EV Digest 6064
Topics covered in this issue include:
1) Re: EV controllers? the 4th option...
by Eric Poulsen <[EMAIL PROTECTED]>
2) Re: EV controllers? the 4th option...
by "Lawrence Rhodes" <[EMAIL PROTECTED]>
3) RE: EV controllers? the 4th option...
by Steve Condie <[EMAIL PROTECTED]>
4) 72V Power Supply - Can I build one?
by "martin emde" <[EMAIL PROTECTED]>
5) Strange battery/charger behavior? Check your Anderson connector!
by Bob Bath <[EMAIL PROTECTED]>
6) RE: 72V Power Supply - Can I build one?
by Cor van de Water <[EMAIL PROTECTED]>
7) Re: EV controllers? the 4th option...
by "Rich Rudman" <[EMAIL PROTECTED]>
8) Re: 72V Power Supply - Can I build one?
by Jack Murray <[EMAIL PROTECTED]>
9) Re: EV controllers? the 4th option...
by GWMobile <[EMAIL PROTECTED]>
10) Re: Strange battery/charger behavior? Check your Anderson connector!
by "Rich Rudman" <[EMAIL PROTECTED]>
11) Re: EV controllers? the 4th option...
by Lee Hart <[EMAIL PROTECTED]>
12) Re: EV controllers? the 4th option...
by Lee Hart <[EMAIL PROTECTED]>
13) Re: Cursit controllers revisited (squealing); precharge 'circuit' again
(please)
by "Paul G." <[EMAIL PROTECTED]>
14) RE: Bradley GTE Project
by "David (Battery Boy) Hawkins" <[EMAIL PROTECTED]>
15) Mechanical control, was: Re: EV controllers? the 4th option...
by James Massey <[EMAIL PROTECTED]>
16) Re: clutch release bearing
by John <[EMAIL PROTECTED]>
17) Re: Mechanical control, was: Re: EV controllers? the 4th option...
by GWMobile <[EMAIL PROTECTED]>
18) Re: Precharge Circuit Design
by Lee Hart <[EMAIL PROTECTED]>
19) Re: Mechanical control, was: Re: EV controllers? the 4th option...
by "Ted C." <[EMAIL PROTECTED]>
20) Re: Mechanical control, was: Re: EV controllers? the 4th option...
by Lee Hart <[EMAIL PROTECTED]>
21) RE: EV controllers? the 4th option...
by Cor van de Water <[EMAIL PROTECTED]>
22) Re: Mechanical control, was: Re: EV controllers? the 4th option...
by "Ted C." <[EMAIL PROTECTED]>
23) Re: Cursit controllers revisited (squealing); precharge 'circuit'
again (please)
by Eric Poulsen <[EMAIL PROTECTED]>
24) RE: Precharge Circuit Design
by Cor van de Water <[EMAIL PROTECTED]>
--- Begin Message ---
You did? I haven't seen any Otmar posts ... but since the list has been
flaky lately ...
Rich Rudman wrote:
All good ideas
But..
Simple assembly, wide operating windows,
NO plumbing..
Are very serious features.
Serious enough to over shadow the draw backs.
And.. I succeded in DElurking Otmar...
Mission accomplished.
--- End Message ---
--- Begin Message ---
I may be out of my mind but why can't a DC controller of the chopper kind
have a dual purpose?Charger/controller? If it was priced at 2 to 3k it
would take care of two functions that usually cost more than 3k if bought
seperatly. Is this possible or am I smoking bad stuff? Lawrence Rhodes...
--- End Message ---
--- Begin Message ---
<snip>
> What DC'ers need is a Curtis-killer, not something that tries to compete
> with Otmar's already excellent offerings.
This is exactly what I am proposing... High voltage Curtii Killer, with some
goodies, Not many.
<snip>
So if I understand this correctly Rich Rudman (Manzanita Micro) is talking
about designing and building an IGBT based DC controller which is "dumb as a
box of rocks" - i.e. has analog control to speed up, slow down, etc. and not
much else (Curtis dumb) which would handle 300+ volts but closer to 500 than
1000 motor amps. Rich figures the "market will bear" price range as comparable
to Zilla low voltage 1000 amp model, which Otmar (Cafe Electric) is currently
not building but which he has said he will resume construction at no price
increase in coming months.
My feedback, for what it's worth: Kilowatts is kilowatts when it comes to
power. A DC motor can't handle more than about 170 volts so a pack voltage
above that has to be stepped down. The motors typically can't handle 500+ amps
for an extended time period, either. But it's nice to have over 500 motor amps
for brief accelleration, I'd pay for that. And you're usually using those amp
draws to accelerate from a slow speed or stop, so you're stepping down your
voltage, and getting current multiplication, even with a ~150 volt pack. Going
to a higher voltage means fewer amps per battery - good for Peukert, I guess -
but pound for pound a 30 kw pack gives the same performance whether it's 150
volts and 200 amp hours or 300 volts and 100 amp hours. Given the weight per
watt of available batteries is the same either way, and the voltage limits of
available DC motors I'm not sure that having a 300 volt controller supplying
your DC motor with 500 amps instead of a 144 volt one
with the same current capacity really gets you anything as long as the total
kilowatt capacity of the battery pack is the same.
So what I'm hearing is more of a "slightly better than a Curtis" at Zilla
prices than a "Curtis killer" filling the price/performance gap. Am I missing
somethng?
---------------------------------
Yahoo! Messenger with Voice. Make PC-to-Phone Calls to the US (and 30+
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--- End Message ---
--- Begin Message ---
Greetings,
I have a GEM NEV that is in disrepair. I have all the parts (less the
batteries), schematic, and manual and would like to see if I can get it
going. I'd like to troubleshoot the car without having to invest in the
batteries, and then later find that the controller or circuit board is
fried. Is it possible to build an inexpensive, 72V power supply that would
source enough current to power -up the car and maybe turn the wheels under
no load? Maybe a large transformer and bridge rectifier? If you know of a
design (schematic and parts list) or any other solutions I would appreciate
it.
Thanks.
Martin
--- End Message ---
--- Begin Message ---
Hey all!
For the last 1.5 years, I've been racking my brain
to figure out why my 144V pack o' flooded batteries no
longer go past 175V, despite the fact that they'd
regularly go to 193 before that. I've spent hours in
thought, or reading/responding to posts from Nawaz,
Roger, Roland, Rich, etc., all to no avail.
Finally yesterday, I thought I had a dead charger.
Upon pulling the charger, I noted that burnt carbon
smell, and a stubborn Anderson connector. After
prying the Anderson connector apart, it became
apparent that it had melted. From my limited
understanding of electronics, I can imagine that over
a year ago, it melted slightly, so as to function as a
bit of a resistor, thereby limiting my charger
voltage. For $14 in fresh connectors, 15 minutes
time, and crossed fingers-- the charger was fine.
Clearly the issue is that the Anderson had finally
melted to the point that there was discontinuity
between the pack and the charger. I was quickly back
on the road!
More importantly, today's charge saw 181V, and I'll
be slowly upping the charger voltage and seeing if the
pack will come to the full 186-193 (temp. compensated
voltage) per USB.
A larger question: If my Anderson is rated to 50A,
and I'm running no more than 30, clearly there is a
rating issue. I wonder if the 50A rating is at 125V,
or something...
peace,
Converting a gen. 5 Honda Civic? My $20 video/DVD
has my '92 sedan, as well as a del Sol and hatch too!
Learn more at:
www.budget.net/~bbath/CivicWithACord.html
____
__/__|__\ __
=D-------/ - - \
'O'-----'O'-'
Would you still drive your car if the tailpipe came out of the steering wheel?
Are you saving any gas for your kids?
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
--- End Message ---
--- Begin Message ---
See if you can find (or already have) a transformer that
supplies 48V or so, you can even use a transformer that is
used by people moving from abroad - they are pretty cheap
at Frys and similar outlets, but instead of connecting
the 110 side to the wall outlet to make 220V, you connect the
220 side to the 110V wall outlet, so the 110 side now has 55V.
Make sure it is a heavy transformer - probably need more than
500 Watt to avoid burning up the transformer.
Run the output of the transformer through a bridge rectifier
and - dependent on whether the controller already has large
capacitors on its input - you may want to add some large
80V or 100V capacitors between the + and - output of the
bridge rectifier.
Another alternative that may be even more realistic is to
go to a local golf club or other place where they service
the golf carts and ask if you can have a removed pack
for testing your cart.
It may not be good, but will likely allow you to test and
even drive (albeit with shortened range) your cart.
This latter solution should cost you little to nothing.
Success,
Cor van de Water
Systems Architect
Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [EMAIL PROTECTED]
Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
Fax: +1 408 731 3675 eFAX: +31-87-784-1130
Proxim Wireless Networks eFAX: +1-610-423-5743
Take your network further http://www.proxim.com
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of martin emde
Sent: Wednesday, October 25, 2006 4:20 PM
To: [email protected]
Subject: 72V Power Supply - Can I build one?
Greetings,
I have a GEM NEV that is in disrepair. I have all the parts (less the
batteries), schematic, and manual and would like to see if I can get it
going. I'd like to troubleshoot the car without having to invest in the
batteries, and then later find that the controller or circuit board is
fried. Is it possible to build an inexpensive, 72V power supply that would
source enough current to power -up the car and maybe turn the wheels under
no load? Maybe a large transformer and bridge rectifier? If you know of a
design (schematic and parts list) or any other solutions I would appreciate
it.
Thanks.
Martin
--- End Message ---
--- Begin Message ---
Missing something?
Yea. Clearly I intend to have some sort of motor current and motor side
voltage limit.
If you take it a step farther.. You really don't get 450 volts on a locked
rotor motor, You get full motor amps, at fractions of a volts. So... Unless
you floor it and let it spin way up.. you simply won't get full battery
volts and full motor current... EVER.
So.. a solid current control loop.. and maybe a a preset motor side voltage
limit.. But these are small details of product.
Yes I thought of that.
Two with that in mind.... having a VERY wide input range simply lets you
select what ever Battery voltage that works.. and lets me build a single
power stage that does it all. So.. I don't need 4 voltage flavors. And you
can have your 30 AGMs running a 72 volt brushed motor.
3 watts is not Watts in a battery string that is 3 times the voltage of
another. Puekert and I2R will get you way worse than you think. So.. the
higher the votlage the less losses for the same watts in a high voltage
system. Ask Westinghouse and Edison... Also the big point is ... a Sagging
150 volt pack leaves you wanting more to keep your 96 volt motor pulling,
Sagging a 360 volt pack to 180 , Still gives you more motor voltage that you
need, So the Ev keeps pulling hard.. While th e150(120) nominal is done for.
OR.. since we now have large Lion packs around that CAN't support 1200 amps
of 156 volts, But can support 600 amps or 312... You get the point...??
Everybody I talk to wants to add a couple more batteries.. and with a low
voltage limit.. you need to upgrade.. with a Wide voltage.... Well you can
run at lower Eff, And then up grade later or at your pleasure.
So.. I think this proposed controller is a LOT more that a expensive
Curtii... and has attributes that the Zilla don't. But this is a Virtual
controller right now.. We are getting close to specing out What it has to
be. So.. I am looking for interest.. and ideas.
Too many features.. and it ceases to a simple affordable product.
Rich Rudman
Manzanita Micro
----- Original Message -----
From: "Steve Condie" <[EMAIL PROTECTED]>
To: "EV List" <[email protected]>
Sent: Wednesday, October 25, 2006 4:09 PM
Subject: RE: EV controllers? the 4th option...
<snip>
> What DC'ers need is a Curtis-killer, not something that tries to compete
> with Otmar's already excellent offerings.
This is exactly what I am proposing... High voltage Curtii Killer, with
some
goodies, Not many.
<snip>
So if I understand this correctly Rich Rudman (Manzanita Micro) is talking
about designing and building an IGBT based DC controller which is "dumb as a
box of rocks" - i.e. has analog control to speed up, slow down, etc. and not
much else (Curtis dumb) which would handle 300+ volts but closer to 500 than
1000 motor amps. Rich figures the "market will bear" price range as
comparable to Zilla low voltage 1000 amp model, which Otmar (Cafe Electric)
is currently not building but which he has said he will resume construction
at no price increase in coming months.
My feedback, for what it's worth: Kilowatts is kilowatts when it comes to
power. A DC motor can't handle more than about 170 volts so a pack voltage
above that has to be stepped down. The motors typically can't handle 500+
amps for an extended time period, either. But it's nice to have over 500
motor amps for brief accelleration, I'd pay for that. And you're usually
using those amp draws to accelerate from a slow speed or stop, so you're
stepping down your voltage, and getting current multiplication, even with a
~150 volt pack. Going to a higher voltage means fewer amps per battery -
good for Peukert, I guess - but pound for pound a 30 kw pack gives the same
performance whether it's 150 volts and 200 amp hours or 300 volts and 100
amp hours. Given the weight per watt of available batteries is the same
either way, and the voltage limits of available DC motors I'm not sure that
having a 300 volt controller supplying your DC motor with 500 amps instead
of a 144 volt one
with the same current capacity really gets you anything as long as the
total kilowatt capacity of the battery pack is the same.
So what I'm hearing is more of a "slightly better than a Curtis" at Zilla
prices than a "Curtis killer" filling the price/performance gap. Am I
missing somethng?
---------------------------------
Yahoo! Messenger with Voice. Make PC-to-Phone Calls to the US (and 30+
countries) for 2¢/min or less.
--- End Message ---
--- Begin Message ---
Go to the junkyard and buy some old 12v car batteries,
might even buy them back from you after your testing, so effectively
you'd be renting them.
Would those large square 6v flashlight batteries put out enough juice
to at least test functionality? They are about $4 ea I think.
Jack
Cor van de Water wrote:
See if you can find (or already have) a transformer that
supplies 48V or so, you can even use a transformer that is
used by people moving from abroad - they are pretty cheap
at Frys and similar outlets, but instead of connecting
the 110 side to the wall outlet to make 220V, you connect the
220 side to the 110V wall outlet, so the 110 side now has 55V.
Make sure it is a heavy transformer - probably need more than
500 Watt to avoid burning up the transformer.
Run the output of the transformer through a bridge rectifier
and - dependent on whether the controller already has large
capacitors on its input - you may want to add some large
80V or 100V capacitors between the + and - output of the
bridge rectifier.
Another alternative that may be even more realistic is to
go to a local golf club or other place where they service
the golf carts and ask if you can have a removed pack
for testing your cart.
It may not be good, but will likely allow you to test and
even drive (albeit with shortened range) your cart.
This latter solution should cost you little to nothing.
Success,
Cor van de Water
Systems Architect
Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [EMAIL PROTECTED]
Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
Fax: +1 408 731 3675 eFAX: +31-87-784-1130
Proxim Wireless Networks eFAX: +1-610-423-5743
Take your network further http://www.proxim.com
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of martin emde
Sent: Wednesday, October 25, 2006 4:20 PM
To: [email protected]
Subject: 72V Power Supply - Can I build one?
Greetings,
I have a GEM NEV that is in disrepair. I have all the parts (less the
batteries), schematic, and manual and would like to see if I can get it
going. I'd like to troubleshoot the car without having to invest in the
batteries, and then later find that the controller or circuit board is
fried. Is it possible to build an inexpensive, 72V power supply that would
source enough current to power -up the car and maybe turn the wheels under
no load? Maybe a large transformer and bridge rectifier? If you know of a
design (schematic and parts list) or any other solutions I would appreciate
it.
Thanks.
Martin
--- End Message ---
--- Begin Message ---
What is needed for a controller. (Not charger)
I mean the real basics.
Why not make a huge rheostat and hook it up to the batteries?
You could do it with a parralel series of graphite rods and big copper
brushes on a lever hinge.
They could handle a huge current load and voltage.
Nothing fancy just more or less juice to the motor just like a gas
engine pedal.
Revlimiting could be done mechanically with a rev sensor disengaging
the rheostat with a servo motor.
Why wouldn't this work?
www.GlobalBoiling.com for daily updated facts about hurricanes,
globalwarming and the melting poles.
www.ElectricQuakes.com daily solar and earthquake data.
--- End Message ---
--- Begin Message ---
Nope it's in clear air at 68 F.
And.. it's like a 75C rise.
Burry it somewheres, and it gets hot and corodes, and well you get Green
fuzz instead of copper conductors..
Madman
Love it when the chargers heal themselves...
----- Original Message -----
From: "Bob Bath" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Wednesday, October 25, 2006 4:38 PM
Subject: Strange battery/charger behavior? Check your Anderson connector!
> Hey all!
> For the last 1.5 years, I've been racking my brain
> to figure out why my 144V pack o' flooded batteries no
> longer go past 175V, despite the fact that they'd
> regularly go to 193 before that. I've spent hours in
> thought, or reading/responding to posts from Nawaz,
> Roger, Roland, Rich, etc., all to no avail.
> Finally yesterday, I thought I had a dead charger.
> Upon pulling the charger, I noted that burnt carbon
> smell, and a stubborn Anderson connector. After
> prying the Anderson connector apart, it became
> apparent that it had melted. From my limited
> understanding of electronics, I can imagine that over
> a year ago, it melted slightly, so as to function as a
> bit of a resistor, thereby limiting my charger
> voltage. For $14 in fresh connectors, 15 minutes
> time, and crossed fingers-- the charger was fine.
> Clearly the issue is that the Anderson had finally
> melted to the point that there was discontinuity
> between the pack and the charger. I was quickly back
> on the road!
> More importantly, today's charge saw 181V, and I'll
> be slowly upping the charger voltage and seeing if the
> pack will come to the full 186-193 (temp. compensated
> voltage) per USB.
> A larger question: If my Anderson is rated to 50A,
> and I'm running no more than 30, clearly there is a
> rating issue. I wonder if the 50A rating is at 125V,
> or something...
> peace,
>
>
> Converting a gen. 5 Honda Civic? My $20 video/DVD
> has my '92 sedan, as well as a del Sol and hatch too!
> Learn more at:
> www.budget.net/~bbath/CivicWithACord.html
> ____
> __/__|__\ __
> =D-------/ - - \
> 'O'-----'O'-'
> Would you still drive your car if the tailpipe came out of the steering
wheel? Are you saving any gas for your kids?
>
> __________________________________________________
> Do You Yahoo!?
> Tired of spam? Yahoo! Mail has the best spam protection around
> http://mail.yahoo.com
>
--- End Message ---
--- Begin Message ---
From: Lawrence Rhodes
> why can't a DC controller of the chopper kind have a dual purpose?
> Charger/controller?
Mainly because they perform different functions:
- Motor controllers deal with at least 10 times the power of chargers.
- Motor controllers aren't isolated
Chargers are usually isolated.
- Motor controllers don't deal with voltages much higher than pack voltage.
Chargers must survive the very high peak voltages found on the AC line.
- A motor controller drives an inductive load (motor).
A charger drives a capacitive load (batteries).
- A motor controller has a fixed input voltage, and variable output voltage.
A charger has fixed input and output voltages.
It is possible to design a combination charger/controller. For example, any
controller that can do regen is close to it. But in general, a separate charger
and controller have been cheaper.
--- End Message ---
--- Begin Message ---
From: Rich Rudman
> This is exactly what I am proposing... High voltage Curtis Killer, with
> some goodies, not many... 96V to perhaps 192V... 500 amp... is going
> to cover most anyone who would have bought this controller instead
> of a Curtis... I am proposing an IGBT module based machine.
IGBTs are generally good for higher voltages and lower currents than
this. Your controller will have on the order of a 3v drop; that's 1500 watts
at 500 amps. Dissipating 1500 watts takes some pretty impressive (and
expensive) heatsinks.
Under 200v, I'd prefer MOSFETs. Use them for both the transistors and
freewheel diodes (synchronous rectification). This will get the drop under 1v,
which mean 1/3rd the heat to get rid of.
Modules are really nice because they get rid of dozens of tiny little devices
that must be meticulously wired in parallel. A controller like this would need
a dual MOSFET "half bridge" module.
>The voltage limits I think are a waste of time.
I disagree. The low limit prevents you from ruining your batteries by running
them dead. The high limit keeps you from destroying the controller from
excessive voltage (typically caused by chargers, or by too much battery
inductance or resistance).
> The point is a easy to buld easy to service, simple power stage simple
> analog controller that just gets the job done.
I agree. There is little point to micros and software in a basic controller.
Add a micro-controlled "hairball" if you want bells and whistles, like cruise
control, regen, series/parallel contactor switching, etc.
> precharge/contactor control
> basic fault detection (open/short throttle, high pedal lockout)
Yes; it's so simple that it would be foolish to leave it out.
> rev limiter (and a tach drive output sure would be nice)
For a simple "black box" controller, such functions should be simple
enough to add that it doesn't need to be designed and integrated into
the controller. For instance, the controller might just have an "inhibit"
input that shuts it down if it exceeds X volts. The user could work out
circuits to apply a voltage proportional to RPM, or temperature, or
whatever.
> packaged to survive the automotive underhood environment.
Definitely! Too many controllers are being built in places that don't
have weather. They are packaged like indoor office equipment.
> No I am not making a submersible product.
I would! :-) Use a NEMA enclosure with a heatsink on the outside.
--- End Message ---
--- Begin Message ---
On Oct 24, 2006, at 11:39 AM, David Roden (Akron OH USA) wrote:
Seth Myers wrote:
Precharge Circuit ...
Lee Hart has published a few here on the list. They're not difficult
to make.
The Curtis manual's suggestion of using a simple resistor across the
main
contactor to keep the caps charged all the time is what your advice
refers to,
and I would concur : this is not a great idea for a road EV.
If you use a relay, in parallel with the main contactor, to disconnect
the Curtis ksi input when the car is off its a lot better. With this
the precharge only charges the input caps and the only pack drain is
the bleeder resistor across the input caps (without this the controller
is kept fully ON.) I use this on my 1221b controller and have only a
few volts drop across a 7.5 watt light bulb (without out this relay I
need a 25 watt bulb to keep the drop to a few volts.) In the winter,
when the Buggy goes dormant, I unscrew the light bulb. I also do that
before I equalize the battery pack.
Paul "neon" G.
--- End Message ---
--- Begin Message ---
Don,
What Zivan reliability issues? The NGn's are rock solid. Are you referring
to the older model Kn's, which were European 200 + volt 50 Hz models that
would burn up on 120 volts?
BB
>From: "Don Cameron" <[EMAIL PROTECTED]>
<snippage>
>PFC chargers are in wide use and have high reliability. Some care needs to
>be taken when hooking up. Best bang for the buck. I did not choose Zivan's
>as there were a number of people with reliability issues.
<snippage>
--- End Message ---
--- Begin Message ---
At 04:28 PM 25/10/06 -0700, GWMobile wrote:
What is needed for a controller. (Not charger)
I mean the real basics.
Why not make a huge rheostat and hook it up to the batteries?
You could do it with a parralel series of graphite rods and big copper
brushes on a lever hinge.
They could handle a huge current load and voltage.
Nothing fancy just more or less juice to the motor just like a gas engine
pedal.
Revlimiting could be done mechanically with a rev sensor disengaging
the rheostat with a servo motor.
Why wouldn't this work?
It'd work, just be exceptionally inefficient if you tried to do it with a
series motor. Instead of having 80% of the battery available energy turned
into motion, you may be as bad as 30%. And the price of the parts would
probably run out at more than a Curtis controller. Why so inefficient? If
your motor is needing 400A to accelerate, you start off with 120V pack
delivering 400A with 20V across the motor and the rest across the rheostat,
100V @ 400A = 40kW, that's a big rheostat!. plus your battery amps always
equals motor amps, so puekert bites hard.
If you can find a shunt or sep-ex motor you can do that for field control,
and get reasonably efficient control. Do some research at 1920s EV
technology and you'll find what you're describing, but in ways that work
reasonably well. If you are mechanically clever, you can build a
centrifical 'gadget' that mounts the rheostat on it and prevents you from
having too little field at too low an RPM, giving current limit. If you are
not mechanically clever, someone could build you one for around, oh, I
dunno, the price of a Zilla? So just go out and buy a Zilla and get
something more compact, probably safer and more reliable.
Just my $0.02
RTegards
[Technik] James
--- End Message ---
--- Begin Message ---
Thanks Roger.
A follow-up if I may.
On Wednesday, October 25, 2006, at 12:19 AM, Roger Stockton wrote:
John wrote:
Not being a car guy I ask,
Is the release bearing supposed to spin smoothly?
It should spin smoothly, but may feel/sound "different" from other
bearings you may be familiar with (such as wheel bearings).
I'm not really familiar with ANY bearings 8-)
That being said, as I spun it, there were some sticky spots. So I feel
ok with having returned this particular one.
Is the size of the assembly recess that gets packed
with grease important?
You don't pack clutch release bearings with grease. They are
permanently lubricated (graphite, I believe, which is why they
feel/sound different from wheel bearings, etc.). Bear in mind that the
only time the release bearing spins is while you have the clutch pedal
depressed, which is a very small fraction of the time you spend
driving.
I guess the correct term is bearing holder. The service manual shows a
cut away of the bearing holder with instructions to grease a recess on
the the inside that contacts the transmission input shaft. As I
understand it, the transmission input shaft spins inside the bearing
holder so it seems the significantly smaller area on the bearing may be
problematic.
I don't have a bearing puller so unless I want to buy another tool, I
need to get a replacement bearing/holder combination.
I'll keep looking.
John
--- End Message ---
--- Begin Message ---
Thanks.
Ok so scrap the rheostat .
Would it be more efficient as a pure full on full off switch with some
sort of motor smoothing in the drive tran?
On Wed, 25 Oct 2006 7:41 pm, James Massey wrote:
At 04:28 PM 25/10/06 -0700, GWMobile wrote:
What is needed for a controller. (Not charger)
I mean the real basics.
Why not make a huge rheostat and hook it up to the batteries?
You could do it with a parralel series of graphite rods and big copper
brushes on a lever hinge.
They could handle a huge current load and voltage.
Nothing fancy just more or less juice to the motor just like a gas
engine pedal.
Revlimiting could be done mechanically with a rev sensor disengaging
the rheostat with a servo motor.
Why wouldn't this work?
It'd work, just be exceptionally inefficient if you tried to do it with
a series motor. Instead of having 80% of the battery available energy
turned into motion, you may be as bad as 30%. And the price of the
parts would probably run out at more than a Curtis controller. Why so
inefficient? If your motor is needing 400A to accelerate, you start off
with 120V pack delivering 400A with 20V across the motor and the rest
across the rheostat, 100V @ 400A = 40kW, that's a big rheostat!. plus
your battery amps always equals motor amps, so puekert bites hard.
If you can find a shunt or sep-ex motor you can do that for field
control, and get reasonably efficient control. Do some research at
1920s EV technology and you'll find what you're describing, but in ways
that work reasonably well. If you are mechanically clever, you can
build a centrifical 'gadget' that mounts the rheostat on it and
prevents you from having too little field at too low an RPM, giving
current limit. If you are not mechanically clever, someone could build
you one for around, oh, I dunno, the price of a Zilla? So just go out
and buy a Zilla and get something more compact, probably safer and more
reliable.
Just my $0.02
RTegards
[Technik] James
www.GlobalBoiling.com for daily updated facts about hurricanes,
globalwarming and the melting poles.
www.ElectricQuakes.com daily solar and earthquake data.
--- End Message ---
--- Begin Message ---
From: Chris Jones
> Regarding the resistor choice: the RAC handbook suggests 50%
> power derating (and 70% for voltage) for power wire wound
> resistors. So something like the Ohmite WHF90L750J 90W, 750 ohm
> resistor for $21 from Allied Electronics seems like a better match.
That's why I use light bulbs. A 100w light bulb is 50 cents. :-)
Seriously, the precharge resistor should never be able to dissipate all
that many joules. The capacitors will precharge so quickly that the
resistor's temperature rise is very low. The only hazardous failure
mode is if the precharge is in the circuit when the controller tries to
turn on. You can have interlock or safety circuits to protect against this.
For example, a slow-blow fuse in series with the precharge resistor.
> Of course selecting an automotive relay with contacts rated at a
> high enough voltage and DC current is important.
Automotive relays normally have substandard contact ratings and
isolation ratings. For this application, you want an industrial relay
that has a clearly defined high isolation voltage between coil and
contacts (1500v or more), and contacts rated for your pack voltage
(and this means *DC* voltage ratings, not AC!)
> Considering the inductance of these high power
> resistors, I wonder what voltage this relay would see?
Full DC pack voltage.
> If this is an issue, I have seen non-inductive power
> resistors that might go up this far wattagewise but I
>haven't looked in to them yet.
The inductance of standard wirewound resistors is plenty
low enough for these circuits! "Non-inductive" resistors are
only called for in RF circuits operating at MHz.
> Shouldn't we insert a fuse in series with the precharge
> resistor and relay?
You use a fuse when failures in the circuit could produce an
unsafe condition. If the precharge resistor can fail shorted,
or if failures somewhere else can overload the resistor until
it causes a fire, then use a fuse.
Here again, a light bulb can avoid the problem. They can
handle the full pack voltage indefinitely. They don't normally
fail shorted, but if they do, they quickly revert to open. There
is no fire hazard if you mount them appropriately.
--- End Message ---
--- Begin Message ---
It'd work, just be exceptionally inefficient if you tried to do it with a
series motor. Instead of having 80% of the battery available energy turned
into motion, you may be as bad as 30%.
What's the problem with that? Millions of people every day drive cars
powered by ICE motors every day. We don't hear to many of them complain
about 30% efficiency.
Ted
Olympia, WA
N47 02.743 W122 53.772
"THE Stone Age did not end for lack of stone, and the Oil Age will end long
before the world runs out of oil."
Quotation is from Sheikh Zaki Yamani, a Saudi Arabian who served as his
country's oil minister three decades ago.
--- End Message ---
--- Begin Message ---
>> It'd work, just be exceptionally inefficient if you tried to do it with a
>> series motor. Instead of having 80% of the battery available energy
>> turned into motion, you may be as bad as 30%.
From: "Ted C."
> What's the problem with that? Millions of people every day drive cars
> powered by ICE motors every day. We don't hear to many of them
> complain about 30% efficiency.
An ICE has a range of perhaps 300 miles even with its 30% efficiency.
If its engine was 100% efficient, its range would be more like 1000 miles
on a tank of gas.
An EV has a range of more like 30 miles, and that's *with* an efficiency
of 80% or more. If its efficiency were 30%, its range would be more like
10 miles. That's unacceptable.
I think what you're looking for is a contactor controller. This is what they
used 100 years ago for EVs. They are crude and jerky, but almost 100%
efficienct and very simple. Basically, it is a bunch of switches that wire
the batteries in various series/parallel combinations to get the desired
motor speed.
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--- Begin Message ---
It could work, but severely reduce your range, due
to the inefficiencies. You are burning about half
your power in the hreostat and you make your batteries
work harder every takeoff to boot.
This is technology from well before the end of the last
century and there is a reason for everyone switching over
to switching controllers instead of resistive controllers.
In fact, there have already been two generations of
switching controllers: SCR without the benefits of
high frequent switching (squeal) and current multiplication
(more battery current). That is what we gained from the
second generation, with some of them adding a rich feature
set like automatic rev limiting, current and voltage control,
pre-charge and main contactor status checking, series and
parallel switching and so on.
We can go back if there is a good reason, like very cheap
to implement, but a lot of EVers will gladly pay $2000 for
a controller that protects their batteries and gives them
twice as much range as the cheap solution, every new pack.
(Which will last twice as many miles due to the increased
range alone)
Hope this clarifies,
Cor van de Water
Systems Architect
Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [EMAIL PROTECTED]
Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
Fax: +1 408 731 3675 eFAX: +31-87-784-1130
Proxim Wireless Networks eFAX: +1-610-423-5743
Take your network further http://www.proxim.com
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of GWMobile
Sent: Wednesday, October 25, 2006 4:28 PM
To: [email protected]
Cc: [EMAIL PROTECTED]
Subject: Re: EV controllers? the 4th option...
What is needed for a controller. (Not charger)
I mean the real basics.
Why not make a huge rheostat and hook it up to the batteries?
You could do it with a parralel series of graphite rods and big copper
brushes on a lever hinge.
They could handle a huge current load and voltage.
Nothing fancy just more or less juice to the motor just like a gas
engine pedal.
Revlimiting could be done mechanically with a rev sensor disengaging
the rheostat with a servo motor.
Why wouldn't this work?
www.GlobalBoiling.com for daily updated facts about hurricanes,
globalwarming and the melting poles.
www.ElectricQuakes.com daily solar and earthquake data.
--- End Message ---
--- Begin Message ---
An ICE has a range of perhaps 300 miles even with its 30% efficiency.
If its engine was 100% efficient, its range would be more like 1000 miles
on a tank of gas.
An EV has a range of more like 30 miles, and that's *with* an efficiency
of 80% or more. If its efficiency were 30%, its range would be more like
10 miles. That's unacceptable.
I was being sarcastic. I don't think the genral public realizes how poorly
the energy in the gasoline is use to make motion. But it sure keeps you warm
in the winter.
I think what you're looking for is a contactor controller. This is what
they
used 100 years ago for EVs. They are crude and jerky, but almost 100%
efficienct and very simple. Basically, it is a bunch of switches that wire
the batteries in various series/parallel combinations to get the desired
motor speed.
Isn't that how the citicars worked? The relays pick different combinations
of series/parallel. I think it was called the citcars, But I could be wrong.
I'll stop hijacking this thread now.
Ted
Olympia, WA
N47 02.743 W122 53.772
“THE Stone Age did not end for lack of stone, and the Oil Age will end long
before the world runs out of oil.”
Quotation is from Sheikh Zaki Yamani, a Saudi Arabian who served as his
country's oil minister three decades ago.
--- End Message ---
--- Begin Message ---
Unless you have a prefabed kit that can go in in a weekend, just get the
zilla last, It is really worth it. (Safety,power, convienence of error
codes, valet mode, s/p switching...)
Haha, like that's a choice ... =)
--- End Message ---
--- Begin Message ---
The 90W (with the proper derating for longevity) would
be required if you would run the precharge resistor for
a long time.
NOTE that the total time that a precharge resistor is
active is a few hours over the lifetime of the car.
Every time you drive the car adds a fraction of a second,
after which the main contactor shorts the remaining
voltage over the pre-charge resistor and it has nothing to
do until the next time you start the car.
My truck has a 50 Ohm (I believe) pre-charge resistor,
which gets a jolt of 312V, resulting in 6.2 Amps and an
increadible 2kW which is dissipated in a 100 Watt metal-
would resistor that has such a large thermal mass that it
does not heat up during the precharge, so there is no
degradation.
NOTE that there is a 2 Amp fuse in line with the resistor
so if something goes wrong, that will protect the circuit.
25W resistor for a peak of 41W sounds perfect to me.
It is a bit high resistance though, if you want to load
the pre-charge circuit with the Iota ro another DC/DC
to avoid electrical stress when it is switched to full pack
voltage, then the DC/DC must have a very low idle draw, else
the 750 Ohm cannot get the pre-charge voltage high enough.
Hope this clarifies,
Cor van de Water
Systems Architect
Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [EMAIL PROTECTED]
Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
Fax: +1 408 731 3675 eFAX: +31-87-784-1130
Proxim Wireless Networks eFAX: +1-610-423-5743
Take your network further http://www.proxim.com
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of Chris Jones
Sent: Wednesday, October 25, 2006 1:49 PM
To: [email protected]
Subject: Precharge Circuit Design
Thank you everyone for the precharge circuit
discussion. I want to add a precharge circuit to my
conversion to help minimize contactor welding and
controller filter capacitor failure. But I have a few
design questions:
Regarding the resistor choice:
I have a Curtis 1231C-8601. The manual says 750 ohms
at only 25W, but fresh off a charge I too am at it's
peak input of 175V, so that's 233 mA and 41W. Since
25W is the continuous rating and this is a very narrow
and occasional occasional pulse, 25W would probably
do. But the Reliability Analysis Center (RAC)
Electrical Derating for Optimum Performance handbook
suggests 50% power derating (and 70% for voltage) for
power wire wound resistors. So something like the
Ohmite WHF90L750J 90W, 750 ohm resistor for $21 from
Allied Electronics seems like a better match.
Regarding the relay choice:
As suggested for efficiency, I would like to power a
12V coil relay in series with this resistor from the
ignition path, downstream of my AC interlock relay but
upstream of my potbox microswitch which powers the
main contactor and KSI relay so it goes on with the
key when the charger isn't powered up. Of course
selecting an automotive relay with contacts rated at a
high enough voltage and DC current is important.
Considering the inductance of these high power
resistors, I wonder what voltage this relay would see?
If this is an issue, I have seen non-inductive power
resistors that might go up this far wattagewise but I
haven't looked in to them yet. The relays I have
bought from Kragen don't come with specs -- any
suggestions on a relay to use? And similar question
for the KSI relay -- I just put in an automotive
relay, but I don't know it's contact rating, so at
175V I might be overstressing it voltagewise. I think
the KSI circuit has less inductance than a wire wound
precharge resistor will have.
And what about a fuse?
Shouldn't we insert a fuse in series with the
precharge resistor and relay? I'd hate to see that
resistor burn if it developed a short, even though the
RAC estimates only a 4% chance that shorting would be
its failure mode. Current rating for my case would be
~.5A, and I think it won't see the voltage spike so
they typical 250V automotive type would suffice.
Thank you,
Chris Jones
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