Strange pulsing in 12V circuits

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Strange pulsing in 12V circuits

joe-22
Hi, all!

I'm working on  a Dodge Dakota for someone else that was originally
converted by Toledo Power in Ohio. I'm having two problems that maybe
someone here can help me with.

When the 12V accessory circuit is powered up, I get a pulsing effect, lights
dim, then bright, clicking in the radio speakers even when the radio isn't
on, displays flickering, on a frequency of about every second. This happens
whether the circuit is powered off just the battery, or off the Vicor DC/DC
(right now some stuff is powered by one, some by the other, as the wiring
isn't complete) only when the key is full on - this doesn't happen in the
acc. position on the key, so the contactors aren't engaged.

Another problem (may be related!) is that I get full pack voltage from the
battery pack positive to ground at all times. This is a safety issue, as far
as I am concerned, but it could cause other problems as well. I can't see
anywhere in the pack neg. where it is grounded to the frame, but I suppose
it is possible, as I can't see all of the wiring very well (don't have eye
extension stalks, or a hoist to put the beast up on!).

Any thoughts about where to look for these issues?

Joseph H. Strubhar

Web: www.gremcoinc.com

E-mail: [hidden email]

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Re: Strange pulsing in 12V circuits

Roland Wiench
Hello Joe,

When you get the full pack voltage from the pack positive to ground, while a
non-isolated charger is on, and your input AC plug is self grounding to the
frame and the battery charger is a not isolated, this is normal for this
type of setup.

If you still get full battery voltage from the battery pack to the frame of
the EV, it is a conductive path problem.

In some EV's the negative of the battery pack may go through a shunt that is
then connected directly to a dc motor.  The brush dust may provide a
conductive path from the commentator down to the motor shaft and finally to
the frame of the vehicle.

Remove the motor leads from the controller, if see what the resistance is
from the motor terminals to the frame ground.  For a new DC motor it may
read above 20 Mohms.  After about 10 years, the resistance could be down to
or below 20 Kohms, it is time to clean the motor.

I had these two problems in my first EV and modified the circuits in my next
EV to prevent this conductive path.

I am using a non-isolated PFC charger, which I made the AC input power
isolated from the frame by first using it as a off board charger.  Only the
case of the charger was grounded that sat on the bench.

You could also install a GFI circuit breaker for you charger receptacle. I
have this type of breaker install on board, so I can plug into any
receptacle with a voltage range from 120 to 240 volts.

I then install the charger in a non-conductive equipment cabinet that was
install in the EV.  Only the steel case of the charger is grounded.  The
input AC plug and connector is a isolated grounded type which is a nylon
non-conductive material.

When the battery charger is on, the batteries are disconnected by two safety
contactors from the main contactor, controller and motor.  This prevents the
higher charger voltage to be standing on these devices.  I could see arc
over from my motor commentator to ground when I was charging the batteries.

I also install a DC contactor between the battery charger and the batteries.
I found that when I had the PFC charger connected up at all times, and using
a CableForm controller that had REGEN, It would charge up the capacitors in
the charger.

One time, I remove the a battery link for maintenance and I received a large
discharge spark from the battery charger, even if the battery charger was
not plug in.  So the DC contactor between the battery charger and battery
prevented this type of discharge.

The only thing, I have to remember is to shut down the charger before I
disconnect the charger from the batteries.  You do not want to operated this
type of charger in a open circuit.

The DC-DC converters may not be isolated.  I do not ground my 12 volt
negative to the vehicle ground.  The 12 volt devices that come off the DC-DC
converters are isolated from the frame of the vehicle.  I do not use the
vehicle as a ground path, but use a isolated negative 12 volt conductor that
runs to all the 12 volt devices.

I do not use the DC-DC converter connected to my 12 volt battery, I use a
alternator that is design to charge a 12 volt deep cycle battery.  Using a
Zilla controller which does not have REGEN yet, I use the alternator to
provide a mechanical REGEM load which assist in slowing my EV on steep icy
hills.

Doing all of the above and after super cleaning my batteries, battery
enclosures, this battery pack voltage is reduced to 0.7 volts.  But again as
time goes on, it will start to raise.  This is cause by the venting fumes of
the battery, which provides a conductive path across non-conductive,
plastic, epoxy surfaces.

Even if the batteries look super clean, I may have to clean them before the
voltage to ground gets too high.

Roland




----- Original Message -----
From: "joe" <[hidden email]>
To: "Electric Vehicle Discussion List" <[hidden email]>
Sent: Monday, February 11, 2008 8:08 AM
Subject: [EVDL] Strange pulsing in 12V circuits


> Hi, all!
>
> I'm working on  a Dodge Dakota for someone else that was originally
> converted by Toledo Power in Ohio. I'm having two problems that maybe
> someone here can help me with.
>
> When the 12V accessory circuit is powered up, I get a pulsing effect,
> lights
> dim, then bright, clicking in the radio speakers even when the radio isn't
> on, displays flickering, on a frequency of about every second. This
> happens
> whether the circuit is powered off just the battery, or off the Vicor
> DC/DC
> (right now some stuff is powered by one, some by the other, as the wiring
> isn't complete) only when the key is full on - this doesn't happen in the
> acc. position on the key, so the contactors aren't engaged.
>
> Another problem (may be related!) is that I get full pack voltage from the
> battery pack positive to ground at all times. This is a safety issue, as
> far
> as I am concerned, but it could cause other problems as well. I can't see
> anywhere in the pack neg. where it is grounded to the frame, but I suppose
> it is possible, as I can't see all of the wiring very well (don't have eye
> extension stalks, or a hoist to put the beast up on!).
>
> Any thoughts about where to look for these issues?
>
> Joseph H. Strubhar
>
> Web: www.gremcoinc.com
>
> E-mail: [hidden email]
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>

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Re: Strange pulsing in 12V circuits

Jon Glauser
In reply to this post by joe-22
as for the pulsing, could it be something like a turn signal? I've  
seen turn signals dim everything, even in ICE cars (usually with a  
trailer attached).

There are lots of things that could cause high voltage to show up on  
the frame. Battery electrolyte was my problem. Then it was a  
non-isolated E-meter.





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Re: Strange pulsing in 12V circuits

Doug Weathers
In reply to this post by joe-22
joe wrote:

> When the 12V accessory circuit is powered up, I get a pulsing effect, lights
> dim, then bright, clicking in the radio speakers even when the radio isn't
> on, displays flickering, on a frequency of about every second. This happens
> whether the circuit is powered off just the battery, or off the Vicor DC/DC.

It could definitely be something else, but:

That sounds (to this ignorant non-EE) like a crowbar circuit cycling on
and off.  Some device somewhere is shorting its 12v input leads in an
attempt to blow a fuse, in order to shut itself off for safety reasons.
  This drops the voltage on the 12v bus, causing the momentary brownout.
  When it opens the short, it causes a spike on the vehicle ground,
causing the speakers to pop.

Since the fuse isn't blowing, apparently this device isn't fused
correctly (or at all).

Does it still happen when you pull out all your fuses?

Which fuse stops the behavior?  That will narrow it down to a particular
circuit.

If *no* fuse stops the behavior, it's evidence for the crowbar scenario.

An ammeter on the 12v system should show heavy current draw during the
brownout, too.

If it goes on for long enough something may heat up dramatically, which
should help you find it :)  Or a master fuse will blow if it gets hot
enough, but the 50% duty cycle might not let it get hot enough.

Of course it might be something else entirely.  The above might be total
nonsense.  Hopefully someone will correct me if so.

Good luck,

Doug

>
> Joseph H. Strubhar
>
> Web: www.gremcoinc.com
>
> E-mail: [hidden email]
--
Doug Weathers
Las Cruces, NM, USA
http://www.gdunge.com

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Re: Strange pulsing in 12V circuits

Roger Stockton
In reply to this post by joe-22
joe wrote:

> I'm working on  a Dodge Dakota for someone else that was
> originally converted by Toledo Power in Ohio. I'm having two
> problems that maybe someone here can help me with.
>
> When the 12V accessory circuit is powered up, I get a pulsing
> effect, lights dim, then bright, clicking in the radio
> speakers even when the radio isn't on, displays flickering,
> on a frequency of about every second. This happens whether
> the circuit is powered off just the battery, or off the Vicor
> DC/DC (right now some stuff is powered by one, some by the
> other, as the wiring isn't complete) only when the key is
> full on - this doesn't happen in the acc. position on the
> key, so the contactors aren't engaged.

I'm not familiar with the Dakota specifically, but on my ICE Aerostar I have had similar behaviour.  In my case, it happened if the rear wiper got stuck; it's motor would be stalled and so draw a large current (large enough that I could see the voltmeter swing significantly down as the motor loaded the 12V ssytem beyond the alternator's ability to keep up!).  After a short time, the voltmeter would pop back to normal and a second or two later the cycle would repeat.  This would continue even if the wiper was switched back off, as it would continue cycling until I got out an jiggled the wire so the motor could return the wiper to the 'park' position.

I expect that what was happening is that the large stall current would quickly cause a thermal circuit breaker to open, and then afer a second or two to cool, the breaker would reset and the cycle would repeat.

Since you are seeing the behaviour only with the key on and not in the acc position, I would check the 12V wiring diagram (if you have one) to see which items are only powered when the key is on.  Sometimes wipers or the heater fan are powered in one position but not the other.

> Another problem (may be related!) is that I get full pack
> voltage from the battery pack positive to ground at all
> times. This is a safety issue, as far as I am concerned, but
> it could cause other problems as well. I can't see anywhere
> in the pack neg. where it is grounded to the frame, but I
> suppose it is possible, as I can't see all of the wiring very
> well (don't have eye extension stalks, or a hoist to put the
> beast up on!).

My first though would be to disconnect the DC/DC from the traction pack entirely to check for a loss of isolation there.

If the vehicle has a ceramic heater, my next thought would be to try disconnecting the traction pack from it.  Perhaps there is a connection between pack -ve and chassis there, or even some connection to the 12V system (heater fan?) that might relate to your other symptoms.

Lastly (or firstly?), try disconnecting the traction system from the motor and controller (disconnect whichever lead is not switched by the main contactor if there is only one contactor).

Hope this helps,

Roger.

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Re: Strange pulsing in 12V circuits

joe-22
In reply to this post by Roland Wiench

----- Original Message -----
From: "Roland Wiench" <[hidden email]>
To: "Electric Vehicle Discussion List" <[hidden email]>
Sent: Monday, February 11, 2008 8:51 AM
Subject: Re: [EVDL] Strange pulsing in 12V circuits


> Hello Joe,
>
> When you get the full pack voltage from the pack positive to ground, while
> a non-isolated charger is on, and your input AC plug is self grounding to
> the frame and the battery charger is a not isolated, this is normal for
> this type of setup.

The charger not only wasn't on, but isn't even connected.

> If you still get full battery voltage from the battery pack to the frame
> of the EV, it is a conductive path problem.

That's what I'm thinking this is; it acts like a ground loop problem.

> In some EV's the negative of the battery pack may go through a shunt that
> is then connected directly to a dc motor.  The brush dust may provide a
> conductive path from the commentator down to the motor shaft and finally
> to the frame of the vehicle.

There is a shunt that is directly off the pack negative - but the motor
leads aren't connected,
and the motor has been completely rebuilt, so not dust there in any case.
But there may be a
conductive path to ground at the shunt, or in the box that holds the
controller and relays.

> Remove the motor leads from the controller, if see what the resistance is
> from the motor terminals to the frame ground.  For a new DC motor it may
> read above 20 Mohms.  After about 10 years, the resistance could be down
> to or below 20 Kohms, it is time to clean the motor.

The controller is installed now, but again isn't hooked up yet. I'm a little
afraid to hook it up
with this problem; I don't want to fry the controller!


> I had these two problems in my first EV and modified the circuits in my
> next EV to prevent this conductive path.
>
> I am using a non-isolated PFC charger, which I made the AC input power
> isolated from the frame by first using it as a off board charger.  Only
> the case of the charger was grounded that sat on the bench.
>
> You could also install a GFI circuit breaker for you charger receptacle. I
> have this type of breaker install on board, so I can plug into any
> receptacle with a voltage range from 120 to 240 volts.

Again, the charger isn't even in the circuit.

> I then install the charger in a non-conductive equipment cabinet that was
> install in the EV.  Only the steel case of the charger is grounded.  The
> input AC plug and connector is a isolated grounded type which is a nylon
> non-conductive material.
>
> When the battery charger is on, the batteries are disconnected by two
> safety contactors from the main contactor, controller and motor.  This
> prevents the higher charger voltage to be standing on these devices.  I
> could see arc over from my motor commentator to ground when I was charging
> the batteries.
>
> I also install a DC contactor between the battery charger and the
> batteries. I found that when I had the PFC charger connected up at all
> times, and using a CableForm controller that had REGEN, It would charge up
> the capacitors in the charger.
>
> One time, I remove the a battery link for maintenance and I received a
> large discharge spark from the battery charger, even if the battery
> charger was not plug in.  So the DC contactor between the battery charger
> and battery prevented this type of discharge.
>
> The only thing, I have to remember is to shut down the charger before I
> disconnect the charger from the batteries.  You do not want to operated
> this type of charger in a open circuit.
>
> The DC-DC converters may not be isolated.  I do not ground my 12 volt
> negative to the vehicle ground.  The 12 volt devices that come off the
> DC-DC converters are isolated from the frame of the vehicle.  I do not use
> the vehicle as a ground path, but use a isolated negative 12 volt
> conductor that runs to all the 12 volt devices.

I don't know if the Vicor is isolated or not; this pulse still happens when
the DC/DC isn't
hooked up (12V system running off the battery Optima RedTop only). But the
12V system
does use the vehicle frame as a common ground - and I see no way to avoid
it, as this system
is way too complicated to rewire for an isolated negative on the 12V system!


> I do not use the DC-DC converter connected to my 12 volt battery, I use a
> alternator that is design to charge a 12 volt deep cycle battery.  Using a
> Zilla controller which does not have REGEN yet, I use the alternator to
> provide a mechanical REGEM load which assist in slowing my EV on steep icy
> hills.
>
> Doing all of the above and after super cleaning my batteries, battery
> enclosures, this battery pack voltage is reduced to 0.7 volts.  But again
> as time goes on, it will start to raise.  This is cause by the venting
> fumes of the battery, which provides a conductive path across
> non-conductive, plastic, epoxy surfaces.

Pack is brand-new Optima BlueTops, very little possibility of conductive
path.

> Even if the batteries look super clean, I may have to clean them before
> the voltage to ground gets too high.
>
> Roland

I'm thinking that the problem is either a conductive path that allows the
pack negative
to the frame, which might cause the pulsing due to the fact that the 12V
controls use
the frame also. OR a defective shunt? I'm not an engineer, so am having
trouble visulaizing
where to look for the problem!

Joseph H. Strubhar

Web: www.gremcoinc.com

E-mail: [hidden email]


> ----- Original Message -----
> From: "joe" <[hidden email]>
> To: "Electric Vehicle Discussion List" <[hidden email]>
> Sent: Monday, February 11, 2008 8:08 AM
> Subject: [EVDL] Strange pulsing in 12V circuits
>
>
>> Hi, all!
>>
>> I'm working on  a Dodge Dakota for someone else that was originally
>> converted by Toledo Power in Ohio. I'm having two problems that maybe
>> someone here can help me with.
>>
>> When the 12V accessory circuit is powered up, I get a pulsing effect,
>> lights
>> dim, then bright, clicking in the radio speakers even when the radio
>> isn't
>> on, displays flickering, on a frequency of about every second. This
>> happens
>> whether the circuit is powered off just the battery, or off the Vicor
>> DC/DC
>> (right now some stuff is powered by one, some by the other, as the wiring
>> isn't complete) only when the key is full on - this doesn't happen in the
>> acc. position on the key, so the contactors aren't engaged.
>>
>> Another problem (may be related!) is that I get full pack voltage from
>> the
>> battery pack positive to ground at all times. This is a safety issue, as
>> far
>> as I am concerned, but it could cause other problems as well. I can't see
>> anywhere in the pack neg. where it is grounded to the frame, but I
>> suppose
>> it is possible, as I can't see all of the wiring very well (don't have
>> eye
>> extension stalks, or a hoist to put the beast up on!).
>>
>> Any thoughts about where to look for these issues?
>>
>> Joseph H. Strubhar
>>
>> Web: www.gremcoinc.com
>>
>> E-mail: [hidden email]
>>
>> _______________________________________________
>> For subscription options, see
>> http://lists.sjsu.edu/mailman/listinfo/ev
>>
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>
>
>
> --
> No virus found in this incoming message.
> Checked by AVG Free Edition. Version: 7.5.516 / Virus Database:
> 269.20.2/1271 - Release Date: 2/11/2008 8:16 AM
>
>

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Re: Strange pulsing in 12V circuits

joe-22
In reply to this post by Roger Stockton
Thanks, Roger - I don't have a diagram to work  off, unfortunately. I will
try to disconnect the DC/DC from the traction pack, but I doubt that is it.
One thing I know is on when the key is in the #1 postion is the Ahr meter.

As mentioned in the post to Roland, the motor and controller are not hooked
up yet.


----- Original Message -----
From: "Roger Stockton" <[hidden email]>
To: "'Electric Vehicle Discussion List'" <[hidden email]>
Sent: Monday, February 11, 2008 10:37 AM
Subject: Re: [EVDL] Strange pulsing in 12V circuits


> joe wrote:
>
>> I'm working on  a Dodge Dakota for someone else that was
>> originally converted by Toledo Power in Ohio. I'm having two
>> problems that maybe someone here can help me with.
>>
>> When the 12V accessory circuit is powered up, I get a pulsing
>> effect, lights dim, then bright, clicking in the radio
>> speakers even when the radio isn't on, displays flickering,
>> on a frequency of about every second. This happens whether
>> the circuit is powered off just the battery, or off the Vicor
>> DC/DC (right now some stuff is powered by one, some by the
>> other, as the wiring isn't complete) only when the key is
>> full on - this doesn't happen in the acc. position on the
>> key, so the contactors aren't engaged.
>
> I'm not familiar with the Dakota specifically, but on my ICE Aerostar I
> have had similar behaviour.  In my case, it happened if the rear wiper got
> stuck; it's motor would be stalled and so draw a large current (large
> enough that I could see the voltmeter swing significantly down as the
> motor loaded the 12V ssytem beyond the alternator's ability to keep up!).
> After a short time, the voltmeter would pop back to normal and a second or
> two later the cycle would repeat.  This would continue even if the wiper
> was switched back off, as it would continue cycling until I got out an
> jiggled the wire so the motor could return the wiper to the 'park'
> position.
>
> I expect that what was happening is that the large stall current would
> quickly cause a thermal circuit breaker to open, and then afer a second or
> two to cool, the breaker would reset and the cycle would repeat.
>
> Since you are seeing the behaviour only with the key on and not in the acc
> position, I would check the 12V wiring diagram (if you have one) to see
> which items are only powered when the key is on.  Sometimes wipers or the
> heater fan are powered in one position but not the other.
>
>> Another problem (may be related!) is that I get full pack
>> voltage from the battery pack positive to ground at all
>> times. This is a safety issue, as far as I am concerned, but
>> it could cause other problems as well. I can't see anywhere
>> in the pack neg. where it is grounded to the frame, but I
>> suppose it is possible, as I can't see all of the wiring very
>> well (don't have eye extension stalks, or a hoist to put the
>> beast up on!).
>
> My first though would be to disconnect the DC/DC from the traction pack
> entirely to check for a loss of isolation there.
>
> If the vehicle has a ceramic heater, my next thought would be to try
> disconnecting the traction pack from it.  Perhaps there is a connection
> between pack -ve and chassis there, or even some connection to the 12V
> system (heater fan?) that might relate to your other symptoms.
>
> Lastly (or firstly?), try disconnecting the traction system from the motor
> and controller (disconnect whichever lead is not switched by the main
> contactor if there is only one contactor).
>
> Hope this helps,
>
> Roger.
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>
>
>
> --
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.5.516 / Virus Database: 269.20.2/1271 - Release Date: 2/11/2008
> 8:16 AM
>
>

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Re: Strange pulsing in 12V circuits

joe-22
In reply to this post by Doug Weathers
Thanks, Doug, this sounds like it might be a good lead. There is a lot of
stuff on this rig that isn't fused!

Joseph H. Strubhar

Web: www.gremcoinc.com

E-mail: [hidden email]
----- Original Message -----
From: "Doug Weathers" <[hidden email]>
To: "Electric Vehicle Discussion List" <[hidden email]>
Sent: Monday, February 11, 2008 10:26 AM
Subject: Re: [EVDL] Strange pulsing in 12V circuits


> joe wrote:
>
>> When the 12V accessory circuit is powered up, I get a pulsing effect,
>> lights
>> dim, then bright, clicking in the radio speakers even when the radio
>> isn't
>> on, displays flickering, on a frequency of about every second. This
>> happens
>> whether the circuit is powered off just the battery, or off the Vicor
>> DC/DC.
>
> It could definitely be something else, but:
>
> That sounds (to this ignorant non-EE) like a crowbar circuit cycling on
> and off.  Some device somewhere is shorting its 12v input leads in an
> attempt to blow a fuse, in order to shut itself off for safety reasons.
>  This drops the voltage on the 12v bus, causing the momentary brownout.
>  When it opens the short, it causes a spike on the vehicle ground,
> causing the speakers to pop.
>
> Since the fuse isn't blowing, apparently this device isn't fused
> correctly (or at all).
>
> Does it still happen when you pull out all your fuses?
>
> Which fuse stops the behavior?  That will narrow it down to a particular
> circuit.
>
> If *no* fuse stops the behavior, it's evidence for the crowbar scenario.
>
> An ammeter on the 12v system should show heavy current draw during the
> brownout, too.
>
> If it goes on for long enough something may heat up dramatically, which
> should help you find it :)  Or a master fuse will blow if it gets hot
> enough, but the 50% duty cycle might not let it get hot enough.
>
> Of course it might be something else entirely.  The above might be total
> nonsense.  Hopefully someone will correct me if so.
>
> Good luck,
>
> Doug
>
>>
>> Joseph H. Strubhar
>>
>> Web: www.gremcoinc.com
>>
>> E-mail: [hidden email]
> --
> Doug Weathers
> Las Cruces, NM, USA
> http://www.gdunge.com
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>
>
>
> --
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.5.516 / Virus Database: 269.20.2/1271 - Release Date: 2/11/2008
> 8:16 AM
>
>

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Re: Strange pulsing in 12V circuits

Jeff Major
In reply to this post by joe-22

--- joe <[hidden email]> wrote:

> Thanks, Roger - I don't have a diagram to work  off,
> unfortunately. I will
> try to disconnect the DC/DC from the traction pack,
> but I doubt that is it.
> One thing I know is on when the key is in the #1
> postion is the Ahr meter.


Hi Joe,

Some of the old Ahr (or kWhr) meters required a 12v
supply with common negative to the high voltage pack.
To keep the high voltage negative off vehicle ground,
an isolated 12-12 converter is needed.  Suggest you
look at that.  Maybe disconnect the Ahr meter and see
if the ground goes away.

Regards,

Jeff M.


      ____________________________________________________________________________________
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Re: Strange pulsing in 12V circuits

Roger Stockton
In reply to this post by joe-22
joe wrote:

> Thanks, Roger - I don't have a diagram to work  off,
> unfortunately. I will try to disconnect the DC/DC from the
> traction pack, but I doubt that is it.
> One thing I know is on when the key is in the #1 postion is
> the Ahr meter.
>
> As mentioned in the post to Roland, the motor and controller
> are not hooked up yet.

Glad to help.  I've seen from your other responses that the vehicle has a fresh set of blue tops, and a red top for the house battery.  While this isn't related to any of the problems you've mentioned, I'd just like to point out that the red top is not a deep cycle battery and will probably not last long, especially since you refer to a Vicor DC/DC; nothing wrong with Vicors, mind you, they are a quality product, however, most often people use a single module and don't properly heatsink it, nor provide the required supporting circuitry, and as a result they aren't beefy enough to keep up with the house loads unless left running 24/7 (and even then only maybe).

I think Jeff's suggestion about disconnecting the supply to the Ah meter is a good one.  I'd be inclined to work my way up the traction wiring to find the path to chassis instead.  That is, you've already go the motor and controller disconnected, but I presume the traction wiring is intact up to the main contactor?  So, disconnect the -ve cable at the most negative battery terminal and check to see if there is continuity between the cable and chassis; if not then the problem is in the pack wiring somewhere; if so, then onwards and upwards!  Break the circuit on the downstream side of whatever is next (shunt, etc.); as soon as you interrupt the circuit and find that the bit further away from the pack is no longer connected to chassis, then you know that the bit just towards the battery from you is the problem (or is involved).

If you find that the connection to chassis goes away after disconnecting the shunt (traction wire only), have a peek at the shunt to see if it may have been mounted carelessly.  Shunts usually are screwed/bolted to an insulating base, and the insulating base if then mounted to whatever.  If mounted carelessly, there might be contact between one of the mounting bolts and a metal bit of the shunt, or between a metal bit of the shunt and a metal enclosure or the chassis itself.  If you can't see a problem there, there probably isn't one and any connection to chassis is likely via the Ah meter and its sense connections to the shunt.

Good luck,

Roger.

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Re: Strange pulsing in 12V circuits

Cor van de Water
In reply to this post by Jon Glauser
You could try pull all relays (after marking them or
doing it one-by-one) to see if the turn signal relay does this.
I would expect your wiring also to get hot in these cases of a
shorted circuit.
There may actually be a bunch of wire involved:
Say it is a blinker (or the emergency lights) and one of your
taillights has a short to ground, then you'd have 15 to 20 ft
of cable that is shorting the 12V when the blinker is on.
That could cause the situation where the current is too low
to blow a heavy fuse and also not smoke the wire instantly.
Did you measure current draw from 12V?

Success,

Cor van de Water
Systems Architect
Proxim Wireless Corporation http://www.proxim.com
Email: [hidden email]    Private: http://www.cvandewater.com
Skype: cor_van_de_water     IM: [hidden email]
Tel: +1 408 542 5225    VoIP: +31 20 3987567 FWD# 25925
Fax: +1 408 731 3675    eFAX: +31-87-784-1130
Second Life: www.secondlife.com/?u=3b42cb3f4ae249319edb487991c30acb

-----Original Message-----
From: [hidden email] [mailto:[hidden email]] On Behalf Of [hidden email]
Sent: Monday, February 11, 2008 9:37 AM
To: [hidden email]
Subject: Re: [EVDL] Strange pulsing in 12V circuits

as for the pulsing, could it be something like a turn signal? I've seen turn signals dim everything, even in ICE cars (usually with a trailer attached).

There are lots of things that could cause high voltage to show up on the frame. Battery electrolyte was my problem. Then it was a non-isolated E-meter.





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Re: Strange pulsing in 12V circuits

joe-22
Well, Cor, you hit the nail on the head!! It was the blinker, and the switch
was on (blush). I thought I had checked that, but apparently not. Now to
figure out WHY the blinker being on affects the rest of the 12V system (bad
relay, or a shorted wire?).

Thanks to all for your input on this - that's why this list exists!!

Joseph H. Strubhar

Web: www.gremcoinc.com

E-mail: [hidden email]
----- Original Message -----
From: "Cor van de Water" <[hidden email]>
To: "Electric Vehicle Discussion List" <[hidden email]>
Sent: Tuesday, February 12, 2008 2:00 PM
Subject: Re: [EVDL] Strange pulsing in 12V circuits


> You could try pull all relays (after marking them or
> doing it one-by-one) to see if the turn signal relay does this.
> I would expect your wiring also to get hot in these cases of a
> shorted circuit.
> There may actually be a bunch of wire involved:
> Say it is a blinker (or the emergency lights) and one of your
> taillights has a short to ground, then you'd have 15 to 20 ft
> of cable that is shorting the 12V when the blinker is on.
> That could cause the situation where the current is too low
> to blow a heavy fuse and also not smoke the wire instantly.
> Did you measure current draw from 12V?
>
> Success,
>
> Cor van de Water
> Systems Architect
> Proxim Wireless Corporation http://www.proxim.com
> Email: [hidden email]    Private: http://www.cvandewater.com
> Skype: cor_van_de_water     IM: [hidden email]
> Tel: +1 408 542 5225    VoIP: +31 20 3987567 FWD# 25925
> Fax: +1 408 731 3675    eFAX: +31-87-784-1130
> Second Life: www.secondlife.com/?u=3b42cb3f4ae249319edb487991c30acb
>
> -----Original Message-----
> From: [hidden email] [mailto:[hidden email]] On
> Behalf Of [hidden email]
> Sent: Monday, February 11, 2008 9:37 AM
> To: [hidden email]
> Subject: Re: [EVDL] Strange pulsing in 12V circuits
>
> as for the pulsing, could it be something like a turn signal? I've seen
> turn signals dim everything, even in ICE cars (usually with a trailer
> attached).
>
> There are lots of things that could cause high voltage to show up on the
> frame. Battery electrolyte was my problem. Then it was a non-isolated
> E-meter.
>
>
>
>
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
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> _______________________________________________
> For subscription options, see
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>
>
> --
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.5.516 / Virus Database: 269.20.2/1271 - Release Date: 2/11/2008
> 8:16 AM
>
>

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Re: Strange pulsing in 12V circuits

jwolfe@doitnow.com
In reply to this post by joe-22

Subject: Re: [EVDL] Strange pulsing in 12V circuits
To: "Electric Vehicle Discussion List" <[hidden email]>

Well, Cor, you hit the nail on the head!! It was the blinker, and the
switch
was on (blush). I thought I had checked that, but apparently not. Now to
figure out WHY the blinker being on affects the rest of the 12V system (bad
relay, or a shorted wire?).

Don't rule out the lamps themselves. I once had a newer vehicle that
developed that problem and it turned out to be one of the turn signal lamps!

Jim
'93 Dodge TEVan
'88 Fiero ESE
www.evalbum.com/804

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Re: Strange pulsing in 12V circuits

jwolfe@doitnow.com
In reply to this post by joe-22

Subject: Re: [EVDL] Strange pulsing in 12V circuits
To: "Electric Vehicle Discussion List" <[hidden email]>

Well, Cor, you hit the nail on the head!! It was the blinker, and the
switch
was on (blush). I thought I had checked that, but apparently not. Now to
figure out WHY the blinker being on affects the rest of the 12V system (bad
relay, or a shorted wire?).

Don't rule out the lamps themselves. I once had a newer vehicle that
developed that problem and it turned out to be one of the turn signal lamps!

Jim
'93 Dodge TEVan
'88 Fiero ESE
www.evalbum.com/804

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Re: Strange pulsing in 12V circuits

joe-22
Thanks, Jim!

Joseph H. Strubhar

Web: www.gremcoinc.com

E-mail: [hidden email]
----- Original Message -----
From: <[hidden email]>
To: <[hidden email]>
Sent: Wednesday, February 13, 2008 7:13 AM
Subject: Re: [EVDL] Strange pulsing in 12V circuits



Subject: Re: [EVDL] Strange pulsing in 12V circuits
To: "Electric Vehicle Discussion List" <[hidden email]>

Well, Cor, you hit the nail on the head!! It was the blinker, and the
switch
was on (blush). I thought I had checked that, but apparently not. Now to
figure out WHY the blinker being on affects the rest of the 12V system (bad
relay, or a shorted wire?).

Don't rule out the lamps themselves. I once had a newer vehicle that
developed that problem and it turned out to be one of the turn signal lamps!

Jim
'93 Dodge TEVan
'88 Fiero ESE
www.evalbum.com/804

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--
No virus found in this incoming message.
Checked by AVG Free Edition.
Version: 7.5.516 / Virus Database: 269.20.2/1271 - Release Date: 2/11/2008
8:16 AM


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Re: Strange pulsing in 12V circuits

Jon Glauser
In reply to this post by jwolfe@doitnow.com
It is not just an EV problem. I notice many cars on the road whose  
other lights (brake lights, tail lights, etc) dim slightly (barely  
noticeable) when the turn signal flashes or the brake lights come on.

If it's not something obvious such as a faulty lamp/relay or short,  
another possibility is that the lamp is drawing enough current (its  
normal draw) to cause a voltage drop in the mile of wire that goes  
from the battery to the fuse panel, which feeds all the other lamps.

-Jon Glauser


> It was the blinker, and the
> switch was on (blush). I thought I had checked that, but apparently  
> not. Now to
> figure out WHY the blinker being on affects the rest of the 12V system (bad
> relay, or a shorted wire?).
>
> Don't rule out the lamps themselves. I once had a newer vehicle that
> developed that problem and it turned out to be one of the turn signal lamps!
>



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Re: i MiEV

rodhower
Mitsubishi inovative EV,
http://www.autoexpress.co.uk/carreviews/firstdrives/217122/mitsubishi_i_miev.html

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Re: Strange pulsing in 12V circuits

Adrian DeLeon
In reply to this post by joe-22
> It is not just an EV problem. I notice many cars on the road whose
> other lights (brake lights, tail lights, etc) dim slightly (barely
> noticeable) when the turn signal flashes or the brake lights come on.

Ditto to that! Turning on the headlights in my VW causes the 12V meter to  
drop almost 1V! Curiously, turning the heater fan on HI (an even larger  
load) only causes a 0.5V drop. In both cases I still measure a full 13.8V  
at the DC/DC and SLI battery terminals.

On my wife's '05 Accord you can see the headlights dim noticeably if the  
power windows are used.

They're all voltage drops caused by resistance of the miles of wire inside  
the car. Fuses, fusible links, bad connections and corrosion don't help  
much either...

-Adrian

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