Attaching Negative Lead - Battery Tender/Trickle Charger

[Davie Boy]

I know dick about electrical stuff, so forgive me if this is a stupid question. Where in this mess should I attach the negative lead for a battery tender / trickle charger? I understand the positive lead should be attached to the positive post on the battery, but the negative lead should be attached to a ground someplace on the car. Where's the best / safest place? These are leads that will be left attached to the car indefinitely and plugged into the charger when the car is parked. This is on a 1971 911 T.

[gazzerr]

On the left side of the car in the frunk near the front there's an oval opening in the bodywork on my 82 SC. I like to clip mine there. Any good ground like a bolt or latch on the body work is usually fine.

[RSBob]

See where your ground strap attaches? That's th copper colored flat thing coming from the negative terminal, attach it where it attaches to the chasis

[Rawknees'Turbo]

You can attach it to the bolt that is holding the capet snap bracket in place (directly above the positive battery terminal) - works perfectly and is a much smaller diameter bolt than the one for the ground strap.

[Davie Boy]

Thanks all for the info.

[MIK911]

I know less than Davie Boy. Why don't you want to attach the Negative lead from the Batter Tender directly onto the Negative post on the battery?

[A horse with no name]

Originally Posted by MIK911

I know less than Davie Boy. Why don't you want to attach the Negative lead from the Batter Tender directly onto the Negative post on the battery?

+1...Yes, if it is a permant wire that unplugs at the other end for your charger, then for sure, attach it to the battery the same way as the positives wires are.

[T77911S]

you don't have 2 6volt batteries do you

to the neg post is fine.

putting the neg side on body ground is a jumper cable thing. they do that because of the spark.
you really don't want the spark near the battery.
for the really old cars they use to just touch bumpers, now its hard to find bare metal to clamp to and in some cases its hard to find the battery. by BMW has posts in the engine bay for battery connections. battery in the trunk.

[911pcars]

In that vein, if it's a permanent connection, you could also attach the positive lead to an active 12V fuse in the box so your added charge circuit is fuse-protected when the car is running.

Sherwood

[Joe Bob]

Don't use the alligator clip one, use this and attach to the battery full time. Negative to the bolt on the end of the clamp, same for +. Red = "+", Black= "-" -

The pigtail is a simple plug into the tender. + is shielded and pretty much idjut proof. ONCE you hook up the pigtail CORRECTLY....





I leave the shielded plug hanging by the front plate, I don't even have to open the hood. The one comment I got I told them my SC was a Hybrid and that was the home charging port....