Starting car with Battery Tender attached?

I almost started mine the other day with it attached, but looked up and saw the cord before I started it... Not sure what could happen--I imagine nothing...

 

Nothing. I do it all the time with my BMW, and a few times with my 355. Have done it many times with my motorcycle as well. (I have several of these things as you can see)

 

That could be a problem for trikle charger but not for the Tender.

 

For a real tender, one of those units that actually senses the charge and adjusts accordingly, probably not a problem. They have built-in circuit protection, usually. For those trickle charger units that are just a transformer you plug into the wall and connect two leads to the battery, probably not a good idea. Those are not very sophisticated, just a simple transformer.

Personally, I disconnect the charger unit, even though it has a protective circuit in it. It takes all of 10 seconds to do, so no biggie. I figure better safe than sorry, so why take the chance.

 

I've been starting cars with a charger attached for as long as I have been messing with cars. I've never noticed a problem with any chargers when doing this.

Bob Wassam

 

Agree with this description

 

I'm saying this because if a battery goes to fully charge even when a Tender is hooked up, the Tender just goes to FLOAT Mode, there for it's safe.

 

I am not an electrician, but would could possibly happen without such protection circuitry? We are not shorting the terminals or anything, just starting the car, which would draw some current, that is all.

 

Not a good idea...
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LOL!

 

So far I have always remembered to detach the tender before starting. I have nightmares about driving off with it attached and causing damage to the car.

 

Now thats the best technical reason for not starting it with the battery tender attached that has been posted so far.

 

I have started many cars with a battery charger on them including my 328 when the battery was low and I have to use the start function on my charger. Never have done it with the tender on. Shouldn't cause a problem but why take the chance? I would avoid doing it unless you have to for some reason. Not good for the car if you are just going out there and starting it over the winter unless you run it long enough for the exhaust system to get hot enough to bake out any moisture. There was a good thread talking about this a month or two ago if that's what you are thinking?

 

Mine is attached through the cig lighter, not going to happen.

 

Don't start your car with the battery tender attached.

I had a tech explain to me why it is bad, but I cannot remember the details. Has to do with the alternator and the charging system.

 

Because the answer is not clear, the tender is not cheap and repairs to a Ferrari very high...why take the chance? My charger connections are all in easy to reach spots so I always disconnect them before starting the cars. Plus...I don't want to drive off with one connected like the lady with the gas pump!

 

I've talked to DELTRAN the makers of the Tender and ask if it's ok to start the engine if tender is attach?

Their answer is YES it's ok as long as you don't let the engine run for a long time.

I also like to add that the Tender has the Reverse Polarity safety feature where it will NOT charge if reverse.

 

THANK YOU!! I have a Deltran on mine and I've always wondered about the same issue. Mine is pig-tailed to the rear-battery in a 348, not ciggy lightered.