Add a second battery to a Giant Twist.

Grandads bike     Add a 2nd battery     Batt Connect    Batt Rack   Batt. Rejuvenation   Lights 

Flecc's electric bike site.                          Jeff's Cartoons

Please note that if you use this idea you do so at your own risk.

I recommend that  that a qualified electrician makes the alterations as any wiring errors will be dangerous.


This page describes how to use a second Salisibury battery purchased from PowaCycle to increase the distance you can travel on your electric bike.


Click on any image to enlarge it.


Safety note:    Before commencing work, remove the Giant battery from the cycle frame. 

It would be wise not to commence work on the bike's wiring until until the residual voltage in the motor control circuitry has been discharged.  To do this switch on the controller on the handlbar for an hour, then switch it off.


The modification can easily be removed by unplugging the crimp connectors from the relay and reconnecting the Giant battery white & red wires back to the motor using the fitted crimp connectors.


Circuit diagram (theoretical) showing the relay connections.

With the Salisbury battery switched off, the relay contact (30) connects the motor to the Giant battery  positive terminal.

It can be seen that when the Salisbury battery is switched on, relay contact (30) changes the motor supply to the Salisbury positive terminal.


The practical circuit diagram showing the underside of the relay.



 The relay wired up ready for installation.



Now..............where did those screws come from?

I used a piece of plastic foam with a rough drawing to retain & show each screw location as I removed it before removing the left motor cover to gain access to the wiring .


Click on any image to enlarge it.

The left cover removed, ready to go to work. Nice of Giant to provide a spare, already threaded hole.




The relay mounted to the bike frame (a snug fit) and wired up to the second battery.


Parts reqd: 

Maplin Electronics:  

XS73Q   20A Figure 8 Red/Black cable.

N01AW 30A SPDT Auto 24Vdc relay.

HL17T   USA Mains Plug

 HL19V USA Mains Line Skt

A22GF   Screws for 25mm fans m3 x30mm screws and nuts · 8mm washers (Needed if you clamp two plugs together.)
A23GF   Screws for 15mm fans m3 x 20mm screws and nuts 8mm washers (Needed if a tab is attached to the outside casing of one plug) 

 PowaCycle:  Tel: 01279 821243 

Spare NiMH Battery for Salisbury: £99
Spare Charger: £39.99
Delivery: £10
Prices include VAT.

Connecting the Battery.  

Making a Battery Rack.