Truck #1 (Nicad)


Now the bed is finally hinged!! Also found the last two bed bolts
holding the thing down. I’m slowly working the bed upwards so I can
get the gas struts installed. I’ve got it up about 12″ now. That
toolbox seems a bit heavy.

Here are the new hinges pics for the #2 truck.

This Heim joint system not only tilts the bed, it moves the bed rearward away from the cab to keep the bed from hitting the cab.

This Heim joint system not only tilts the bed, it moves the bed rearward away from the cab to keep the bed from hitting the cab.

Here is my #1 trucks hinge system.

Here is my #1 truck's hinge system.

My experience with finding ground faults using the voltage method with
a dvm was 100% until this week.

I modified my usual debug pattern and found the ground fault. With the
pack completely assembled, measuring along until I found the fake
ground fault, I would take out one battery connector. Then the ground
fault would go away. Then I’d put back that first connector and take
out another one about 20 cells away. So only one connector was removed
at a time. Removing multiple connectors does not work as I discovered
a long time ago. After a while the real ground fault was at hand. But
only because there was a single break in the pack right before the
real ground fault.

The culprit may have been of my own doing. When I pulled that bad cell
out, there was a major puddle of KOH on the box floor. I had to take
out about 12 cells to clean it all up. And in doing so found an old
dried up koh path that needed attention just to be thorough. Something
like 40 cells were pulled today, wiped off with diluted vinegar and
had the tops brushed off.

Earlier in the week when I had to remove the 27 bluetops for what
appeared to be a ground fault, I must have over stressed a cell, as it
was cracked down the corner for about an inch and had been recently
toped off with water. So it drained alot of electrolyte into the
battery box. As it turns out I must have been careless as there were
two other cells with cracks on the top that I had to leave out. So the
pack is running with 3 less cells.

Man, I have had the ground fault from hell. Sunday there was rain and
the pack was fine. I went through the pack expecting for it to be time
for a full watering. The charger setup has worked great at not boiling
off water very fast. But Monday morning the truck faulted. I put the
fan over the pack to dry it out. This has worked well before, but not
this time. It helped, but not enough.

So Monday, Tuesday, and Wednesday I worked each night hunting down and
killing ground faults. There was a sizable one regarding the 27
bluetop nicads on the drivers side of the pack that I fixed on Monday.
They had lots of KOH on each of their sides. Cleaning them up took
care of that ground fault and allowed the truck to run. Software
showed a bit of ground fault still left, but good enough for now. When
Monday morning rolled around, the truck faulted again. So I took the
10mpg wagon to work. I traced the ground fault to another area. These
were greentops and were nearly clean and in the end didn’t change
anything for all of that work. Still faulting.

The pattern of finding and cleaning up ground faults has not produced
a running truck yet. Bummer. So far I’ve put $125 in gas in the wagon
for the past month in just two tanks. That’s a year’s worth of
electricity at work. They charge me $10/month.

The hard part is that the ground faults seem to move around the pack.
I’ve seen this before. It usually means the ground fault encompasses
many cells. But this time it seems to imply a huge portion of the pack
is ground faulting. So tonight after eating, I think I’ll just watch
the tube and whine since I’m so tired.

The worst part is that the rain has stopped and it’s sunny with blue
sky’s and I’m stuck with a gas hog. This weekend I’m going hunting
with a big gun and am going to kill me a wild ground fault or two….

Here are the 5 Prius packs in my truck. They are wired in parallel. The pack impedance is so low that the rear tires can break loose during heavy regen. Each pack was good for about 1.0kwh. So the pack was good for about 5kwh’s total. Nominal pack voltage was 273 volts. The charger’s software was tweaked to account for this. The dolphin charged the packs fine.

Here is a scope shot of the precharge circuit current level during charging of the system capacitors.

Here is a scope shot of the precharge circuit current level during charging of the system capacitors.

Here are tons of scope shots that I took of the various parts of the Dolphin electronics.

The solid state vacuum switch went in the truck tonight. It worked just like it did on the bench. I'm glad. Took 4 days from concept to completion. Maybe that $12 for shipping from EV parts isn't that steep
after all.

The solid state vacuum switch went in the truck tonight. It worked just like it did on the bench. I'm glad. Took 4 days from concept to
completion. Maybe that $12 for shipping from EV parts isn't that steep after all.

I took this whole week off just to work on the truck. I hope I can get
to the rest of the to do list.

Vacuum circuit build
Ground faults cleaned up
Helicoil remaining battery box holes
Transmission fluid change to Mobile1 0W-20
Adjust specific gravity in blue top cells
Replace radio. It pulls 1/4 amp when off
Fan mounting and lid machining
Bypass transformer. ($50 for just the connectors, hmmm)

I ordered some leds and swapped out the ones for the 3 dash indicators
our trucks have. They worked ok, but were very dim in the daylight. So
tonight I installed a set of brighter ones. Neither set was an exact
fit. They had to soldered in. As it turns out there is a wiring
harness that USE installed to make the stock Chevy dash work with the
Dolphin. So soldering to the flex circuit board is ok. Now they are
very bright, at least in my garage. Tomorrow I’ll see how they do in
daylight. The other reason for opening up the dash was because I
forgot to plug the antenna back into the radio a couple of weekends ago.

test

The top pair are the original brushes with 10500 miles on them. The lower replacement pair are the 65705K27 brushes from McMaster.

test

The upper parts are the old brushes and the left over springs from the McMaster brushes. The bottom pair is the modified and finished pair of brushes. The carbon part of the brush needed to be shortened to .500

The buzzing is from the H-bridge that powers the IGBT’s. Half of the
fets are not getting a gate signal. The driver is not getting one of
it’s two gate signals. So I spent alot of time trying to buzz out the
board to find the pwm source for the H-bridge but could not. Anyone?

I’m glad I have a functional board now for reference. I can complete
my test fixture in minute detail. I’d like to duplicate the truck on
my bench so I can more completely test and characterize the board.
I’ve learned from rebuilding motor controls that just because
something spins a motor does not ensure that the various voltages and
pwm signals are at their nominal values. I’ve seen that a few times.
So I have a list of “test points” on my customers hardware that I go
thru and make sure are meeting spec. This took some time to figure
out. Our Dolphin boards need the same thing. I noticed that the pwm
firing the 300v supply chopper fet was 12v on one board and 10v on
another. Something is up. The board functions fine, but it strikes me
as trouble waiting to happen. A detailed test fixture makes looking at
these things much more thorough, accurate and repeatable, because
sometimes the tech gets tired 😉

Now where’s my celebration beer?

Here is the bridge board that helped save my Dolphin tonight!!

http://www.rotordesign.com/s10/fusepcbproto.jpg

My Dolphin Main board is now officially working!! I figured out how to
rework the bridge circuitry with minimum trauma to the Dolphin PCB.
Now the bridge is located on the new prototype fuse board as seen in
the above link.

Can there even be better news? So I turn on the ignition key and
everything boots up. Stable and fine. So I decide to try plugging into
120vac for some charging. Everything boots up again and then
pppppffffssstttttttkkkkkssstt!!……pppppffffssstttttttkkkkkssstt!!

What was that? So After the 3rd verification that something was wrong
I turned off all of the lights and fired her up in pitch darkness. Ya
know how polished the aluminum Dolphin case is on the inside? It was
acting like a mirror and reflecting back to me some high frequency,
low amperage intermittent arcing from under the charger!!

So I guess the charger needs to come out. I’m wondering if this was
the demon that trashed my main board! I’ll find out soon.

Feeling like I’ve conquered a small army of gremlins, I tried to fire
up another board that had the same sort of damage. The board is
buzzing back at me when power is applied on the bench. All 4 of the
regulators and the chopper fet are working fine. The pwm to the
chopper fet is clean and pretty. Not sure where the buzzing is coming
from but it’s keeping the board from talking to the laptop.

I’m not much of a drinker and it’s time for a beer!

1 down, 3 to go.

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