Can a Battery Tender simply be plugged into a touring bike's cigarette lighter (on a 2009 FLHT in this case) using the appropriate adapter, or is it necessary to run a pigtail directly from the battery? Your patience with my limited electrical knowledge is appreciated.

 

I've been running a battery tender on my bike for years through the pgtails off the battery. I didn't get an adapter to go to the lighter. I don't know if I'd run a charging unit through an auxillary input.

 

When the ignition is off there is no connection to the battery from the lighter so this will not work. Only takes a few minutes to hook it to the battery.

 

You DO need a pigtail direct off the battery! I have fitted an accessory socket into the side-panel near my battery to take my tender. Looks similar to a lighter socket, but smaller, with a hinged cover. BMW bikes come with one standard and I got mine from an independent BMW parts shop.

 

No cause there's no power to the lighter when the ignition is off. Your battery tender should have come with a pigtail connected to the battery via 2 rings. You leave it on the bike and connect the battery tender whenever you need.

 

BMWs do come with one. Only problem is their elctrical system is so complicated it requires a $200 (yes two hundred) special BMW charger to work

I wired mine direct to the battery as well.

 

Are you sure the pigtail isn't on there already? My 07 vrod came with it on and my 10 road king has it on already too. Check under the seat on the front side of the battery it might already be there. I think harley does this so you'll buy their tender.

 

Harley does not include the pigtail. Some dealers install them theirselves. Mine does this, but then charges for the Battery Tender seperately. I bought mine at Walmart.

 

Its best to put the pigtail on the battery.
The cigarette lighter is off when the ignition is off.

 

Hook a pigtail up to the battery and you are good to go.