Tuesday, October 13, 2009

Battery Mangement System 0.1b

It's been awhile since I have updates anything. I finished my brakes, but I did the bleeding all wrong because I have NO stopping power. I can jammed the brakes to the firewall and the EV will stop, but barely. So I either did the bleeding wrong (which I think I did, pressed the pedal too far) or I killed my Master Cylinder/Brake Booster.

I also have replaced most of my pack under warranty because they were not working right. I have one left to replace, which I plan to do soon. They needed equalizing, but I didn't know until after I replaced most of them. I am going to replace the last one just so it's new like the others.

Anyways, I have really good results with my BMS. Here are pics of a few modules, and then installed in the EV.

I installed these and took them on their maiden drive to school (with funky brakes, but that's another thing) and found bugs in the software. I have a visual error reporting function that is supposed to activate for about 5 minutes, while disable the module, then go back to normal. They would not get to normal, so I sat in the parking lot rewriting the code at 8:30 AM and then updated all the modules.

They have been working really well. During the charging phase, the voltages are pretty much every where because of the batteries each being slightly different in age. (Well, one's about a year older than others.) But once the charger gets to the end, the balancers help spread the final voltages pretty evenly. I was having some problems where some batteries were charging at 15.2 volts and other at 14.0 volts. Now they all charge around 14.6-14.9 volts.


Brian said...

A couple things on your brakes.

What order did you bleed them? You should start with the side farest from the master cylinder. So if your master cylinder is on the drivers side front, start on the passenger side rear, then driver side rear, then passenger side front, then driver side front.

Work the emergency brake to get the rear shoes set properly on the drum. If the e-brake seems to run out of travel before it catches, adjust the cable it's normal to strech the cable a bit when you install the shoes.

Did you "bed in" the pads and rotors? You need to slow from a high speed to a slow speed pretty quick a couple of times to get the pad to transfer some material to the rotor. However, normal driving should take car of it in most cases.

David Harrington said...

I bled the brakes in the order that the factory manual specified, but I don't think the reservoir cap was on tight.

The emergency brake does work fine, it seems to work better than the entire brake setup at the moment.

I have driven about 40 miles on these pads, so I would assume that they would have broken in by now, but maybe not. I still think they need to be bled again.

Brian said...

I bled the brakes in the order that the factory manual specified, but I don't think the reservoir cap was on tight.

That shouldn't matter. Perhaps re-bleeding is a good idea. What you are doing is removing the air from the system. Most modern mechanics use a vacuum to do that, but it is fairly easy to do at home.

What I would do, is fill the reservoir, bleed the brakes, making sure you don't let the reservoir go empty. Once your done, use a turkey baster to remove the extra fluid.

David Harrington said...

Yeah, I plan to re-bleed them this weekend. I am going to follow these directions I found: http://www.clubcivic.com/board/showthread.php?t=153653

David Harrington said...

I just did a quick check on my lines to see if there is any air in them, and it's a resounding YES! It's like 45F out at the moment, but I did a small gravity bleed and lots of air come about before any fluid did, then bubbly fluid.

If the weather is any better tomorrow, I will attempt a proper gravity bleed. I can't do a conventional bleed because at the moment it's just me working on the EV, but a gravity bleed should do what I want, just take a lot longer.