# [EVDL] Bridge diode failure



## EVDL List (Jul 27, 2007)

I have been using a boosted bad boy charger for opportunity charging
for 3 years. There are not that many opportunities around here, but I
probably have 30 hours on it.

With an unanticipated trip extension and 10 degree weather, I needed a
boost so I prevailed upon the Stop & Shop manager for some juice.
Around the back at a loading dock they unplugged a light and plugged
in the Suzuki. A loud bang indicated that all was not well. One lead
was blown completely off the diode and lots of soot in the area. Their
fuse didn't blow.

Is this a normal failure mode? Could the low temperature be the
reason? I would expect this kind of failure when plugging in a new
component, but would think an older one would just die.

Anybody else have this happen? Anything I should do differently?

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

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## EVDL List (Jul 27, 2007)

Hello Storm,

There is a distance factor in the circuit wire, plus the resistance of the 
connections and splices. Also, if it's a older type of circuit breaker, it 
may not have the interrupting time factor as a new one.

Example of a demonstration I did shorting out a Square D 20 amp 10,000 AIC 
Circuit breaker on a 120 volt circuit using a No. AWG 12 19 stranded copper 
wire for a run of 20 feet to a 20 amp 120 vac receptacle.

I took a paper clip and bend it, so it would insert it into the receptacle, 
using my bare fingers. The circuit breaker trip so fast, that the paper 
clip did not get warm.

Now changing the circuit breaker to a XXX brand type, and this time, I held 
the paper clip with a 12 inch long nose, with insulated line man cloves and 
face shield and hard hat. This time when I insert the paper clip, the paper 
clip burn red hot in two, which may or may not not trip the circuit breaker.

Also A length of the size of conductor run may not blow the circuit.

Another demonstration I did, was to run out a circuit loop of 4000 feet of 
No. 10 Awg 19 stranded copper wire, and connected one end to the neutral and 
the other end to a 20 amp circuit breaker.

Turning on the breaker, it did not blow. The 4000 feet of No. 10 wire 
dissipated about 18 amps on this test.

Another test we done, is to demonstrate what happens when you run out long 
lengths of extension cords which plug into a receptacle that may have up to 
5 other receptacles on the circuit and some other loads.

The extension cord was 30 feet of No. 18 awg conductor which was plug into a 
20 amp No. 12 awg receptacle circuit that was about 50 feet from the panel, 
but the conduit ran 15 feet up and down the walls to get to the panel.

We put a 16 amp load on this wire, and the connections at the cord ends got 
hot and melted the plastic.

Any time you run over 42 feet for a No. 12 awg 20 amp circuit, this circuit 
should be a No. 10 awg 19 stranded wire. The cord in should be a No. 14 
wire size for 15 amp maximum for a run of 15 feet if you do not want more 
than a 1 percent voltage drop.

A No. 12 wire size should be use for a 20 amp with a maximum run of 20 feet 
for a 1 percent voltage drop. Lets say the voltage at the panel is 120 
volts, and at the receptacle on a No. 10 wire has a 1 percent voltage drop 
or about 118.8 volts. You are allow to run up to 3 percent voltage drop 
using a longer cord, which would be about 115.2 volts.

Some equipment has a service factor where it can run on a over or under 3 
percent voltage drop.

Assuming you had about a 1500 watt load on your charger and the run was 
about 100 feet of different size wires on other type of loads, you could 
have possible have a voltage between 100 to 105 volts.

I have seen circuits as low as 90 volts try to run a 1500 coffee pot that 
was plug in at the end of a line of receptacles more than 75 feet in length.

Roland

----- Original Message ----- 
From: "storm connors" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Tuesday, December 23, 2008 4:55 PM
Subject: [EVDL] Bridge diode failure


> I have been using a boosted bad boy charger for opportunity charging
> for 3 years. There are not that many opportunities around here, but I
> probably have 30 hours on it.
>
> With an unanticipated trip extension and 10 degree weather, I needed a
> boost so I prevailed upon the Stop & Shop manager for some juice.
> Around the back at a loading dock they unplugged a light and plugged
> in the Suzuki. A loud bang indicated that all was not well. One lead
> was blown completely off the diode and lots of soot in the area. Their
> fuse didn't blow.
>
> Is this a normal failure mode? Could the low temperature be the
> reason? I would expect this kind of failure when plugging in a new
> component, but would think an older one would just die.
>
> Anybody else have this happen? Anything I should do differently?
>
> -- 
> http://www.austinev.org/evalbum/1059
> http://stormselectric.blogspot.com/
> Storm
>
> _______________________________________________
> General EVDL support: http://evdl.org/help/
> Usage guidelines: http://evdl.org/help/index.html#conv
> Archives: http://evdl.org/archive/
> Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev
>
> 

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----------



## EVDL List (Jul 27, 2007)

Thanks Roland. I got clever once and set up a 250' coil of #12 wire as
an extension cord. Plugged in my saw and it wouldn't turn- just
hummed. But what does this have to do with my exploding bridge diode?



> Roland Wiench <[email protected]> wrote:
> > Hello Storm,
> >
> > There is a distance factor in the circuit wire, plus the resistance of the
> ...


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## EVDL List (Jul 27, 2007)

It may be that the diode shorted or had a poor connection and causing a high 
resistance plus the resistance of the length of the circuit which absorbed 
all the ampere where the circuit breaker would not trip.

A 250 feet of No 12 power cord will have a voltage drop to about 90 volts. 
And if plug into another circuit with a long run, the voltage drop will be 
more.

Roland


----- Original Message ----- 
From: "storm connors" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Tuesday, December 23, 2008 7:11 PM
Subject: Re: [EVDL] Bridge diode failure


> Thanks Roland. I got clever once and set up a 250' coil of #12 wire as
> an extension cord. Plugged in my saw and it wouldn't turn- just
> hummed. But what does this have to do with my exploding bridge diode?
>
>


> Roland Wiench <[email protected]> wrote:
> > > Hello Storm,
> > >
> > > There is a distance factor in the circuit wire, plus the resistance of
> ...


----------



## EVDL List (Jul 27, 2007)

Storm,

It may be that the circuits you used before had long wires
to the service panel, so there was enough voltage drop to
avoid too high current, while the shop may have had a
short run or higher than your normal voltage level, causing
your bad boy to draw way more than the usual amperage.

There may have been other reasons as well, if your bad boy
allows dialing up a variac it may still have been set to
the high level of the end of last charge and not reset to
the low level you needed to start at,
just guessing here.

Yes - a diode blowing can cause internal short-circuiting
the component due to excessive heating from over-current,
which causes a current high enough to blow a lead off the
component.
If their fuse is 20A then it may take 40A for 1 sec to blow,
which can easily evaporate your diode lead.

Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [email protected]
Tel: +1 408 383 7626 VoIP: +31 20 3987567 FWD# 25925
Tel: +91 (040)23117400 x203 XoIP: +31877841130

Please consider the environment before printing this e-mail.
-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Roland Wiench
Sent: Tuesday, December 23, 2008 6:11 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Bridge diode failure

Hello Storm,

There is a distance factor in the circuit wire, plus the resistance of
the connections and splices. Also, if it's a older type of circuit
breaker, it may not have the interrupting time factor as a new one.

Example of a demonstration I did shorting out a Square D 20 amp 10,000
AIC Circuit breaker on a 120 volt circuit using a No. AWG 12 19 stranded
copper wire for a run of 20 feet to a 20 amp 120 vac receptacle.

I took a paper clip and bend it, so it would insert it into the
receptacle, using my bare fingers. The circuit breaker trip so fast,
that the paper clip did not get warm.

Now changing the circuit breaker to a XXX brand type, and this time, I
held the paper clip with a 12 inch long nose, with insulated line man
cloves and face shield and hard hat. This time when I insert the paper
clip, the paper clip burn red hot in two, which may or may not not trip
the circuit breaker.

Also A length of the size of conductor run may not blow the circuit.

Another demonstration I did, was to run out a circuit loop of 4000 feet
of No. 10 Awg 19 stranded copper wire, and connected one end to the
neutral and the other end to a 20 amp circuit breaker.

Turning on the breaker, it did not blow. The 4000 feet of No. 10 wire
dissipated about 18 amps on this test.

Another test we done, is to demonstrate what happens when you run out
long lengths of extension cords which plug into a receptacle that may
have up to
5 other receptacles on the circuit and some other loads.

The extension cord was 30 feet of No. 18 awg conductor which was plug
into a 20 amp No. 12 awg receptacle circuit that was about 50 feet from
the panel, but the conduit ran 15 feet up and down the walls to get to
the panel.

We put a 16 amp load on this wire, and the connections at the cord ends
got hot and melted the plastic.

Any time you run over 42 feet for a No. 12 awg 20 amp circuit, this
circuit 
should be a No. 10 awg 19 stranded wire. The cord in should be a No.
14 
wire size for 15 amp maximum for a run of 15 feet if you do not want
more than a 1 percent voltage drop.

A No. 12 wire size should be use for a 20 amp with a maximum run of 20
feet for a 1 percent voltage drop. Lets say the voltage at the panel is
120 volts, and at the receptacle on a No. 10 wire has a 1 percent
voltage drop or about 118.8 volts. You are allow to run up to 3 percent
voltage drop using a longer cord, which would be about 115.2 volts.

Some equipment has a service factor where it can run on a over or under
3 percent voltage drop.

Assuming you had about a 1500 watt load on your charger and the run was
about 100 feet of different size wires on other type of loads, you could
have possible have a voltage between 100 to 105 volts.

I have seen circuits as low as 90 volts try to run a 1500 coffee pot
that was plug in at the end of a line of receptacles more than 75 feet
in length.

Roland

----- Original Message -----
From: "storm connors" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Tuesday, December 23, 2008 4:55 PM
Subject: [EVDL] Bridge diode failure


> I have been using a boosted bad boy charger for opportunity charging
> for 3 years. There are not that many opportunities around here, but I
> probably have 30 hours on it.
>
> With an unanticipated trip extension and 10 degree weather, I needed a
> boost so I prevailed upon the Stop & Shop manager for some juice.
> Around the back at a loading dock they unplugged a light and plugged
> in the Suzuki. A loud bang indicated that all was not well. One lead
> was blown completely off the diode and lots of soot in the area. Their
> fuse didn't blow.
>
> Is this a normal failure mode? Could the low temperature be the
> reason? I would expect this kind of failure when plugging in a new
> component, but would think an older one would just die.
>
> Anybody else have this happen? Anything I should do differently?
>
> -- 
> http://www.austinev.org/evalbum/1059
> http://stormselectric.blogspot.com/
> Storm
>
> _______________________________________________
> General EVDL support: http://evdl.org/help/
> Usage guidelines: http://evdl.org/help/index.html#conv
> Archives: http://evdl.org/archive/
> Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev
>
> 

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Usage guidelines: http://evdl.org/help/index.html#conv
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## EVDL List (Jul 27, 2007)

What amp bridge?
I would guess this is the lowest you let the pack get before using the 
oppertunity charger and
the voltage drop of the cord combined with the lower pack voltage 
caused the amperage to exceed the diodes rating.

It seems even 2:1 safety factor is insufficient for bridge rectifiers, I 
think it is the packaging not allowing the cooling and very optomistic 
specs.
> I have been using a boosted bad boy charger for opportunity charging
> for 3 years. There are not that many opportunities around here, but I
> probably have 30 hours on it.
>
> With an unanticipated trip extension and 10 degree weather, I needed a
> boost so I prevailed upon the Stop & Shop manager for some juice.
> Around the back at a loading dock they unplugged a light and plugged
> in the Suzuki. A loud bang indicated that all was not well. One lead
> was blown completely off the diode and lots of soot in the area. Their
> fuse didn't blow.
>
> Is this a normal failure mode? Could the low temperature be the
> reason? I would expect this kind of failure when plugging in a new
> component, but would think an older one would just die.
>
> Anybody else have this happen? Anything I should do differently?
>
> -- http://www.austinev.org/evalbum/1059 
> http://stormselectric.blogspot.com/ Storm

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Usage guidelines: http://evdl.org/help/index.html#conv
Archives: http://evdl.org/archive/
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----------



## EVDL List (Jul 27, 2007)

You have suffered a typical bridge rectifier failure. A diode in the bridge 
suffers a short circuit. This provide a low resistance path across the 
battery pack and a large pulse of battery current explodes the shorted diode 
which disappears with a loud bang and a puff of smoke. 

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## EVDL List (Jul 27, 2007)

> storm connors wrote:
> > I prevailed upon the Stop & Shop manager for some juice. ...A loud
> > bang indicated that all was not well. One lead was blown completely
> > off the diode and lots of soot in the area. Their fuse didn't blow.
> ...


----------



## EVDL List (Jul 27, 2007)

> Lee Hart wrote:
> > storm connors wrote:
> > > I prevailed upon the Stop & Shop manager for some juice.
> ...A loud
> ...


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