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Re: [EVDL] Modified K&W BC-20 questions

Hello Hunter,

I had the same problem with wiring diagrams back in 1976 for my EV
controller and battery charger which was made by Cableform in Great Britain.
The drawings are a mix of block diagrams, schematics and wiring diagrams
with terms like valves for the solid state devices and symbols that are not
standard.

All the components were sandwich between two large heat sinks and could not
tell what values they was or how the internal components was connected
together, which only show up as block diagrams.

The components in this proto type EV was assemble in a bread board
installation. It was a test bed of componets, circuits and wirings that was
constantly changing during test runs.

The wiring of the components were not up to my standards, which I was use to
industrial wiring, where components are not connected directly to each
other, but to a industrial terminal strip or power blocks are track mounted
on DIM tracks that also houses terminal blocks for a number 22 to a 4/0 gage
wire. On this type of mounting track, I also have small contactors, plug in
relay sockets, fuse holders with blown fuse indications, and any type of
track mount sensor device.

Using this type of track mounting devices, a wiring modification is simple
to do, by just re-cross connecting between two sets of terminal block
sections.

So after about 10 years of running this EV, I removed every component from
this car, and had everything replace, except for the sheet metal body and
frame and turn it back into a original concurs 1975 Chevy Chevelle which is
still store today.

At that time, I completely broke down the controller to separate components
and made my own schematic which also show all the values and manufacture
numbers on the controller and battery charger.

I was able to get a complete set of replacements and spare components parts
from NTE which has a local distributor here. Back in 1985, a complete spare
parts kit cost $3500.00 from Cableform which was about four times the cost
over the NTE components.

I then transfer the GE 11 motor, controller and battery charger into a
sister car, a 1977 El Camino that had the same body panels from the doors to
the front end as the 1975 Chevelle, so the conversion was simple to make.

The EV ran from 1986 to 2002 which I did the next mod. Replace the
Cableform controller with a Zilla 1k which fit exactly in the same chassis
plate that the existing controller sat on.

Replace the Cableform SCR 50 amp charger with a PFC-50 that also fit in the
fiberglass compartment that is isolated from the body of the EV. Rich Rudman
was worry that this charger in a close compartment would get to hot. Not to
worry, the charger rises out of this compartment on air struts with the air
exhaust pointed up ward, and cool air is pipe in using a filter 6 inch
filter blower.

In the original EV, I did not like having the battery charger, contactors
and electrical arc making devices in the same atmosphere as the the
batteries. So each section is in its own non-conductive isolated
compartments.

To see if your batteries are isolated from the frame while charging, take a
voltage reading from any one battery to the body to see if there is any
voltage leakage. It is normal with any venting type batteries, you will get
a conductive surface even across a plastic surface.

When the voltage leakage build up to about 48 volts, it then time to clean
the batteries, even though they look super clean.

Roland


----- Original Message -----
From: "Hunter Cook" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Tuesday, October 02, 2007 5:17 PM
Subject: Re: [EVDL] Modified K&W BC-20 questions


> I've now examined things further, and also found some schematics and
> manuals the original owner included that I had missed. I now have a much
> better understanding of what's going on here.
>
> The Signal Transformer MPI-900-40 is doing just what I thought, and the
> BC-20 has a 107k resistor. There was also a 118k resistor in a ziplock,
> for 144v use, as well as the original card full of resistors to set it
> from 48-120.
>
> So my original thought that it has been bootstrapped for 144v seems
> about right. What's more interesting to me is that the schematic that
> shows the charger setup for 132/144v (well, and the rest of them for
> that matter) is on KTA Services letterhead. Dated 12/96. So this
> somewhat out-of-spec BC-20 installation wasn't just the maveric idea of
> the prior owner of this truck...it came to him from some reputable folks
> in the industry who've been around a while and seen some things. That
> makes me feel quite a bit better about the setup.
>
> Anyway, it's probably clear from my last post that I didn't get some of
> what you were saying, Roland. But now from the schematics I see what you
> are talking about with regard to the two 120v inputs going in parallel
> for 120v output or series for 220...it's wired through this little strip
> and hard to see that it's going two places. But definitely for 120v.
> Similarly, now I see what you mean with the output options; there's an
> adjacent diagram of a 114-120v system and the only difference is the
> secondary wiring is parallel.
>
> Of course, this leaves me wondering a bit why I can't get the batteries
> above about 140v. I guess the batteries are just that bad? I'm thinking
> about getting a 6v or 12v charger and just pulling a few off to see if
> they'll take anything under more civilized conditions. After all, I need
> to do some rewiring before I can charge the whole pack again...
>
> Thanks
>
> Hunter
>
>
>
Hunter Cook wrote:
> > Roland,
> >
> > As always, thanks for all the info. Not sure I grok all of what you're
> > saying, but I think I'm getting most of it. I don't think we're talking
> > about quite the same setup...it looks like in this truck there is only
> > the one transformer doing what you describe a pair doing in the boost
> > circuit. Note that I'm describing the way it came to me wired up (as
> > opposed to something I'm considering wiring up). My assumption is that
> > he did it this way because he wanted the charge to handle a
> > higher-voltage pack. It's just one transformer with a single 120v
> > primary and two 20v secondaries. The 120v from the wall comes into a
> > terminal strip and goes to both the transformer and the BC-20. Then the
> > two primaries are series run to provide 40v to the BC-20 on the boost
> > circuit inputs, which are expecting 20v from the LB-20 boost module.
> >
> > So, in other words, it's getting twice as much from its boost circuit as
> > the designers intended, which I assume means it needs a resistor
> > different from the one for 120v that the manual specs. I'm not sure what
> > it would need to be...all the voltages seem to have resistors about 4-6k
> > apart, except the last one (the jump to 120 with the boost unit) is 11k.
> > I guess given that it's a 12v increase and the rest are 6, that makes
> > sense and the 144v resistor would be about 22k higher, but that's just
> > my simple-arithmetic approach to the problem...not any real electrical
> > theory going on over here. I'll look inside and find out what resistor
> > is actually in there soon.
> >
> > Meanwhile, if any of you Zivan owners has seen the light in that other
> > thread and want to upgrade to one of these fancy Brusa units, let me
> > know ;-)
> >
> > Thanks again Roland.
> >
> > Hunter
> >
> >
> >
> > On Tue, 2007-10-02 at 09:53 -0600, Roland Wiench wrote:
> > > Hello Hunter,
> > >
> > > The series connections in the primaries of several transformers is
> > > corrected
> > > for connecting to a higher input AC voltage, or increasing the out
> > > voltage
> > > on the total sum of the windings which will increase the secondary
> > > voltage.
> > >
> > > For example:
> > >
> > > Lets say you have two transformers that have a 120 volt primary with
> > > leads
> > > mark L1 and L2 and a 120 volt secondary leads mark T1 and T2. This is
> > > normally a 1:1 ratio transformer.
> > >
> > > The normal way to connect to this transformer is to supply 120 vac to
> > > the
> > > primaries to each transformer, which parallels the primary leads L1 to
> > > L1
> > > and L2 to L2.
> > >
> > > The secondary of each transformer will have a output of 120 volts.
> > >
> > > Now is we series the primaries of the transformers by connecting one
> > > leg of
> > > the 240 volt input to L1 and connect L2 of the first transformer to L1
> > > of
> > > the second transformer and the second leg of the 240 volt input to L2
> > > of the
> > > second transformer, you will still get 120 volts out each transformer
> > > secondary.
> > >
> > > If we connect the secondary of each transformer in series like we did
> > > with
> > > the primary, you can also get 240 vac out or can get 120/240 volt out
> > > if you
> > > center tap the secondary series connections that go between the two
> > > connections.
> > >
> > > Another way to connect the 120 vac input power to two transformers
> > > that
> > > primaries are series together, is to connect 120 volts to the first
> > > transformer primary L1 and L2. Connect the first transformer L2 to
> > > the
> > > second transformer L1 and no connection to the second transformer L2.
> > >
> > > You can apply the 120 vac power to the primary of the first
> > > transformer and
> > > using a volt meter, you will read 240 volts between the leads of the
> > > L1 of
> > > the first transformer and the L2 lead with no connection in the
> > > primary of
> > > the second transformer.
> > >
> > > This is what is call a boast circuit or some transformers call a
> > > potential
> > > transformers which have several taps in the primary.
> > >
> > > So the series connections you have for the 108 v battery pack should
> > > increase for a 120 v battery pack.
> > >
> > > Also check to see if you have the correct resistor for the 120 v
> > > battery
> > > pack as listed on page 7 of the manual.
> > >
> > > Tightening all the wire connections and inspecting the wire for crack
> > > insulation and etc, should be ok to fire it up or give it a smoke
> > > test.
> > >
> > > Using Uve's EV calculations, a 120 v battery psck of T-145's should
> > > give you
> > > a range of 66 miles at 10%D0D, or 33 miles at 50%. A pack of T-105's
> > > would
> > > be at about 15 miles 50%D)D at a speed of 60 mph with a vehicle weight
> > > of
> > > 4260 to 4460 lbs.
> > >
> > > Roland
> > >
> > >
> > > ----- Original Message -----
> > > From: "Hunter Cook" <[email protected]>
> > > To: "Electric Vehicle Discussion List" <[email protected]>
> > > Sent: Tuesday, October 02, 2007 8:18 AM
> > > Subject: [EVDL] Modified K&W BC-20 questions
> > >
> > >
> > > > Hello again,
> > > >
> > > > Some of you may recall that I've got an old K&W BC-20 charger trying
> > > > to
> > > > charge a 132v (used to be 144v) pack, which should not (and in my
> > > > observation, does not) work very well. Some very knowledgeable folks
> > > > have said it's good only to 108v, or 120 with the LB-20 booster. So
> > > > far
> > > > this has all sounded very reasonable, as in my experience the
> > > > charger
> > > > will only bring the pack up to about 140-145v.
> > > >
> > > > This morning I really got in and looked at the way things were wired
> > > > up
> > > > for the first time. It appears that it is wired with a larger
> > > > transformer in an LB-20-style boosting role.
> > > >
> > > > Specifically, there is a Signal Transformer model MPI-900-40 wired
> > > > up
> > > > exactly the way the BC-20 manual shows an LB-20, except that the MPI
> > > > is
> > > > using 2 20v outputs together in series rather than just the one 20v
> > > > output of the LB-20. Here's the pdf of the manual, which has a good
> > > > diagram of it: http://evdl.org/docs/bc-20.pdf
> > > >
> > > > I also found a loose connection from the plug to the MPI. Complete
> > > > with
> > > > burn marks. Awesome. This may be related to the truck flipping the
> > > > breaker this morning when I plugged it in, which is what prompted me
> > > > to
> > > > take a more serious look at where the wires were going.
> > > >
> > > > So...this brings me to a few questions:
> > > >
> > > > 1. Should this transformer + K&W setup work for a pack of my size?
> > > > It
> > > > seems logical enough I suppose, assuming he also changed out the
> > > > internal resistor (haven't had a chance to check, and not sure what
> > > > the
> > > > value should be as the target voltage is higher than the table goes
> > > > in
> > > > the manual) and assuming the other components in the BC-20 can take
> > > > the
> > > > extra voltage. Since the vehicle is pretty old, I guess they can.
> > > >
> > > > 2. How bad is it that I've got minor burns on my input terminal
> > > > strip
> > > > for the transformer? I tightened up the connection and it works
> > > > again,
> > > > though I didn't try for long.
> > > >
> > > > 3. Is this dangerous?
> > > >
> > > > I'm still in the market for a new charger, no doubt about that. But
> > > > I
> > > > hope I can still keep limping around on this one for a minute. I do
> > > > need
> > > > to move the truck about 6 miles this week (from my old house to my
> > > > new
> > > > one) which believe it or not will probably require a charge in the
> > > > middle. I'm not really equipped to tow it.
> > > >
> > > > Thanks again for all the help everybody's been giving me.
> > > >
> > > > Hunter
> > > >
> > > > _______________________________________________
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> > > >
> > >
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> >
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>
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