Project: The Electric Booger (budget EV conversion - '92 Mazda MX-3)

[bennelson]

I'd agree on everything just said. I've had pretty much the same experience on the Electro-Metro.

[MetroMPG]

Congrats on plug & walk away status! I also have that, but only because I'm currently tapping one pair of 6v floodies for my 12v needs. Not the best solution, but I'm OK with it because the pack is unbalanced anyway (and I'm tapping the strongest pair).

Ooo, the 3 future EV drag racers meet in the same thread...

[puddleglum]

Originally Posted by mechman600

I almost bought a Kelly "sepex" controller. The " " is because it really isn't a real sepex controller. Notice that on their ordering screen you specify what field voltage you want. The controller gives the field this voltage whenever the throttle is depressed and does not vary it like a proper sepex controller.

I was curious about this so I emailed Kelly. They verified that that is the way their HSE controller works (and that's the high power one) but their KDZ controller is available with a current tracking function on the field. The field current varies with armature current, much like what you are doing with your two controllers. Thought it might be worth noting, although they are relatively low power controllers as well and they didn't specify what the max field current was.

Hey, is your motor fairly quiet or does it whine? I ran this forklift that has the motors in it and it had a really loud high pitched whine. I couldn't really tell where it was coming from so it may have been the controllers or brakes and I didn't have time to investigate. It sounded like controller noise, (wouldn't be using those anyway) but I know I wouldn't want that whine in a car, it would drive me nuts.

[mechman600]

The whine your hear is actually caused by the controller. Some controllers whine more than others. My Alltrax is absolutely silent. The whining noise is coming from the motor (I think) but the controller is the culprit, due to the PWM frequency.

EDIT: Good to know about the Kelly. It might not be a bad option then.

[mechman600]

My Kill A Watt died. I plugged it in this morning at work and nothing happened on the display. Power is still getting through to the car.

Seems I need to contact P3 International for some warranty....

[Miller88]

Originally Posted by mechman600

My Kill A Watt died. I plugged it in this morning at work and nothing happened on the display. Power is still getting through to the car.

Seems I need to contact P3 International for some warranty....

Mine ran away

I used it a lot when I moved so I could caluclate the cost of EVERYTHING ... well everything that was 110V.

[mechman600]

Today on the way home from my evening shift, I noticed pack voltage was a bit low going up the kilometer long hill. Normally it goes down to ~68V, but this time it was at ~65V. I quickly reached over and plugged in my battery monitoring gauges and was stunned to see one pair of batteries sitting at ~5V(!!!) while the rest of the pairs were above 11V. So I feather footed it the rest of the way home and started diagnosing.

Turns out that one charger had a blown fuse. Crazy thing is, I have been noticing that the batteries have been a bit saggy for a couple of days, but I just attributed it to the colder weather. A few days....yikes...how thrashed are those two batteries?? I have been charging all batteries except two.

I blame my dead Kill A Watt. When I first plug in, it draws 1070W. And right after my Kill A Watt dies and I am unable to notice that something is off by a change in power draw, something DOES go wrong.

The two uncharged batteries rested at 11.38V after getting home tonight. What do you think....are they ruined?

I am going to fully charge the car tonight and float at 13.8V for many hours after that.

[pete c]

Hopefully running them down once didn't kill them. Does keeping them monitor plugged in all the time consume much power? Might be a good idea? Or at least set it up so that you can switch it on/off frequently to see how things are doing.

[MetroMPG]

If they're resting at 11.3v, I don't think they're toast.

But if they were cats, you definitely used up a couple of lives there!

Instrumentation FTW!

[mechman600]

Originally Posted by pete c

Does keeping them monitor plugged in all the time consume much power? Might be a good idea? Or at least set it up so that you can switch it on/off frequently to see how things are doing.

They take up basically no power at at all. They are bright red LED volt meters.


It's just annoying having them plugged in, and ever since the new batteries went in I haven't felt the need to very often. A better tool would a small monochromatic display that would stay on at all times - inconspicuously installed in the center console or something.

I will be much quicker to use it when I sense something is wrong from now on. We'll chalk this up to another learning experience.

The car has now been plugged in for almost 13 hours and the dead pair still isn't fully charged - presently at 14.5V @ 10A, so they should be done soon.