Since I am swapping around complete Dolphin systems for testing, it made it very
easy to reach down and pull out a water pump brush. Was I surprised. The brush
still had about 85% of it’s length left after over 10k miles were put on it. The
originals only lasted a total of 10500 miles! What an improvement! If you look
at my photo album there are pics, descriptions and part numbers of the brushes I
bought and mdified for my water pump. They were only around $15 or something
compared to the $75+ factory brushes.

I thought for sure I’d be replacing them again. Some day I’ll pull the motor out
to check the commutator for wear since these are obviously harder brushes. Rough
math shows they will last about 60-70k miles.

Seriously. It’s freakin’ solved after 4 years of research….

One of the boards that arrived for repair last week, was by far the worst I’ve
ever seen for dropouts, and it flashed the fault indicator in a very radical
fashion. It is now perfectly drivable!! No dropouts under acceleration or regen!
I was in total disbelief!! It works? Must be a mistake!! So I grabbed the second
board in for repair. Dropped out every 15-20 seconds. Made the same
modifications to it. Now it’s smooth as glass too! Zero dropouts under
acceleration or regen!! I had a third board laying around for years who’s only
crime was having massive repetitive dropouts. The modifications completely
stopped all traces of dropouts on it too. All 3 of these boards drive perfectly
now! Am I dreaming!!?? Feels like the Twilight Zone around here!!

Three boards saved from the junk pile. I have seen many more just like them.
That feels so good!! Many owners have this problem right now.

The Dolphin hardware has component values that are just barely within spec. With
miles of driving, time, and thermal cycles, the hardware goes out of spec, and
the Dolphin starts faulting, usually without any faults shown in Dolcom/Dol7.
I’ve posted this in the past. But the faults are felt as a sudden shudder in the
drive train. An instant loss and then instant return of power lasting only a
split second. It can rattle your fillings loose!! Some do it rapid fire, one
dropout after another. It’s all the same problem with the hardware going out of
spec. I found the faulty hardware!! Finally!!

During this research, I found an old quality control document from USE. It was a
long list of things that needed to be checked on their test fixture after each
board was assembled. The items on that list were very telling. So I have figured
out the procedure for checking most of the items on that list on my test
fixture. This ensures that the board gets thoroughly checked. I use it on every
board, just like the factory did.

Since it’s still very cold over most of the country, now is the best time to
have the offending boards with dropout issues repaired. The cold always makes
the dropouts worse. It’s the best season to ensure that the boards work in the
worst conditions of the year. Dropouts are less common in the warm months.

Send me your board and I’ll make the classic dropout modification and put your
board through the checkout list on my test fixture for $50 + shipping. Pack your
board very carefully, like it was your first born baby.

Mike

Working hard on Analog Lithium BMS board.
– Using Toner Transfer process.
– Print reverse image on a LASER writer only.
– Iron or laminate to copper.
– Etch in Ferric Chloride.
– Drill holes
– Test
– Next version could have an Atmel processor.
– Pulsarprofx.com for Toner Transfer details.
– Trying out GBC H310 Laminator

Bought 30 more A123 Lithium cells
– Hand tested each one.
– They are used cells.
– Most tested at 95% capacity with a 35 amp load.
– Will retest at 5 amps to see what cut Peukert takes.
– Rotordesign.com/blog

HexaYurt Building
– Goal to have it half done by Monday or I quit building it and get a tent!
– Canvas K-Hinge makes for attaching all roof and wall panels together so tape is not needed.
– All panels are hinged to each other with canvas K-Hinge.
– Unit folds out in one continuous piece.
– between some panels a #10 zipper is sewn in so the joint won’t fold.
– Need some form of cooling.
– Spray bottle has been claimed to work inside Yurt for cooling.
– Rotordesign.com/bm

Purchased 8 Dolphin boards.
– Two needed repair.

Saturday Aug 29th, 2009 EAA Rally.

Move the SJEAA website!!!!

I finished testing all 30 of the used A123 cells. They were all about 2.18ah with a 35 amp load. I’ll retest a few of the cells at 10 amps to see how much of a cut Peukert is taking. The fan was helpful in cooling the cells down. As the cells warmed up the voltage would noticeably rise on each cell.

Here is the A123 cell charging fixture without any cells loaded.

Here is how I was discharging each A123 cell at 35 amps. That blue plastic clamp made this mundane testing go by more quickly.

Here is a charging fixture that I made today to charge 10 A123 cells at the same time. I machined slots into the wood to keep the copper plates from rotating. There is also a 1/2 inch wide slot under each cell to hold them in place. The power supply is set to 3.70v. Each cell can reach its finishing voltage separately from the others due to a one ohm resistor feeding each cell. The other important thing the resistors allow is that a drained cell can be put into the fixture next to a fully charged one. The charging takes a little longer with the resistors, but it gets them all fully charged equally. Then I can load test them one at a time to see what their capacity really is with a 50 amp load. There are currently 30 cells awaiting testing. A group of 10 cells in parallel will eventually find its way into a module that will replace a nicad cell in the #1 truck. A complete pack will only take up the driver’s side half of the battery box. The trick will be to make a BMS board that will fit on top of the closely spaced cell posts like the nicads have.

Here are a couple of links for Thundersky cell load tests. 1, 2 .

The board layout for the 160ah Thundersky/Sky Energy lithium cell BMS is finished. I’d like to scale it down to also fit the 90-100ah cells, but that takes another board layout session since the 160ah cells are so large compared to the 90-100ah cells. For now getting the thermal paths, thermal cycling, and basic operation tested is a higher priority. Making a board that will fit both the 90-100ah and 160ah cells would be the next task. At this point it’s setup to bypass 3 amps. 5+ amps is possible.

The BMS will control the charger output as well as the motor control if any of the set points are hit. I’ll get the BMS to Dolphin interface board going as well.

Here is a paper doll of the 160 ah Thundersky BMS board that I’m developing. Someday I’ll fab a board using the Toner Transfer process. Always a helpful process before paying for a batch.

I ordered 30 used A123 cells this morning. Should be here in a week. I’ve sketched up a diagram of how I can charge so many cells at the same time. I think strapping the whole thing to a 2×4 will work nicely. From the testing I did on Ray’s pack of A123’s, I think they will work great for the scooter and hopefully for the truck. This could be CNC’d and then a lid screwed on. The posts are close together. I don’t know how I’ll get a BMS board across those posts.

Here is a concept sketch of how the A123 module will duplicate the volume of a flooded nicad.

Here is an idea Mike Swift gave me for housing 10 parallel A123 cells in a similar shape to how the nicads are made. It’s tough to see all of the detail on the back of this receipt.

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