Hey Team,

Ive noticed the ISF doesn’t store well. It seems to discharge its battery quickly. Last year I threw a Costco battery in it since it seemed like it was discharging quickly.

I’m having the same issue this winter. I would have hoped it could sit a couple months without dying, but I’m finding that it’ll completely discharge a battery pretty quickly. It was dead 2 weeks ago, I jumped it and ran it for 30 minutes. Came out today to start it and it was so dead that the door wouldn’t even unlock.

Is this par for the course on this car, or is there something up with mine?

 

A couple months is a long time for any car as far as I'm aware. I usually only let my cars (any) sit for a couple of *weeks* max before I throw a battery tender on it. Cold weather makes it worse too.

It's also not good for traditional batteries to let them run down to very low charge so if you are doing that on any common interval then it's likely you are making the issue worse (reducing the life/retention of the battery).

 

Yep, battery tender every winter.

 

Your intermittent use is causing sulfating on the plates. You need to either change battery chemistry or get a charger specifically designed to reduce sulfation and keep it on your battery when you are not using the car. I learned this valuable lesson with motorcycles years ago. When I didn't own a car and rode my bike every day I never had battery problems. When I finally bought a car and quit riding daily, my batteries (the expensive hot rod ones) were dying quickly and unrecoverable. My good friend who owned a small fleet of bikes told me to buy the cheap batteries, they tolerate the abuse of non-use much better, and when they sulfate, just recycle it and get a new cheap battery. In the mid-90's I learned about Pulse Tech and their patented chargers capable of de-sulfating lead acid batteries, and found the military was using this technology to literally save millions annually on batteries for vehicles in storage.

My Supra suffered the same issues you are describing, and I got a charger capable of maintaining a charge on AGM batteries (yes, this isn't the same as a conventional flooded battery) and it worked for a good long time, but then I got the LiFePo4 Antigravity, and I've never looked back.

A couple of important points - keep your key at least 5 meters away from the car to let it go into sleep mode. If the key can be read by the car, it will stay in a higher state of power consumption anticipating use in very short order. If you can't get this distance, remove the battery from the key when not using it. Get the appropriate charger for the battery you have, and keep in mind an AGM battery has different needs than a conventional flooded battery. Just starting the car and running it barely charges anything. Real charging starts at 2k rpm. Anything less is a waste of fuel.

 

^^ Ditto..

See my posts here:

? on use of a battery tender

Joe Z

 

Same experiences here. Once the car sits for over a week, a tender goes on it until it's driven again.

 

Can you elaborate on the 5 meter part? My keys hang on the house side of the garage door, so they are within 5 meters. They are not so close that I can walk up to the car and lock or unlock it. Is the car still sensing them, or is there a way to tell? Since I noticed my is350 is cranking slowly lately, I want to make sure they aren’t to close. That battery is about 4 years old, so it may just be coincidence.

I ordered the antigravity for the ISF. Excited to lose another 30 pounds.

 

No easy way to tell. Lexus documentation says 5 meters, but walls can make this significantly less. Might want to try a Faraday cage on the key to see if there is a difference at your storage point.