Like the battery warning light in a car ... but better!
These Charge Warning Lights (CWLs) tell you :-
Universal fit CWLs with integral 10mm RED or TRI-colour LED and mounting bezel for modern and classic motorcycles and cars
Standard CWLs that power your choice of incandescent bulb or LED
Deluxe CWLs with Lucas style LED for super easy fitting to classic British motorcycles and cars
Combined Charge and Oil pressure warning lights for classic British motorcycles
All CWLs are 12V only with 6V CWLs made on request
How the monochrome Charge Warning Lights work
Please watch the above video that demonstrates two of these CWLs. To avoid distractions or having to monitor an indicator lamp while driving or riding, these CWLs work on the principle that no news is good news - if the light is off then everything is working ok
Turn the ignition on and the light flashes twice to tell you the unit has powered up correctly and then the light stays on (slow regular flash for combined Charge/Oil warning light). If instead it repeatedly shows two short flashes followed by one long flash, the battery is flat and needs charging
Start the engine and the light goes out when the alternator is detected as working and producing sufficient power to cope with demand and keep the battery charged
If the light repeatedly shows one short flash followed by a long pause then this is warning you that the vehicle's charge regulation system has failed and the battery is being overcharged
Simple to install, simple to use - never be in doubt whether you will be left stranded with a flat battery.
Once you have got familiar with the rpm and electrical loads the light comes on or goes off at, you will be alerted to problems the moment they occur. These CWLs not only warn of complete charging failure but by being aware of the normal routine, partial failures such as an alternator coil shorting to earth are easily detected
Better than an ammeter - how much current is too much? Measuring voltage instead of current gives you a precise warning of overcharging
The Standard Charge Warning light - £16.63 inc UK P&P
The warning lamp must be a maximum of 5W. An LED can be used if fitted with an appropriate current limiting series resistor.
If your Ducati's Voltmeter / Voltimetro has failed or you have replaced the regulator / rectifier and lost the charge warning feature, the negative earth Standard CWL is the perfect way to restore it.
The Deluxe Charge Warning Light with Lucas style LED - £17.93 inc UK P&P
The same as the Standard CWL but without the third wire with no pre-fitted connector. Instead there is a wire already connected to an LED moulded into a lamp holder. The lamp holder slides into the Lucas warning light lens used on classic British motorcycles and cars. Deluxe CWLs usually require no rewiring and simply plug in.
You supply the warning light lens. The lens must be red or amber for the red LED to look right. Check its internal diameter is 10mm before ordering. NOTE: The LED holder will not fit the lens used on later Norton Commandos with four warning lights surrounding the ignition switch in a plastic pod mounted between the speedo and tacho - order a Standard CWL to power your existing Assimilator light bulb.
Treat your classic to some 21st century technology while retaining a completely original look!
The Deluxe combined Charge/Oil pressure Warning Light with Lucas style LED - £18.93 inc UK P&P
The same as the Deluxe CWL but with an extra wire with pre-fitted Lucar/Faston flag connector that connects to the oil pressure warning light switch. Ideal for late 1960s and 70s classic British motorcyles already fitted with an oil pressure switch and warning light lens eg BSA Starfire, A50, A65, Rocket 3, Triumph Daytona, Bonneville, Trident.
Low oil pressure is displayed as regular flashes of the LED - slow flashes if the engine isn't running, urgent fast flashes if it is.
Once the engine is started and oil pressure rises the LED behaves exactly like the Charge only CWL.
Also available as a Standard CWL without LED.
Norton Commando Assimilator Light
The Charge only Standard or Deluxe CWL is an ideal replacement for the assimilator warning light system fitted to Norton Commando motorcycles (Lucas 3AW or 066393). And a better system than fitted to Norton rotary engined bikes. Both feature a sense circuit to detect that the alternator is working but they don't tell you if power is getting through to the battery. Although very good systems in their time, modern electronics makes a better system possible.
"Fitted it this morning and all works first time. At last a product that works on a Norton commando (converted to three phase charging). On at ign on and off at engine start. On again at full beam but off at 1100 rpm just as it should be." - Commando owner in south UK.
The CWLs contain a small but powerful microprocessor that measures voltage 15,000 times a second to a resolution of 0.017 volt. The bulb or LED status is updated 30 times a second - they react almost instantly. Sophisticated programming techniques eliminate flicker and reliably detect alternator ripple. I first started programming microprocessors in 1979. What you get is a properly developed, bug free product.
12V CWLs have a working voltage range of 4.2V to 22V DC and a safe voltage range of -16V to +22V. All CWLs are protected against voltage spikes from the ignition coil and can be used with all suppressed ignition systems including points and coil.
CWLs that power the bulb you supply use a maximum of 0.06W plus the power required by the bulb. CWLs with integral LED use a maximum of 0.5W
Hundreds of these CWLs are now in use on a wide range of classic and modern cars and motorcycles around the world, with applications including light aircraft, ride on mowers, E-type Jaguars and boats.Made in Britain
Terms and conditions
The most popular CWLs are held in stock and all others are made to order. Order through the "Buy CWLs" page. Customised versions made to your own specifications are available - please e-mail for details.
All CWLs come with a one year guarantee of replacement or refund unless damaged by incorrect fitment or use. Comprehensive fitting instructions are included - follow these carefully and you can't go wrong.
These CWLs are indicators of vehicle faults. Although they have proven to be robust and reliable, indicators can fail. No responsibility for loss or damage will be accepted under any circumstances for problems that lie elsewhere in your vehicle. You are advised to always check for the double flash at startup (colour cycle for tri-colour CWL) and that the combined Charge/Oil pressure CWL shows a regular flash indicating low oil pressure before starting the engine.
Will this work on my vehicle?
The CWLs should only be used with a suppressed ignition system. Unsuppressed may affect the operation of the CWL and is anti-social as it causes picture breakup on TVs in some of the houses you go past. Email for advice on how to test if unsure whether your system is suppressed or not.
These Charge Warning Lights work on any vehicle where turning the ignition on connects the battery to the ignition coil(s) or electronic ignition system.
To test suitablility, disconnect all but the wire going to the battery from the ignition switch. If you can find an ignition switch terminal that has no voltage with respect to earth with the ignition off but has battery voltage with the ignition on, then your vehicle is suitable.
If in doubt, please ask before ordering. Include your vehicle's circuit diagram if possible.
To report problems or for all enquiries please e-mail firstname.lastname@example.org