Have a friend with a 2007 SC. Doesn't drive it much and 5 batteries have been replaced. The Tender is probably a nuisance for her to use. Is there a device that limits battery draw more than what is needed to maintain electronic memories?

 

Short of pulling fuses every time, I can't imagine how such a device would work. You could put a battery disconnect, but the electronics would lose settings every time. There's always a chance the batteries aren't bad in the first place, or incredibly inferior batteries are being used. Unlikely. Has she ever had a competent mechanic look at it? I can't imagine a shop just changing batteries that often and never giving her any commentary as to what's going on. Not driven much is not that great of a diagnosis for what's going on.

 

if a battery tender is to much trouble then she should start the car more often or is that to much trouble also.

 

He said that out loud, LOL

 

Putting a battery tender is more nuisance than replacing 5 batteries? Even if the batteries were under warranty I don't see it..
I have a ctek battery charger/tender with quick disconnects on my cars and my bike..
http://store.phantasmusa.com/ctek56158.html

 

There are a bunch of threads on the phantom battery drain in the SC. Generally speaking, if the car has been parked more than a week, I don't expect it to start. In my trunk at all times is a that is the best $65 I ever spent. It's small enough to fit in the little cubby on the far side of the trunk, but has enough power to easily start a completely dead battery. After about three jumps, it needs to be recharged.

I think this is what you are suggesting, although I have never tried it. As Rudy points out, once you disconnect the battery, you would have to reset memory devices (clock, seat, NAV settings, etc.)

From the manufacturer:

PriorityStart! is the only totally automatic battery/alternator/electrical protection system in the market today. PriorityStart! monitors the battery voltage. If battery voltage gets below 11.7 volts for a full minute, when the key is off, PriorityStart! automatically disconnects the battery. The unit then automatically reconnects the battery - simply operate a light switch, push on the brake pedal, or activate any other accessory and then turn the key! And START! NO DEAD BATTERY.

PriorityStart! ProMax and ProMax H.D. units are small, computer chip driven, electro mechanical devices with a bi-directional motor and 10 gear system that delivers 243 to 1 gear drive ratio and closes with 100 pounds of linear force, (Heavy Duty (H.D.)) unit has been enhanced to deliver 40% more linear force for heavier duty vehicles).

It will handle a maximum of 1000 starting amps (Heavy Duty ProMax H.D. Unit handles 1600 starting amps) and uses proven technology. Its housing is polypropylene - the same material as a battery case, weight, approx. 1.5 pounds.

Vehicle computer systems have memory that resets itself. Clock and radio may need resetting. Remember, PriorityStart! has protected your battery starting power. Without it you would still have to reset memory devices.

 

They aren't Optima batteries by chance are they?

 

Very Interesting product. This may work for other cars but I doubt that will be able to start an SC430 with a battery that has been discharged to the point that the resting voltage is 11.7 vdc.

 

Battery tender is key in a case when you just don't use any vehicle, but the sc430 and my lx450 lexus are really bad.

My advice is to buy batteries with 5 year warranties. Walmart is good source. 3 years full replacement, then 2 years prorated. Only cost about $15 more. I am sure it is the same battery, but you buy that insurance. KEEP THE RECEIPT.

I have not had to buy a new battery in years! With all the discharging they last about 3 years, go bad and I get a replacement.

 

I installed this thing in my SC a few weeks ago.
http://www.interstatebatteries.com/p...351-2147384906

 

Something else that was mentioned recently was to turn the lights off every time rather than leaving them on automatic. The extra drain caused by leaving the lights on for a little while after shutting the car off may be a large portion of the problem. Also, make sure that the doors and the trunk are all being properly closed. (You can replace the dome lights and trunk lights with LEDs to mitigate some of the problem with doors or trunk being left partially open though.)

Other than that, no one has really had much success overcoming this problem if their car has the problem. Some cars will drain the battery in less than a week and others can leave it for 3 weeks without a problem. We haven't been able to find the smoking fuse yet (so to speak).

 

This car is sometimes too smart for our own good! I just finished fighting the good fight with the passenger door lock actuator. When the car is parked and the driver door is locked, the computer tries to lock the passenger door as well. If the lock actuator motor is shot or the mechanism won't allow it to lock OR the contacts inside the black box actuator are broken or for some other reason don't make contact, the car will continue to try to lock itself. My battery went dead inside of a week before I fixed the problem.
You can tell you have the problem by sitting quietly for a while after exiting the vehicle and locking the door with the remote--you'll hear it try every few minutes.
If the problem is the motor (most likely), you can stop the recurring locking signal by manually locking the offending door. If the problem is the internal black box contents, you must leave both doors unlocked (not a good security thing).
There are probably other things that eat up the battery, but since I fixed the lock actuator, my battery stays up for a couple of weeks without a problem.

 

Even the owners manual says if you are not going to use the car for awhile you should turn the headlight switch from auto to off.

 

I have wing nuts on my battery posts disk connect very quick then no draw. no big deal.