Danfoss VFD Switching Frequency

I tried variable switching frequency (Parameter 412) this morning but it works the opposite to what I was hoping. It does sound cool though!

It increases frequency with RPM as per the manual. I wanted a low frequency at low RPM.

Low switching frequency (Parameter 411) seems to be the key to prevent lurching and brief rear wheel lock up when decelerating to a stop. I could also try raising the stop frequency (Parameter 123) but I didn’t like this set higher than 0.

Zener - Resistor battery balance circuits

I have had to make a few more Zener- resistor balance circuits as some were not evenly matched and caused 2 batteries to discharge below 13.2 at rest. They should be 13.6v (2x6.8V)

The Zener diode voltages would seem to be too low. I need to fix my adjustable PSU and measure the reverse knee voltage on them to verify the voltage and match them in sets of 4 for charging.

Worlds first, registered totally industrial EV conversion

I began this planing this project after visiting the AEVA field day in October 2007. After much planing and calculating in Excel, I started purchasing parts (the motor) in December 2007. 

It took a while to find a vehicle that would suit. I looked at Toyota Town Aces, Suzuki Carrys Toyota SBVs and finally settled on a Toyota Hilux extra cab ute in April 2008. My requirements were to carry 360kg of SLA batteries + inverter and have 4 seats (for kids) without significant chassis modification. 

It was cheap for the model, but reasonably tidy. Some rust that needed dealing to but OK. This model is popular with young guys and this one had been painted black and had dark tinting, so I had to de-bogan it as well. 

To get to the point, I finally got it registered on the 7th of March. 

I am very happy with its performance on road. Thanks to Tuarn (acmotor on the AEVA formus) for your inspiration in leading the way, despite me bing first to register.  

The tweaking and fiddling with settings took a while but got there in the end. It even has regeneration which is necessary in my hilly area. 

If there are any other registered industrial AC conversions around, do challenge my "subject" as I would be interested to know more about theirs, and concede to a lesser accolade of Australia or NSW.     

Mental Note, Check the battery terminals!

It would seem that I did not have one of the battery terminals tight enough.
The battery still tests OK, but I have replaced it and the balance circuit with some spares.

30km drive in Electro-Lux

I took a 34km drive last night. According to the volt meter, that equates to a final SoC of 32%. Not quite as efficient as I had hoped but there were some long hills. This amounts to 241Wh / km.

Improved Motor Cooling

The motor was getting a bit toasty after long uphill drives.

During operation the motor was cool enough but as soon as there was no air movement, the heat had nowhere to go.

I removed the shaft fan and replaced it with a 10 inch 'ICE' brand electric fan. 

The fan was attached to an aluminum plate to prevent air escaping around the fan. Coincidentally the fan mounting holes almost line up with the 4 bolt holes. I 'moved' the holes in the plastic fan by about 5mm and it looks like it was made to fit!

There is a 50 deg C 'clickson' NO thermal switch that drives a relay, that in turn drives the fan direct from the battery. This way the fan can run if necessary even if the key is off when most needed.

Air flow around the motor is very will designed. The air is blown toward the rear of the motor length ways down the cooling fins and the air exits at the rear of the motor.

i have also removed the air dam from the radiator opening to allow improved cooling.

The motor is noticeably quieter  which is a nice touch.

Here are some photos of the installation.

Old Shaft Fan

New electric fan

Temperature Switch.

Latest Danfoss VFD Parameters

By request here are my latest parameters that are changed from default...  

ID Name Setup 1 Unit (Notes)

009 Display line 2 Output energy [kWh] 

010 Display line 1.1 Dc link voltage [V] 

011 Display line 1.2 Reference [%] 

012 Display line 1.3 Torque [%] 

014 Local stop Disable 

102 Motor power 15.00 kW 

103 Motor voltage 415 V 

105 Motor current 28.00 A 

106 Motor nom. speed 1450 RPM 

108 Stator resist 0.2722 Ohm 

109 Stator react. 20.47 Ohm 

113 Lo spd load comp 150 % (For hill starts) 

114 Hi spd load comp 100 % 

115 Slip compensat. -300 % (Gives better throttle response at high speed) 

119 High start torq. 0.5 s 

128 Mot.therm protec Etr warning1 

129 Motor extern fan Yes

200 Out freq rng/rot 132 hz both direct. 

202 Out freq hi lim 132.0 Hz 

205 Max. reference 132.000 

206 Ramp type S2 

207 Ramp up time 1 6.00 s (Economy) 

208 Ramp down time 1 1.00 s 

209 Ramp up time 2 2.00 s (Power) 

210 Ramp down time 2 1.00 s 

221 Torq limit motor 348.5 % 

222 Torq limit gener 60.0 % 

224 Warn. current hi 97.6 A 

227 Warn. feedb. low -4,200.000 

228 Warn. feedb high 4,200.000 

300 Digital input 16 No operation 

301 Digital input 17 No operation 

302 Digital input 18 Latched start 

305 Digital input 29 Ramp 2 

306 Digital input 32 No operation 

307 Digital input 33 Encoder fb, input a 

314 Ai [mA] 60 funct No operation 

319 Ao 42 function Fb min-max =0-32000p (Speedo) 

320 Ao 42 puls scale 66 Hz 

321 Ao 45 function 0-tlim = 0-32000p (Tacho) 

322 Ao 45 puls scale 99 Hz 

323 Relay 1-3 funct. No operation 

326 Relay 4-5 funct. No operation 

329 Encoder pulses 40 (Inductive pickup gear) 

405 Reset mode Automatic x 2 

410 Inv.fault delay 35 s 

411 Switch frequency 3.0 kHz 

415 Max. feedback 4,500.000 

416 Ref/feedb. unit Rpm 

417 Speed prop gain 0.015 

445 Flying start Enable 

446 Switch pattern 60° avm 

457 Mains imbalance Warning

Motor heat

As I live in a very hilly area, the motor is heating up a lot.

I will use Tuarns example and add a 12v cooling fan to the motor.

I am looking at a 10" radiator fan adapted to replace the existing mechanical fan. 

I will use a 'clickson' switch to allow the fan to continue running when the vehicle is off.

First decent drive observations

First of all. What fun!

Now for some stats.

24.6km Hilly terrain

Start voltage was 657v. 100%SoC according to the greensaver battery data sheet.

End voltage was 621v. 50%SoC.

Energy used (probably) = 6kwh. Efficiency = 250Wh/km

I am mixing measurements here however, the kwh counter read 8.2kwh. This is motor energy both driven and regen. This gives 2.2kWh regen which I find very hard to believe, considering the charge efficiency will not be great.

For now I will rely on the pack voltage for SoC while stationary. I have printed out a lookup table to translate voltage into SoC.

I had the regen set for 10kW (66.6%). This gave over voltage warnings (801+ volts) and was a bit much for the batteries at 16v per cell, but did not trip on a full charge. This equates to a charge current of 12.5A. minus about .5A through the balance circuit.

I have backed this off to 8kW (53.3%) to try and minimise over voltage on the batteries.

Video of electric Hilux

Here is a video, thanks to our friend Kelly.

My ute is now road legal.

After about 4 months of planing and another 11 of construction. The Hilux is now fully road legal!

What a marathon, and a relief.

I got the blue slip, green slip and plates this morning.

Now it is time to enjoy the fruits of my labour. The first thing to do is take the family to lunch to celebrate!

WAHOO. Just past engineering signatory inspection.

The Engineer was dissapointed he couldnt make any suggestions or reccomendations. :)

I pick up the paperwork on Friday and then go for a blue slip and finally rego.