1994 US Electricar Repair Blog by Mike

Ooops. Overshot a bit. Hit 107.00kw today.

Pavement dried out. The acceleration is stretching the front suspension upward
nicely.

98.44kw so far. Getting there. I bet any sagging is caused by the pack.

I’ve got the pack doing better. But now it’s raining. Anywhere from 0-10 mph I
can spin the tires right up in the rain! More testing on dry pavement will force
more current from the system. That will let me know how close to 100kw I am.

Some prototyping netted 91kw of output from my truck recently. The acceleration was unbelievable. That’s still an 80% improvement. The pack is sagging more than normal right now. So I’m correcting that as of now. I suspect that would be worth a few more kw. Looking forward to 100kw soon as the pack gets updated and the R & D progresses.

The data sheets say the factory igbt’s are rated at 400 amps. Almost there now. If I can keep the pack above 250vdc at 400 amps, then I’ll be at 100kw.

I have had an igbt/hv buss redesign going. Might have to put more priority into that since the factory igbt’s are nearly at their max current rating. Although for maybe only 10-15 seconds at a time, 400 amps may not be a threat to their longevity.

With the A123 prototype modules doing fine, a full pack would have such low impedance that 100kw would be easy to hit. Maybe too easy. Going to build about 12 more A123 modules soon.

Tonight I finally got this system debugged. Turns out it had a bad transformer on phase A. Runs smooth as glass now. I left it outside since it’s so cold here now. This will cold soak the Dolphin and help to test if it’s prone to classic dropouts or not. Cold and humid weather pushes any marginal board right into classic dropout mode. Clunk clunk!

Got another customers board today from Hawaii. It needs the dropout mod and also I’ve been requested to add the 70kw upgrade. Busy weekend.

I have have gathered up all of my individual schematics of the Dolphin system and am drawing them up to make a master schematic.

Since I’ve been hammering away at debugging this east coast system, I built up another system to help me. So now I have another completely assembled system that runs.

I’ve been working like a dog on making an electric vehicle system for a guy on the east coast. It’s been assembled for days. Runs too. But it has this kind of miss to it. Almost like it’s got one bad spark plug wire. It just runs rough. I’ve not seen that kind of problem before with an AC electric vehicle system.

Also have the spot welder nearly assembled. It just needs some finishing. I hope to create a process to spot weld braided flat cable to lithium battery cells. The cable allows flexing without breakage. Mostly for our combat robot buddies. For automotive use it’s not really necessary. But it will be a great process to have under my belt.

After this system gets shipped, I have gathered all of my hand drawn individual schematics, and will create one large schematic for the entire Dolphin main board. I have almost every square inch documented. Just a little remains. But even a mostly completed schematic will be helpful in debugging. I’m still deciding what cad package to use.

Today it was time to get the Dolphin chargers that are not running back into running condition. The first step was to remove all of the bad parts. Most get thrown away, but the T1 transformer gets rewound. Four of them were rewound today.

I’m building a super charger for a customer. It runs cooler and does a much more reliable job at charging the battery pack.

Today I just announced the opening of the US Electricar store to the US Electricar Yahoo group.

If you have not noticed or heard, I’ve opened the US Electricar.net store for USE owners so they can get repairs and parts to keep their vehicles running. There are links on this blog to take you there. Enjoy!

Today I finally got a fixture together to wind the T1 transformers that fail on the Dolphin chargers. I used an IR led pair tied to a counter to tell me how many windings were made. I wrote several types of G-code to have the cnc mill help in the winding of these parts. It worked out well in the end after several iterations. I settled in the 532-540 ohm range after they were wound. This was a few turns under 3k. I have one more transformer to wind. I’ll take some better video with a better source. It took days to figure all of this out and get it built and tested. The original estimate for rewinding was 15 hours. By working on the G-code and the cnc hardware I knocked is down to just over 2 hours. But last night I had a better idea. Now the full rewind takes 5 minutes while the hardware counts every turn. Sweet!

The brightness of this IR led was too high. The Rx led did not like so much light. These pics were taken with my G1 cell phone since the human eye cannot see Infra-red light. Thanks to Bob at Halted for that great tip! Video camera with night shooting have the same capability of seeing IR.

This brightness worked well. I might even be able to drop it a bit more, but for now it worked fine.

Here is a winding video from my G1 cell phone. You need Quicktime to play it. I didn’t sit still long enough to show that the transformer is moving up and down via the cnc. It spaces the windings out very nicely. I borrowed the counter from my automated battery load tester.