars. Yes, there were factory units like you describe
but they were not installed by GM and have all been bought at this
point and installed by owners or kit-car builders. If I recall
correctly some of them went into the EV1? Don't quote me on that last
though... I'm a Fiero fan more than an EV1 junky. : ]

It does pay to note that an EV doesn't have an ignition to run. I
don't know how the various contactor draws balance that out though.



> Peter VanDerWal <[email protected]> wrote:
> > The Fierro is a bit of an odd duck because it drives the power steering
> > pump off the 12V supply.
> >
> ...


----------



## EVDL List (Jul 27, 2007)

I'm new to this list, so take it easy on me if I'm way off base, but 
wouldn't some of the Vicor modules suit this need? They have many 
different input voltages, each with a pretty wide range; though I don't 
think they get to 500V. You may have to parallel several to get the high 
amps, but I think they share nicely. They aren't real cheap , but they 
are good.

- SteveS




> Peter VanDerWal wrote:
> > The Fierro is a bit of an odd duck because it drives the power steering
> > pump off the 12V supply.
> >
> ...


----------



## EVDL List (Jul 27, 2007)

Replying in text...


-----Original Message-----
From: Peter VanDerWal <[email protected]>
To: Electric Vehicle Discussion List <[email protected]>
Sent: Thu, 10 Jan 2008 3:36 pm
Subject: Re: [EVDL] DC/DC with flexible pack voltage?



>The Fierro is a bit of an odd duck because it drives the power steering
>pump off the 12V supply.

The Fiero does not have power steering. No Fiero was ever sold with 
power steering. That was a future option (which was electric) but 
production was canceled in 1988 before power steering option was 
available, although the rack was issued a part number.
Additionally, the Fiero came stock with a 96 amp alternator. I replaced 
it with a 140 amp because the original 96 amp unit struggled to keep it 
above 13 volts with with the lights, heater, wipers, etc. The 140 amp 
sits solid at 14.7 regardless of what's on. I kinda like that!

>I'm not an expert, but I'm not aware of any other car that comes stock
>with 140 amp alternators.

>My F-250 diesel Super Duty pickup with tow package comes stock with a 
110
>amp alternator and it has dual batteries (for cranking over the 
diesel.)

>Having lots of current is nice, and a wide input range is nice, but 
most
>folks who build EV are looking for "cheap". I think that is your 
primary
>market.

>If it was me, I'd start by offering a few different models with smaller
>input ranges, i.e. 100-190V @ 70 Amps would satisfy the majority of 
your
>market. Maybe have a second model that handles 135-220V, etc.

That is already available. I don't see any reason to duplicate that 
effort. I have seen many wishes on this list for a wide input range 
converter. So, that is why I am pursuing this.

>Save the does everything model for when you get a customer that 
demands it
>and is willing to pay the premium price.

>Heck you've been on the list long enough to know that many folks think
>that $2,000 is too much to pay for a controller, let alone a dc-dc.

Yes! that is not just this list! That is our current society that wants 
everything cheap. Many do complain that the Zilla is too expensive, but 
they are bought so fast that Oatmar can't keep up. People also want 
quality, reliability and versatility. The original post subject is, 
DC/DC with flexible pack voltage? So, that is what I am talking about.

Ken





> The expense is in the input range. The current capability adds some
> expense, but is dwarfed by the cost of tracking that large of input
> voltage range. I chose 140 amps because many OEM cars come with 90 to
> 140 amp alternators. My personal conversion project, a Pontiac Fiero
> has a 140 amp alternator, so I want to maintain that capability and
> reliability.
> Many EVs use an aux battery to fill in for generally poor DC/DC 
convert
> reliability. I would like to provide a system with enough headroom,
> both on the input side as well as the output side to be at least OEM
> automotive standard reliable.
> Certainly, a DC/DC converter could be designed with less current
> capability, but the cost reduction would not be linear.
>
> So, ignoring the output current, what do you think would be a workable
> price for a 70 to 500 volt input, OEM automotive reliability DC/DC
> converter would be?
>
> Ken
>
>
>
>
> -----Original Message-----
> From: (-Phil-) <[email protected]>
> To: Electric Vehicle Discussion List <[email protected]>
> Sent: Thu, 10 Jan 2008 10:53 am
> Subject: Re: [EVDL] DC/DC with flexible pack voltage?
>
>
>
> 140 amps is nice, but that is a LOT of headroom. Could you offer a
> smaller
> model for less?
>
> Personally, half that would be fine. The biggest load in my EV is the
> blower fan @ 28a. I have never seen any combination of accessories 
pull
> more than 68a peak.
>
> -Phil
> ----- Original Message -----
> From: <[email protected]>
> To: <[email protected]>
> Sent: Thursday, January 10, 2008 8:20 AM
> Subject: Re: [EVDL] DC/DC with flexible pack voltage?
>
>
>> This certainly seems to be a weak spot in EV components. Therefore, I
>> am developing a DC/DC converter that has an input range of 70 to 500
>> volts with an output of 14.7 volts from 0 to 140 amps. This is a Hot
>> Juice Electric project and the progress can be monitored at:
>> http://www.hotjuiceelectric.com/development.html
>>
>> I bring this up for feedback.
>>
>> At this time, a working prototype is in testing. All good so far
> except
>> for one problem. There is approximately $1,200 in parts alone. I am
>> afraid that adding labor and enough profit to maintain sustainability
>> would push the price out of most peoples range.
>>
>> The project is now being refined to maintain the current
> specifications
>> and reliability while reducing the cost. The progress is encouraging,
>> but I think it would help if I could get some feedback.
>>
>> So, I present this question to the list: What would be a reasonable
>> price for a DC/DC converter (I call it Chassis Power Module) that
> would
>> maintain 14.7 volts output from 0 to 140 amps with an input range of
> 70
>> to 500 volts?
>> Check out the website for additional information.
>>
>> Keep the Juice flowing!
>>
>> Ken
>>
>>
>>
>>
>>

________________________________________________________________________
More new features than ever. Check out the new AOL Mail ! - 
http://webmail.aol.com

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

Yes Steve, you are absolutely correct! There are Vicor modules that 
will suite most pack voltages, but none that will span 70 to 500 volts 
without rewiring or some form of configuration.

The niche I am looking into is the wishes that I have seen for a wide 
input range DC/DC that would allow pack flexibility without having to 
do workaround stuff with the DC/DC.

Ken


-----Original Message-----
From: SteveS <[email protected]>
To: Electric Vehicle Discussion List <[email protected]>
Sent: Thu, 10 Jan 2008 3:15 pm
Subject: Re: [EVDL] DC/DC with flexible pack voltage?



I'm new to this list, so take it easy on me if I'm way off base, but
wouldn't some of the Vicor modules suit this need? They have many
different input voltages, each with a pretty wide range; though I don't
think they get to 500V. You may have to parallel several to get the 
high
amps, but I think they share nicely. They aren't real cheap , but they
are good.

- SteveS




> Peter VanDerWal wrote:
> > The Fierro is a bit of an odd duck because it drives the power
> steering
> > pump off the 12V supply.
> ...


----------



## EVDL List (Jul 27, 2007)

> SteveS wrote:
> > I'm new to this list, so take it easy on me if I'm way off base, but
> > wouldn't some of the Vicor modules suit this need? They have many
> > different input voltages, each with a pretty wide range; though I don't
> ...


----------



## EVDL List (Jul 27, 2007)

Now we're getting somewhere...

> The expense is in the input range.

Then I'd consider a narrower input range.

1) A Zilla -HV runs 72-348V nominal, 400V max.
2) 24-80V input has lots of sub $400 units from Sevcon, CC Power, Curtis, 
etc.
3) 80-144V has Belktronix, but with added precharge circuitry
4) 120-170V is AC power supply territory (Iota, MeanWell, Astrodyne)
5) Most EVs are 96V and above

I think 90-400V input is plenty. It would cover a 120V pack at 1.5V/cell 
up to the limit of a Zilla -HV. Over 300V and you start competing with MES 
and Brusa OEM products. A swappable DC/DC "prescalar" to cover different 
ranges might also be feasible.

Zivan NG1-DCDC 600W, 108-168V input, $490
Iota DLS-45/55 600/700W, 110-170V input, $200-300
CC Power 400W, $450
Absopulse custom DC/DC, 500W $760 ($480 qty. 5 or more)
Brusa 125-370V, 1200W $2,700
Brusa 250-750V, 1200W $3,900

Considering the above, I'd fork out $800 to $1,500 for your DC/DC IF:

1) Heavily ruggedized, spray/splash proof - doesn't need mounting in a box
2) No SLI battery required
3) Reliable, reliable, reliable
4) I was planning to change the voltage of my conversion in the future

I'd also argue that most people converting a daily driver would opt for a 
$200 Iota + SLI battery instead. Search the archives for discussions 
between Victor and others about doing things "right" vs "cheaply".

-Adrian

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

>>The Fierro is a bit of an odd duck because it drives the power steering
>>pump off the 12V supply.
>
> The Fiero does not have power steering. No Fiero was ever sold with
> power steering.

Sorry, I was thinking of the MR2.

>>If it was me, I'd start by offering a few different models with smaller
>>input ranges, i.e. 100-190V @ 70 Amps would satisfy the majority of
> your
>>market. Maybe have a second model that handles 135-220V, etc.
>
> That is already available. I don't see any reason to duplicate that
> effort.

There is an affordable DC-DC designed for EVs?

I'm just thinking that if someone made a DC-DC that didn't need to
parralel two to get 55-70 amps, and was enclosed so it could survive under
the hood and was reasonably priced, they would probably end up with the
same problems that otmar is having (can't keep up with the demand).

If there is one out there now, who makes it? 'cause I'm going to need
one soon.

Perhaps I'm wrong, but I don't see a huge market the one you described. I
mean it sounds awsome and all, but it seems like a lot of work for a 1/2
dozen potential customers.
-- 
If you send email to me, or the EVDL, that has > 4 lines of legalistic
junk at the end; then you are specifically authorizing me to do whatever I
wish with the message. By posting the message you agree that your long
legalistic signature is void.

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

----- Original Message ----- 
From: "Peter VanDerWal" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Thursday, January 10, 2008 5:43 PM
Subject: Re: [EVDL] DC/DC with flexible pack voltage?


>>>If it was me, I'd start by offering a few different models with smaller
>>>input ranges, i.e. 100-190V @ 70 Amps would satisfy the majority of
>> your
>>>market. Maybe have a second model that handles 135-220V, etc.
>>
>> That is already available. I don't see any reason to duplicate that
>> effort.
> 
> There is an affordable DC-DC designed for EVs?

Yes, there is - Belktronics.

Joseph H. Strubhar

Web: www.gremcoinc.com

E-mail: [email protected]

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

> Josh Creel wrote:
> > Could this system be reversed to put voltage back into you drive pack one
> > set of 12vdc batts. at a time from an alternator off the shaft of your
> > motor, say if you were pulling the ev somewhere or even using a pusher
> ...


----------



## EVDL List (Jul 27, 2007)

> [email protected] wrote:
> 
> > At this time, a working prototype is in testing. All good so far except
> > for one problem. There is approximately $1,200 in parts alone. I am
> ...


----------



## EVDL List (Jul 27, 2007)

> Lee Hart wrote:
> >> almost any DC/DC (or even AC/DC power supply being used as a DC/DC)
> >> will work. The key is that they need to have an adjustable output
> >> voltage, so you can set them to each provide half the load current.
> ...


----------



## EVDL List (Jul 27, 2007)

Thanks Adrian,

That is more of what I am looking for.

The concept goal of this project is to provide a DC/DC converter for street 
vehicles that doesn't require a lot of extra wiring or auxiliary parts to keep 
it from being overvolted while charging, spiked by the controller, or 
protected from the environment, etc. One that can just be connected across the pack, 
any pack, and forgot about. I suspect there is a reasonable niche for such a 
converter. Yes, most people will opt for the cheapest possible, but there 
appears to be plenty who want rugged, bullet proof parts for their car. There 
are plenty more Curtis controllers out there than Zilla 2K's, but there is 
certainly a substantial demand for the Zilla.

I have no plans to market the current prototype, even though it is working 
fine, because it is too expensive. The magnetics to cover that range is cost 
prohibitive. I am modifying the design to get around that limitation and it is 
still too early to know what that is going to cost. So, I thought I would 
just throw this question out there to see how close I can get it.

Your listed requirements are very encouraging! If you check the website: 
_http://www.hotjuiceelectric.com/development.html_ 
(http://www.hotjuiceelectric.com/development.html) you will see that it is:

1) not just splash proof, it is waterproof - submersible.
2) intended for perpetual operation eliminating the need for an aux battery.
3) fault tolerant. Lots of inherent protection and headroom.

Thanks to everyone for you input!

Ken





In a message dated 1/10/2008 6:42:19 PM Central Standard Time, 
[email protected] writes:
Now we're getting somewhere...

> The expense is in the input range.

Then I'd consider a narrower input range.

1) A Zilla -HV runs 72-348V nominal, 400V max.
2) 24-80V input has lots of sub $400 units from Sevcon, CC Power, Curtis, 
etc.
3) 80-144V has Belktronix, but with added precharge circuitry
4) 120-170V is AC power supply territory (Iota, MeanWell, Astrodyne)
5) Most EVs are 96V and above

I think 90-400V input is plenty. It would cover a 120V pack at 1.5V/cell 
up to the limit of a Zilla -HV. Over 300V and you start competing with MES 
and Brusa OEM products. A swappable DC/DC "prescalar" to cover different 
ranges might also be feasible.

Zivan NG1-DCDC 600W, 108-168V input, $490
Iota DLS-45/55 600/700W, 110-170V input, $200-300
CC Power 400W, $450
Absopulse custom DC/DC, 500W $760 ($480 qty. 5 or more)
Brusa 125-370V, 1200W $2,700
Brusa 250-750V, 1200W $3,900

Considering the above, I'd fork out $800 to $1,500 for your DC/DC IF:

1) Heavily ruggedized, spray/splash proof - doesn't need mounting in a box
2) No SLI battery required
3) Reliable, reliable, reliable
4) I was planning to change the voltage of my conversion in the future

I'd also argue that most people converting a daily driver would opt for a 
$200 Iota + SLI battery instead. Search the archives for discussions 
between Victor and others about doing things "right" vs "cheaply".

-Adrian



**************Start the year off right. Easy ways to stay in shape. 
http://body.aol.com/fitness/winter-exercise?NCID=aolcmp00300000002489

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

Not to sound negative, but, for me, this is impossible to answer because
I see no need for 140Amps at 14.7 Volts. Even the auto industry has been
talking about getting rid of the 12V system and has started going to
42V(for the electric PS) The new lights take 90V in so I would rather
see a supply with multiple outputs 14.7/42/90/110VAC with more
reasonable amperages.

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

If the wide range input is the major cost (and I know that it is and by
the time you have reasonable current at the low input level you have
high current at the high input level) Can you make it a dual range?

A switch on the input side allows two overlapping ranges. The customer
chooses.
Perhaps three wire input, one from mid pack using a push-pull into the
transformer vs connecting two of the wires to pack+ and running in parallel.
(two parallel or serial dc-dc's internal.

How about a master board and 70 amp parallelable slave units. Sell the
unit with one 70 and sell add ons when people discover they need more

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

> [email protected] wrote:
> > I am developing a DC/DC converter that has an input range of 70 to 500
> > volts with an output of 14.7 volts from 0 to 140 amps. There is approximately $1,200 in parts alone. I am
> > afraid that adding labor and enough profit to maintain sustainability
> ...


----------



## EVDL List (Jul 27, 2007)

> [email protected] wrote:
> > I am developing a DC/DC converter that has an input range of 70 to 500
> > volts with an output of 14.7 volts from 0 to 140 amps... approximately
> > $1,200 in parts alone.
> ...


----------



## EVDL List (Jul 27, 2007)

> SteveS wrote:
> > I'm new to this list, so take it easy on me if I'm way off base, but
> > wouldn't some of the Vicor modules suit this need?
> 
> ...


----------



## EVDL List (Jul 27, 2007)

> Dan Frederiksen wrote:
> > it's not unlike PSUs for PCs and they can do 60A 12V for around 50$ all
> > neatly assembled. there should be plenty of ways to reduce the 1200$
> >
> ...


----------



## EVDL List (Jul 27, 2007)

> Chuck Homic wrote:
> > But seriously, is there any reason why one of these, even with slight
> > modifications, wouldn't work? (Understanding that it won't charge a
> > battery correctly.)
> ...


----------



## EVDL List (Jul 27, 2007)

> <[email protected]> wrote:
> 
> > Even the auto industry has been
> > talking about getting rid of the 12V system
> ...


----------



## EVDL List (Jul 27, 2007)

> Adrian DeLeon <[email protected]> wrote:
> > ================================================================
> > What would REALLY be useful is a 5KW, 72-400V input AC inverter.
> > ================================================================
> ...


----------



## EVDL List (Jul 27, 2007)

You might look at inverters intended for use with wind turbines...by their nature they would have to handle variable voltage inputs....


_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

Hmmm. Only thing is to find one thats a voltage source instead of
current source. Most of the ones I know of are current sources, which
doesn't do much good unless you already have an AC voltage source.



> [email protected] <[email protected]> wrote:
> > You might look at inverters intended for use with wind turbines...by their nature they would have to handle variable voltage inputs....
> >
> >
> ...


----------



## EVDL List (Jul 27, 2007)

Perhaps I am missing something. Why would you want to run a dc/dc
while the pack is charging? Or while the car is not running? If the
dc/dc will handle the power requirements, the house battery will never
need much charging.

At the suggestion of Lee and some others on the list, I set up the
dc/dc to produce 14.7v only while the car is turned on. (I had
previously set it up to do 13.5v float all the time and was told that
was not a good idea.)

storm


>
> Well, this is very interesting to me. I've been looking for a DC-DC
> but nothing seems to fit.Here are some round numbers. Currently I have
> 144 NiCads in my pack for a nominal voltage of 172. Empty would be
> around 144 volts and probably as high as 230 on charge.
>
> As soon as possible I want to increase my pack to as many as 300
> cells. This would put me in the 360 volt range. 300 volts empty to as
> high as 480 volts during charge. I'd prefer not to have to disconnect
> the DC-DC during charge, but I do have contactors for this purpose.
> The simpler the better.
>
> I don't know what a reasonable sag voltage is for NiCads, but let's
> assume I won't get into the pedal when the pack is too low. These are
> round figures for now, I don't have a lot of road time on the car. The
> only other request I have if for some smarts to protect the house
> battery. If the unit could throttle down at rest, that would be a
> bonus. I don't anticipate not having a house battery.
>


>
> Dave Cover
>
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>



-- 
http://www.austinev.org/evalbum/1059
http://stormselectric.blogspot.com/
Storm

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev


----------



## EVDL List (Jul 27, 2007)

I hooked the output of a laptop power brick up to a small $20 solar
controller and it charged a battery just fine.
storm



> Chuck Homic <[email protected]> wrote:
> > Dan Frederiksen wrote:
> > > it's not unlike PSUs for PCs and they can do 60A 12V for around 50$ all
> > > neatly assembled. there should be plenty of ways to reduce the 1200$
> ...


----------



## EVDL List (Jul 27, 2007)

> storm connors <[email protected]> wrote:
> > Perhaps I am missing something. Why would you want to run a dc/dc
> > while the pack is charging? Or while the car is not running?
> 
> ...


----------

