Category | Design

Design

Written by chivey on July 5, 2026 Tags: Design

Project design goal

My daily commute is 8 miles one way, reaching a max speed of 55mph (usually only for 3 miles and only in the morning going to work – never in the evening – ATL traffic!)

Minimum system performance is a range of = 16 miles (round trip to work) reaching a top speed of 55mph for about 30-40% of time. Daily recharge option.

Ideally would like to be able to make a round trip to the airport. ATL international is 40 miles door to door from my house, most of the way is freeway at 55-65mph. The ideal would be able to make the trip there and back (80 mile round trip), but an option could be talk to some of the off site parking lot folks and see if a recharge option could be found. Would definitely be good promotional opportunities here…

Target design range = 80 miles spending 70%-80% between 55-65 mph.

This design would require significant power and capacity to achieve and the question about the aerodynamics of a VW bus becomes serious consideration.

An intermediate design (using recharging at airport parking lot) would reduce the design to 40 mile range spending 70-80% at 55-65 mph – much easy to achieve and similar to existing designs and builds found on the internet.

Starting the design considerations with this in mind will plan on specify components with good ranges above our initial application to allow growth in to hopefully the ideal design if not achievable in the first phase.

Research

Some related projects from the internet: Reference designs

Key component selection

The key components I focused on the design are:

Motor

Controller

Batteries

Charger

Clutch

!!!Design revisions

Based on initial research and reference designs initial design specification: Design v1.0

2009 01 11 – after discussion with David and more research updated design: Design v1.1

2009 07 11 – Update for new battery selection and more details: Design v1.2

!!!Current design

Current version of Schematics an associated Theory of operation

EV calc model

V1.0 DRAFT – Project design

|Motor|Net Gain Wrap 9|

|Controller|Curtis 1231C|

|Batteries|Costco 115Ah/12v x 12|

|Charger|Zivan NG 3 110/220 charger|

|Clutch|Yes|

V1.1 DRAFT – Project design

|Motor|Net Gain Wrap 9|

|Controller|Logisystems 144-156v 750A|

|Batteries|Costco 115Ah/12v x 12|

|Charger|Manzanita Micro PCF 20|

|Clutch|Yes|

|Primary circuit|Fuse, Contactor, Manual disconnect (with driver operated cable)|

|Secondary circuit|Fuse, Key-switch, Inertia kill switch, Charger interlock|

V1.2 DRAFT – Project design

|Motor|Net Gain Wrap 9|

|Controller|Logisystems 144-156v 750A|

|Batteries|Max Rate AGM 12 x 12v|

|Charger|Manzanita Micro PCF 20|

|Clutch|Yes|

|Primary circuit|Fuse, Circuit breaker, Contacter (x2), Manual disconnect|

|Secondary protection circuit|Fuse, Key-switch, Inertia kill switch, Charger interlock, (Brake interlock)|

|Secondary warning system|Motor overheat, Charger interlock, System ready, Brush wear warning|

EV calc model

Written by chivey on  Tags: Design

EV calc (http://www.evconvert.com/tools/evcalc/?s=b) model of the StealthBus.

!!!Motor (Net Gain – Warp 9)

Standard model from EV Calc tool.

|!Voltage|192|

|!Weight|135|

|!Horse Power|36|

|!Maximum RPM|5000|

|!Motor a|46239|

|!Motor b|0.4564|

|!Motor c|2436|

|!Motor d|303|

|!Motor k|0.0069|

|!Motor n|1.5845|

!!!Vehicle (1973 Volkswagen Bus)

From various VW specifications

|!Drag Coeff|0.38|

|!Frontal Area|27|

|!Initial Curb Wt|2900|

|!Drive efficiency|0.91|

|!1st gear ratio|17.366|

|!2nd gear ratio|9.40963|

|!3rd gear ratio|5.76277|

|!4th gear ratio|4.06273|

|!Final ratio|4.57|

!!!Battery Pack (C&D Tech Max Rate AGM 138Ah)

From C&D datasheet, converted to Puekerts using EV calc tools.

|!Voltage|12|

|!Weight|100|

|!Puekerts Exp|1.082|

|!Puekerts Cap|163.244|

|!Resistance|0.0023|

!!!Controller (Logisystems AFX 156)

From Logisystems datasheet

|!min voltage|120|

|!max voltage|156|

|!max current|750|

|!weight|20|

|!efficiency|95|

!!!System

|!Voltage|144|

|!# Batt Strings|1|

|!% DOD|100|

|!Charger Weight|20|

|!lbs Removed|600|

|!Misc Added lbs|500|

|!Incline|1|

|!Wind|0|

|!Tire Section|195|

|!Tire Aspect|50|

|!Tire Rim|15|

|!Rolling Resistance|0.015|

|!Brake/Steer Resistance|0.003|

|!Kwh Rate|0.09|

|!Commute Miles|20|

Reference designs

Written by chivey on  Tags: Design

|!Model|!Motor|!Controller|!Batteries|!Volts|!Charger|!MPH|!Range|!Link|

|1957 S/Cab|ADC 9”|Curtis 1221|20 x 6v|120|n/s|65|60|http://www.evalbum.com/115|

|1966 Split|ADC FB 1 4001A|Curtis 1231C|10 x 12v AGM|120|PCF 50/75|70|49|http://www.evalbum.com/384|

|1967 Sundial|Warp 9|Cafe Electric|n/s|n/s|n/s|n/s|n/s|http://www.evalbum.com/1755|

|1970 Bus|Net Gain Warp 9|Kelly 144V/650A|18 x 8v flooded|144|Zivan NG 3|65|50|http://www.evalbum.com/1581|

|1971 Bus|ADC 9”|Curtis 1221|20 x 6v|120|n/s|n/s|n/s| |

|1971 Bus|ADC FB 1 4001A|Curtis 1231C|24 x 6v flooded|144|PFC 30|60|45|http://www.evalbum.com/2100|

|1972 Bus|ADC FB 1 4001|Curtis 1231C|10 x 12v flooded|120|Lester 110/220|65|40|http://www.evalbum.com/1755|

|1973 Bus|Custom 9 inch|Curtis 1231C|24 x 6v flooded|144|Zivan NG 3|55|50|http://www.evalbum.com/1804|

|1973 Bus|ADC FB 1 4001|Curtis 1231C|20 x 6v flooded|120|Dual KTA|65|40|http://www.evalbum.com/159|

|1977 Bus|ADC FB 1 4001A|Curtis|12 x 12v flooded|144|2 x chargers|65|30|http://www.evalbum.com/1915|

|1978 Bus|Net Gain Warp 9|Curtis 1231|24 x 6v flooded|144|PFC 1500|60|60|http://www.evalbum.com/2843|

|1979 Bus|ADC 9”|Kelly|20 x 6v flooded|120|10 x 12v chargers|50|50|http://www.evalbum.com/2075|