Battery Tender ?

Westy · 01-10-2016, 04:31 PM

I've had this thing on a brand new (charged) battery for almost three days now, and it's still got the red LED glowing. I have a ghost draw on my 911, but still, the light turns green within a day. Also on my SXS, lawn tractor, and Camaro. I've been thinking the charging system on the car itself is faulty, but I really don't know. All I can think of is the radio alarm and the clock. The car alarm is off. Is there a ghost drain on these vehicles where a Battery Tender won't keep it topped off. This car is relatively new, and I have a lot to learn about it, but this just doesn't seem right. I don't even drive it 'cause right now it's cold and rainy!

GreenWater · GreenWater's Garage

Kind of interested in this too.

My car will drain my new battery in about 6 or 7 days if I don't drive it. I guess that's a good excuse to drive the car. lol.

I have a small battery tender, and it takes forever to charge the battery. It's made for smaller batteries and doesn't put enough power back into the battery. If the battery is dead, and disconnected from the car it takes about 5 days. A battery charger or tender with more power would be better for recharging the battery.

I've tried to find the drain in my car before with no luck, but I'm not a genius when it comes to this kind of thing.

And I too have the factory alarm in the car.

thomasryan · 01-11-2016, 08:02 AM

Hmmm...I would load test the battery or check the specific gravity of the electrolyte.

Tenders are like an amp so a parasitic drain like alarms, clocks and radio presets might cut that in half.

Plates get crusty and limit current flow so you might pop off the caps and take a peek inside.

Westy · 01-11-2016, 08:53 AM

This is a brand new battery. About a week ago I put a charger on it. The green light never came on, but the analog gauge dropped to around '2', which is correct. As I've said in other posts, this car is fairly new to me and I have a lot to learn about it. As with my 911, it will be the norm to keep my Battery Tender on when not in use. Besides, I have a history with auto batteries,,,none of it good!

88Silver924S · 88Silver924S's Garage

Have fun browsing the articles on cold wet nights:

Basic to Advanced Battery Information from Battery University

Even though a battery is "new" it may have been sitting on a shelf, in a warehouse, on a truck, etc for weeks and months and may appreciate a good charge when actually put into service so it may take a few days with a 1 amp maintenance charger to get the battery up to full charge all the while the parasitic drains of alarm, clock, radio or whatever is draining off a little.

Did you get a new battery for a reason such as a bad diode in your alternator or something? That is maybe there was an electrical short that killed your old battery? Good Luck!

Westy · 01-11-2016, 01:43 PM

^^^ When I bought the car the battery, which was about 2 years old, stopped holding a charge. I've had a charger on my new battery twice 'cause it almost went dead from non use after a couple weeks. My NAPA guy also put the meter on on the battery while the car was running. He said it appeared the alternator wasn't fully putting out. I can't remember, but it was 12.4 or 12.7 volts. I'm already thinking the alternator is acting up, but that has no bearing on why the battery would discharge so quickly during a short period of inoperation. I'm sure there's a drain. I'll leave it plugged in from now on. Not a huge problem. It's more important right now to find the coolant leak!

grendiers · 01-12-2016, 07:29 AM

Pull the far left gauge, and feel around for the relays back there. One might be warm, and there's your draw. My '85 911 did this, I think it was the window relay, but not sure, sold the car a year ago. But, after replacing the relay, I still had a draw, but not as bad. Installed a battery tender.