For anyone using a Battery Tender, are you clipping the negative clamp to the battery's negative post, or to the grounded negative metal bar at the back of the engine, under the cover?

 

Perhaps I'm living on borrowed time but I clip directly to the battery posts/terminals. The batter tender doesn't have any voltage present on its clips until it senses the battery voltage so no sparks are generated when attaching. Detaching is a different story though so I suppose you could make some sparks when detaching, so technically it's best to attach the ground somewhere away from the battery and not directly above it. If a battery out-gasses it is hydrogen gas which is lighter than air so it rises. Sparks just above a battery are therefore not so good.

 

I have mine hooked-up permanent. So I have it bolted to the positive side, (red) on the battery, and the other to a bolt. I don't remember exactly which bolt I loosed and put it under. Worked last year on the SC, and I'm hooking 1 up on the ES this year also.

 

Where are you running/storing the cord for permanent hookup? Sounds like a good idea.

 

Mines just on the battery, but I always unplug from the mains before disconecting from battery. The instructions I got with my Detran only mentioned connecting to the battery, so never occured to me to ground to the body.

 

I keep a Battery Tender ( Deltran ) on all my cars and motorcycles. Each vehicle has a pigtail which installs on the battery post. Been using them for years. Example, last year I replaced a 9 year old OEM battery in my LX470 and it wasn't because I had to.

 

Maybe its just lore, but I thought the point of connecting the negative jumper to the engine block was to keep any potential spark away from the battery vapors. That's also why I was taught to do that connection last.

 

Your theory is correct when you are jump starting a car from another vehicle. However Battery Tenders only put out 1.25 amps. That's the difference.

 

I have the battery tender pigtail permanently attached to the battery posts. I keep it outside of the car when its charging [ hood not fully closed ] I unplug the cord first then cap the pigtail with its attached tether cap and close the hood before I start teh car. I keep the tender on all the time when the car sits in the garage.

 

I tend to use a chasis point for the ground.

 

Keep in mind though that even interrupting 1.25 amps when there is any inductance will cause sparks, small as they may be. Yes, the higher the current the bigger the sparks but there's always a chance of a problem. Unplugging the charger first, or using a remote ground is the safest bet. This is a good thread as it reminds me not to get lazy and tempt fate.

 

After disconnecting from wall, I unplug, reinstall plug cover, then just tuck it next to the battery, out of the way. On the ES I do the same and put the cover back over the battery.

 

Yesterday after three battery failures in less than a year due to not being able to drive much I purchased a Battery Tender at the dealership for my '02 RX300.

The mechanic installed the line that goes to the battery so that it can be hooked up to the charger from my grill area. I was so grateful as I don't know how I would have been able to lift the hood and do all the hookup otherwise.

 

Could anyone that has attached the "permanent" pigtail setup post some pics of what it looks like..I drive my '02 on weekends, and never in the rain ( has been raining on and off for the last 2 weeks in AZ...) need to be able to show this to my wife (AZKATY) so she does not get upset with me doing this!!! Thanks, Bob

 

It's ver simple.

I use a 2 station Deltran tender for my Boxster and ES300. Prior to the Porsche I used it on my SC430.

I used the battery clips, these simply clamp onto the battery poles the way a jumper cable does. Very simple and my wife is able to ndle it.

It also comes with another connector - an eyelet - the you bolt onto the battery clamps. These 2 connection require you being able to tell RED FROM BLACK and are simple to make.

Both of these connectors terminate in a POLARIZED CONNECTOR that connects to the cable coming from the tender. This connection IS IDIOT PROOF!!!!!

Real simple and works great, no more dead batteries