Prius 12V Battery

[Deet]

Is my Prius 12v Battery a lead acid or AGM Battery?

My Prius is 13yrs old so im assuming that its not the original Battery and due to water around the battery the labels are not that readable. Im putting a Maintenance charger to keep topped up and would like to use the correct mode on the charger.

The Part number that I can make out from the top is 28800-YZZCA and the only pichture I can find is:-

 

[Bob110023]

AGM is usually used for stop start technology. 

[Deet]

6 minutes ago, Bob110023 said:

AGM is usually used for stop start technology. 

I was under that impression as well however doing a search I am getting results for both AGM and Lead acid. I think i have consused myself as I was under the impression that the original Battery was a AGM?

[Ancient Nerd]

Don't forget the Gen 2 and Gen 3 Prius have the Battery in the passenger space. You really don't want a conventional lead acid Battery emptying Battery acid in the event of a crash. It is well worth the extra cost of the AGM battery to prevent this.

[QuantumFireball]

12 hours ago, Deet said:

I was under that impression as well however doing a search I am getting results for both AGM and Lead acid. I think i have consused myself as I was under the impression that the original battery was a AGM?

AGM batteries are a type of lead acid Battery, so the two terms aren't mutually exclusive. The traditional type are "flooded" lead acid batteries, but they are rarely described as such.

[kithmo]

Same settings on my Ctek charger for AGM and lead acid. As Aaron says above, same basic technology.

[kithmo]

15 hours ago, Ancient Nerd said:

Don't forget the Gen 2 and Gen 3 Prius have the battery in the passenger space. You really don't want a conventional lead acid battery emptying battery acid in the event of a crash. It is well worth the extra cost of the AGM battery to prevent this.

The original Battery is Lead acid, just make sure the vent tube is fitted to take away any fumes.

[Bob110023]

The difference is the AGM Battery is a glass mat which in theory allows the Battery a larger depth of discharge but in doing this it requires a different charging profile than a standard lead acid flat plate.

[kithmo]

17 hours ago, Bob110023 said:

The difference is the AGM battery is a glass mat which in theory allows the battery a larger depth of discharge but in doing this it requires a different charging profile than a standard lead acid flat plate.

I guess my CTek intelligent charger can detect this then.

[Bob110023]

Hi Keith. The Ctec is a very good charger. Just press the button to select AGM when starting charge.

[kithmo]

Hi Bob, the 3 selections are:

1 ) Motorcycle (a motorcycle icon)

2) Lead acid, Gel and some (?) AGM (a car icon)

3) Cold weather and high power AGM (a snowflake icon)

I guess the 3rd one is the different charging profile (higher rate ?). 

[Deet]

Cheer's for the help, I got the CTek MXS 5.0 The modes I have are:

1) Small Battery Program 14.4v/0.8a

2) Normal Battery  14.4v/5a (for Wet, Gel and Many AGM Batterys)

3) AGM 14.7v/5a (AGM batterys like Optima and Odyssey)

4) Recond Option (uses mode 2 or 3 then charges  15.8v/1.5a)

Just wondering where do you guys connect the maintenance charger whilst the Battery is still in the car. I know you connect the Positive to the Battery and the Negative to ground but the Ctek Manual just refers you to check the Cars owners manual.

Cannot make my mind up whether to connect it up in the boot or in the engine bay at the Jump starting terminal.

 

Many Thanks

[kithmo]

I have the Ctek leads with the little two pin plug permanently attached to the Battery and just plug the charger in to recondition the Battery in situ every 4-6 weeks (I only do 3k miles a year). As long as the car is switched off there should be no problem.

I also bought SWMBO another lead to attach to her 2006 Gen 2 Battery and usually charge hers in situ as well, the little lead I leave sticking out behind the trim so I don't have to remove anything. Not sure if charging it at the jump point would affect the Ctek's performance due to the longer lead to the battery ?

[t4ed]

I am just getting another 12v Battery replaced in my 2008 Prius. The last replacement Battery lasted just beyond 3yr warranty period, but died last week. Despite charging, it now only keeps 11.5v.

Looking at the posts above, I have also recently seen rain water in bottom 12v Battery well.

Is this water ingress a common problem? Is there a fix?

 

[Catlover]

If your Battery is in the boot, you need an AGM Battery for safety sake. If your car gets slammed up the back, the Battery may burst throwing acid everywhere (if non AGM battery).

[t4ed]

I am getting Toyota dealer to supply and fit 12v Battery, so should be to correct spec.

No answer to water ingress issue though.

[Deet]

9 hours ago, t4ed said:

Is this water ingress a common problem? Is there a fix?

 

Think there is an issue. In the corner of the roof/gutter a small crack forms which allows water in over time. I just got NO NONSENSE ALL-WEATHER SEALANT CLEAR 310ML from Screwfix. It was a  easy fix, I will take some photos tonight to show where to do it and I'll try to find the link for the YouTube video explaining how to do it.

Video Link is not the best Quality

 

 

[Deet]

Just a quick note, I only sealed from the Plastic guttering down 2" on both sides of the roof (altho I only had a leak on the Battery side)

 

Hope this helps

[t4ed]

@Deet. Does the plastic trim just lift up easy?. Looks like 3rd photo shows a gripper of some sort for the plastic trim.

BTW. When I mentioned the water problem to Toyota service person (after my 12v batt replacement), they also mentioned this area at rear part of roof gutter trim as a potential cause.

I will now take a look there.

Many thanks for taking time to post the photos.

[t4ed]

The trim strips lifted easier than I had expected. I have now applied same waterproof clear selant to both sides. Hope that cures the problem.

[Martin J]

I also have had small amounts of water in the Battery well of my 2005 NHW20 - no more than 2 cm deep judging by the rusty tidemark when the Battery is removed. It explains the excess interior condensation the car has suffered in cold weather for the last few years, but was only discovered when I had a new 12V Battery installed recently. I lifted the plastic roof gutter covers and, sure enough, a hairline crack in the drivers' side gutter valley was apparent running for about 4 or 5 cm either side of the clip.  Planning to clean and seal this with flowable silicone sealant.  Will have to lift the new battery out and attack and repaint the rusty area in the well, but that's a job for a later date.  Would be interested to know if others who've done the sealant repair have found it to be a durable solution.