Using a MOSFET Voltage Regulator Rectifier with a Lithium Battery on Classic Motorbikes

As more riders upgrade their classic motorbikes with modern electrical components, we often get asked whether our MOSFET voltage regulator rectifier is suitable for use with a lithium battery. It’s a fair question—and one that doesn’t have a simple yes-or-no answer.

While we can’t give a definitive endorsement of the combination, we can share our experience and offer some guidance for those considering this setup.

A Popular Upgrade Path

Replacing an aging regulator rectifier with a modern MOSFET unit is one of the most popular electrical upgrades for classic bikes. The benefits are well-known:

• Smoother voltage control
  
  

• Better heat handling
  
  

• More efficient operation at all RPMs
  
  

MOSFET Voltage Regulators are specifically designed to maintain a very stable voltage output. This characteristic is one of the key benefits of MOSFET technology, as it helps to reduce stress on all electrical components within your motorcycle's system.

Lithium Batteries on Classic Bikes

Lithium (LiFePO₄) batteries are increasingly popular for older machines due to their lightweight construction and low self-discharge. However, they also come with caveats:

• Sensitive to over-voltage
  
  

• Do not tolerate deep discharge
  
  

• Often include a built-in Battery Management System (BMS)
  
  

These characteristics mean they’re not as forgiving as traditional lead-acid batteries when it comes to fluctuations in charging voltage.

So, Are They Compatible?

We don’t claim definitive compatibility between our MOSFET voltage regulator rectifier and lithium batteries. However, no issues have been reported by customers who have run this combination, even over the long term. Riders report stable charging and trouble-free operation.

Still, there are a few points worth noting:

✔️ Voltage Control

Our MOSFET units regulate output to around 14.2–14.4V, which sits within the typical charging range recommended for lithium batteries. However, not all lithium batteries are built the same, so you should check the specs of your battery before use.

✔️ Solid Electrical Connections

Good wiring practice is essential—especially with lithium batteries. Ensure all terminals are clean, tight, and well-grounded. Any poor connection or voltage spike could stress the battery’s BMS.

✔️ Battery Choice Matters

We recommend choosing a lithium battery from a reputable brand that includes over-voltage and thermal protection. Cheap, unprotected batteries are a risk in any charging system.

Final Thoughts

If you're thinking of running a lithium battery with a MOSFET voltage regulator on your classic bike, the short answer is: it seems to work well, based on real-world usage. While we can't offer official confirmation or warranty around this combination, we’ve seen no problems to date from riders who’ve gone this route.

As always, use common sense when working on your charging system. Double-check voltages, inspect wiring, and make sure your components are up to the task. If you’re ever unsure, feel free to get in touch.