Evitzee

A couple of weeks ago I started a thread regarding the battery in my IS that went dead after sitting for just 17 days. After jumping the battery and taking it in to the Lexus dealer they told me that they see Lexus’s coming in with flat batteries if they sit for two weeks or more due to the current draw of the supporting electronics. They recommend a trickle charger to keep the charge up. Here is a simple DIY to solve the problem.

First, I would not recommend the simple trickle charger. They are cheap and they allow the value of charge current to trickle down to what appears to be a safe level, but the output voltage of the charger rises well above 15 VDC which is well above the gassing voltage of a lead acid battery. If the battery remains connected to this high level of voltage for an extended period of time extreme damage can be done to the battery. So, a better solution is to use a charger with smart technology, I have had excellent results with the BatteryTender which I’ve used on my motorcycles for over ten years. Batteries will often last five to seven years when set up with a BatteryTender with absolutely no maintenance. The advantage of a smart charger is it delivers 1.25 amperes during the bulk charge mode, holds the battery charge voltage constant during the absorption charge mode, then it automatically switches to a float charge mode. This keeps the battery topped off while minimizing any detrimental effects due to gassing. These complex switching functions are handled by an internal microprocessor. See www.batterytender.com for more information, including lots of data on battery charging. You can get these in all the usual places, including the Bay, for $50 or less.

Basically you hook up the leads to the + and – terminals of the battery which has an inline 7.5 amp fuse and terminates in a quick disconnect plug. There is another quick disconnect plug coming from the charger which eliminates any chance of incorrect attachment. If done carefully you can attach the ring leads to the terminals without disconnecting the battery, just use a 10mm socket to remove the nut, slip the ring lead on, and reinstall the nut. Total installation takes less than 10 minutes and even the proverbial caveman/cavewoman can handle it.

Since I sometimes let the car sit for two to three weeks (I work elsewhere), I’ve now put the IS on the BatteryTender; I don’t expect to see any more problems with a flat battery, and will probably see an extended battery life.



The disconnect plug; there is a matching plug coming from the charger:


Attached to the + terminal, there is another one for the – terminal:


Quick disconnect leads plugged into each other:


Setup and monitoring/charging the battery. When ready to go just unplug, tuck the lead next to the battery, and you are good to go. Theoretically you can leave the BatteryTender connected to the battery forever and it will keep it topped up with no chance to overcharge the battery. This could be useful to those who put up their vehicles for the winter. Your battery will be fresh to go in the springtime:

taylorjste

interesting write-up.. ive never considered this an issue since i usually dont leave my car for more than a few days.. but it's definitely good for the guys up north who fire up the winter beater for several months of the year.. thanks!

as3.0cl

iTrader: (2)

got about 3 of those at my house for the bikes during the winter since me and my father doesn't ride them, but when they are hooked up the battery is never dead.