12v aux battery needs water

How short is "so short?"

 

More for some than others.

 

Thanks! More specifically how long should one expect a battery in a 2010 Prius to last?

 

I don't know whether the the 14.2v charging system in the Gen 3 Prius shortens or lengthens battery life, or whether adding a little distiller water adds to battery life or not. It seems logical that adding a little distilled water to ensure that the battery plates in each cell is submerged is better for the battery than letting the plates remain exposed. Our two Gen 3 Prii have a little over two years of service and the batteries seem to be working fine. I'm hoping for at least 4 years, but have read that the Gen 3 Prius gets quirky when the 12v battery is marginal.

 

Can someone please comment on this part I posted in my previous post?
There are no problems with the car anymore, but I'm curious about it.

 

No facts other than postings on this forum. With that said, I'd guess worst case, three years, normal, four years, those who are lucky get five years.
GII was worst case four years, normal five years, lucky get just over that.

Though full discharge (left the lights on, for example) will dramatically shorten those numbers.

Pearl's battery is still going strong at 4 1/2 years. Added water last summer. Keeping fingers crossed.

-Traditionally-, here in Edmonton where we do have "real" winter, 5 years is normal life for a non-hybrid vehicle, with proper maintenance (distilled water usually required after 2-3 years). But that's for a "starter battery" that has to deliver 150+ Amps each time the engine is started. The Prius doesn't require that of the battery. Just a 50 Amp 1/2 sec pulse or two.

Should the Prius 12V lead-acid battery last longer than a "normal" starter battery? Maybe. It would be nice to have a better charging system with more "smarts". Maybe the GIII has that and I just don't know of it.

BTW, the -reason- the plates should be immersed in water or covered by a wet pad is otherwise they would dry out and oxidize. That destroys them as far as being useful for energy storage/recovery. I'm not sure how they are protected in the batteries that are shipped dry.

Just saw your request for comment, and yes, it's normal. When I added water to Pearls battery I disconnected it and took it into the basement for torture. When I reconnected it I had to press "ON" twice, as described in your post.

 

After reading all those great posts, I decided to check out my 2010-III battery. Mine is solid on top too & says "never add water" I cannot see any access ports for filling the battery.

44.5mpg in hilly terrain. Blizzard White. Very noisy bumpy ride, except on newly paved roads & buzzy engine when revving up ramps on freeways. Seat comfort is adequate but could be better. Large center post cuts visibility(for passing), and in my opinion is dangerous. Fun to drive short distances. Great car for younger people. Miss my '02 Avalon comfort and visibility, but not the 20mpg mileage, especially today when gas is $4.32 gal. Rated high Reliability and recommend buy by a leading consumer magazine. (3/10/12)

 

Mine was made in 03/10 and has no caps, just a solid black unit, with side vent and strange electrical connector on top that goes nowhere?

 

Sorry to bump the thread, but as someone who responds to any edict with "okay, why?", I think this bears explaining:

Pure (distilled or deionized) water is an electrical insulator. Tap water has (small or large amounts of) minerals dissolved in it, which make it electrically conductive. (Bottled water usually has even more minerals added for flavor.)

If you pour conductive liquid into a battery, it begins to discharge along the new electrical path that you've given it. Even just a few drops of tap water (or a few flakes of crud from the top of the housing) can impart enough conductivity to the affected cell, to ruin the battery. The instantaneous discharge may be slow, but eventually the weak cell "falls behind" the rest of the battery, and this imbalance hastens eventual failure.

If the electrolyte level is low and you don't have distilled water available, wait until you do. It's not like oil where you can run 5w20 in a pinch and switch back to 0w20 later -- once the battery is contaminated with tap water, it's done.

So, wipe the crud off the battery with a damp cloth before opening the filler caps. If you're using a funnel, rinse it first with distilled water. Wear gloves and goggles, because splashing sulfuric acid, while unlikely, will really complicate your day. It's all simple stuff, but an ounce of prevention really is worth a pound of cure.

Hope a bit of background info satisfies some of my excessively curious brethren, and saves someone from ruining their battery. Cheers!

 

The GEN III prius using a two level charging system 14.5-6 and 13.5-8 I have been monitoring this for a while .... when you start up the car will charge the battery with the higher voltage for a while (depending how depleted it was what the temperature, also what is the load on the 12V system etc.) and then it drops the voltage .... to about 13.5 which a good floating voltage ...

The very curious thing is that putting the car to P will set the charging voltage to the higher level ... .(someone suggested that this is for the dealers to enable them to proper 12V battery maintenance ... as long as the traction battery has enough charge it will charge the 12V with the higher voltage a little bit quicker )

Also this dual charging helps to avoid under charge ... in case the car is driven infrequently short periods ....

 

This is normal if you disconnect the battery.

 

Is there a diagram or pictures somewhere that shows how to run a temporary 12v battery parallel to the system when changing the 12v battery in order to keep all the saved settings from going away?

 

1) Attach the battery or power supply to the jump points under the hood.

2) Carefully remove and replace the battery. With the backup battery or power supply in place, the positive cable remains energized. Do not allow the positive (red) lead to touch anything grounded, such as the body, frame, etc.

3) Remove the backup battery or power supply.

That's all there is to it.

Tom

 

Thanks, forgot about the jump points. Always learning something new on my Prius.

 

I would add a small amperage fuse in line with the backup battery's positive terminal, 5 amp should be more than adequate.
This way if you hook the backup battery up backwards, all that's gonna blow is the small fuse!