sktn77a

iTrader: (2)

Yes, I read the threads on this and had the alternater belt tightened, and the battery and charging system tested. Everything is A OK. The clock resets itself to 1.00am every time I start the car but the radio stations and mpg, etc, are still there. Alternater belt wasn't loose but had screached a couple of morning when it was cold, so I had them tighten it. It can be twisted still, but not 90 degrees. Battery tests 12.7 volts and when I connect it up to the charger shows fully charged (not low) and the battery place told me the alternater was just fine.

Any ideas?

Lil4X

Still sounds like the battery. It can produce about 12v while no heavy demands are placed on it, but during an electrical deep knee bend, it shows its true condition. Voltage is not the whole story - voltage while cranking the engine would tell you more. Put that puppy under a load and I suspect you will see the voltage crash through 8-9v pronto. The clock resets to 1:00 when it is not getting sufficient voltage - it's sort of an early warning, whether by accident or design.

Have your battery checked UNDER LOAD (free) at Autozone or other retailers - my local Firestone shop does it too (minimal charge for that and other tests, refundable with purchase). It takes some special equipment to do it properly, but the results are instructive.

sktn77a

iTrader: (2)

Yes, that come up on my google search. I also thought about a memory fuse but (a) don't know if the RX300 has one, (b) the clock doesn't reset every time, just some, and (c) no other radio/info memory is lost. I was also considering a bad starter with excessive current draw in some positions, but not others (?)

mikey00

It's the battery. Change it and your clock problem will be history, no mater what all the tests indicate. Many others have gone through this already. Battery usually passes a load test no problem, but change it and clock issue is gone.

salimshah

Listen to Lil4x ... the clock resets when the battery voltage falls below the threshold and it happens under load and will be dependent on the duration of crank.

If after an overnight charge, the thing happens again, it is time to get a new battery. And get it before you get stranded.

Salim

Lil4X

If you are experiencing any kind of electrical gremlins in that center stack, most notably with the clock resetting - and your battery is over 48 months old, it's the first place to look for a problem. Even very expensive batteries can fail well before that time. It's rare, but it happens.

The reason I recommend a load test is to determine that your alternator (and diodes) are working properly - even if the battery is moribund. No point in replacing the battery only to have your investment zapped by a malfunctioning alternator/voltage regulator.

sktn77a

iTrader: (2)

Tested the battery voltage under load (when starting) and it went down below 10 volts. So, I take it that the battery is bad?

salimshah

Yes. You can wing it for a bit, but you know what is about to happen. In any case all the electronics are usually happy with good voltage ... the sensors put out incorrect information when the voltage is low ... It seems the alternator is restoring things to normal after the heavy draw.

Use the interim time to figure out which battery to buy and when things are on sale.

Salim

mikey00

My fairly new Costco battery, which has better specs than the original battery, will dip to 10.9 volts when cranking. You can bet the clock threshold is somewhere between 10.9 and the less than 10 that you are getting. Your battery may last a long time yet at 10 volts cranking but if you want to fix the clock thing, just change the battery. The RX clock is sensitive, which may be a good thing.

sktn77a

iTrader: (2)

OK, I've been looking at replacement batteries (I'm a little leery of Batteries Plus now, as I've never had a battery crap out on me this quickly before). I usually go for Sears Die Hard batteries because of their availability but I can't find the CCA spec for the OEM Lexus battery and their Die Hard South batteries look a little on the low side - 500 CCA (?) The Die Hard North battery is the same price but had a much better spec - are we southerners subsidising those carpetbaggers in the north again

thomas1

Buy a Costco battery, they are reasonable and will last a long time...

sktn77a

iTrader: (2)

Unfortunately, I'm not a costco member and when you add the membership to the price, it doesn't look as good.

Anybody know the answer to my original question - OEM CCA for the RX300 battery?

sktn77a

iTrader: (2)

Never mind - found it after searching through almost a 1000 posts (need a more intelligent search function)! It's 585 CCA.

salimshah

Keith:

The cca number just puts battery in class of min requirements. The physical size, terminals, orientation etc are the other considerations. I always harp on sealed batteries .. a bit expensive but keeps the engine bay clean of fumes.

Salim

lexus114

sealed batteries are my favorite too,but seem like they are harder to find.