Battery replacement *before* failure

i've got an '06 w/ 45K miles. had a couple of incidents where i didn't drive for 4-5 days.
when i returned, battery low/dead enough that i couldn't get the READY lite to come on (prob should have turned off the SKS).
had to do the jump-start technique from under the front hood (that's a good procedure to know!).
anywho...after the 2nd time I decided to go with the eLearnaid Optima Yellow.

that's the best choice, and has worked great for me.

 

If you would be unduly inconvenienced with a dead 12V auxiliary battery, then certainly it would make sense to replace it soon as a preventive maintenance move. This makes even more sense if you live in extremely hot or cold areas.

OTOH, my 2004 with 71K miles has the original battery installed; I will probably replace it in late 2009 (if it doesn't die before then) as it will be 6 years old then.

 

My 2004 Prius just finished 5 years inspection (Japanese SHAKEN process).
The dealer checked the 12V battery using a battery tester and told me the battery is going to be weak. They also told me the battery will die in six months.

Ken@Japan

 

If I was paranoid I'd change my battery at 4 years old. I replace a car battery if it goes flat just once, maybe I am paranoid? My Camry battery was 6 years old when I replaced it.

 

I posed a similar question here.

 

You -could- be environmentally conscious and not replace it until it goes dead. Instead, right now get a portable booster device so you're ready. It will come in handy if someone else wants a boost, it can provide 12V power when picnicking etc., and will let you get on your way -when- your Prius 12V battery finally runs out of life. This will happen anywhere from 3 to 7 years after its' new.

-Fully- using up the resources you buy before disposing of them IS the most environmentally conscious thing to do.

 

If only our medical doctors could prognosticate as efficiently...............

 

Especially with a prostate exam. Why do their fingers have to be ICE COLD?

Back to topic: the Prius battery isn't known for long life. The Optima replacement *might* be better, but they also haven't been around long enough in the Prius to know for sure

Since I've used a VDC Battery Minder on my Prius battery since early 2005, my battery is still going strong. If I have to replace the battery, I'd probably go with the Optima one

Make sure to properly and fully charge whatever replacement battery you get, before installation.

 

Fascinating, we'll check back with you in September to see if this prediction turned out to be true or false.

Yes, this depends upon your personal situation, who is driving the vehicle, and the amount of drama already in your life. Its not impossible that someone can screw up a jumpstart and kill the inverter, as we've read those stories a few times here. The good news is that each member has the info to make a decision that works for him/her.

 

I'd like to hear more about the VDC product.

How often do you use it ?
Can the terminals in the front of the car be the access points ?
Other important things to know ?

Thanks! -- Eric

 

we just replaced ours recently, but we had evidence of weakness. it's probably most prudent if you haven't had problems yet to get it load tested before just replacing it.

 

Galaxee, can you suggest a simple 'load test' I can do at home ? I presume it means check voltage after draining the battery for a while, but specifics are welcome !

 

My 2004 Prius has 108000 miles battery still takes about 85% charge. I would not replace at 50,000.

 

a digital tester is recommended for prius batteries, but they're pretty expensive. wouldn't recommend splurging on that yourself to do it at home.

 

I get in the habit of leaving it plugged in overnight, certainly if I'm away on business

Probably. I hooked directly to the 12 vdc battery

Closeup

http://i653.photobucket.com/albums/uu256/jayman_photo/Prius Stuff/Closeupchargeharness.jpg

Harness run out hatch

http://i653.photobucket.com/albums/uu256/jayman_photo/Prius Stuff/Chargeharnessouthatch.jpg

The actual unit isn't waterproof, so if you have to park outside you'd probably have to run an extension cord into the hatch and keep the transformer inside.

It's entirely safe to leave it plugged in 24x7, as it senses float charge on the battery. Not sure if it will reliably sense float charge if hooked up at the front jump start point

 

Toyota has changed the SST's they recommend for testing/charging the aux battery. Per TSB SS006-07, Toyota now recommends the fancy-schmancy Midtronics GR8 Battery Diagnostic Station

Battery Diagnostic Station - Midtronics

They used to recommend a tester by Associated

If you suspect your aux battery, I'd just remove it, fully charge it with a good automatic battery charger, then have a shop perform a load test. If it passes, fully charge it before putting it back in

A simple test is to use an automatic battery charger to fully charge the battery out of the vehicle. Then wait 24 hours minimum to let surface charge dissapate.

Use a good quality DMM to ensure >12.8 vdc. Eg if I do this test on my Prius, 13.1 vdc

 

A few notes about the photos of my VDC harness.

First, the harness has an inline fuse. You don't have to rig up your own inline fuse protection system

Second, I have flexible wire sleeve over the charge harness wires. I took the sleeves off to photograph

 

Thanks Jayman. I have to admit that many of your solutions are too complex for me. A bit embarrassing, but I don't own an automatic charger or spare battery, and a 48 hour test is a lot of time explaining to my SO why the Prius cannot be used. I'm interested in the 'almost as good, and able to be done by idiots' approach to identifying a dying battery.

In this vein (of proving how little I know) is there any merit, after a 30+ minute drive and then 60ish minutes of IG-OFF, of taking a voltage reading from the Prius' MFD display in ACC-ON without accessories, then with lights on, and then after a period of time with the lights on ? I'm guessing that I should be able to extrapolate reasonably accurately the battery's SOC as a percentage of maximum, and then I would just need to replace when the 'charged' SOC is below some value.

 

The built-in self test procedure requires no tools and gives a pretty good idea of battery health. See jdenenberg's entry here:

PriusOnline.com • View topic - how to put 12V battery in sleeping mode?

If the battery reads much less than 12.0V at any point it is nearing the end.