**Using MightyBoyEV - Real ***
Test Drive Data....*

Note the following tests are being performed using a 3 day permit from the Department Motor Transport

*Vehicle will be fully registered on new plates soon.....*

**First test drive data on performance**

Distance travel = 27 km

MaxSpeed = 66.6 km/h *(limited by road speed limits in my area of 50 or 60 km/h)*

AvgSpeed = 40.2 km/h

Gear Used = 4th only

Trip duration = 29.8 mins

MaxAmps = 290.5 amps

VMin = 60.8 volts *(as occurred when 290.5 Amps pulled,,,)*

Watt-Hours per Km = 103.3 w-h/km

Watt Hours used from pack = 2756.9 watt-hrs

Motor Temp = 40 degrees C* (max)*

Controller Temp = 26 degrees C *(max)*

Air Temp = 17 degrees C

Starting pack voltage was 79.3 volts *(fully charged)* and after the 27
km trip, the pack voltage dropped to 74.8 volts with a recovery to 75.7 volts
after 2 hours

Using the Power-Sonic supplied **Open-Circuit Voltage Characteristics**
**Graph** - a
start voltage of 79.3 div 6 or **13.22 volts** and 74.8 div 6 or
**12.47 volts** for the end voltage, the **Residual Capacity**
of the battery pack would be just over 60%.

*(Reference **
http://www.power-sonic.com/index.php?id=98** for full details)*

*See the next section for more on this.....*

**How much can I safely take from the battery back?**

*Power-sonic* actual quote
111Ah for these batteries *(see *
*Power Sonic
PG-12V103 AGM SLA batteries**)….*. So for my battery pack* (6 batteries)* this
works out to be 72 volts x 111 Ah *= 7992 Watt-hours (but this is at 20 Hour rate and not
really useful for EV calculations)*

De-rating the battery pack to the quoted 1 hour rating
*(which is only about 62 Ah)* gives me
about 4464 Watt-hours. This is a first approximation and does not take into
account all the various effects or voltage droop that occurs when pulling high
currents.

Being extremely conservative, and looking at a worst case scenario, I intend to not to take more
than 3600 Watt-hours* (this equals an approximate 80% D.O.D. of the heavily
de-rated 4464 Watt-hours)* from
the
pack. Using the limited results so far, this gives me a safe range of 35 km.
With more conservative driving habits, limiting my start-up currents via
programming the controller and cycling the batteries over the next few months,
this all should improve. It is my aim to get the watt-hours/km below 100, after
all this car only weights about 560kg (plus 190kg of batteries and the weight of the
driver….. *and maybe a passenger*). *In addition, the work in reducing
all the factors that effect rolling resistance and drag should now pay off....*

*As mentioned previously on this site, for my use a range
of 20 to 25 km is more then required....*

**How much does it cost to charge the battery pack?**

I am legally charging on the “Off Peak” night rate available in South Australia which is currently about 7 cents per kilowatt hour. So for this run of about 27 km using approximately 2800 watt hours and assuming maybe 80% charging efficiency the cost would be ((2.8 div by .8 X 7 cents) div by 27 km) = about 1 cent per km.

**The down side…..**

Amortising the cost to the batteries *(maybe a 3 years
life if treated correctly with a well designed charger)* – it’s costing
$1600 div by 50 km *(the total distance driven so far) *or
only $30 per km so far!!

For most EV drivers the charging costs are fairly irrelevant compared to recouping the battery pack costs, this is especially true when expensive Li-Ion cells are used .

**After some controller adjustments (trying to the limit start-up
current slightly) here are some more results....**

Test trip involved driving into the Adelaide CBD area and North Adelaide

Distance travel = 17 km

MaxSpeed = 65.6 km/h *(limited by road speed limits in my area of 50 or 60 km/h)*

AvgSpeed = 44.3 km/h

Gear Used = 4th only

Trip duration = 22.5 mins

MaxAmps = 250 amps

VMin = 61 volts *(as occurred when 250 Amps pulled,,,)*

Watt-Hours per Km = 87.1 w-h/km

Watt Hours used from pack = 1426.9 watt-hrs

Starting pack voltage was 78.8 volts and after the 17 km trip, the pack voltage dropped to 75.5 volts

*Other notable things.... *with the start current reduced slightly the
4th gear wheel spin now far less when you really hit the pedal

and

on the road 60 km/h = 2,800 rpm at the motor

So I think that is about the best I am going to achieve from this combination - but very happy with a 87 Watt-Hour / Km result.

**Third Test Drive (to get the vehicle registered)**

Test trip involved driving to Vehicle Inspection Centre

Distance travel = 34 km

MaxSpeed = 83 km/h

AvgSpeed = 43.4 km/h

Gear Used = 4th only

Trip duration = 47 mins

MaxAmps = 289 amps

VMin = 60.3 volts *(as occurred when 289 Amps pulled,,,)*

Watt-Hours per Km = 87 w-h/km

Watt Hours used from pack = 2950 watt-hrs

Starting pack voltage was 78.9 volts and after the 34 km trip, the pack voltage dropped to 72.8 volts

(DOD would be roughly 60 to 65 % for this run)

*Other notable things.... *driving in an 80 km/h zone on the way home
presented no problem with 80 km/h corresponding to a motor speed of 3,900 rpm
and drawing 160 Amp.

So still not sure of the vehicles top speed but achieving 85 km/h would most definitely not present any issues. But driving at 80 km/h would certainly reduce the useable range!