Ben Nelson's Electro-Metro Build thread

[MPaulHolmes]

It's true. It's sort of set to a sort of "eco mode". There is a variable called "throttle_ramp_rate". Joe's is set to 8. Ben's is set to 6. Once in a great while, Joe was able to "latch up" the controller, meaning that the 12v power had to be turned off then on. Sort of equivalent to a computer freezing up and being rebooted. The reboot time is instantaneous though, unlike modern computers. haha. It happened because of too fast of a change in current with respect to time.

I added some schottky diodes to the throttle, current, and temperature inputs on the micro-controller, which shunt voltage away from the micro if the voltage goes over 5v or below 0v (the cause of the latchups). To hedge on my bets, I slowed down the rate of change of current. I'm glad it is working so far. It makes me sick when a controller is just getting tried out. Hundreds of things could go wrong. hehe. There are like 150 steps, and if you get sloppy on one of the steps, DISASTER! duh duh duhhhhhh....

[TheSGC]

This is great seeing these controllers getting drive time!

Hey Ben, is there any chance of getting some video action while climbing a serious hill? I want to see if these suckers can maintain hills speeds cause my Kelly can't maintain 30 MPH up the hills on my commute......

[MPaulHolmes]

Ya, Ben, is there any chance that there are some really small, gentle hills that you could get video of driving up? hahahahaha

[electricman]

Originally Posted by bennelson

It seems like the range I get with my current set of 6 lead batteries is about 18 miles.
Battery Type: Lead-Acid, Gel

Hi Ben - I would say that (not knowing the size of your 12V Batteries) sounds pretty good range, but wanted to know - have you anything on the pack (I might have missed it in th thread) to monitor individual Batteries in the pack like a PakTrakr or PakTrakr Display with SD Card Reader/Writer for Data Logging?

My Blog - Enhanced PakTrakr Display ordered
First Look at my PakTrakr Enhanced Display
Quick sample of my Logging Display's Data

I ask - becasue I drove with just Voltmeter and Ammeter before they were installed - and the informaiton returned is quite different - and changes what I do and how I drive and how far I go on a charge, particularly when I start seeing one of the Batteries go south fast before the rest of the pack.

It used to be Battery #2, and now it is Battery #8 after one incident caused a serious pack drain - like parking the car and accidentally leaving the controller turned on for 2 -3 weeks!
Robert

[bennelson]

Hey Guys,

I did go up a hill today that seemed like the Open Source controller didn't perform as well as the Curtis did.

I can't say for sure though, because my charge may have been a little low. I have been messing around with the float voltage on the charger a bit lately, so it might be that.

Also, I have 6 voltmeters, one for each battery, for use as my poorman's battery monitoring system. However, they were all shoved under the passenger seat while I was going up that hill, so it was hard to say if one of the batteries wasn't doing its job compared to the others.

[MPaulHolmes]

The software may be limiting current to around 400 amps. Joe had set his software current limiting to 480 amps, but was going from 0 to 80 amps instantly, and then smoothly from 80 to 480 I think, so then I added something to make it start at 0, then go smoothly all the way up, but I don't think we changed the upper end, so it might end at 400. Do you have an ammeter? If the current feels a little wimpy, it's easy enough to change it. He also had it set to feel normal at 144v. Maybe you need a little more torque at 72v.

[bennelson]

My ammeter only goes to 300, so anything beyond that is unknown!
The only time the ammeter peaks out is on hard acceleration, otherwise I use it to know how much power I am using to cruise, etc.

Here are some photos from my controller upgrade.

Here's the 12V fuse panel I added to the car. It's salvaged from an RV and installed in a plain plastic box. I like how it has LEDs that light up if a fuse blows.


The Open Source controller is in the same location that the Curtis was, in the radiator space on the passenger side.



I ran a couple of wires through the firewall to an illuminated rocker switch for the controller power.


I might some day actually take the dashboard apart so I can mount it near the steering column.

[MPaulHolmes]

I like that last picture: "Unleaded Fuel Only". I really need to get an ammeter for motor current. Also my stupid $1.99 harbor freight battery pack ammeter just ran out of batteries! makes me mad.

[bennelson]

http://www.youtube.com/watch?v=z9KS8Hzqp-E

By the gas cap, it says "UNLEADED FUEL ONLY". I crossed off the "UN" with a marker....

[MPaulHolmes]

Stupid Youtube! Load! OK. It's loaded now! ya!