WOSP Alternators & Dynators

Dynamos

If your car was on the road before 1965, it is likely to be fitted with a dynamo. Under ideal conditions, such as steady driving on an A-road at around 50 mph, a typical dynamo will produce approximately 13.5 volts at 20 amps. As soon as engine speed drops, output falls significantly, and when idling the battery will often begin to discharge.

In modern driving conditions, dynamos rarely provide enough output to properly charge the battery. With additional electrical loads such as electric cooling fans, they often do little more than keep pace with basic demand. Lead-acid batteries perform best when kept fully charged, and extended periods of discharge accelerate performance loss and premature failure, regardless of battery capacity.

The traditional solution is to replace the dynamo with an alternator. Alternators produce more power, operate more efficiently, and continue to charge the battery even at idle. However, thanks to WOS Performance, an electrical engineering firm based in Aylesbury, Buckinghamshire, there is an alternative solution.

WOSP Dynator

WOSP has engineered the internals of a modern, high-capacity Denso alternator into the housing of a traditional Lucas-style dynamo. This approach delivers modern charging performance while retaining the original appearance of the engine bay.

The key benefits include:

• Significantly improved charging capacity
• Extended battery life
• Immediate charging as soon as the engine starts
• Retention of the correct period appearance
• Straightforward replacement with no major engineering or modifications required

Over the past nine years, we have fitted dozens of WOSP Dynators across a wide range of classic cars, from early MGBs through to Aston Martin Le Mans models. Without exception, these installations have resolved charging issues while maintaining long-term reliability.

Most dynamos are mounted in relatively accessible positions within the engine bay. Replacement, including new cabling and reworking the engine bay wiring to suit, can usually be completed by one of our experienced technicians within a morning.

Why do I need a more powerful  alternator?

Most cars built after 1965 are fitted with an alternator. Typically, these units produce around 45 amps, which was entirely adequate at the time. When cars were used daily and driven for extended periods, the charging system had ample opportunity to replenish the battery, as relatively little electrical demand was placed on it.

Modern usage is very different. Classic cars are often left unused for weeks at a time, then expected to perform immediately. Owners start the engine, plug in mobile phones, switch on the radio, run high-output headlamps, and expect the battery to cope without issue. Unfortunately, this often highlights the limitations of original alternators.

Even when new, many of these systems were operating close to their limits. It is little known that a standard alternator can take around 20 minutes of driving simply to recover the power used during engine start-up, before it begins to charge the battery properly.

WOS Performance alternators, manufactured in Aylesbury, Buckinghamshire, offer a reliable solution. Their range of high-output replacements delivers between 65 and 200 amps, while being engineered as direct replacements for original units. All WOSP alternators are built using high-quality Denso cores, ensuring durability and consistent performance.

WOSP alternators represent excellent value and are available for almost every classic car on the market. We have fitted dozens over the past eight years and have yet to see a vehicle return with charging-related issues.