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Discussion Starter #1
Some may recall I was reading almost full pack voltage between my traction
pack + and the chassis. I discovered that this phenomenon went away when I
turned the key on. I had installed a relay to protect the precharge circuit
of the Raptor from charging voltage. By removing this relay and leaving the
precharge connected just through the 60 watt current limiting light bulb,
there is no voltage between pack + and ground.

So, I solved the problem, but have no idea why this should be true.

Now I have another related problem.

I have an old transformer based charger in my garage that I use for charging
the batteries. I also have a transformer boosted "bad boy" for an on board
charger. To insure a modicum of safety, I included a GFI into the source for
the on board charger. A secondary use of the on board charger is to increase
the charging rate since I can plug it into a different circuit and run both
chargers at the same time. I have done this a number of times in the past
and it works fine.

Today, I plugged in the bad boy and the GFI immediately blew. I turned off
the big charger and the bad boy worked fine. When I unplugged the green
plug on the Raptor controller, the two chargers worked just fine together.

The pack under charge is at 167v and there is now 108.8v from the pack+ to
the chassis with the green plug removed. This is also strange since there
used to be almost 167.

I'm befuddled.



--
http://www.austinev.org/evalbum/1059
http://stormselectric.blogspot.com/
Storm
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70 Posts
Discussion Starter #2
Hello Storm,

What is happening that when you connect two power sources in parallel to a
load, both circuits in each unit must be circuit balance, and if not
balance, the GFI will open.

For example, in a 120 volt GFIC receptacle, the hot (L1) may have 10 amps
and for a balance circuit, the white (N) should have about 10 amps on it.
If there is a set amount of difference, then it will open the GFI. It does
not have to be a short, a GFIC recepticle will even work without a ground,
you just cannot test it.

Now when you add a second parallel line, and the circuit that the GFIC is on
has a higher resistance than the other one, which may be cause by the plug
connections or a electrical set screw not as tight as the other, then more
current take the path of least resistance and cause the GFI to trip.

That's remind me, I should polish the contacts of the input plug, because
there is a higher resistance causing a temperature rise in the contacts.

It can also be that you may have a leaking conductive path from a battery to
the ground frame of the EV, which will trip the GFI circuit. Connect one
lead of a volt meter from one of the battery terminals and the other lead to
the EV chassis. Then spray the top of the batteries with Windex with
ammonia, which I use as a acid neutralizer, to see if this reduces the
voltage.

Another path to ground is from one of the battery leads that may go right
through a controller and to a DC brush type motor. The motor terminals
resistance to ground may read over 20 meg ohms when new, but as time goes
on, this can reduce to 10 k ohms which is cause by the conductive path of
the brush dust. I normally clean the motor when it reaches 30 to 50 k ohm.

Roland


----- Original Message -----
From: "storm connors" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Wednesday, October 31, 2007 9:21 AM
Subject: [EVDL] Ground leak- solved- Raptor at root


> Some may recall I was reading almost full pack voltage between my traction
> pack + and the chassis. I discovered that this phenomenon went away when I
> turned the key on. I had installed a relay to protect the precharge
> circuit
> of the Raptor from charging voltage. By removing this relay and leaving
> the
> precharge connected just through the 60 watt current limiting light bulb,
> there is no voltage between pack + and ground.
>
> So, I solved the problem, but have no idea why this should be true.
>
> Now I have another related problem.
>
> I have an old transformer based charger in my garage that I use for
> charging
> the batteries. I also have a transformer boosted "bad boy" for an on board
> charger. To insure a modicum of safety, I included a GFI into the source
> for
> the on board charger. A secondary use of the on board charger is to
> increase
> the charging rate since I can plug it into a different circuit and run
> both
> chargers at the same time. I have done this a number of times in the past
> and it works fine.
>
> Today, I plugged in the bad boy and the GFI immediately blew. I turned off
> the big charger and the bad boy worked fine. When I unplugged the green
> plug on the Raptor controller, the two chargers worked just fine together.
>
> The pack under charge is at 167v and there is now 108.8v from the pack+ to
> the chassis with the green plug removed. This is also strange since there
> used to be almost 167.
>
> I'm befuddled.
>
>
>
> --
> http://www.austinev.org/evalbum/1059
> http://stormselectric.blogspot.com/
> Storm
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>

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