TCH Auxiliary Battery
 

I had a ''Check Hybrid System'' message pop up on my message screen yesterday. Diagnosis by my Toyota Technician shows the auxiliary battery (12 Volt Battery) has low power output. Does this imply that I should replace the battery?

Has anyone ever experienced this? A Toyota Manual - PD020-06 -Maintenance for HV and Aux Battery states that:

'' The Camry HV auxiliary battery is a special Valve Regulated Absorbed Glass Mat (AGM) design and should NEVER be replaced with a conventional battery design.''

Thank you!

Re: TCH Auxiliary Battery
 

That's right. The AGM battery should be replaced with another AGM battery. The manual does NOT say that it should never be replaced -- only that when replacement is necessary, the replacement part should not be a conventional wet-cell battery. The OEM battery is an AGM battery. When replacement is necessary, it should be replaced by another AGM battery. To understand the difference between AGM batteries and conventional batteries, see, http://en.wikipedia.org/wiki/VRLA_battery .

If I had to replace mine this month, I would use an Optima D35 YellowTop®; Deep Cycle Battery. There are other brands that also make AGM batteries in group-size 35, of course.

Re: TCH Auxiliary Battery
 

Thanks SteveHansen. This battery came with the vehicle from the factory - since July 2007. This one was built by Panasonic for Toyota. I guess 3+ years of use is indeed a long time. I just hope I'm not alone in this. Haroldo stated in one of his Sticky FAQ that these batteries are pretty expensive. How much do they go for really? Thanks again!

Re: TCH Auxiliary Battery
 

Amazon has them for $174.
http://www.amazon.com/Optima-Batteri...ef=au_pf_pfg_s
But, if you don't have Amazon Prime, I'm sure the shipping would be expensive.

I recall also seeing optima batteries at Costco, but I haven't been there for a while. Looking around google, the cheapest prices seem to be in the $170 range.

Re: TCH Auxiliary Battery
 

AGM batteries often last ten years or longer.

The usual failure mode for a conventional wet-cell is when one of the lead plates warps and touches an adjacent plate, shorting out the cell. Because AGM batteries have fiberglass mat between the lead plates, there is a physical barrier the usually prevents the plates from making contact. The usual failure mode for AGM batteries happens when they are charged too rapidly. When charged too rapidly, it vents hydrogen through the overpressure valve, and then the cell does not have enough hydrogen after it cools down. That's why they tell you not to 'jump' these cars -- the battery cannot take the rapid charging. (But, you can hook up a trickle charger, or something like that, if needed.)

But, of course the "usual" failure mode may have nothing to do with the particular case.

Re: TCH Auxiliary Battery
 

Maybe the battery that came with my TCH wasn't AGM . . .I've never done any jumping with the battery.

Re: TCH Auxiliary Battery
 

Has anyone replaced his/her 12V auxilary battery in the TCH recently? Please share your experience. Thanks!

Re: TCH Auxiliary Battery
 

There was another thread in this forum about a year ago:
https://www.greenhybrid.com/discuss/...-photos-23466/

It seems the OEM battery has a temperature sensor, which can be transferred to the new battery. That is useful information.

Re: TCH Auxiliary Battery
 

Anyone know the actual cost from Toyota for the 12V AGM battery?

Re: TCH Auxiliary Battery
 

SteveHansen,
At the advice of a friend in Pennsylvania, I took the ''dead'' battery for recharge and charged it for some 16 hrs at 5A current. Bettery SoC was about 4 Volts prior to charging. In the end, we got it up to some 12V - initial value after 16 hrs.

Then I installed the battery and did a test run. Performance has significantly increased. No more ''Check Hybrid System'' error message and MPGs kept going up. It's some 29mpgs now. I was doing less than 20mpgs before recharging the 12 volt battery.

I want to thank you for coming to my aid here. Greatly appreciate your help.