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

Roland Wiench wrote:
> 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
> >
> >
> > On Tue, 2007-10-02 at 14:47 -0500, 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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