Supercaps Part I

My Supercaps have arrived - all 49 of them.  I got them on Ebay for cheap.  Notice I'm not using Ultracaps.  Why? They require balancing boards and are usually more expensive.  I played with a Maxwell Ultracap 12V bank once after reading about the EV1 that uses them to drag race. You should definitely google that one!

Some observations:  The supercaps are a little heavier that what I thought, they have no voltage when they arrive - that's good!

The next step is to make bus bars out of 3/8 inch OD copper tubing that I bought from a hardware store.  BTW, copper ain't cheap anymore.  I made a small busbar just to make sure it was going to fit right, so far so good.  The entire area will be approx 18" X 18" X 4".  This pack, when complete, will run in parallel to the main battery bank. 

Quite a few folks have tried this before with much success, look at DIYelectriccarforum and see what others have done.  I'm no pioneer, just a guy that likes to steal from the best.  Yes, there are skeptics and no I don't have any kind of equipment to quantify the results.  I figure if it helps my $5K battery pack perform better and last longer for under $120 bucks - I'm in!!!

Decals

When you were young, did you ever put together model cars?  I always loved putting on the decals.  You'd soak them in water then carefully place it on the model hoping they didn't stick to your fingers.

The original Bradley had decals.  A quick goggle search on the original ads will show this.  Kitcarguy on the bradleygt site will make the decals for anyone who wants them.  He has quite the selection.  I got silver, my second choice was black.  Four of the logos and four of the text.  My wife likes the way the silver turned out, so I must say, I made the right choice.

If I ever do paint the car, the $50 bucks to get the stickers done again will pale in comparison to the cost of the paint job.  I called the other day, and because it's fiberglass, the estimate was $6K.  Wowsers!  I didn't expect that price. 

E-Brake Fix

Yes, I complain about EMPI often, but they are way cheaper than the competition.  Plus, since I installed EMPI disc brakes I need to stay with the same brand to install the E-Brake.

Previously, the E-brake cables were too short and I tried to cut the cable housing to elongate the amount of cable going into the cab.  Basically, the cables were about an inch too short. THIS DIDN'T WORK WELL.

What I did this time was cut about an inch off the tube that comes out of the chassis that the cable goes into.  Yes, this did work. The first pict is before the cut.  The second is after the cut.

Works well and I hope a very long time.

Baby Got New(er) Shoes!

OK, not really new but new to the Bradley.  Yes, I bought some used tires.  Why?  The tires that came with the Bradley were cracked on the tread.  Really, I mean cracked.  I've never seen cracked tires except at a junkyard.  I needed tires that weren't so wide, P235 60R16, the old ones were actually tearing into the fiberglass in the front when I made a sharp turn.  At $35 bucks each, I'm a happy camper.  The new size is P215 60R 16.  I did a quick test drive and they seem to be working just fine.
Some will say the 3 inch lift I installed makes the car look like a "monster truck."  I think that's absurd. This car wasn't meant to have large tires.

Electric cars aren't usually driven year round, unless you live somewhere warm in the winter, like Arizona.  These have enough tread to last a year or two.  Ideally, you should buy low resistance tires and over-inflate them.  On a fiberglass car, that translates into NOISE!!!  And that's with the Rammat that I installed way back when.

Brake Solution

Lots of noise coming from the back when I drive and hit bumps.  I decided to look at the brakes.  The main metal bracket that attaches the caliper to the axle had come loose on both sides.  Despite my best efforts to tighten, all I did was strip the bolt heads.  Of course these are no ordinary bolts.  They're metric and they have a reduced head.  I suspect the bolt sleeve was getting in the way, or the washers weren't thick enough.  I ended up going to Fastenal and the guy asks me if I could use an allen hex bolt.  Same length, no sleeve and the head looks about the same size.  Sure...let's give it a go!  These bolts with the lock washers worked perfectly!!!

And what a huge difference this has made.  Tonight's 6 mile test drive was amazing, I could hear the electric motor purring while I drove.

Now if I could fix the little vibration in the shifter.......

Adjusting the Charger

My PFC 20 was going to need to be adjusted.  Three dead cells means 9.6 volts difference in the maximum charge. (Not to mention almost a full KWh of power source gone) The PFC 20 has a voltage limiter that ensures the batteries don't get toasted.  But you have to adjust the setting.  There's a download area at manzanitamicro that details this.  One thing you must absolutely make certain of: that switches 1 and 4 are turned on!

When I had my overcharge situation, the switches were off and the MINIBMS was not completely hooked up.  In the long run, my bad! And now three cells total are dead. At $100 a cell, that's a bad mistake to make.  But both are working well together and I'm at the point where my confidence is high.

I did a charge tonight and this worked perfectly: I started charging at 15 amps then it throttled back when the battery pack came close to the set "full" voltage then went into a top balance mode of 1.75 amps while the timer was flashing blue. All the batteries were shunting, perfectly equalized, with the red lights on.  Excellent!!

Another Dead Cell

It's good thing Jesus can raise from the dead, because one of my cells is long gone!  BTW Happy Easter.

Yes another cell has bit the dust.  The story goes like this: drove 10 miles started getting an alarm from the MINIBMS.  This means a cell, maybe more, was at 2.7 volts or less.  If a LiFePO4 cell goes to less than 2.5 volts, it's probably a goner.  One thing is for certain, you'll definitely lose capacity and if you keep stressing the battery it could reverse itself or even blow up!  But you can't just whip out your voltmeter and say "Aha! I have found the cell!" It's hard to test a cell unless it's under load. Also, this low cell will also cause serious "sag" (lack of gusto) in the pack.  Your pack is only as strong as it's weakest link.

Charged up the battery bank, then did a top balancing.  In the end, three batteries did not shunt - no red light on the circuit boards.  I whipped out my individual charger and charged each one of them up. This can take some time for each battery - 4 -6 hours because the charger I have is only 2 amps.

Out for another drive, 20 miles (mostly 35-45 mph), and no alarms.  Repeat charging and top balance process. All batteries were shunting when I looked.

This time I went for the stress test - drove the first 10 miles of my commute which has a few steep climbs at 55 mph.  Alarm happened at 6 miles.  Bummer!!  Came home, recharged the pack, top balanced and one cell did NOT shunt.  This was one of the batteries I had individually charged earlier.

Rather than try to revive it, even if that's possible; I wired around it.  Once I did, I noticed that it had leaked electrolite previously, which I couldn't see due to the BMS board covering the vent hole. I then drove the first 10 miles of commute again and NO ALARMS!!  (Yeah!...the crowd goes crazy.)  I was pulling approx 150 - 200  amps going uphill. This is good because the next 15 miles of my commute is pretty much flat or downhill.