Will a USB charger drain a motorcycle battery?

Are you running accessories on your motorcycle through a USB charger and worried it would drain your battery and leave you stranded?

Yes, a USB charger will drain a motorcycle battery. However, the power draw is so low that it takes days to drain the battery, if not a week or more. The motorcycle’s alternator/stator should be able to charge your battery adequately while you use your accessories through the USB port.

Will a USB charger drain a motorcycle battery?

Yes, if it powers an ancillary device like a GPS, it will draw power from the battery. However, the alternator/Stator should be able to charge the battery sufficiently to replace any charge used by the USB and GPS.

Many motorcyclists complain about the rate of power drawn from a USB. If the USB is causing your battery to be flat, something is wrong.

If you are only using your motorcycle at the weekend, then having a USB powering an ancillary when the motorcycle is not being used will deplete the power battery.

USB ports only draw 0.5 amps to 1 amp. This is an insignificant amount of power and should not drain the battery unless, as said before, you have been using that power for days while the motorcycle is not being used.

If you are experiencing a full drain on the battery, check with a voltmeter. There is no another problem. Lose battery terminals can cause havoc. A faulty alternator/stator will not replace the charge faster than the battery is being drained.

Can you put a phone charger on a motorcycle?

Yes, if you have a USB port, there is no reason you can’t charge a mobile phone as long as it is securely attached to the motorcycle.

If you are retrofitting the USB port, using an SAE cable for your connections to the battery and the USB is recommended. You could also fit a relay, so the USB only receives power when the ignition is switched on.

What would drain a motorcycle battery?

If your battery is drawing while riding, you may have too many gadgets drawing power or a power leak in the circuits. More commonly, the battery terminals are corroded or loose. 

A bad stator or rectifier will cause your battery to drain sometimes. It’s just the battery has reached the end of its life.

Does the USB drain battery?

Yes, if you connect a gadget to charge from a USB, it will be pulling power directly from your motorcycle battery.

But, your alternator/stator should be supplying ample power to the battery to replace and power being drawn by an ancillary item.

Even leaving an unused USB connected to your battery will draw a tiny amount of power. This is not a problem if the motorcycle is used daily.

To combat this situation, you can wire a simple on-off switch for the USB to ensure no power drain when not connected to a gadget.