new member 2007 Miles ZX40S

[SeniorSell]

Originally Posted by cbaker

Thanks for the model number. I've searched it, but can't find a pdf with a schematic. I'll just email delta q and see if they will send me one. It looks easy, mine just has an ac input. One of the dc outs goes to the batteries, but the other one I'll have to trace. It might go to the voltage meter, or to some feature that keeps you from driving off when the charger is hooked up. The tranny swap is great for what I do. I did get the old 2nd gear up to 40+ mph a time or two going down a big hill. It just sounded like it was going to blow up, and actually limited the speed. Being able to throw it out of gear on the downhill parts of my route allows it to coast more freely. I just don't know if exactly what was causing the battery problems I've been having, so the charger is the first thing to explore. I'll try to post updates when I have them.
Thanks again

I have the PDF Spec sheets but ecomodder won't let me post the links until I create 5 posts. I can email them to you if you do not find them online. Where did you purchase your Charade tranny?

Dave

[rmay635703]

Originally Posted by SeniorSell

Ryan, I have a 2007 miles ZX40 with the larger 9hp 72V DC version motor. Curtis controller. We know that this motor will take 6,000 rpm for some time, not constant. That = about 42-45mph stuck in second gear. Bone stock at 25mph indicated is at or about 3,300 rpm. I read that field weakening is the quickest way to attain more speed but couldn't I also pull the controller and send it to Curtis and have them raise the RPM limit to say 5,500 rpm?

Dave Upton

Controller is dumb and ignorant of what your motor is doing. The limiting factor is you motor will only accept so much amperage at a given RPM, BACK EMF prevents current flow, reducing field strength reduces EMF and increase current flow which reduces power but increases max RPM of the motor.

From what I have been told 6250rpm is the max on both the small and big motor (my mistake), which is fairly impressive, so don't go over 46mph with stock gearing.

Motors are moderately robust but can be overheated if you abuse them for long periods.

[cbaker]

OK, I think I see it. The stock charger has a 72v and 12v dc output. I guess for the traction and aux. I would love to see the schematic. I'll pm you if you don't mind sending them. I don't see where the delta q would take care of the aux battery. Does your aux battery have a different charger?

[SeniorSell]

Hey Ryan, I read your earlier forums on a piece of bare wire shunted across by an aux contactor once above 25 or so. Is that correct? Going back and looking at it all over again, what is the best way I should weaken the field. Throw it at me, a schematic, I have been an industrial electrician for years but my DC theory is a little weak as the old MG sets went out years ago and were replaced by AC Frequency Drives. Miles 2008 and newer. For what it is worth, we like the Miles. We have driven over 2,500 miles in 12 months time here locally in North Bend OR, up and down hills, with the stock controller and AGM 150 AH batteries. Totally dependable. Every now and then the display does not work so you give the dash the old slap and it comes right up. I am thinking of the movie Armageddon with Bruce Willis and Ben Affleck, and Peter Stormare’s, whom plays the Russian Cosmonaut says "This is how weeee fix things in RUSSIA" !! Too funny! Thank you for your help and input.

Dave Upton

[rmay635703]

Originally Posted by SeniorSell

Hey Ryan, I read your earlier forums on a piece of bare wire shunted across by an aux contactor once above 25 or so. Is that correct?

Nope, the main contactors on the miles have nothing to do with field weakening.
Everything you need to do is done by tapping the field terminals on the motor itself. The motor has 4 terminals (2) are for field, add some addition cables to those to mess with the field.

Anyway...

My first version was two 6' sections of 8 guage wire with a hacksaw blade resistor, it worked poorly.

I used a jumper cable clamp and did the same thing and omitted the hacksaw blade and it worked great but put a lot of stress on components. Top speed went from roughly 29mph to 36-38mph.

I ended up with a starter relay and went down to 10 guage wire. Top speed is 32-36mph but there is less stress on the motor and controller. I also can flip a switch on the dash to turn it on and off instead of attaching a jumper cable under the dash.

SO what is is field weakening?

The motor has a field winding, you "short out" the field winding with wire that hopefully has roughly the same resistance as the field itself more and it is less effective, less it can become TOO effective and burn something up.

Cheers
Ryan

[SeniorSell]

Thank you, Thank you! I was making this way to hard. What you are explaining makes perfect sense. Firewall mounted starter relay controlled by the 12 car battery and a fused maintained switch. Attach #10 Solid to Field terminal (1) and the other end to the starter relay side (a). Attach another #10 solid to terminal (b) on the starter relay and attach the other end to Field terminal (2).

Is the length of wire important? 6", 12", 20" each?

Thanks again,

Dave

[rmay635703]

Originally Posted by SeniorSell

Thank you, Thank you! I was making this way to hard. What you are explaining makes perfect sense. Firewall mounted starter relay controlled by the 12 car battery and a fused maintained switch. Attach #10 Solid to Field terminal (1) and the other end to the starter relay side (a). Attach another #10 solid to terminal (b) on the starter relay and attach the other end to Field terminal (2).

Is the length of wire important? 6", 12", 20" each?

Thanks again,

Dave

Yes the length is very important, my 48v motor requires about 12 FEET, a 72v motor would require more in general.

[SeniorSell]

Sorry I was being so dense. You used the #10 wire to create a coil, more or less, that it's overall length creates the same omeg value as what I read with my DVM across the field windings itself. That makes perfect sense. To little an omeg value and it can go up in smoke and too great a value becomes less effective. Thank you very much for clarifying. : )

Dave

[cbaker]

I found a great deal on an unused paktrakr system that came in this week. In the meatime I've noticed that my batteries rest pretty well if they are not hooked up in the vehicle, but they lose a considerable amount if left hooked up for several hours. Something in the system might be leaking or shorting or something. I might try just using the disconnect and see if that makes any difference. I don't see how the cables would make a difference with the key off. I'll have to disconnect the batteries to install the paktrakr so that would be the perfect time to test the system. I'm open to any suggestions as to how to perform that procedure.
The new DeltaQ charger for the miles is made special for miles. DeltaQ won't sell them, you have to get it from miles. At 425.00 it seems like a pretty good price, but they won't ship till next week so I might just tie up two weekends with this. It is running strong after the batteries being charged individually so it does seem to be some kind of voltage issue I was having and not the controller. I still might have pulled too many amps or overcharged them with the chinese charger or both. Only time will tell I guess. Floodies are looking more appealing every day.

[cbaker]

Well I didn't get to the paktrakr because of a finishing mower emergency. The batteries are resting without losing much voltage now that I removed the pulse thingies. Come to find out if you get the deltaq charger, you also need a dc/dc converter replacement.