As standard the DNO-5 and DNO-10 have their current limited to approx 50A and 100A respectively. These values are controlled by the value of the DNO current limit adjustment resistor R25 in the diagram below, Read More

This page describes how to use the “pot learn” feature of the Pro-150 to set it up for operation with a hall effect throttle. Before starting this sequence the Pro-150 should have power connected to Read More

Although the DNO does not have an under voltage protection cut-off fitted as standard it is easy to retro-fit this feature. There are two ways to do this; Method 1; the easiest, is to cut Read More

If you need to control a Pro-150 via forward / reverse push buttons, a neat way to do it is to use the Pro-150 in joystick mode. This diagram shows how to wire it up. Read More

We recently encountered a strange issue with a 4QD-300 driving an Ampflow A28-400-F24 motor. Forward operation worked as expected but in reverse a very slight pulsing or oscillation of the motor speed could be detected Read More

The old PDQ wiring used a Scientific Generics controller, a lot of which are failing after many years service. The Porter 5 is a good replacement, here are some steps for fitting a Porter to Read More

We’ve written this guide to help customers diagnose and fix problems that may occur with the Pro-150. We don’t release complete circuit diagrams for current models but we hope this guide will shed some light Read More

It doesn’t happen often but when the mosfets in a 4QD series controller do blow they can take a number of other components with them. If you are attempting a DIY repair this photo shows Read More

We are sometimes asked how to disable the regen braking on the Porter series of controllers. It’s a 5 minute job if you’re handy with a scalpel and soldering iron, here’s how to do it…. Read More

The DNO PCB number is 30-2D-01. The following is a list of modifications listed by serial number. The DNO was originally designed to block transition from ahead to reverse without reducing the throttle to zero. Read More

Although the DNO is very similar to the VTX, one feature that it does not have is the provision for disabling regen braking via on-board links. A number of people have asked if it is Read More

This optional battery contactor arrangement can be fitted as part of the 4QD-200/300 installation to provide reverse polarity protection and also an emergency power disconnection. The relay should be chosen so that it is capable Read More

It is possible to adjust the Porter current limit setting by fitting either a fixed resistor or a potentiometer across the pads circled in red below A resistance of 100k gives a motor current limit Read More

If a Pro-150 gives the Pt [pot top] fault code, or just gives a continuous rapid beeps, this indicates a pot or wiring fault or blown F1 fuse track such that the voltage on the Read More

Unless specifically requested for 48V, we usually configure the 4QD series for 24V operation. When operating at 48V the acceleration ramp control may need to be adjusted as well as the gain control in order Read More

Pro-150 mechanical information Dimensions Board only: 145mm x 102mm x 38mm With base and cover: 181mm x 121mm x 46mm Weight Board only: 320 gm Complete: 630gm Power connectors 9.5mm push-on for battery, combined with Read More

The 4QD series has a speed input and a forwards/reverse input. Also, being designed for vehicle use, it also has high pedal lockout which prevents the controller working is a demand speed is present when Read More

The Pro-120 and Scoota series controllers have some sophisticated internal power supply circuitry which includes reverse polarity protection, pot fault detection and high pedal lockout. This is a description of the features and of some Read More

The 4QD series controllers are designed for Permanent Magnet motors, but they can be made to work with series wound motor with some modifications to the wiring. To control speed and direction of a Permanent Read More

In early 2003 we released a redesigned Pro-120 controller. However – in general it’s such a popular and good controller that not a huge redesign was possible. The main change is that it uses sub-miniature Read More

The Pro-120 series are card controllers, open to the elements – and users. They are similar to the VTX and older NCC series – but have several more sophisticated protection mechanisms built in. This page Read More

All controllers made by 4QD are generally wide voltage operating range: limits are the operating voltages on the MOSFETs and the relays, and the power dissipation in the current source transistor used for the internal Read More

Faults on the Pro-120 series are not common, but there are a few which occur, mainly because the ‘bare board’ style of the controller makes it susceptible to certain abuses. These fault finding tips may Read More

This applicaton note applies to Mark 2 Pro-120 controllers only. The Pro-120 has an expansion connector that may be used to connect a master controller to a single slave. Connecting to more than one slave Read More

The Pro-120 series acceleration and deceleration ramps are adjustable down to as fast as about 330mS. It is possible to reduce this timing but any modifications should be done with extreme caution. The ramps are Read More

This modification will cause the Forward relay to be energised by the ignition switch. When speed is zero, this relay will not switch off (until the ignition is switched of) so the motor will not Read More

The Pro is available in two versions, the standard version and the -RW version. This page explains the differences. Input decoupling There is, on the input to the standard controller, a noise decoupling circuit – Read More

The Power relay drive circuit on the Pro-120 can be factory configured in three different ways. This page explains them. The power relay is switched on and off by a transistor that detects the internal Read More

The 4QD series has a Parking Brake solenoid driver. Optionally controllers can be supplied from the factory with this converted to a ‘Braking’ Light driver. This page describes the modification. Warning. The parts that need Read More

This applies to control boards issue 15 or earlier. With issue 16 a bridge point was added that may be linked out to disable HPLO. High pedal lockout is a safety device to make sure Read More

The inhibit input on the 4QD controllers is designed to be used in conjunction with a microswitch sensing the foot brake on an electrical vehicle. Our features area explains this operation of the Foot-Brake inhibit. Read More

If the battery is ever disconnected (either accidentally or via an isolation switch) on a controller with regen braking, then if the controller tries to brake it will simply pump up its own supply line Read More

This page specifically refers to modifying pre issue 15 boards. From issue 15 onwards there is an on-board jumper to alter the deadband. With issue 17 boards, the half-speed reverse feature was changed to make Read More

This modification applies to 4QD series controllers, top boards issues 4 through 8. As the voltage to a motor is reduced, it will slow down and when the voltage gets low enough, the motor will Read More

Notes on the current limit resistors for the 4QD series. The control board current limit resistors have changed frequently, as MOSFET improve the Rds generaly decreases. This increases the current, but it has to be Read More

The circuit of the standard tacho-generator feedback board is described on the 4QDTEC.com site and a drawing with other information is available. Mechanically, this board is designed to plug into the NCC and Pro series Read More

Control board modification This page details two modifications The first part should be done to all controllers with serial numbers below 4028. After that, the modification was included in production. Modification is to the top Read More

How to adjust the maximum reverse speed on earlier 4QD control boards. This information applies to earlier 4QD series only. With issue 17 control boards the method of incorporating half speed reverse changed. It is Read More

The reversing latch holds the existing direction and compares it with the requested direction. If the two conflict, the controller ramps down to zero speed and when this is detected, the latch changes state. The Read More

If you reverse the battery to a 4QD series controller – it is likely to destroy all the MOSFETs. The current that flows with a reversed battery is dependant on the battery capacity and on Read More

With several ‘caveats’, the control boards and base boards of the 4QD series are interchangeable and may be mixed and matched. However – it is important that you understand the potential problems. 4QD 300: This Read More

This page lists the different versions of the 4QD series circuit boards, and their date of introduction. This listing was originally generated for 4QD internal use only so the descriptions may not be as full Read More

This modification should be applied to all Pro-150 controllers with serial numbers 0198 or higher and lower than 0550. On 0550 and later controllers the capacitor is not fitted. On serial numbers 0198 and lower Read More

The circuit of the Pro-150 is available as a pdf. Current limit amplifier is in the bottom right corner. Current is monitored by sensing the voltage drop across the lowside MOSFETs when they are conducting. Read More

These notes are by serial number, rather than by date. The list is mainly for 4QD internal reference so is somewhat technical. 0000 to 0105 Are Mark 1. In these, there was no 12v connection Read More

Notes on how to create a positional servo control. There are two types of servo system: speed and position. These are explained in our Answers to FAQs on Battery Motors & Controllers. There is also Read More

This page describes how to use the “pot learn” feature of the Pro-150 to set up joystick programming, [or wig-wag operation]. Before starting this sequence the Pro-150 should have power connected to B+ and B-, Read More